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View Full Version : Just saw nova's "The Ghost Particle" and i have some questions....



The Incredible Bloke
2006-Feb-21, 05:06 AM
I have a question. If the neutrino is so small and passes through whole planets without effect, then how can it be detected? :think:

mantiss
2006-Feb-21, 05:36 AM
Not a question of size as much as a question of mass. The neutrinos are incredibly light (in all their forms, be it Electron Neutrino, Muon Neutrino or Tau Neutrino) so they do not interact very well with the everyday matter, or any baryonic matter for that matter.

However, very little interaction does not mean NO interaction, and the number of neutrinos out in the universe is staggerring compared to the rest of the stuff.

While you read this, millions upon millions of them shot through you.

On a large scale, like SNO or other detectors, there is always the chance that a neutrino will interact with the detector, hence we see a few of them, a very limited few ;)

Hope this helps

George
2006-Feb-21, 05:58 AM
NOVA is doing a show tomorrow night on these little characters.

The Davis and Bahcall using 100,000 gallons of perchloroethylene (fluid used by dry cleaners), down 4800 ft. underground in S. Dakota, did the trick. Still, IIRC, only about one neutrino reacted with the liquid once every other day. This reaction rate was 1/3 less than predictions and caused considerable debate, apparently. This all helped lead to determining the neutrino has a little bit of mass.

Blob
2006-Feb-21, 10:49 AM
Hum,
When the particle was first proposed it was generally agreed that it was impossible to every detect it.
This gave rise no doubt to a whole host of alternative theories that involved changing or tweaking the fundamental laws of Thermodynamics...

trinitree88
2006-Feb-21, 01:07 PM
I have a question. If the neutrino is so small and passes through whole planets without effect, then how can it be detected? :think:


The probability of interaction in a particle interaction is a product of two things...flux, the rate of flow(neutrinos/sec...here), and crosssection. The first is denoted by Greek letter phi, the second is Greek letter sigma. So, the probability P(x)= phi*sigma. Although the flux is high, the cross section is tiny, so you need a lot of targets, and to be patient to see them. The crosssection is measured in "barns". Tiny nuclear cross-sections during the Manhatten project hindered fissioning, bigger ones were promising, and they began joking that ~ 10-24cm2was..."Oh, that's as big as a Barn!"...and it stuck as a unit. Crosssections are typically graphed with units of inverse nanobarns...10-9 barns....or ~ 10-33cm2. That's tiny, hence a huge flow of neutrinos can pass through you like photons through pure glass.
Though the cross-sections are tiny, it's not impossible for an energetic neutrino to kick off a nerve axon, but that can also happen from beta decay of C-14, K-40, or a cosmic-ray secondary. So the ghostly particle is entitled to slip into your unsuspecting nervous system, and give you one of those spastic zings of muscle movement once in a blue moon. A neutrino made you do it. That which is not forbidden in the physical world, must occur.The lawyers will love it in court. :naughty:

The data to date does not rule out a zero-mass neutrino traveling at c. The reported masses are upper bound limits. Neutrinos emitted from the sun (or any star) travel through substantial lengths of mass. While it breaks conservation of momentum to have a massless particle mix flavors in a true vacuum, superposition of the neutrino's eigenstates with massive particles was MSW flavor mixing(Mikheyev-Smirnoff-Wolfenstein). So the Sudbury results confirm that mixing (oscillations) occur, but not that it happens in a pure vacuum proving massiveness. There is a prolonged path through the sun (average density of water)...and the atmosphere. A distinct day-night oscillation has been seen for the path though the Earth,too.
In addition, the hard "vacuum"of space though free of solid, liquid, gas, or plasma, is never free of the neutrino sea. So, it is not "empty" in any sense of the word. A solar generated neutrino can annihilate with a head on collision with a "sea" antineutrino of same family. The resulting photon, or Z0 can produce a real fermion pair (e+/e-.(energy .>1.022 Mev....or a real photon pair, or a real boson pair
..Z0/anti-Z0....any energy. As long as the Hierarchy of Conservation Laws holds...these pairs should annihilate, leaving a trace of energy from what is net annihilation of sea neutrinos. (here neutrinos is used generically to mean either neutrino or anti-neutrino). Experimental data from particle detectors to date confirms associated pair production...always equal.
But,interestingly, if one abandons Lorentz Invariance and invokes the same asymmetry in matter/antimatter production invoked in BB theory (implying that there will be a found higher limit on the half-life of the proton >> 1031 yrs., and a mediating lepto-quark boson to boot,....X-particle).....Then annihilation of neutrino/antineutrino pairs will produce an occasional proton and electron, and Fred Hoyle has his net production of hydrogen in "free space".
It is ironic that the argument for creation of the universe from an asymmetry in matter over antimatter production in BB theory may be equally well convoluted to provide one of the essential ingredients for quasi-Steady State. The true mystery then would be the exact matching of the asymmetry in baryon production (the protons involved)...to the asymmetry in leptons (the electrons involved)...otherwise charge conservation in the universe gets woefully out of kilter.
Personally, I believe the Hierarchy of Conservation Laws will be found intact, preserving Lorentz Invariance. Pete.

This post has been edited for a boo-boo.. Err in haste, repent in leisure. Youll see the corrections by GBendt.Spaceman Spiff.etc....Pete. To err is human ,to forgive is divine.I'll slow down and double check a little better.

peter eldergill
2006-Feb-21, 01:19 PM
I thought the consensus about the 1/3 detection rate was due to the idea that there are 3 different types of neutrinos, roughly equally distributed, and the detectors were only detecting one type of netrino.

Is this at least the general idea?

Pete

Fortunate
2006-Feb-21, 01:47 PM
NOVA is doing a show tomorrow night on these little characters.

At 8 PM where I live (Miami).
http://www.pbs.org/wgbh/nova/neutrino/

Eta C
2006-Feb-21, 01:50 PM
Boy, I seem to be posting these links a lot lately. Just did so in the Electric Universe thread in the ATM section. The solar neutrino "problem" referred tot he fact that only about 1/3 of the predicted electron neutrinos the sun should produce were observed. So, was the solar model wrong, or was there something about neutrinos we didn't understand. It turned out to be the latter. An experiment in Sudbury, Canada detected the entire flux in all three flavors (e, mu, and tau) and the total corresponds to the prediction by the solar model. Here's an account (http://www.aip.org/pnu/2002/split/586-1.html) from the American Institute of Physics. A pertinent quote.
The upshot: all the nu's from the sun are directly accounted for. The missing nu-e flux shows up as an observable mu-nu and tau-nu flux. This conclusion is established with a statistical surety of 5.3 standard deviations, compared to the less robust 3.3 of a year ago. The measured e-nu flux (in units of one million per cm2 per second) is 1.7 while that for the mu-nu and tau-nu combined is 3.4. (When one includes all the other types of neutrinos, the flux from the sun is billions/cm2/sec.)

For those with a more technical bent here is the SNO site iteself (http://www.sno.phy.queensu.ca/)

Spaceman Spiff
2006-Feb-21, 02:59 PM
The probability of interaction in a particle interaction is a product of two things...flux, the rate of flow(neutrinos/sec...here), and crosssection. The first is denoted by Greek letter phi, the second is Greek letter sigma. So, the probability P(x)= phi*sigma. Although the flux is high, the cross section is tiny, so you need a lot of targets, and to be patient to see them. The crosssection is measured in "barns". Tiny nuclear cross-sections during the Manhatten project hindered fissioning, bigger ones were promising, and they began joking that ~ 10-44cm2was..."Oh, that's as big as a Barn!"...and it stuck as a unit. Crosssections are typically graphed with units of inverse nanobarns...10-9 barns....or ~ 10-53cm2. That's tiny, hence a huge flow of neutrinos can pass through you like photons through pure glass.


Thanks for that quite informative overview. However, just for the record a "barn" has units of 10^-24 cm^2. The electron scattering cross section for photons at low energies is 0.665 barns, and the hydrogen photoionization cross section at the threshold energy is about 6 Mbarns (megabarns). Or is there a nuclear unit of "barn" which is 20 orders of magnitude smaller? I'd be surprised if there were two definitions.

Nereid
2006-Feb-21, 03:34 PM
[snip]

But,interestingly, if one abandons Lorentz Invariance and invokes the same asymmetry in matter/antimatter production invoked in BB theory (implying that there will be a found higher limit on the half-life of the proton >> 1031 yrs., and a mediating lepto-quark boson to boot,....X-particle).....Then annihilation of neutrino/antineutrino pairs will produce an occasional proton and electron, and Fred Hoyle has his net production of hydrogen in "free space".
It is ironic that the argument for creation of the universe from an asymmetry in matter over antimatter production in BB theory may be equally well convoluted to provide one of the essential ingredients for quasi-Steady State. The true mystery then would be the exact matching of the asymmetry in baryon production (the protons involved)...to the asymmetry in leptons (the electrons involved)...otherwise charge conservation in the universe gets woefully out of kilter.
Personally, I believe the Hierarchy of Conservation Laws will be found intact, preserving Lorentz Invariance. Pete.Just a quick note on this ... AFAIK (as far as I know), any 'occasional proton and electron' production via the mechanism described here would be many, many OOM (orders of magnitude) too small to support any variant of QSSC (though perhaps I've missed something?).

Which in turns illustrates a common practice in science - consistency checking of ideas. In this case, while in principle there might seem to be some similarity between the Hoyle theory and an implication of neutrino oscillations, the day after this idea occurs to you, a quick consistency check - via OOM calculations - may show it cannot work.

Gsquare
2006-Feb-21, 03:40 PM
..., it's not impossible for an energetic neutrino to kick off a nerve axon, but that can also happen from beta decay of C-14, K-40, or a cosmic-ray secondary. So the ghostly particle is entitled to slip into your unsuspecting nervous system, and give you one of those spastic zings of muscle movement once in a blue moon. A neutrino made you do it. That which is not forbidden in the physical world, must occur.The lawyers will love it in court. :naughty:

.

Yea, I think these cosmic slueths blasting through my brain, without my permission mind you, ought to be considered an invasion of privacy! I take some consolation in the fact that all that go in must also depart without creating exit wounds, and hopefully not taking anything with them when they depart! Hopefully.

G^2

trinitree88
2006-Feb-21, 03:50 PM
Thanks for that quite informative overview. However, just for the record a "barn" has units of 10^-24 cm^2. The electron scattering cross section for photons at low energies is 0.665 barns, and the hydrogen photoionization cross section at the threshold energy is about 6 Mbarns (megabarns). Or is there a nuclear unit of "barn" which is 20 orders of magnitude smaller? I'd be surprised if there were two definitions.

My bad...shoud've checked. Stuff's in storage I'll edit post. Kudos. Thanks Pete:clap:

George
2006-Feb-21, 06:23 PM
Looks like just a simple transpose, trinitree88. Hey, how many barns in a neuron, maybe a freak conicidence struck? ;)

Does the flavor change happen within the sun, or much nearer to Earth? Is it this change in flavor which supports sn shockwave propogation, or simply the fact they have mass?

trinitree88
2006-Feb-21, 07:42 PM
Looks like just a simple transpose, trinitree88. Hey, how many barns in a neuron, maybe a freak conicidence struck? ;)

Does the flavor change happen within the sun, or much nearer to Earth? Is it this change in flavor which supports sn shockwave propogation, or simply the fact they have mass?

OOOhhhh!...a neutrino made me do it...lol. Good George.:dance:
As for the flavor change it most likely occurs inside the sun before they exit. Bigger path amidst mass by far. Pete.

Grey
2006-Feb-21, 08:46 PM
Not a question of size as much as a question of mass. The neutrinos are incredibly light (in all their forms, be it Electron Neutrino, Muon Neutrino or Tau Neutrino) so they do not interact very well with the everyday matter, or any baryonic matter for that matter.Just a small correction. It's not the mass, it's the fact that neutrinos only interact via the weak force (and gravity, as well) that makes them so much less likely to interact. In principle, it would be possible to have more massive particles that also only interact via the weak force, and these would be just as ghostly. Indeed, the most common view at the moment is that dark matter is primarily composed of just such particles.

George
2006-Feb-21, 10:56 PM
Just a small correction. It's not the mass, it's the fact that neutrinos only interact via the weak force (and gravity, as well) that makes them so much less likely to interact.
Does this mean unstable atoms, i.e. radioisotopes, that are the most susceptible to a neutrino's interaction?

Gsquare
2006-Feb-22, 12:17 AM
.... While it breaks conservation of momentum to have a massless particle mix flavors in a true vacuum, superposition of the neutrino's eigenstates with massive particles was MSW flavor mixing(Mikheyev-Smirnoff-Wolfenstein). .

One question that bugs me, trinitree, while we are on the topic.
How would validation of massive neutrinos force a re-definition of parity violation in the weak interaction?

G^2

--The works of the Lord are great, studied by all who have pleasure therein.-- Inscribed in the Archway to the Entrance of James Clerk Maxwell's Cavendish Laboratory - Cambridge

Fortunate
2006-Feb-22, 12:38 AM
Does this mean unstable atoms, i.e. radioisotopes, that are the most susceptible to a neutrino's interaction?

The Superkamiokande detector uses pure water as a target, Sudbury uses heavy water, and IceCube will use pure ice, so the target material is very stable. The limiting factor is a number called the "cross-section" - maybe that is a measure of how dead-center it has to hit, the particles being close to point-like, I'm not sure - maybe it's just some kind of probability.

Dave Mitsky
2006-Feb-22, 01:18 AM
The program tonight on Nova (8:00 p.m. EST) is about neutrinos so tune in your local PBS station right now.

Dave Mitsky

Dave Mitsky
2006-Feb-22, 01:58 AM
"The Ghost Particle" was quite interesting. For more on the show, browse http://www.pbs.org/wgbh/nova/neutrino/

Dave Mitsky

Eta C
2006-Feb-22, 02:07 AM
Just finished watching it (EST). Those of you on the west coast set the tape players or TIVO. It's an excellent program. There's a bit of hyperbole here and there, but on the whole, a good description of the origin of the solar neutrino "problem" and its resolution. I'd like to take a few of our ATM hypothosists, tie them down in a chair, and force them to watch it while telling them "Pay attention! This is how science is really done!"

P.S. for those who don't know, that is Wolfgang Pauli as my avatar.

George
2006-Feb-22, 03:26 AM
I would guess its unique energy level is the key to interaction. However, I am curious how the weak force gets involved.

I just watched NOVA's "Ghost Particles", I think that was the title. Very nice show! :clap:

Most was explained beautifully. However, some things seemed a little lacking, due to time limits, no doubt.

1) What evidence indicates that any given neutrino can change constantly ("oscillate") from one flavor to another?

2) Why wouldn't you expect fewer atmospheric neutrinos coming from below the sensor and through the entire planet? Surely there would be many chlorine atom encounters traveling through the earth.

3) I just got through telling my son that matter and antimatter anihlate each other upon contact. Of course, I appear to be wrong. Did I understand correctly, only charged matter and antimatter are so hostile to each other? The neutrino and antineutrino are not self-destructive when they encounter each other? This may have been the source of all surviving matter in the universe?

The 1987 supernova neutrino surprise was not mentioned, which was another slight disappointment.

Still, another great job by NOVA (with a little help from Google and BP).

Knowledge_Seeker
2006-Feb-22, 03:30 AM
it talked about neutrinos traveling from the sun to the earth and all and they said some things that i have questions about...


1. "For something to change time needs to pass, but for something moving at the speed of light, time is still, or does not pass. therefore the object does not change."

Is this true? I heard all of this in the documentary except the sentence begining with therefore, that is an interpretation of mine.

2. If the fact that, for something moving at the speed of light, time is still, then doesnt that mean the concept of traveling to the future by using the speed of light become false? Shouldnt something moving at the speed of light, when returning to earth, come back to an earth that has not changed at all in time?

Um.... while watching the segment i had a lot of more questions, but i seem to have forgotten them, when, or if i remember them ill be sure to post them.

George
2006-Feb-22, 03:38 AM
it talked about neutrinos traveling from the sun to the earth and all and they said some things that i have questions about...


1. "For something to change time needs to pass, but for something moving at the speed of light, time is still, or does not pass. therefore the object does not change."

Is this true? I heard all of this in the documentary except the sentence begining with therefore, that is an interpretation of mine.
Yes. It literally doesn't have time to change. Kinda like coming home at 6pm and having to leave home by 6pm, you can't change or shower. :) A massless neutrino would travel at the speed of light and would experience no time, so it has no time to do anything before it gets to where it is going.


2. If the fact that, for something moving at the speed of light, time is still, then doesnt that mean the concept of traveling to the future by using the speed of light become false? Shouldnt something moving at the speed of light, when returning to earth, come back to an earth that has not changed at all in time?No, the earth would have to travel at the speed of light itself if it wanted to stop time. However, that would take infinite energy to accomplish such a task.

A really nice show. I watched it, too. :clap:

George
2006-Feb-22, 03:43 AM
Just finished watching it (EST). Those of you on the west coast set the tape players or TIVO. It's an excellent program. There's a bit of hyperbole here and there, but on the whole, a good description of the origin of the solar neutrino "problem" and its resolution. I'd like to take a few of our ATM hypothosists, tie them down in a chair, and force them to watch it while telling them "Pay attention! This is how science is really done!"
:) I was curious as to your impression. It was nicely done, IMO.


P.S. for those who don't know, that is Wolfgang Pauli as my avatar. I used to have a typewritter like his. Hope he wasn't too late to the ball. ;)

Knowledge_Seeker
2006-Feb-22, 03:50 AM
I would guess its unique energy level is the key to interaction. However, I am curious how the weak force gets involved.

:question: I dont remember the program discussing any weak energy. i remember them discussing about how sometimes energy from protons is distributed to electrons and neutrinos.



I just watched NOVA's "Ghost Particles", I think that was the title. Very nice show!

Just saw it too, and very excellent



1) What evidence indicates that any given neutrino can change constantly ("oscillate") from one flavor to another?

I think, according to the program, as time changed, because they had mass, they changed at certain times. but i dont think they talked much about this.



2) Why wouldn't you expect fewer atmospheric neutrinos coming from below the sensor and through the entire planet? Surely there would be many chlorine atom encounters traveling through the earth.

I think they didnt expect a difference in numbers because at that time scientists thought that neutrinos traveled at the speed of light without mass, meaning, no matter what obstacle in its path, it could easily go through it.



3) I just got through telling my son that matter and antimatter anihlate each other upon contact. Of course, I appear to be wrong. Did I understand correctly, only charged matter and antimatter are so hostile to each other? The neutrino and antineutrino are not self-destructive when they encounter each other? This may have been the source of all surviving matter in the universe?

Yes. your explanation is correct based on the information given in the program. Matter and antimatter 'cancel' each other out. But since neutrinos have no charge, they are not self-destructive and this is why the big bang works out so well with neutrinos, because the opposing matters could have destroyed each other. but the neutrinos continued to exist.
(and may i ask how old your son is? [you dont have to ])



The 1987 supernova neutrino surprise was not mentioned, which was another slight disappointment.

Really? Could you tell me more?



Still, another great job by NOVA (with a little help from Google and BP).

I agree :clap:

Knowledge_Seeker
2006-Feb-22, 03:53 AM
I just remembered another question.

Is it true that to travel at the speed of light, the object cannot contain any mass?

So does this mean light does not have any mass?

And if so, doesnt that mean that if something doesnt have mass it cannot exist?

Fortunate
2006-Feb-22, 04:22 AM
I just remembered another question.

Is it true that to travel at the speed of light, the object cannot contain any mass?

We believe so. The special theory of relatvity says that the energy of an object with mass traveling at the speed of light would be infinite.


So does this mean light does not have any mass?

We believe that photons are massless.


And if so, doesnt that mean that if something doesnt have mass it cannot exist?

Photons don't have any mass, but they seem to exist.

Fortunate
2006-Feb-22, 04:35 AM
Why wouldn't you expect fewer atmospheric neutrinos coming from below the sensor and through the entire planet? Surely there would be many chlorine atom encounters traveling through the earth.

The fraction of the neutrinos that would interact with chlorine or anything else on their way through the Earth is extremely miniscule.

snarkophilus
2006-Feb-22, 05:19 AM
That was good! Thanks for letting us know about it!

One funny thing I noticed: even on science shows, you can't get away from sex on television. When they introduced the experiment in Sudbury, what was the first part of the facility they showed? Two women taking off their clothes and having showers. (For context, they were describing how clean the place had to be.) It's like they don't think science is sexy enough on its own.... :)

Anyway, my favourite part was seeing the big Japanese apparatus -- it was way bigger than I'd imagined. That's what science should be like all the time! (The addition of explosions might have improved it... or maybe if they'd implemented the proposed experiment where they would detonate a nuclear weapon to generate neutrinos.)

Jeff Root
2006-Feb-22, 07:25 AM
1. "For something to change time needs to pass, but for something
moving at the speed of light, time is still, or does not pass.
therefore the object does not change."
That's pretty accurate.


2. If the fact that, for something moving at the speed of light,
time is still, then doesnt that mean the concept of traveling to
the future by using the speed of light become false? Shouldnt
something moving at the speed of light, when returning to earth,
come back to an earth that has not changed at all in time?
Next time, think about it first. You got it exactly backward.
A photon takes about eight minutes to go from the Sun to the
Earth. The photon sees no time pass. It is born on the Sun,
and at the same instant, dies on the Earth. To anyone watching,
though, eight minutes pass from the time the photon is born to
the time it dies.


Is it true that to travel at the speed of light, the object
cannot contain any mass?
Something like that, yes.


So does this mean light does not have any mass?
Yes. All measurements so far are consistent with mass = zero.


And if so, doesnt that mean that if something doesnt have mass
it cannot exist?
Exactly the opposite.

You know light exists. So, if light has no mass, then you know
that something which has no mass can exist.

I don't understand why so many people think that everything has
to have mass. Some particles are Protestant, some are Taoist,
some are fundamentalists, some are atheist. Virtual particles
tend to be agnostic.

-- Jeff, in Minneapolis

Tobin Dax
2006-Feb-22, 11:06 AM
I would guess its unique energy level is the key to interaction. However, I am curious how the weak force gets involved.

I just watched NOVA's "Ghost Particles", I think that was the title. Very nice show! :clap:

Most was explained beautifully. However, some things seemed a little lacking, due to time limits, no doubt.
I thought it was pretty good, myself, but I had a few issues with their presentation. For instance, repeating that neutrinos don't interact because they're chargeless while completely ignoring neutrons. Neutrons do have a dipole moment due to the quarks that make them up, but that had to confuse someone. I would have rather heard them say that neutrinos don't interact because they're chargeless and very small (i.e. fundamental).


1) What evidence indicates that any given neutrino can change constantly ("oscillate") from one flavor to another?
Offhand, I think it's the fact that we have observed oscillation at different length (and therefore time) scales. Atmospheric neutrinos are indicative of this since they travel different distances. The solar neturinos give us other pathlength information. Even from these, we can see evidence of how and when they change flavor.


2) Why wouldn't you expect fewer atmospheric neutrinos coming from below the sensor and through the entire planet? Surely there would be many chlorine atom encounters traveling through the earth.
First, neutrinos can interact with any atom; the chlorine solution produced an observable output of radioactive argon that Davis wanted to detect. So there's more than just chlorine that a neutrino can react with.
Remember, though, that there are trillion of neutrinos passing through the earth every second. Even SuperKam only detects a small number of these, even if it's detecting 100s of events a day. If you lose a few skin cells during the day, your body has very, very close to the same number of cells as it did before, right? The same with neutrinos; only the tiniest number won't make it through the earth, and the difference should be undetectable. Since it was significantly detectable, that indicated a flavor change.


3) I just got through telling my son that matter and antimatter anihlate each other upon contact. Of course, I appear to be wrong. Did I understand correctly, only charged matter and antimatter are so hostile to each other? The neutrino and antineutrino are not self-destructive when they encounter each other? This may have been the source of all surviving matter in the universe?
I suspect that this was oversimplified, though I could be wrong. I was thinking that photons could anhilate each other (i.e. electron-positron pair creation), but I don't know how right I am. There's got to be more to the definition of antimatter, but I don't recall getting it in my particle astrophysics class. The fact that different reactions require one or the other (neutrino or antineutrino), that seems to indicate to me that if those particles are the same, they should be different manifestations of each other, perhaps involving more osciallation. That's just my thought, though.


The 1987 supernova neutrino surprise was not mentioned, which was another slight disappointment.

Still, another great job by NOVA (with a little help from Google and BP).

I was waiting for 1987A, but there was really nothing it could have contributed to the show. It would have been a fun fact, but it really doesn't help us learn too much more about neutrinos.

I agree, though, that was definitely a good NOVA show.

NEOWatcher
2006-Feb-22, 02:21 PM
That was good! Thanks for letting us know about it!
Ditto; :clap:


One funny thing I noticed: even on science shows, you can't get away from sex on television. When they introduced the experiment in Sudbury, what was the first part of the facility they showed? Two women taking off their clothes and having showers. (For context, they were describing how clean the place had to be.) It's like they don't think science is sexy enough on its own.... :)

I noticed that too. And I just thought I picked up on something subtle (snicker, snicker) :eh:


Anyway, my favourite part was seeing the big Japanese apparatus -- it was way bigger than I'd imagined. That's what science should be like all the time! (The addition of explosions might have improved it... or maybe if they'd implemented the proposed experiment where they would detonate a nuclear weapon to generate neutrinos.)
Maybe if neutrinos were only a myth, we might see an episode on the Discovery Channel.

Too bad it was only an hour long. It left me with sooo many things to learn about. The biggest one is, how do you isolate 3 argon atoms in a large tank?

George
2006-Feb-22, 02:28 PM
I would guess its unique energy level is the key to interaction. However, I am curious how the weak force gets involved. I dont remember the program discussing any weak energy. I remember them discussing about how sometimes energy from protons is distributed to electrons and neutrinos.
I was referring to Grey’s comment. I also do not recall the weak force discussed, though it may have been.


2) Why wouldn't you expect fewer atmospheric neutrinos coming from below the sensor and through the entire planet? Surely there would be many chlorine atom encounters traveling through the earth. I think they didnt expect a difference in numbers because at that time scientists thought that neutrinos traveled at the speed of light without mass, meaning, no matter what obstacle in its path, it could easily go through it.
Yes. However, I thought they could have concluded the additional matter, found below the surface, was the reason for the reduction; like reduced electron flow in a wire with greater resistance. My logic was too simple and wrong.


First, neutrinos can interact with any atom; the chlorine solution produced an observable output of radioactive argon that Davis wanted to detect. So there's more than just chlorine that a neutrino can react with.
Remember, though, that there are trillion of neutrinos passing through the earth every second. Even SuperKam only detects a small number of these, even if it's detecting 100s of events a day. If you lose a few skin cells during the day, your body has very, very close to the same number of cells as it did before, right? The same with neutrinos; only the tiniest number won't make it through the earth, and the difference should be undetectable. Since it was significantly detectable, that indicated a flavor change.
Yes, thanks to all, including Fortunate. I see it now, but, shoot, it wasn’t intuitive for me. Essentially, to get 1/3 fewer neutrinos from the direction below the planet, the entire neutrino flux would have to be reduced by 1/3, which doesn’t happen.



3) I just got through telling my son that matter and antimatter annihilate each other upon contact. Of course, I appear to be wrong. Did I understand correctly, only charged matter and antimatter are so hostile to each other? The neutrino and antineutrino are not self-destructive when they encounter each other? This may have been the source of all surviving matter in the universe? Yes. Your explanation, is correct based on the information given in the program. Matter and antimatter 'cancel' each other out. But since neutrinos have no charge, they are not self-destructive and this is why the big bang works out so well with neutrinos, because the opposing matters could have destroyed each other. but the neutrinos continued to exist.
(and may i ask how old your son is? [you dont have to ])
That’s what I thought. He is 17 and I am allowing him in motorcross; how smart am I? In terms of barns, again, what is the broadside of my neurons? ;)

I suspect that this was oversimplified, though I could be wrong. I was thinking that photons could annihilate each other (i.e. electron-positron pair creation), but I don't know how right I am. There's got to be more to the definition of antimatter, but I don't recall getting it in my particle astrophysics class. The fact that different reactions require one or the other (neutrino or antineutrino), that seems to indicate to me that if those particles are the same, they should be different manifestations of each other, perhaps involving more oscillation. That's just my thought, though. This is pretty amazing to hear for the first time an explanation for the asymmetry in matter/antimatter at the bang.
Are you saying their oscillation may help prevent annihilation?


The 1987 supernova neutrino surprise was not mentioned, which was another slight disappointment.
Really? Could you tell me more?

IIRC, there was a surge in the neutrino count on, or about, the day the blast from 1987A sn hit us. This helped confirm neutrinos came from stellar furnaces. It had to be a big morale booster and exciting for Davis.

Grey
2006-Feb-22, 02:30 PM
Does this mean unstable atoms, i.e. radioisotopes, that are the most susceptible to a neutrino's interaction?I wouldn't expect so. Those nuclei have internal reactions that are mediated through the weak force, but that should not have any particular effect on whether they'll interact with an external particle. Those nuclei don't have a "stronger weak force" or anything; they're just in a configuration where a specific weak interaction (the particular radioactive decay) is likely to take place.

The real issue is mostly just that the weak interaction is quite short ranged, so the particles have to be extremely close to have any chance of interacting at all, and atoms are almost entirely empty space.

sidmel
2006-Feb-22, 02:34 PM
OK, now I’m a bit confused. Doesn’t the Doppler Effect describe a photon gaining or losing energy, shifting to a higher or lower EM wave length? Wouldn’t that be considered change? Or is that just an observational phenomenon due to the changing distance?

Grey
2006-Feb-22, 02:35 PM
3) I just got through telling my son that matter and antimatter anihlate each other upon contact. Of course, I appear to be wrong. Did I understand correctly, only charged matter and antimatter are so hostile to each other? The neutrino and antineutrino are not self-destructive when they encounter each other? This may have been the source of all surviving matter in the universe?No, the matter doesn't have to be charged. A neutrino and an antineutrino can indeed annihilate each other. However, if you think a neutrino interacting with a baryon has a small cross-section, two neutrinos have an even smaller one. It's just not likely to be observed.

Eta C
2006-Feb-22, 02:47 PM
As my father would say (attempting to imitate Greek accent) "With great di-fi-culty." Given the difficulties of the experiment it's no wonder Davis' results were treated skeptically. After all, just the statistical uncertainty was probably on the order of his signal size (not to mention systematics).

The size of the Super-K and SNO detectors is a direct testimony to the low cross section of neutrino interactions. You need a lot of material to get a measurable rate. It was mentioned in passing by the program, but the reason Kamiokande and other early underground experiments (aside from Davis') was to attempt and detect proton decays. These are forbidden in the standard model, but were predicted to occur (rarely) by some grand unified theories. Since the proton lifetime was on the order of the age of the universe, very few were expected, none ever found. It's a good thing that the neutrino background turned out to be more interesting than the anticipated signal.

George
2006-Feb-22, 02:50 PM
The real issue is mostly just that the weak interaction is quite short ranged, so the particles have to be extremely close to have any chance of interacting at all, and atoms are almost entirely empty space. So, we're back at the barn; :) it's a cross section issue, right?

Yet, is there some picture you can paint that helps me grasp the interaction with the weak force? I tend to think in terms of billiard balls colliding. Does the weak force exert a special field which neutrinos are sensitive?

George
2006-Feb-22, 02:54 PM
No, the matter doesn't have to be charged. A neutrino and an antineutrino can indeed annihilate each other. However, if you think a neutrino interacting with a baryon has a small cross-section, two neutrinos have an even smaller one. It's just not likely to be observed.
That seems contrary to the shows direction. What did I miss? How could neutrinos and antineutrinos be candidates for all matter if they do annihilate each other?

alainprice
2006-Feb-22, 02:54 PM
Wavelength is a measurement....
Energy is also a measurement....

Obviously, when we are allowed to have multiple observers in uniform motion, the measurements will vary. But with relativity, we have the power to have an observer measure something, and tell the results of a different observer(whose motion is known).

So, are they coming up with different answers, or different versions of the same answer? You tell me.

George
2006-Feb-22, 03:06 PM
OK, now I’m a bit confused. Doesn’t the Doppler Effect describe a photon gaining or losing energy, shifting to a higher or lower EM wave length? Wouldn’t that be considered change? Or is that just an observational phenomenon due to the changing distance?
It is only gaining or losing relative to us, not to itself. It is easier to catch a football [if you are] running in its direction than running toward it, yet the football's energy, from its point of view, is the same either way.

Grey
2006-Feb-22, 05:13 PM
So, we're back at the barn; :) it's a cross section issue, right?Absolutely.


Yet, is there some picture you can paint that helps me grasp the interaction with the weak force? I tend to think in terms of billiard balls colliding. Does the weak force exert a special field which neutrinos are sensitive?You can view it as a field vaguely similar to an electromagnetic field, though current theory view at these interactions as mediated by virtual particle exchanges instead. The billiard ball colliding view isn't all that bad, except that you need to remember that they don't actually touch, but just come in range of the relevant fields. The weak force has a range of about 10^-18 m, or about 1/1000th the diameter of a proton, so the neutrino has to be almost dead on to even have a chance of interacting. And remember that the proton is really composed of three quarks that are either pointlike or very small, so even if the neutrino passes right throough the middle of the proton, that's still mostly empty space, and there's no chance of interaction unless the neutrino passes quite close to one of the constituent quarks.


That seems contrary to the shows direction. What did I miss? How could neutrinos and antineutrinos be candidates for all matter if they do annihilate each other?I didn't see the show, so I'm not sure what case they were making, but I'm confused by this suggestion. First, it's true that they don't all annihilate each other, but it's not because they can't, but because they aren't likely to interact at all. But I don't see how they could be candidates for all matter anyway. A neutrino can't suddenly become a proton or anything like that.

George
2006-Feb-22, 05:44 PM
You can view it as a field vaguely similar to an electromagnetic field, though current theory view at these interactions as mediated by virtual particle exchanges instead. The billiard ball colliding view isn't all that bad, except that you need to remember that they don't actually touch, but just come in range of the relevant fields. The weak force has a range of about 10^-18 m, or about 1/1000th the diameter of a proton, so the neutrino has to be almost dead on to even have a chance of interacting. And remember that the proton is really composed of three quarks that are either pointlike or very small, so even if the neutrino passes right throough the middle of the proton, that's still mostly empty space, and there's no chance of interaction unless the neutrino passes quite close to one of the constituent quarks.
So, it is the cross section of the main portion of the weak force's field strength surrounding each of the three proton quarks?


I didn't see the show, so I'm not sure what case they were making, but I'm confused by this suggestion. First, it's true that they don't all annihilate each other, but it's not because they can't, but because they aren't likely to interact at all. But I don't see how they could be candidates for all matter anyway. A neutrino can't suddenly become a proton or anything like that.
Yes, they did not eschew obfuscation. :) IIRC, they briefly stated neutrinos have no charge, so they would not annihilate each other as the other particles likely did at the time of their creation. As a result, they suggested this could be how we obtained more matter in the universe than anitmatter. Maybe I misunderstood, however.

Grey
2006-Feb-22, 06:39 PM
So, it is the cross section of the main portion of the weak force's field strength surrounding each of the three proton quarks?More or less. A cross section has units of area, and just figuring out the area of a circle with a radius equal to the range of the interaction sometimes gives you a very rough estimate of the cross section; the particle has to first "hit the target" by passing close enough to interact. But then there's a factor based on the interaction itself, to determine how likely the particle is to actually interact, assuming that it's close enough that it could do so in principle.


Yes, they did not eschew obfuscation. :) IIRC, they briefly stated neutrinos have no charge, so they would not annihilate each other as the other particles likely did at the time of their creation. As a result, they suggested this could be how we obtained more matter in the universe than anitmatter. Maybe I misunderstood, however.Hmm. I can't see how that explanation does any good at all in getting baryons here without as many antibaryons. :eh:

Knowledge_Seeker
2006-Feb-22, 08:11 PM
thanx for the help, but will someone tell me what the doppler effet is?

gethen
2006-Feb-22, 08:19 PM
I agree that some ATM theorists should have seen this program--particularly the part in which one female physicist talked about how scientists had spent years attempting to find flaws in the favored theory of matter and were actually delighted to find a problem with it that required refining the model. The more attacks it sustains and weathers, the more robust the theory. If a theory can't handle an all out attack, it's probably not a good theory. Very interesting program.

Knowledge_Seeker
2006-Feb-22, 08:21 PM
That’s what I thought. He is 17 and I am allowing him in motorcross; how smart am I? In terms of barns, again, what is the broadside of my neurons? ;)


lol. im 14 (surprise!:surprised ) but i just have a very deep interest in these kinds of things.
........................i wanna motorcross:( dumb chicago, with your streets, and downtown......

Duane
2006-Feb-22, 08:25 PM
If the thread seems a bit disjointed, it's because I merged three threads all discussing this same topic.

trinitree88
2006-Feb-23, 02:01 AM
One question that bugs me, trinitree, while we are on the topic.
How would validation of massive neutrinos force a re-definition of parity violation in the weak interaction?

G^2

--The works of the Lord are great, studied by all who have pleasure therein.-- Inscribed in the Archway to the Entrance of James Clerk Maxwell's Cavendish Laboratory - Cambridge


I'll try with the original experiment. Madam Wu and Kenneth Ambler deposited radioactive Co-60 on a metal foil. The nuclear spins were aligned and the beta decays were found to be magnetic pole sensitive. You could use this set up to define handedness, or magnetic North and South (see Martin Gardner's.. Mirror Asymmetry and Time-Reversed Worlds...for an exceptional lead-in discussion.). In the first sense, one might imagine a neutron in the polarized nucleus converting to a proton, and simultaneously ejecting a high speed electron. But, that view was missing something...the anti-neutrino.
Studies of beta decays showed missing energy and momentum in these decays. The invention of the neutrino by Pauli saved the conservation laws of energy, momentum, angular momentum, and brought a new law of conservation of lepton number.
Later studies of weak interactions (Glashow, Weinberg, Schwinger, Salaam..others)showed that the more correct view was that the neutron turned into a proton by converting a down quark to an up quark, and emitting simultaneously a weak force carrier...the W-....which promptly decayed into an electron (the high speed beta particle), and an electron-type antineutrino. Doing this kept the book-keeping straight as far as conservation laws go....and the high massiveness of the W- meant that it had a very short range, as the theory required. Discovery of the W+, W-, and their cousin, the Z0...the uncharged version at CERN by Rubbia et al was a resounding success.
However, if neutrinos are massive, they may oscillate in vacuo without contacting matter, and that electron-type antineutrino now flits away as a neutrino....messing up the conservation of electron family number, and lepton number. So, you have a parity-defining experiment that upholds all the conservation laws half the time....and trashes them the other half.
I'm very reluctant to buy that until the experimental evidence is incontrovertible (so far, it's not).
Remember the coincidences from 1987a.(Guido Pizella)..within 2.5 seconds the gravitational waves traveling at c (nobody argues that)...and the neutrinos, (clocks not all on Universal Time)arrive together. How much energy must a 0.0003 ev rest-mass particle be given to travel so close to the speed of light, that after 165,000 years of racing a gravity wave at c, it only lags by 2.5 seconds? It approaches infinity. It's unlikely a particle with restmass can go that fast,that long, let alone ~1052ergs of them ejected simultaneously.:naughty: Pete.

antoniseb
2006-Feb-23, 01:27 PM
It's unlikely a particle with restmass can go that fast,that long, let alone ~1052ergs of them ejected simultaneously.:naughty: Pete.

Have you tried an OOM calculation on just how much energy it would take? Please keep in mind that the neutrinos arrived at a similar time to each other, but it was not synchronized within seconds with any other observed event, so all we really know is that the neutrinos were created by a similar process with roughly the same energy, or energy so high that they were close enough to the speed of light that they only got a 12 second spread over 160,000 years of flight time. I grant that one or more of those seconds might have been due to placement of the individual neutrino events. I tried it and got plausible numbers.

trinitree88
2006-Feb-25, 02:39 AM
Have you tried an OOM calculation on just how much energy it would take? Please keep in mind that the neutrinos arrived at a similar time to each other, but it was not synchronized within seconds with any other observed event, so all we really know is that the neutrinos were created by a similar process with roughly the same energy, or energy so high that they were close enough to the speed of light that they only got a 12 second spread over 160,000 years of flight time. I grant that one or more of those seconds might have been due to placement of the individual neutrino events. I tried it and got plausible numbers.

I disagree. Tonite I checked an older post. In the Question & Answers Thread..."Mass and Speed-of-Light", by RobA 14 December, 2005....BAUT. I gave a list of ~ 15 published,many in the Ap. J., peer-reviewed articles on the coincidences between the prompt neutrino bursts and the observed gravitational waves from supernova 1987a...so it is not true that..."it was not synchronized within seconds with any other observed event,"
This physical effect was seen in six major independent international observatories, and was corroboration of a specific prediction made in April 1982 in my paper" The Unified Field Theory, published at The Gravity Research Foundation, Babson College. submitted to George Rideout Jr.,April 1...no joke. (I once lived in New Boston, NH, ..it's original home.)
I'll drag out an SR unit, and calculate the energy of a single 0.0003 ev neutrino tomorrow...traveling at ~0.99999999999c...it's big, bigger than anything seen at Kamiokande, IMB, Mont Blanc....where the energy spread was in decades of ev, I believe. The photons from the Cherenkov cones give an OOM. :silenced: Night. Pete.

Gsquare
2006-Feb-25, 04:50 AM
....

However, if neutrinos are massive, they may oscillate in vacuo without contacting matter, and that electron-type antineutrino now flits away as a neutrino....messing up the conservation of electron family number, and lepton number.


Hello Pete;
Thank you for your response.

Back when Lee and Yang initially proposed the possibility of parity violation in the weak interaction, most could not have imagined that such a long established and widely held symmetry principle could be violated, much less that it could have resulted in the nice work of some unification of forces and even open a whole new branch of physics.

So in my opinion it would be well not to hold so sacred the concept of 'conservation' of lepton number. Personally I am quite willing to sacrifice conservation of lepton number if there exists the possibility to arrive at more fundamental truth in that regard.

To help that idea become more palatable, here's some salt & pepper:
http://pontecorvo.jinr.ru/work/nlc.html

However my original question was not about 'why neutrino interaction can't violate lepton number', but rather 'how will we be forced to re-interpret weak parity non-conservation when it is shown that they actually do!'. :D

BTW, It seems I heard someone on these threads say:

A third rate theory forbids
A second rate theory explains after the fact
A first rate theory predicts... ;)

Gsquare

BY the way, maybe you can help me here: Where I can get the experimental set-up for the mu meson exp. and the kaon exp. which also revealed parity non-conservation in the weak??

--The works of the Lord are great, studied by all who have pleasure therein.-- Inscribed in the Archway to the Entrance of James Clerk Maxwell's Cavendish Laboratory - Cambridge

antoniseb
2006-Feb-25, 11:22 AM
I gave a list of ~ 15 published,many in the Ap. J., peer-reviewed articles on the coincidences between the prompt neutrino bursts and the observed gravitational waves from supernova 1987a...so it is not true that..."it was not synchronized within seconds with any other observed event,"

That's what I get for not reading the forum for five months. Up till now, I'd been under the impression that we have yet to observe one single gravity wave, and I am very surprised that the observance of a gravity wave from six different locations wasn't much bigger news, but I guess my expectations about what would be news is wrong.

I'll go back and look for that posting and the papers. Presuming that what you are saying is true (you've been very reliable so far), this changes a lot for me.

Edit Update 7:15AM 25 Feb 2006
I have looked at the list of papers you pointed to in your 15-Dec-2005 posting. That is I looked at the list, not the papers. I can't find any of the papers online, and I can't find the Weber paper in S&T (which issue is it in?).

I now have a few concerns about your position:
- you seemed to suggest that gravitational waves were detected at six locations, but I see now you listed six locations combined for neutrinos and gravitational waves, and that there were two doubtful detections of gravitational waves plus four locations that saw neutrinos.
- you previously said that photons, neutrinos, and gravitational waves all arrived within seconds of each other, but since backed down on the photons part, saying both that the photons were emitted by a different mechanism, and that they were, in fact not seen as a flash of any sort, just the continuous emission of Sk69+202.
- The LIGO and LISA websites both say that Gravitational Waves have never been unambiguously detected.

So, since I can't conveniently read the papers, I'm hoping for some guidance here. What specifically are Amaldi, Pizzella, and Aglietta calling detection? Also just as a truth filter, how large a signal (OOM) should a bar detector in Rome have seen from the big neutrino emitting transformation of Sanduleak 69+202? BTW, does it matter how the cylinder was oriented compared to the direction of the LMC at the time? Which way was the cylinder pointing?

trinitree88
2006-Feb-25, 02:19 PM
That's what I get for not reading the forum for five months. Up till now, I'd been under the impression that we have yet to observe one single gravity wave, and I am very surprised that the observance of a gravity wave from six different locations wasn't much bigger news, but I guess my expectations about what would be news is wrong.

I'll go back and look for that posting and the papers. Presuming that what you are saying is true (you've been very reliable so far), this changes a lot for me.

Edit Update 7:15AM 25 Feb 2006
I have looked at the list of papers you pointed to in your 15-Dec-2005 posting. That is I looked at the list, not the papers. I can't find any of the papers online, and I can't find the Weber paper in S&T (which issue is it in?).

I now have a few concerns about your position:
- you seemed to suggest that gravitational waves were detected at six locations, but I see now you listed six locations combined for neutrinos and gravitational waves, and that there were two doubtful detections of gravitational waves plus four locations that saw neutrinos.
- you previously said that photons, neutrinos, and gravitational waves all arrived within seconds of each other, but since backed down on the photons part, saying both that the photons were emitted by a different mechanism, and that they were, in fact not seen as a flash of any sort, just the continuous emission of Sk69+202.
- The LIGO and LISA websites both say that Gravitational Waves have never been unambiguously detected.

So, since I can't conveniently read the papers, I'm hoping for some guidance here. What specifically are Amaldi, Pizzella, and Aglietta calling detection? Also just as a truth filter, how large a signal (OOM) should a bar detector in Rome have seen from the big neutrino emitting transformation of Sanduleak 69+202? BTW, does it matter how the cylinder was oriented compared to the direction of the LMC at the time? Which way was the cylinder pointing?

Antoniseb. I went to Nasa Astrophysics Database, online, and entered References, then Astronomy and Astrophysics, (and also Physics and Geophysics). When you type in the author names, dates...the references come up for you to read and print out.
There are several cogent points. My original contact with the coincidences was in the Boston Globe newspaper's Sci-Tech Section following Neutrino 88, the annual neutrino conference which was held that year at Tufts University. I lived about a mile away, on Main Street in Medford, MA., across from the Royal House(British troops Hdqtrs during the Revolution). Despite it's proximity, I had not attended, though interested, as attendance was by invitation only...as per Neutrino 88 poster in the science library. I asked the librarian to no avail.
Guido Pizzella's coincidences were published there by David Chandler, showing the spikes in the data. It became controversial. Some thought the sensitivity of the bar detectors was beyond their limits. Others insisted they were not. Several journal articles I traveled to use had been torn out of the journals they were published in (UMass, Boston , Campus Library)..others disappeared from the stacks, never to be seen again (Tufts). (I always use the photocopier) Fortunately, as always, MIT graciously supplied them.
Then, I had the opportunity to take the NSF-Sponsored Winter Course in Nuclear and Particle Physics for High School Teachers at the Bates Linear Accelerator in Middleton. A series of excellent speakers included Larry Sulak, from BU and one of the principal investigators of the IMB proton-decay experiment. I asked him about the controversy surrounding the results. He repeated that they were indeed real, and that they would be shortly republished in Il Nuovo Cimento C...in the spring. (it was Feb of 92). The confidence level of those results is 99.99%... sigma 4. For me, that's real.
Without treading too ungainly on someone's toes, I believe the LIGO funding proposals were proximate. If you already have a detector that's seeing them,...who'd fund that? So, it might behoove you to see where the primary objections were coming from. (it was late in life before I realized the political forum I so abhorred was alive and kicking in science too)
With regards to the coincidences, yes it was 4 and 2, and there was no conspiracy to fake data. Teams of experimentalists reviewed their time frames to see if they saw 1987a also. They did. They published. Caught flak. Republished. Caught more flak. Republished again, and again. It remains a two-sided view. What would make it definitive is a new supernova where LIGO/bar detectors are coincident again with neutrino detectors. We'll see.
With regards to the photons, some have espoused their belief that the neutrinos have preceeded the SN photons, making them superluminal, others that massive neutrinos may be arriving from there yet. One has to think of the kinematics of the explosion. Their is a fundamental parity asymmetry (my work), so the center of mass moves. That means a gravitational wave is generated. Simultaneously, as neutrino opacity drops, the prompt burst escapes, (also seen at 4 labs). but the photons inside the photosphere need to random-walk their way through the expanding ejecta plasma, so only the outer surface releases photons while the outer volume releases the neutrino burst. Consequently the rise to maximum visible magnitude is constrained to a curve, not a flash, over weeks. Photons are at the surface as the prompt neutrino burst passes by and racing at c, do reach detectors (EUVE), but the optical display is inherently time delayed. Nothing odd there.
There is an opportunity to verify the gravitational waves in yet another manner, which I have previously suggested in another thread. Mossbauer detectors. When Rebka, Pound detected the gravitational redshift at the Lyman Lab at Harvard University..circa 1960..they used a Mossbauer detector in the stairwell. Sensitivity for those detectors is inversely proportional to linewidth. Modern detectors can be quasi-monochromatic...hence are more sensitive to gravitational gradients than older ones, and an analysis of strip charts, or databases might show SN1987a there also. They do not detect prompt neutrino bursts.AFAIK.
Pete.





Then, I happened to take the

Gsquare
2006-Feb-25, 05:35 PM
Antoniseb. I went to Nasa Astrophysics Database, online, and entered References, then Astronomy and Astrophysics, (and also Physics and Geophysics). When you type in the author names, dates...the references come up for you to read and print out.
....
Guido Pizzella's coincidences were published there by David Chandler, showing the spikes in the data. It became controversial. Some thought the sensitivity of the bar detectors was beyond their limits. Others insisted they were not. ....
...With regards to the coincidences, yes it was 4 and 2, and there was no conspiracy to fake data. Teams of experimentalists reviewed their time frames to see if they saw 1987a also. They did. They published. Caught flak. Republished. Caught more flak. Republished again, and again. It remains a two-sided view. ...


Ahh! Experimental results! Makes all the difference.
How could I have missed it? That's what I get for staying away from the forum for 2 months.:wall:
Now I see where you're coming from, Pete. :clap:
I'm impressed; appreciate the refereneces and background info.

Now I need to go read the entire 'Mass & Speed of light' thread, not to mention going back to visit those old dinosaurs we call 'libraries'
Hope you don't mind me re-posting your final post from there so others can benefit:

Gsquare


Posted by trinitree88 (Dec.14, 2005):
"Then you still have to come to the reason dozens of experimentalists, from Baksan, Kamiokande, IMB, Mont Blanc neutrino experiments,and the Maryland, and Rome bar gravity wave detectors put their collective necks in the guillotine of public science forum..Neutrino 88., to declare those coincidences.
As yet, all neutrino experiments are performed with path lengths through the atmosphere, the earth, through the stellar envelope, etc. I do not believe I have seen a published oscillation report that involves a beam "in vacuo" in it's entirety. In the sun, the original source of the well-known deficit...the path is hundreds of thousands of miles of matter...before reaching the vacuum.

EDIT:To save constant refutations I've done a short search on NASA Astrophysics Database, both the Astronomy & Astrophysics section, and the Physics and Geophysics section: Gravitational waves detected
Bibcode 1997Ap...40..244B Baryshev, Y.V.
1997Afz...40..244B Baryshev, Y.V.
1992NCimC..15..931P Pizzella, Guido
1991AZh..68...732K Kuchik, E.C., Rudenko, V.N.
1991ZhETF..99.1057A Alekseeva, E.N.,Alekseeva.L.N., Zakidyshev,V.N., Kogai, I.M., Krivosheina, I.V.
1991NCimC..14..171A Aglietta, M., Castellina, A., Fuglione, W., Trinchero, G., Vernetto, S.
1990NCimC..13...19P Pallotino, G.V.
1990 ICRC...2...242A Aglietta, M., Amaldi,E....and 34 co-authors
1989NCimC....12...75A Aglietta, M...and 4 co-authors
1989NYASA.571..561A Amaldi, E., Bassan, M.,
1989acfp.proc..445P Pallotino, Giovanni V.
1988S&T...75...350W Weber, J
1988snoy.conf...107P Pizzella, Guido
1987EL......3.1325A Amaldi, E., Bonifai, P., Castellano, M.G., Coccia, E., Cosmelli, C., Frasca, S., Gabellieri, M., Modena, I., and Pallotino, G.V.

This is about 2/3 of the references found. A review of a few of these articles indicates that there has been a continuous history published of detections since supernova 1987a along with some refutations. One of the tricky things was that not all the detectors were on Universal Time at the time of SN1987a. They weren't looking for a supernova at the IMB...it was designed to test the limits of proton decay. Ciao. Pete"

peteshimmon
2006-Feb-25, 05:52 PM
This stuff about Gravitational Wave detection
from 1987a is news to me. The neutrino
detection was well covered and was I think one
of the best events in physics in decades. But
it seems you are saying that the gravitational
wave thing was played down because they did not
want to disrupt funding for a super duper new
instrument in the pipeline! I think I want to
go and lie down now.

Disinfo Agent
2006-Feb-25, 06:24 PM
BTW, It seems I heard someone on these threads say:

A third rate theory forbids
A second rate theory explains after the fact
A first rate theory predicts...Forbidding and predicting are really two sides of the same coin, since every prohibition can be expressed as a prediction, and every prediction forbids its own negation from happening.

Gsquare
2006-Feb-25, 07:17 PM
That means a gravitational wave is generated. Simultaneously, as neutrino opacity drops, the prompt burst escapes, (also seen at 4 labs)....... Photons are at the surface as the prompt neutrino burst passes by and racing at c, do reach detectors (EUVE), but the optical display is inherently time delayed. Nothing odd there.
Pete


OK, Pete; no problem; seems to be consistent with the coincident data from Pizzella; (I printed abstract below for the sake of readers):

Title:
Correlation between gravitational-wave detectors and particle detectors during SN1987A
Authors:
Pizzella, G.
Affiliation:
AA(Roma II, Univ., Rome, Italy)
Journal:
Nuovo Cimento C, Serie 1 (ISSN 0390-5551), vol. 15 C, no. 6, p. 931-941. (NCimC Homepage)
Publication Date:
12/1992

1992NCimC..15..931P

Abstract
"A correlation is established between the data recorded during the supernova SN1987A by the gravitational wave antennas of Maryland and Rome and by the neutrino detectors of Mont Blanc, Kamioka, IMB, and Baksan. The correlation exists during a period of 1-2 hrs centered at about 2 h 24 m that includes the time of the 5nu burst detected by the Mont Blanc detector on 23 February, 1987. The correlation is such that the gravitational wave signal precede the neutrino signals by a 1.1 +/- 0.5 s. The physical mechanisms of the correlation are not yet known."


However, just to be fair; there are opposing explanations; (I've printed it below)

Macroscopic interpretation of neutrino events from SN 1987A
Authors:
Kolpachev, V. V.
Affiliation:
AA(AN SSSR, Institut Kosmicheskikh Issledovanii, Moscow, USSR)
Journal:
Pis'ma v Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki (ISSN 0370-274X), vol. 49, June 25, 1989, p. 644, 645. In Russian.
Publication Date:
06/1989

Bibliographic Code:
1989PZETF..49..644K

Abstract
"The interpretation of signals registered on Feb. 23, 1987 from four neutrino detectors is hindered by a number of difficulties, including a lack of proportionality between the number of registered events and the mass of the detectors, differences in the energy of the events, and an elevated anisotropy in the angular distribution. An examination of the data suggests that these signals were not caused by neutrinos from the supernova SN 1987A but are due to an internal effect in the detectors themselves, caused by a gravitational wave."

Again for the sake of 'truth detecting', it seems to me that Kolpachev's possibility would need to be eliminated in order for one to be fully confident in a massless neutrino deduction from the data, (maybe someone has already discredited it - and I am simply unaware).

Cudos...
Gsquare:D

antoniseb
2006-Feb-26, 01:36 AM
"...An examination of the data suggests that these signals were not caused by neutrinos from the supernova SN 1987A but are due to an internal effect in the detectors themselves, caused by a gravitational wave..."

Good find Gsquare.

Fortunate
2006-Feb-28, 11:59 PM
?????????????

trinitree88
2006-Mar-01, 02:33 AM
OK, Pete; no problem; seems to be consistent with the coincident data from Pizzella; (I printed abstract below for the sake of readers):

Title:
Correlation between gravitational-wave detectors and particle detectors during SN1987A
Authors:
Pizzella, G.
Affiliation:
AA(Roma II, Univ., Rome, Italy)
Journal:
Nuovo Cimento C, Serie 1 (ISSN 0390-5551), vol. 15 C, no. 6, p. 931-941. (NCimC Homepage)
Publication Date:
12/1992

1992NCimC..15..931P

Abstract
"A correlation is established between the data recorded during the supernova SN1987A by the gravitational wave antennas of Maryland and Rome and by the neutrino detectors of Mont Blanc, Kamioka, IMB, and Baksan. The correlation exists during a period of 1-2 hrs centered at about 2 h 24 m that includes the time of the 5nu burst detected by the Mont Blanc detector on 23 February, 1987. The correlation is such that the gravitational wave signal precede the neutrino signals by a 1.1 +/- 0.5 s. The physical mechanisms of the correlation are not yet known."


However, just to be fair; there are opposing explanations; (I've printed it below)

Macroscopic interpretation of neutrino events from SN 1987A
Authors:
Kolpachev, V. V.
Affiliation:
AA(AN SSSR, Institut Kosmicheskikh Issledovanii, Moscow, USSR)
Journal:
Pis'ma v Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki (ISSN 0370-274X), vol. 49, June 25, 1989, p. 644, 645. In Russian.
Publication Date:
06/1989

Bibliographic Code:
1989PZETF..49..644K

Abstract
"The interpretation of signals registered on Feb. 23, 1987 from four neutrino detectors is hindered by a number of difficulties, including a lack of proportionality between the number of registered events and the mass of the detectors, differences in the energy of the events, and an elevated anisotropy in the angular distribution. An examination of the data suggests that these signals were not caused by neutrinos from the supernova SN 1987A but are due to an internal effect in the detectors themselves, caused by a gravitational wave."

Again for the sake of 'truth detecting', it seems to me that Kolpachev's possibility would need to be eliminated in order for one to be fully confident in a massless neutrino deduction from the data, (maybe someone has already discredited it - and I am simply unaware).

Cudos...
Gsquare:D


Gsquare. Agreed. It's a two-sided coin, like many positions in science. V.V. Kolpachev's paper was out before I spoke with Professor Sulak at Bates (winter of 91-92). He was adamant about the correlations being real and that he and his co-authors would be publishing (then) in the upcoming months in Il Nuovo Cimento C...and that the statistical confidence level was 9999/10,000...less than one chance in ten thousand that it was a statistical aberration. I decided to kind of champion that result...until proven wrong.
It was that result which prompted me to begin a series of astronomy talks at the AAPT Meetings. It was an accessible forum. Physics people from a wide range of backgrounds would have the opportunity to question the validity of various points. There was no question, from morphological characteristics of supernova remnants, that they were not spheres, but barrel-shaped, indicating an axis of symmetry. I was initially unsure if the effect was as strong in type1a's as type 2's...there was no data on it at the time (two Vassar coeds picked up on that point, and when I found that it was true..I sent their Prof a letter). In addition, absence of pulsars from remnants...generally....and free-floating pulsars without associated remnants both suggested that an ejection mechanism was working here....out the barrel axis, corroborating a presumed suspected parity effect. That means the center of mass moves, and a gravitational wave is generated. A spherically symmetrical explosion obliterates the star, leaves the pulsar resting in the middle of the remnant....not seen.....and produces a prompt neutrino burst with no wave.
I caught some flak from people in a major university because they were positing type1a standard candles....and I'm just a high school teacher....who was I to question them? I was questioning the data. The luminosity of a type1a would depend on your viewing angle... both the surface area and the temperature would be sensitive to the geometry being viewed if it was a barrel, not a sphere. (Nissenson's paper on Mira variables)(Manchester, R.N. and Kesteven...radio maps of SN remnants..Molonglo) I posted for ~ a year on the Astronomy Club on AOL, and all the posts disappeared when the system crashed..circa 1993-4?...I had many toe-toe arguments with novices and some pros over the validity of that methodology....it now seems quite fashionable to question type 1a cosmologies.
There are other gravitational wave detectors on the planet besides the two bars at Rome and Maryland ,but they're classified...so that data is locked away. PM me, I'll tell you where.

Sorry to be slow responding...science fair, progress reports, two trees fell on the house-kind-of-week. Pete.

beskeptical
2006-Mar-01, 09:07 AM
thanx for the help, but will someone tell me what the doppler effet is?I answered this for you here (http://www.bautforum.com/showthread.php?p=692742#post692742) and tried to make a basics thread on neutrinos while leaving this one as the advanced physics folks' thread.

Moderators may change it but that's what I thought might be best.

Fortunate
2006-Mar-01, 08:26 PM
Hi, Pete.
Very interesting thread. Thanx for telling us about these things. I'm not sure I understand your conclusion (perhaps because I haven't read your entire posts).

Are you saying:
1. matter-enhanced neutrino oscillations occur,
but
2. In vacuo oscillations do not occur?

Are you saying that neutrinos are massless?

Sorry for probably asking you to repeat things you have already said elsewhere. Thanx again.

George
2006-Mar-01, 08:37 PM
If I may add some more straws on my end of this camel...

Are neutrinos that different from photons that they are free to zip straight out the door of a star's core, yet photons are ping-ponged for thousands of years?

Eta C
2006-Mar-01, 08:58 PM
If I may add some more straws on my end of this camel...

Are neutrinos that different from photons that they are free to zip straight out the door of a star's core, yet photons are ping-ponged for thousands of years?

You bet. Photons, although neutral, still interact via the electromagnetic force. On the other hand, neutrinos can only interact via the weak nuclear force. The weak force is very short ranged and is, well, weak. As a result, photons are delayed by the many EM interactions they face as they work their way out of the sun. Neutrinos zip through the matter as if it wasn't there.

beskeptical
2006-Mar-01, 09:00 PM
If I may add some more straws on my end of this camel...

Are neutrinos that different from photons that they are free to zip straight out the door of a star's core, yet photons are ping-ponged for thousands of years?I brought this up also in the thread I took the more simpler discussion to. Light waves are unique critters. No mass yet they don't pass through opaque objects. On the other hand, radio waves do pass through opaque objects. So I await some of the more learned members in the field of physics to enlighten us as to why visible light has photons but other wavelengths of the electromagnetic spectrum don't.

Fortunate
2006-Mar-01, 09:07 PM
If I may add some more straws on my end of this camel...

Are neutrinos that different from photons that they are free to zip straight out the door of a star's core, yet photons are ping-ponged for thousands of years?

Yes, they are a lot different. Neutrinos much more difficult to impede.

Eta C
2006-Mar-01, 10:08 PM
I brought this up also in the thread I took the more simpler discussion to. Light waves are unique critters. No mass yet they don't pass through opaque objects. On the other hand, radio waves do pass through opaque objects. So I await some of the more learned members in the field of physics to enlighten us as to why visible light has photons but other wavelengths of the electromagnetic spectrum don't.

All wavelengths of EM radiation have their energy quantized as photons. That goes for radio waves with wavelengths on the order of miles, through microwaves to IR, visible, UV, X-rays up to hard, high energy gammas with wavelengths in the femtometer range. Wavelength (lambda), frequency (nu), and speed are related by c = lambda * nu where c is the speed of light. A photon's (and EM wave's) energy is given by E = h * nu where h is plank's constant.

Neutrinos are not EM radiation or an odd version of a photon. As I explained above, they only interact via the weak interaction (and gravity, but we can neglect that for these purposes). That is why they pass through matter. It has nothing to do with their mass (or lack thereof). They could mave a mass as great as a neutron's and still pass through matter easily if they only felt the weak force.

beskeptical
2006-Mar-01, 10:13 PM
So I'll retune my thought process here. The wavelength determines if the photon will be deflected by an opaque surface.

George
2006-Mar-01, 11:10 PM
You bet. Photons, although neutral, still interact via the electromagnetic force. On the other hand, neutrinos can only interact via the weak nuclear force. The weak force is very short ranged and is, well, weak. As a result, photons are delayed by the many EM interactions they face as they work their way out of the sun. Neutrinos zip through the matter as if it wasn't there.
Thanks, Eta C. I think my problem was my very rusty Schrodenger wave function, which I never really had to learn in the first place. I associated the wave function with EM, but the wave function is more of a probability function instead, right?

Is it disturbance in the weak force which creates neutrinos, such as when a neutron breaks into a proton plus smaller other things?

[Sorry I missed your reference to my prior question, Beskeptical, even though I had scanned prior posts.]

RussT
2006-Mar-01, 11:54 PM
I have read the 1st and 3rd page and have not seen this question, so I will ask it.

How are neutrino's different from High Energy Cosmic Rays (UHECR's), or are they one and the same?

Gsquare
2006-Mar-02, 03:45 AM
V.V. Kolpachev's paper was out before I spoke with Professor Sulak at Bates (winter of 91-92). He was adamant about the correlations being real and that he and his co-authors would be publishing (then) in the upcoming months in Il Nuovo Cimento C...and that the statistical confidence level was 9999/10,000...less than one chance in ten thousand that it was a statistical aberration. I decided to kind of champion that result....
.

Hello Pete. In order to re-state simplistically so there be no confusion among readers:

No one is questioning if the gravity wave/neutrino correlations are real; rather what is being questioned is the source of the correlations, that is, the physical mechanism behind the correlations.

Pizzella himself, in reporting the correlations in the Nuovo Cimento article (which I previously quoted), admitted "The physical mechanisms of the correlation are not yet known."

Kolpachev, however, apparently has provided a reasonable mechanism for the SN 1987 neutrino/gravitational wave correlations which does not require the assumption of a massless neutrino. He is not at all questioning the correlations, but rather the source of the neutrinos, which appear to arise, not from the SN, but from the detector itself, and he provides a mechanism which explains the neutrino coincidence as being a result of the SN gravity wave coincident upon multiple neutrino detectors.

Thus the data suggests, (due to the energy difference of the events, and the anisoptropy in angular distribution, etc.) that it can be interpreted as Kolpachev stated, and I am not aware of any refutation from the Pizzella camp that would invalidate this proposition. If you know of any, please provide it.

Thanks for the response.
Gsquare :)

Gsquare
2006-Mar-02, 04:48 AM
Good find Gsquare.

Iron sharpeneth iron; thanks for the codos.

BTW, You may be interested in this extension on your idea of using Antihydrogen for a test of equivalence principle.

http://th-www.if.uj.edu.pl/acta/vol29/pdf/v29p0123.pdf

It circumvents the problems associated with free fall tests, and instead makes use of the antihydrogen spectra from an excited state, comparing it to normal hydrogen spectra. An EP violation, if existent, should be detectable (see page 127 for the reasoning).

Sorry I was so slow in the response.
Gsquare

--The works of the Lord are great, studied by all who have pleasure therein.-- Inscribed in the Archway to the Entrance of James Clerk Maxwell's Cavendish Laboratory - Cambridge

Nereid
2006-Mar-02, 04:47 PM
I have read the 1st and 3rd page and have not seen this question, so I will ask it.

How are neutrino's different from High Energy Cosmic Rays (UHECR's), or are they one and the same?They are completely different.

Cosmic rays are protons (mostly) and the nuclei of atoms (OK, protons are also the nuclei of H). These nuclei range in atomic number to at least 100 (IIRC, there was a report of a thick emulsion track, flown in a balloon, interpreted as Z ~= 126), though the mass spectrum is poorly constrained for the highest energy CRs.

In some older material, you will see that 'cosmic rays' also includes high energy gammas (such as are detected by CANGAROO (http://icrhp9.icrr.u-tokyo.ac.jp/)).

trinitree88
2006-Apr-08, 12:27 PM
Hello Pete. In order to re-state simplistically so there be no confusion among readers:

No one is questioning if the gravity wave/neutrino correlations are real; rather what is being questioned is the source of the correlations, that is, the physical mechanism behind the correlations.

Pizzella himself, in reporting the correlations in the Nuovo Cimento article (which I previously quoted), admitted "The physical mechanisms of the correlation are not yet known."

Kolpachev, however, apparently has provided a reasonable mechanism for the SN 1987 neutrino/gravitational wave correlations which does not require the assumption of a massless neutrino. He is not at all questioning the correlations, but rather the source of the neutrinos, which appear to arise, not from the SN, but from the detector itself, and he provides a mechanism which explains the neutrino coincidence as being a result of the SN gravity wave coincident upon multiple neutrino detectors.

Thus the data suggests, (due to the energy difference of the events, and the anisoptropy in angular distribution, etc.) that it can be interpreted as Kolpachev stated, and I am not aware of any refutation from the Pizzella camp that would invalidate this proposition. If you know of any, please provide it.

Thanks for the response.
Gsquare :)

Gsquare. I just found this old question. Sorry about the delayed response...working two jobs in the spring, and my time online is less.

Here's my rationale. The SNO....... http://www.sno.phy.queensu.ca/sno/periodicity..... results clearly indicate a day-night periodicity in the solar neutrino flux, presumably due to matter oscillations in the Earth.So, the energy differences in the observed events may be attributed to the attenuation of the cross-section of neutrinos due to their varying terrestrial matter paths on the day of SN1987a. This Southern Hemispere SN sent it's prompt burst upwards through the Earth to the IMB, Kamiokande, MontBlanc, Baksan detectors.
An interesting paper would construct a correlation between the paths through the sphere of the Earth with attenuation compensations for mantle and core densities....and the subsequent limited spectra of the Cherenkov detectors at the neutrino facilities. As Minos results come in, this may point to fruitful numbers.I'd bet the lowest energies were detected at the end of the largest nuclei-count paths...might be longer path mantle only rather than combined but shorter core-mantle...I'm not modeling the arrows through the Earth without a positional map for the LMC and the four detectors.(which I don't have)...nor do I have the time.
As to previous question about massless neutrinos oscillating, I've defended that on another thread..IMHO....until forced to abandon a conservation law, I'm reluctant to do so. Yes oscillations are seen. No, nobody has shown yet that it occurs in vacuo, which would definitively eliminate massless neutrinos. The original paper by Lincoln Wolfentstein..circa 1978 holds. It isn't stubborness, it's prudence. :naughty: Both Bohr and Curie regretted abandoning conservation laws with regards to beta decays.....the original source of the problem. Thanks. Pete.