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PostPosted: Fri, 23-09-11, 17:02 GMT 
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Today I attended an exciting research seminar given in CERN's great amphitheater that was packed with hundreds of people (including Nobel price winners...).

Evidence was announced by the OPERA experiment (at the 6 sigma level!) that neutrinos (produced at CERN) are travelling faster than light along the 730 km distance to Italy's Gran Sasso underground laboratory, where the arriving neutrinos were cleanly observed. The 730 Km distance between source and detector was measured with an accuracy of only 20 cm! The timing accuracy was at the nano-second level.

The results are both hard to believe, and very impressive on account of the many precision cross-checks that were done by the experimentalists during the past years.

If correct, these findings would have very far-reaching implications. Therefore, another independent experiment on the matter is urgently needed!

++++++++++++++++++++++++++++++++
Here is today's press release:
http://press.web.cern.ch/press/PressRel ... 9.11E.html
++++++++++++++++++++++++++++++++

Here is the respective preprint as of yesterday:
http://arxiv.org/abs/1109.4897

Fridger


Last edited by t00fri on Mon, 26-09-11, 13:29 GMT, edited 2 times in total.

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PostPosted: Fri, 23-09-11, 17:58 GMT 
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Quite unbelievable news!

More mystery ahead and probably a bunch of headache for some physicists! :shock:

Let us know the impact of this discovery in the forthcoming months!


PS: Tx for the infos you gave us here from time to time, quite appreciated indeed!


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PostPosted: Fri, 23-09-11, 18:33 GMT 
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ElChristou wrote:
Quite unbelievable news!

More mystery ahead and probably a bunch of headache for some physicists! :shock:

Let us know the impact of this discovery in the forthcoming months!


PS: Tx for the infos you gave us here from time to time, quite appreciated indeed!


Hello Christophe!

nice to read you here from time to time!

The case about "speedy neutrinos" is so "hot" that I'll certainly keep track of the status here.

Unfortunately, a new and independent experiment will take years (and cost lots of money). Moreover, if the second experiment confirms the findings, the first experiment will get the Nobel price, anyway. On the contrary, if the results are disproved, noone will earn any fame ;-) . So the motivations for doing the second experiment might not be "overboarding".

A much faster solution would happen, if someone finds another source of error that was hitherto unaccounted for...

Cheers,
Fridger


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PostPosted: Sat, 24-09-11, 1:25 GMT 
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Hi, there! I'm following the strong resonance that such experiment has raised in my country. Seem that all are become physicists in search for new systematic errors! What is interesting for me is the superluminal behaviour of the neutrinos even for an energy much more lesser than the theoretical inferior limit in which their behaviour should be subluminal. Rightly the scientists in the paper do not find "clues on a possible energy dependence" of the variation of velocity.

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Massimo


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PostPosted: Sat, 24-09-11, 7:54 GMT 
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THIS IS NOT A JOKE!
Below there is the link to the page of the italian Minister of Education in which the Minister itself congratulates with the autors of the experimental results of the CERN/OPERA team.

http://www.istruzione.it/web/ministero/cs230911

For whom doesn't know italian I translate this statement:

"Alla costruzione del tunnel tra il Cern ed i laboratori del Gran Sasso, attraverso il quale si è svolto l'esperimento, l'Italia ha contribuito con uno stanziamento oggi stimabile intorno ai 45 milioni di euro."

Italy has contributed with an allocation of 45 millions of euro to the construction of the tunnel amongst Cern and Gran Sasso laboratories, through which the experiment has been accomplished. :lol: :lol: :lol:

This is the Minister of Education!!! Now you know what distance there is between educated italians and their Ministers. Incredible!


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PostPosted: Sat, 24-09-11, 10:12 GMT 
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fenerit wrote:
Hi, there! I'm following the strong resonance that such experiment has raised in my country. Seem that all are become physicists in search for new systematic errors! What is interesting for me is the superluminal behaviour of the neutrinos even for an energy much more lesser than the theoretical inferior limit in which their behaviour should be subluminal. Rightly the scientists in the paper do not find "clues on a possible energy dependence" of the variation of velocity.


Since we know that neutrinos are not massless, the small mass should actually cause a slight decrease of the speed below c.

Fridger


Last edited by t00fri on Sat, 24-09-11, 10:22 GMT, edited 1 time in total.

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PostPosted: Sat, 24-09-11, 10:15 GMT 
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fenerit wrote:
THIS IS NOT A JOKE!

"Alla costruzione del tunnel tra il Cern ed i laboratori del Gran Sasso,

This is the Minister of Education!!! Now you know what distance there is between educated italians and their Ministers. Incredible!


Simply amazing! :lol:

Fridger


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PostPosted: Sat, 24-09-11, 20:07 GMT 
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Seem to recall there have been various experiments that gave results that at face value give negative values for the best estimate of the square of the neutrino mass.

Obviously need to watch out for systematics - that's where my money would be!


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PostPosted: Sat, 24-09-11, 22:42 GMT 
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ajtribick wrote:
Seem to recall there have been various experiments that gave results that at face value give negative values for the best estimate of the square of the neutrino mass.

Obviously need to watch out for systematics - that's where my money would be!


Most of the talk and the subsequent discussion at CERN was of course about systematics and about the many checks the OPERA experimentalists had already performed! Certainly the intensive search for further sources of systematics will continue ...

A tachyonic nature of neutrinos was actually proposed as far back as 1985 (Chodos et al.) ;-) , but meanwhile there are many constraints from neutrino oszillation experiments etc.

Somewhat negative mass^2 results came from the familiar Tritium beta decay experiment (Mainz/Troitsk), where the behaviour of the beta spectrum near its endpoint is investigated. There the spectrum is sensitive to the neutrino mass. Typically one finds here

m_nu^2 c^4 = -1.6 +- 2.5 (stat) +- 2.1 (syst) eV^2,

which is of course compatible with zero and led to the accepted 95% CL upper limit

m_nu < 2.2 eV /c^2

The reasons for apparent "tachyonic" problems were mainly associated with the complexities of the underlying nuclear physics (Tritium film...) ....

An interesting constraint comes from the neutrinos emitted by the SN 1987A supernova explosion. Had they traveled faster than light by the OPERA factor (1.0000248( 28 ) c), they would have arrived at Earth several years before the photons, in contrast to the observations. Yet the SN 1987A neutrinos were MUCH less energetic than the OPERA neutrinos, whence things might be different. The OPERA group also checked the energy dependence of their effect, and found NOTHING.

The neutrino speed was measured by OPERA over an unprecedented long baseline (730 km)
on Earth and with unprecedented precision...That makes the "speedy neutrino" case so "hot".

Fridger


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PostPosted: Mon, 26-09-11, 0:18 GMT 
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Very interesting stuff here. I can't wait to see where this leads. If this is proven, this will change everything.

The one problem I've always had (with faster than light and not being able to beat it) was how can you drive a particle faster than the energy source being used. Electricity travels at the speed of light. If you use electricity to drive a particle, how can you expect it to go faster? But apparently that is what just happened???????????

cartrite


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PostPosted: Mon, 26-09-11, 0:27 GMT 
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t00fri wrote:
An interesting constraint comes from the neutrinos emitted by the SN 1987A supernova explosion. Had they traveled faster than light by the OPERA factor (1.0000248( 28 ) c), they would have arrived at Earth several years before the photons, in contrast to the observations. Yet the SN 1987A neutrinos were MUCH less energetic than the OPERA neutrinos, whence things might be different. The OPERA group also checked the energy dependence of their effect, and found NOTHING.

Fridger


Was anyone looking back then. I thought these particles were very hard to detect back then and probably even now? Or is there a new way to detect them?


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PostPosted: Mon, 26-09-11, 10:33 GMT 
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cartrite wrote:
t00fri wrote:
An interesting constraint comes from the neutrinos emitted by the SN 1987A supernova explosion. Had they traveled faster than light by the OPERA factor (1.0000248( 28 ) c), they would have arrived at Earth several years before the photons, in contrast to the observations. Yet the SN 1987A neutrinos were MUCH less energetic than the OPERA neutrinos, whence things might be different. The OPERA group also checked the energy dependence of their effect, and found NOTHING.

Fridger


Was anyone looking back then. I thought these particles were very hard to detect back then and probably even now? Or is there a new way to detect them?


During a Supernova explosion a vast amount of neutrinos is produced .
In 1987 three detectors able to track neutrinos from Supernovae were available:


Kamiokande II detector detector (in a zinc mine in Japan)
IMB detector (in a salt mine in Ohio)
Baksan neutrino observatory (in the Baksan gorge, Caucasus)
Image
http://englishrussia.com/2008/04/11/the-neitrino-lab/

Aproximately 3 hours before the visible light signal from the SN 1987A explosion arrived on Earth, a burst of 24 neutrinos in total was observed that clearly stood above the background.

Kamiocande II: 11 antineutrinos
IMB: 8 antineutrinos
Baksan: 5 antineutrinos

The bursts lasted about 10 secs each. So there was indeed a pretty good signal in agreement with the theoretical expectations about the duration of the shock wave from the collapsed core of the star. The quantitative implications for the OPERA results are being investigated.

The observed neutrino events from SN 1987A could be converted into an upper limit on the (average) neutrino mass

<m> < 16 eV,

which is significantly higher than the one from Tritium beta decay (Mainz) I mentioned above.

Note that both the distance to SN1987A and the start time of the core collapse are much less precisely known than the data in case of the OPERA experiment between CERN and GranSasso!

Fridger


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PostPosted: Tue, 04-10-11, 15:16 GMT 
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Here is some further significant theoretical evidence against OPERA's claim of neutrrinos travelling at a superluminal speed.

On Sept 30 a preprint appeared by physics Nobel prize winner Sheldon L. Glashow and his collaborator Andrew Cohen. Here is the link:

http://arxiv.org/pdf/arXiv:1109.6562

The authors start by supposing that e.g. Muon neutrinos indeed travel at superluminal velocities. As in all superluminal processes, certain otherwise forbidden processes are now kinematically allowed, even in vacuum! In particular, the authors focus on the following analogs to the familiar Cherenkov radiation:

nu_mu ==> nu_mu + photon
nu_mu ==> nu_mu + nu_e + anti(nu_e)
nu_mu ==> nu_mu + e+ + e-

These radiation processes cause superluminal neutrinos to loose energy as they propagate. Notably the 3rd process above (nu_mu ==> nu_mu + e+ + e-) causes a severe constraint. An implication from this energy loss due to e+e- Bremsstrahlung is that upon arrival the neutrino beam should have been depleted of high-energy neutrinos. Since this is contrary to observation, the authors refute the superluminal interpretation by OPERA.

Fridger


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PostPosted: Fri, 07-10-11, 0:19 GMT 
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Here is another intriguing theoretical paper from 2 days ago:

http://arxiv.org/pdf/arXiv:1110.0234

Superluminal neutrinos without violation of special relativity! Since the neutrino beam travels large distances between CERN and Gran Sasso within the Earth's crust, one can consider an imaginary 'optical' potential describing the corresponding beam attenuation. It is shown that in this case superluminal speed is possible, leaving the 'holy cow' alive ;-)


Fridger


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PostPosted: Fri, 07-10-11, 7:18 GMT 
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t00fri wrote:
Here is another intriguing theoretical paper from 2 days ago:

http://arxiv.org/pdf/arXiv:1110.0234

Superluminal neutrinos without violation of special relativity! Since the neutrino beam travels large distances between CERN and Gran Sasso within the Earth's crust, one can consider an imaginary 'optical' potential describing the corresponding beam attenuation. It is shown that in this case superluminal speed is possible, leaving the 'holy cow' alive ;-)


Fridger


I'm not sure I understood everything written in that paper but it sounds like neutrinos travel faster through matter than a vacuum. Maybe a good test of this would be to send a "neutrino beam" through the "Sonne" to a spacecraft orbiting another planet / moon like the Moon, Venus, Mars, Jupiter, or Saturn during the time the planet / moon was on the opposite side of the "Sonne" from Earth. Of course this would probably cost more than it's worth.......... :wink: But maybe it could increase communication speeds and who knows what else. :D

cartrite


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