muon neutrinos travel faster than c?

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Re: muon neutrinos travel faster than c?

#221  Postby Pulsar » Nov 20, 2011 3:03 pm

zaybu wrote:Another paper reaffirms the van Elburg's finding:

http://arxiv.org/ftp/arxiv/papers/1111/1111.1922.pdf

That's the same paper I mentioned, see above.

zaybu wrote:It would seem that this issue has been resolved.

No, it's just another proposal, among the countless others. It remains to be seen whether this holds any water.

cavarka9 wrote:
"There is a simple way to check the statements made here – they involve doing the same experiment with light. The results would be identical to the results obtained with neutrinos, i.e., photons would appear 60 ns before they were supposed to. The clocks need to be synchronized identically of course and the experiment could be done over the ground."

Ihavenofingerprints wrote:Sending photons on the same route seems like a logical experiment to confirm the results. Is there a reason they haven't tried this yet?

Any how exactly is the light going to cross the Alps and the Apennines?
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Re: muon neutrinos travel faster than c?

#222  Postby Ihavenofingerprints » Nov 20, 2011 3:05 pm

Pulsar wrote:
Any how exactly is the light going to cross the Alps and the Apennines?


I don't understand physics that's why I asked :D
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Re: muon neutrinos travel faster than c?

#223  Postby Pulsar » Nov 20, 2011 3:16 pm

I guess a really really badass laser might do the trick :lol:

[youtube]http://www.youtube.com/watch?v=xMxVBY70dPU[/youtube]
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Re: muon neutrinos travel faster than c?

#224  Postby home_ » Nov 20, 2011 3:19 pm

Pulsar wrote:
zaybu wrote:It would seem that this issue has been resolved.

No, it's just another proposal, among the countless others. It remains to be seen whether this holds any water.
Did Opera team make any comments on this?
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Re: muon neutrinos travel faster than c?

#225  Postby Pulsar » Nov 20, 2011 3:29 pm

home_ wrote:Did Opera team make any comments on this?

Not that I'm aware of. And I haven't seen it mentioned on any physics blog, so I remain cautious about it.
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Re: muon neutrinos travel faster than c?

#226  Postby tuco » Nov 20, 2011 3:30 pm

hackenslash wrote:Building a measurable source of muon neutrinos is no trivial matter, so developing the technology to fire them from orbit is a long way indeed. This is what the setup looks like:

[img]image[/img]

As you can see, there are several stages to the production of neutrinos, and this would be a very difficult set-up to put in orbit.


I assume the other way around it would be a feat to filter noise out? Surely, such alternative (space/air route) been considered before, still for the reasons stated is it quite attractive. This stuff needs confirmation or a super-paper.
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Re: muon neutrinos travel faster than c?

#227  Postby twistor59 » Nov 20, 2011 3:59 pm

Matt Strassler's interesting proposal for some stats that might give a clue about whether it's a cockup or new physics at the end of this blog post

Strassler.png
Strassler.png (64.82 KiB) Viewed 1471 times

Sketches of plots with hypothetical data, showing that by plotting the arrival time of each neutrino versus its energy, one could potentially help distinguish various options. Red dots show hypothetical OPERA data; the purple dot indicates roughly our knowledge from the 1987 supernova. Upper left: what we would have expected if Einstein's equations were right and the experiment were correct; all neutrinos travel with almost the same speed (just a tiny tiny bit below the speed of light) and arrive as expected. Lower right: most mistakes that OPERA might have made would shift the arrival time of the neutrinos in a way that does not depend on the neutrino energy. Lower left: The supernova neutrinos traveled very close to the speed of light, so if OPERA is correct, neutrino speed depends strongly on energy, and this energy dependence would be expected to show up in the data --- though the precise form of this dependence can't be guessed. Such energy dependence would be additional evidence that Einstein's equations need modification, and would give us our first insights into what modifications are needed.
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Re: muon neutrinos travel faster than c?

#228  Postby cavarka9 » Nov 20, 2011 4:09 pm

Pulsar wrote:
zaybu wrote:Another paper reaffirms the van Elburg's finding:

http://arxiv.org/ftp/arxiv/papers/1111/1111.1922.pdf

That's the same paper I mentioned, see above.

zaybu wrote:It would seem that this issue has been resolved.

No, it's just another proposal, among the countless others. It remains to be seen whether this holds any water.

cavarka9 wrote:
"There is a simple way to check the statements made here – they involve doing the same experiment with light. The results would be identical to the results obtained with neutrinos, i.e., photons would appear 60 ns before they were supposed to. The clocks need to be synchronized identically of course and the experiment could be done over the ground."

Ihavenofingerprints wrote:Sending photons on the same route seems like a logical experiment to confirm the results. Is there a reason they haven't tried this yet?

Any how exactly is the light going to cross the Alps and the Apennines?



No, no, the author is asking to test it above ground to check whether the theory holds or not. Just pick a location where it is possible to check whether the error is due to relativistic effect. Many locations would do. No need to bore holes or anything, just to check the authors proposal is true or not (like a different expt in itself). A couple of kms should do.

It should also be enough to reveal whether there is any simple error(in calculation) at all or not.
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Re: muon neutrinos travel faster than c?

#229  Postby newolder » Nov 20, 2011 5:12 pm

hackenslash wrote:Building a measurable source of muon neutrinos is no trivial matter, so developing the technology to fire them from orbit is a long way indeed. This is what the setup looks like:

Image

As you can see, there are several stages to the production of neutrinos, and this would be a very difficult set-up to put in orbit.

an 2 continue teh trajectory: Image
CERN image source

near-surface (+/- 3km) orography has v little impact on teh muon neutrino path.
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Re: muon neutrinos travel faster than c?

#230  Postby PsYcHoTiC_MaDmAn » Nov 21, 2011 12:13 pm

twistor59 wrote:
Ihavenofingerprints wrote:Sending photons on the same route seems like a logical experiment to confirm the results. Is there a reason they haven't tried this yet?


As Tuco said above, you'd have to bore a straight line tunnel through the earth/mountains and lay some fibre optic cable along it. Bit tricky...


the optic fibre (OF) would slow it down as well

C = 299792458 m/s > 0.0024 seconds to travel the distance
OF = 299792458/1.538 = 194923575 m/s > 0.0038 seconds to travel the distance

so that wouldn't give an accurate figure (not sure what the longest a single fibre optic cable could be, so potentially requiring a splice or two (wiki says 40km link))

so that means you'd have to make a tunnel through the earth that is over 700km long, and make it a vacuum (so I'd assume that means something like steel pipe to stop gases venting from the rock)
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Re: muon neutrinos travel faster than c?

#231  Postby cavarka9 » Nov 21, 2011 2:44 pm

PsYcHoTiC_MaDmAn wrote:
twistor59 wrote:
Ihavenofingerprints wrote:Sending photons on the same route seems like a logical experiment to confirm the results. Is there a reason they haven't tried this yet?


As Tuco said above, you'd have to bore a straight line tunnel through the earth/mountains and lay some fibre optic cable along it. Bit tricky...


the optic fibre (OF) would slow it down as well

C = 299792458 m/s > 0.0024 seconds to travel the distance
OF = 299792458/1.538 = 194923575 m/s > 0.0038 seconds to travel the distance

so that wouldn't give an accurate figure (not sure what the longest a single fibre optic cable could be, so potentially requiring a splice or two (wiki says 40km link))

so that means you'd have to make a tunnel through the earth that is over 700km long, and make it a vacuum (so I'd assume that means something like steel pipe to stop gases venting from the rock)



you have still not got what the author is saying.While there could be many sources of errors.

We have a possible explanation for the source of error, which must be timing gone wrong due to error. So put the same timer mechanism for a fiber optic laser, take even this delay into account, synchronize via GPS, lay it over some 1 or 5km for 2 different places, then check it whether it comes before it was supposed to or not.
There can be only one true error which must be timer mechanism, i.e. it is detecting but calculations make it seem faster than it was supposed to. SO, something must be wrong with the calculation, they might not have considered everything. And so, use similar mechanism to check whether the same error persists, if it does, fine, else it is faster than light.
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Re: muon neutrinos travel faster than c?

#232  Postby Pulsar » Nov 21, 2011 4:12 pm

cavarka9 wrote:We have a possible explanation for the source of error, which must be timing gone wrong due to error. So put the same timer mechanism for a fiber optic laser, take even this delay into account, synchronize via GPS, lay it over some 1 or 5km for 2 different places, then check it whether it comes before it was supposed to or not.

You'd need a baseline long enough to obtain a significant result, i.e. much larger than possible measurement errors. So a distance of at least 100 km is required, I think.
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Re: muon neutrinos travel faster than c?

#233  Postby cavarka9 » Nov 21, 2011 4:20 pm

Pulsar wrote:
cavarka9 wrote:We have a possible explanation for the source of error, which must be timing gone wrong due to error. So put the same timer mechanism for a fiber optic laser, take even this delay into account, synchronize via GPS, lay it over some 1 or 5km for 2 different places, then check it whether it comes before it was supposed to or not.

You'd need a baseline long enough to obtain a significant result, i.e. much larger than possible measurement errors. So a distance of at least 100 km is required, I think.


fine, then throw out even fiber optics and just use laser between 2 spots(take the delay due to air into account). We only need to test the timing mechanism, all other errors even if present must contribute to less than speed of light, so we only need to consider for the factors which make up distance and time(timing synchronization).
we are only interested in error which results in faster than light calculation, so it must be either distance we got wrong or time. And in the expt, the doubt is in timing mechanism. So we just need to check for the timing mechanism.
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Re: muon neutrinos travel faster than c?

#234  Postby twistor59 » Nov 21, 2011 4:23 pm

cavarka9 wrote:
PsYcHoTiC_MaDmAn wrote:
twistor59 wrote:

As Tuco said above, you'd have to bore a straight line tunnel through the earth/mountains and lay some fibre optic cable along it. Bit tricky...


the optic fibre (OF) would slow it down as well

C = 299792458 m/s > 0.0024 seconds to travel the distance
OF = 299792458/1.538 = 194923575 m/s > 0.0038 seconds to travel the distance

so that wouldn't give an accurate figure (not sure what the longest a single fibre optic cable could be, so potentially requiring a splice or two (wiki says 40km link))

so that means you'd have to make a tunnel through the earth that is over 700km long, and make it a vacuum (so I'd assume that means something like steel pipe to stop gases venting from the rock)



you have still not got what the author is saying.While there could be many sources of errors.

We have a possible explanation for the source of error, which must be timing gone wrong due to error. So put the same timer mechanism for a fiber optic laser, take even this delay into account, synchronize via GPS, lay it over some 1 or 5km for 2 different places, then check it whether it comes before it was supposed to or not.
There can be only one true error which must be timer mechanism, i.e. it is detecting but calculations make it seem faster than it was supposed to. SO, something must be wrong with the calculation, they might not have considered everything. And so, use similar mechanism to check whether the same error persists, if it does, fine, else it is faster than light.


I think Psychotic's objection was to my ill-thought-out proposal for "sending photons along the same route as the neutrinos" as suggested by ihavenofingerprints. The idea, I believe was that you'd just compute the difference between (neutrino arrival time - neutrino departure time ) - (photon arrival time - photon departure time ). The problem that Psychotic pointed out was just that the speed of light through a fibre is not c.
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Re: muon neutrinos travel faster than c?

#235  Postby Pulsar » Nov 21, 2011 4:28 pm

twistor59 wrote:The problem that Psychotic pointed out was just that the speed of light through a fibre is not c.

Indeed. And the speed of light through the air is not c either.
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Re: muon neutrinos travel faster than c?

#236  Postby cavarka9 » Nov 21, 2011 4:34 pm

Pulsar wrote:
twistor59 wrote:The problem that Psychotic pointed out was just that the speed of light through a fibre is not c.

Indeed. And the speed of light through the air is not c either.


doesnt matter, what matters is to find whether there is an error in timing mechanism or not. :)
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Re: muon neutrinos travel faster than c?

#237  Postby twistor59 » Nov 21, 2011 4:36 pm

Icarus's objection:

http://www.theglobeandmail.com/news/technology/science/faster-than-light-finding-wrong-say-scientific-colleagues/article2243189/

and an objection to the objection

http://profmattstrassler.com/2011/11/21/why-icarus-doesnt-refute-opera/

I'm not even trying to keep up with this. Wake me up when it's all over someone please ?
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Re: muon neutrinos travel faster than c?

#238  Postby Pulsar » Nov 21, 2011 4:52 pm

cavarka9 wrote:doesnt matter, what matters is to find whether there is an error in timing mechanism or not. :)

Yes, but the additional uncertainties are larger than the proposed error in the timing mechanism. For instance, the speed of light in air is about 0.3% slower than in a vacuum. The uncertainty on that value is bigger than the neutrino anomaly, so it'd be quite difficult to filter out that effect :)
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Re: muon neutrinos travel faster than c?

#239  Postby cavarka9 » Nov 21, 2011 4:56 pm

Pulsar wrote:
cavarka9 wrote:doesnt matter, what matters is to find whether there is an error in timing mechanism or not. :)

Yes, but the additional uncertainties are larger than the proposed error in the timing mechanism. For instance, the speed of light in air is about 0.3% slower than in a vacuum. The uncertainty on that value is bigger than the neutrino anomaly, so it'd be quite difficult to filter out that effect :)

hmmm, (is there no easier way, maybe a very large electric wire with const volt). Not now, have lots of work. Maybe you are right.
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Re: muon neutrinos travel faster than c?

#240  Postby HughMcB » Nov 21, 2011 5:45 pm

Study rejects "faster than light" particle finding
By Robert Evans
GENEVA | Mon Nov 21, 2011 3:37pm GMT


GENEVA (Reuters) - An international team of scientists in Italy studying the same neutrino particles colleagues say appear to have travelled faster than light rejected the startling finding this weekend, saying their tests had shown it must be wrong.

The September announcement of the finding, backed up last week after new studies, caused a furore in the scientific world as it seemed to suggest Albert Einstein's ideas on relativity, and much of modern physics, were based on a mistaken premise.

The first team, members of the OPERA experiment at the Gran Sasso laboratory south of Rome, said they recorded neutrinos beamed to them from the CERN research centre in Switzerland as arriving 60 nanoseconds before light would have done.

But ICARUS, another experiment at Gran Sasso -- which is deep under mountains and run by Italy's National Institute of National Physics -- now argues that their measurements of the neutrinos energy on arrival contradict that reading.

In a paper posted on Saturday on the same website as the OPERA results, http://arxiv.org/abs/1110.3763v2, the ICARUS team says their findings "refute a superluminal (faster than light) interpretation of the OPERA result."

...continues...
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