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Merged Puzzling results from CERN

Oscillation

I've been puzzling over the CERN neutrino results, and I have one idea that I have not found addressed;

It is well known that neutrinos most likely oscillate between flavors, and it occurs to me that if one of the neutrino flavors were a tachyon, you might observe this at particular fixed distances from the source, but that at any random distance you will observe an averaged result as the velocity would oscillate around c.

So, neutrino signals from a supernova will not be separated from the optical signal by years and years, the net effect is zero.
 
BenBurch said:
I've been puzzling over the CERN neutrino results, and I have one idea that I have not found addressed;

It is well known that neutrinos most likely oscillate between flavors, and it occurs to me that if one of the neutrino flavors were a tachyon, you might observe this at particular fixed distances from the source, but that at any random distance you will observe an averaged result as the velocity would oscillate around c.

So, neutrino signals from a supernova will not be separated from the optical signal by years and years, the net effect is zero.
Click to expand...

Answers from standard neutrino physics, which may of course be wrong:

a) Neutrinos don't simply oscillate for their whole lives; they suffer "decoherence" when the different-mass components of the wavepacket get separated from one another.

b) It'd be very weird, perhaps nonsensical, for a *flavor* state to have different kinematics. "flavor" is just a quantum phase relevant to your coupling to the weak interaction. The mass states don't oscillate; they just fly along.

c) OPERA is looking at several flavor states, generally over a fraction of an oscillation length. If these states had different speeds, OPERA could see them separately. (Need to think about the stats though.)

d) The claimed effect is so huge, it implies a very *large* imaginary mass; it's hard to imagine why oscillation experiments have been consistent with a very small (real) mass. If the oscillation scale isn't due to a small real mass, what sets that scale?
 
BenBurch said:
I've been puzzling over the CERN neutrino results, and I have one idea that I have not found addressed;

It is well known that neutrinos most likely oscillate between flavors, and it occurs to me that if one of the neutrino flavors were a tachyon, you might observe this at particular fixed distances from the source, but that at any random distance you will observe an averaged result as the velocity would oscillate around c.

So, neutrino signals from a supernova will not be separated from the optical signal by years and years, the net effect is zero.
Click to expand...

Another criticism of this interpretation would involve the Cohen-Glashow effect, because if you have this hypothetical oscillation of neutrinos into a "tachyonic" state in a periodic manner, then wouldn't you also expect to see a periodic set of pulses of Cherenkov radiation along with the observation of the neutrino beam that coincides with the oscillation into and out of the "tachyonic" state?

And, to my knowledge, no such Cherenkov radiation exists, either in the OPERA experiments or in any observation of naturally-occurring neutrino events (such as SN1987A).
 
MattusMaximus said:
Photons don't travel any slower in the Earth's gravitational field, they merely shift their frequency. This is an effect called gravitational redshifting.
Click to expand...

Actually, photons passing through a gravitational field do slow down, in the sense that passing through a region containing a non-zero gravity field takes longer than passing through a region (of the same size) that doesn't.

The extreme case is a black hole, where the photon never comes out the other side.
 
MattusMaximus said:
Another criticism of this interpretation would involve the Cohen-Glashow effect, because if you have this hypothetical oscillation of neutrinos into a "tachyonic" state in a periodic manner, then wouldn't you also expect to see a periodic set of pulses of Cherenkov radiation along with the observation of the neutrino beam that coincides with the oscillation into and out of the "tachyonic" state?

And, to my knowledge, no such Cherenkov radiation exists, either in the OPERA experiments or in any observation of naturally-occurring neutrino events (such as SN1987A).
Click to expand...

Correct. And I have pointed that out. Perhaps Tachyons do not produce Cherenkov radiation as predicted; We of course have never observed any.
 
Given the number of neutinos in each detected pulse it's unlikely that, even if such detectors were in place (which is unlikely), that we would be able to observe anything. I've generally found that folk install detectors to find the things that they expect, not the things that they don't. ;)
 
sol invictus said:
Actually, photons passing through a gravitational field do slow down, in the sense that passing through a region containing a non-zero gravity field takes longer than passing through a region (of the same size) that doesn't.

The extreme case is a black hole, where the photon never comes out the other side.
Click to expand...

Ah, my bad. I should have clarified that I meant that light doesn't slow down as observed from a localized reference frame. Within a given frame, it's speed will be measured as c.

Thanks for the catch, Sol.
 
The ICARUS team have released a paper on arxiv, 'A search for the analogue to Cherenkov radiation by high energy neutrinos at superluminal speeds in ICARUS', stating that the supposed superluminal neutrinos cannot exist based on their analysis of the energy spectrum.
 
The "Cerenkhov analogue" argument is interesting, and a valid addition to the discussion, but it's a bit of a reach. We'd have to know what the speed of weak force interactions was in the region, and that's not been timed. We coudl suppose that those interactions travel at the same speed as light, but (if their arguments are valid) we know that they don't travel at the same speed as light in rock, or else neutrinos traveling at less than cVacuum but more than cRock would be showing the effect that they haven't seen. If cWeak is essentially always the same as cLightVacuum, then we're basing an argument on an effect that can't really happen under current theory, and if the effect can't detectably exist under current theory, it's a bit cheeky to say that we're so confident about the effect's legitimacy to say that it has to exist under other (unspecified) theories, and that therefore, if we don't detect it, those theories must be wrong about a hypothetical class of motion that /also/ can't be modeled properly in out theory.

OTOH, if the weak force /doesn't/ necessarily have the same speed as cVacuum, because it /is/ appreciably affected by the presence of matter, we don't know for sure that our local speed of light isn't significantly slowed due to the presence of the earth and solar system and surrounding galaxy, compared to the speed of light in an intergalactic void, and if cWeak is closer to the "void speed", then you wouldn't see the Cerenkhov analogue anyway. We normally assume a flat lightspeed background rather than a nonlinear one, but this might be why our galaxy rotation curve predictions were off, so it might not be a safe assumption.

Another couple of potential problems: if superluminal neutrinos are moving at more than cBackground, and radiating, then the radiant energy needs to either reduce their mass, or reduce their speed. If it reduces their speed, then they might only be travelling at more than cBackground for quite a short section of their journey. They could "speed" for long enough to overtake a hypothetical unaffected lightsignal, and then brake to extremely close to the speed of light, so that they still end up arriving ahead of time, even though their speed for most of the journey is subluminal. That would mean that we couldn't calculate the energy losses by assuming superfast travel over the entire 730 km. Any braking radiation might only really be happening at the CERN end.

The "braking" argument also undermines another disproof of superfast neutrinos based on supernova observations, given that neutrino bursts seem to happen only slightly earlier than the optical signal. There've been people arguing that this proves that the supernova neutrinos can't have been be superluminal, because otherwise the offset between the two signal pulses would scale linearly with distance.
But if there's a braking effect (which a general Cerenkhov effect would suggest), then the supernova neutrinos might have initially been travelling at more than cVacuum, radiated and braked, and then carried on for the rest of the distance at fractionally less than cVacuum, but been still sufficiently far ahead of the lightsignal for it not to quite catch up during the journey.

OTO,OH, if there's no significant braking effect, and no significant weak-force Cerenkhov analogue, then some of those earlier arguments might become valid, but the ICARUS team's argument would be wrong.

Things are still interesting.
 
Is there anyone here that can give a summation update understandable to the general public, or a site ? Is this still considered a mystery or a major discovery?
 
chuck4842 said:
Is there anyone here that can give a summation update understandable to the general public, or a site ? Is this still considered a mystery or a major discovery?
Click to expand...

A multinational European enterprise has created a device, using bits made in Britain (measured in feet) and metric tools. They have buried it in a hole under some mountains. Using this device, some Italians have produced some measurements that differ from what was expected.

For some reason, scientists are surprised by this.
 
Soapy Sam said:
A multinational European enterprise has created a device, using bits made in Britain (measured in feet) and metric tools. They have buried it in a hole under some mountains. Using this device, some Italians have produced some measurements that differ from what was expected.

For some reason, scientists are surprised by this.
Click to expand...

Bits made by Brits using metrics? I usually only trust the metrics in the hands of the Japanese. The bits are received by the Italians. The results are translated by the lot?
 
Chuck, maybe I'm missing something, but I think Soapy Sam is kidding entirely.

A major Swiss experiment launched neutrinos towards Italy. The Swiss computer says the launch happened at time T1. The Italian computer says the neutrinos arrived at time T2. You can calculate their velocities by doing V = (T1-T2)/D, where D is the Italy-Switzerland distance.

Well, except that you need both computer clocks set precisely. (If I take a cup of tea out of my microwave, whose clock says 12:30, and walk it over to the living room, where the VCR says it's 12:25, does that mean I went back in time? No, it means the clocks are wrong.) Unfortunately, the clocks are very far apart---in fact the Italian one is down a mine, with several kilometers of cable between it (and a bunch of intervening computers) and the nearest GPS antenna.

Then you need to know the distance accurately. That's done with GPS, supposedly very accurately.

Anyway, the OPERA folks did this calculation as best they could, and the calculated speed tells them that the neutrinos were going faster than light. They arrived "early", according to the Italian clocks, by a few tens of nanoseconds. Most people think that there was a clock-sync mistake, or perhaps a distance-measurement mistake. It could be something very simple, but that doesn't mean it's easy to figure out.
 
ben m said:
Chuck, maybe I'm missing something, but I think Soapy Sam is kidding entirely.

A major Swiss CERN experiment launched neutrinos towards Italy. The Swiss computer says the launch happened at time T1. The Italian computer says the neutrinos arrived at time T2. You can calculate their velocities by doing V = (T1-T2)/D, where D is the Italy-Switzerland distance.

Well, except that you need both computer clocks set precisely. (If I take a cup of tea out of my microwave, whose clock says 12:30, and walk it over to the living room, where the VCR says it's 12:25, does that mean I went back in time? No, it means the clocks are wrong.) Unfortunately, the clocks are very far apart---in fact the Italian one is down a mine, with several kilometers of cable between it (and a bunch of intervening computers) and the nearest GPS antenna.

Then you need to know the distance accurately. That's done with GPS, supposedly very accurately.

Anyway, the OPERA folks did this calculation as best they could, and the calculated speed tells them that the neutrinos were going faster than light. They arrived "early", according to the Italian clocks, by a few tens of nanoseconds. Most people think that there was a clock-sync mistake, or perhaps a distance-measurement mistake. It could be something very simple, but that doesn't mean it's easy to figure out.
Click to expand...

;)
 
ben m said:
Chuck, maybe I'm missing something, but I think Soapy Sam is kidding entirely.

A major Swiss experiment launched neutrinos towards Italy. The Swiss computer says the launch happened at time T1. The Italian computer says the neutrinos arrived at time T2. You can calculate their velocities by doing V = (T1-T2)/D, where D is the Italy-Switzerland distance.

Well, except that you need both computer clocks set precisely. (If I take a cup of tea out of my microwave, whose clock says 12:30, and walk it over to the living room, where the VCR says it's 12:25, does that mean I went back in time? No, it means the clocks are wrong.) Unfortunately, the clocks are very far apart---in fact the Italian one is down a mine, with several kilometers of cable between it (and a bunch of intervening computers) and the nearest GPS antenna.

Then you need to know the distance accurately. That's done with GPS, supposedly very accurately.

Anyway, the OPERA folks did this calculation as best they could, and the calculated speed tells them that the neutrinos were going faster than light. They arrived "early", according to the Italian clocks, by a few tens of nanoseconds. Most people think that there was a clock-sync mistake, or perhaps a distance-measurement mistake. It could be something very simple, but that doesn't mean it's easy to figure out.
Click to expand...

Does this qualify for the MDC? It's at least AMAZING that the greatest scientists on earth weren't prepared for the results of their own test. If JR gave'em his award, they could all retire. (yes I'm joking.)
 
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Sciencedaily has this
http://www.sciencedaily.com/releases/2011/12/111223114121.htm

""We've shown in this paper that if the neutrino that comes out of a pion decay were going faster than the speed of light, the pion lifetime would get longer, and the neutrino would carry a smaller fraction of the energy shared by the neutrino and the muon," Cowsik says.
"What's more," he says, "these difficulties would only increase as the pion energy increases.
"So we are saying that in the present framework of physics, superluminal neutrinos would be difficult to produce," Cowsik explains."
 
ben m said:
ties by doing V = (T1-T2)/D, where D is the Italy-Switzerland distance.

Well, except that you need both computer clocks set precisely. (If I take a cup of tea out of my microwave, whose clock says 12:30, and walk it over to the living room, where the VCR says it's 12:25, does that mean I went back in time? No, it means the clocks are wrong.)
Click to expand...

You still have a VCR? :p Probably requires some explaination for the younger folks on this forum what those are ...

http://en.wikipedia.org/wiki/VCR
 
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