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CERN clocks faster-than-light neutrinos

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M

Mindlog

Member
Well now they have to throw out an episode or two from the new Cosmos series. I bet Tyson is pissed!

or cautiously excited
feel my nips

Either way. Continue the scrutiny.
 
D

DeathIsTheEnd

Member
One of the most important things from that:
It is necessary here to note that since distance from source to detector and time offsets necessary to determine the travel time of neutrinos have not been remeasured, the related systematics (estimated as well as -possibly- underestimated ones) are unchanged. The measurement therefore is only a "partial" confirmation of the earlier result: it is consistent with it, but could be just as wrong as the other.
Click to expand...
 
S

Spider from Mars

tap that thorax
651297_o.gif

CERN should rename themselves SWAG.
 
A

Al-ibn Kermit

Junior Member
The measurement therefore is only a "partial" confirmation of the earlier result: it is consistent with it, but could be just as wrong as the other.
Click to expand...

There's still some doubt about it. The article really needs more bolding by somebody with a better understanding of physics than I.
 
J

Jarmel

Banned
DeathIsTheEnd said:
One of the most important things from that:
Click to expand...

Yea I was just going to note that. It seems the process was repeatable, it doesn't confirm if there was something wrong with the experiment itself.

Precision vs Accuracy.
 
A

AAequal

Banned
DeathIsTheEnd said:
One of the most important things from that:
Click to expand...
Altering the length between CERN and Gran Sasso is rather big job so I doubt it will be done, especially since this is still low priority assignment @ CERN. We have to hope T2K and Minos will repeat the test and release the results ASAP. Only it seems T2K is going to focus even more on CP-violation experiments upcoming year and Fermilab is becoming more and more unmanned so even the Minos results might take a while to surface because lack of workforce.
 
S

slit

Member
It's still only partially confirmed though. However, if true this would be one of the greatest scientific discoveries ever!!!
 
O

Orayn

Member
hteng said:
wait wait wait... so if we can harness Neutrino.. then does that mean we can travel through time?!
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No. Neutrinos are too puny to "harness" for any macroscopic purpose that we know of, much less time travel.
 
A

AAequal

Banned
Napoleonthechimp said:
That is just one experiment.


Or... time as we perceive it may not exist.
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Yup, and it is more focused on check out the possible system errors. We will still have to wait for 3rd party results and even more results from CERN. Title is as it was in the article, I do hope people read the whole thing before jumping into conclusions :)
 
O

Orayn

Member
AAequal said:
Yup, and it is more focused on check in out the possible system errors. We will still have to wait for 3rd party results and even more results from CERN. Title is as it was in the article, I do hope people read the whole thing before jumping into conclusions :)
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Indeed. You have to run the potentially amazing discoveries through every possible test before declaring that they've changed the world. If you don't, you wind up like the Russian scientists who claimed to have performed cold fusion, but went to the media with their "discovery" before doing even a little peer review. That is to say, discredited.
 
A

AAequal

Banned
nvm
edit. Arxiv has revisted paper but doesn't have the same info then the one released in JHEP. So better wait until Arxiv gets the same paper.
 
S

Sibylus

Banned
"In conclusion, despite the large significance of the measurement reported here and the robustness of the analysis, the potentially great impact of the result motivates the continuation of our studies in order to investigate possible still unknown systematic effects that could explain the observed anomaly. We deliberately do not attempt any theoretical or phenomenological interpretation of the results."
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As it seemed with CERN's initial results, success or failure in this venture could be very instructive indeed. I'm the furthest thing from knowledgeable when it comes to this, but the descriptions of the measurement refinements are fascinating.
 
A

AAequal

Banned
source:i nteractions.org
New Tests Confirm The Results Of OPERA On The Neutrino Velocity, But It Is Not Yet The Final Confirmation

New tests conducted at the Gran Sasso National Laboratory of INFN by the OPERA Collaboration, with a specially set up neutrino beam from CERN, confirm so far the previous results on the measurement of the neutrino velocity. The new tests seem to exclude part of potential systematic effects that could have affected the original measurement.

"A measurement so delicate and carrying a profound implication on physics requires an extraordinary level of scrutiny - said Fernando Ferroni, president of Italian Institute for Nuclear Physics (INFN) - The experiment OPERA, thanks to a specially adapted CERN beam, has made an important test of consistency of its result. The positive outcome of the test makes us more confident in the result, although a final word can only be said by analogous measurements performed elsewhere in the world".

"One of the eventual systematic errors is now out of the way, but the search is not over. They are more checks of systematics currently under discussion, one of them could be a synchronisation of the time reference at CERN and Gran Sasso independently from the GPS, using possibly a fiber" said Jacques Martino, Director of National Institute of Nuclear and Particle Physics of French CNRS.

On November 17 the OPERA Collaboration has submitted the paper on the neutrino velocity measurement for publication on JHEP, and in parallel to the ArXiv. The paper is online today November 18. The time passed from the public seminar at CERN on September 23 was used to make the preprint more readable, to take into account valuable suggestions from the community, to further check the main issues of the data analysis, and mainly to conduct a new test with the specially set up neutrino beam from CERN.

This beam was characterized by a better time definition of the proton extraction time, by having about 3 nanoseconds long bunches spaced by as much as 524 nanoseconds. In this way, compared to the previous measurement, the neutrinos bunches are narrower and more spaced from each other. This permits to make a more accurate measure of their velocity at the price of a much lower beam intensity: only 20 clean events have been collected by OPERA in this phase. Additional events could be eventually collected in the next year run.

This achievement was possible thanks to the strong collaboration with the CERN accelerator team. The Collaboration will continue taking data next year also employing a new muon detector at CERN placed behind the hadron absorber to perform additional independent studies.
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Some other sites are reporting it too.
 
A

AAequal

Banned
Also on Guardian:

Neutrinos still faster than light in latest version of experiment
The scientists who appeared to have found in September that certain subatomic particles can travel faster than light have ruled out one potential source of error in their measurements after completing a second, fine-tuned version of their experiment.

Their results, posted on the ArXiv preprint server on Friday morning and submitted for peer review in the Journal of High Energy Physics, confirmed earlier measurements that neutrinos, sent through the ground from Cern near Geneva to the Gran Sasso lab in Italy 450 miles (720km) away seemed to travel faster than light.

The finding that neutrinos might break one of the most fundamental laws of physics sent scientists into a frenzy when it was first reported in September. Not only because it appeared to go against Albert Einstein's theory of special relativity but, if correct, the finding opened up the troubling possibility of being able to send information back in time, blurring the line between past and present and wreaking havoc with the fundamental principle of cause and effect.

The physicist and TV presenter Professor Jim Al-Khalili of the University of Surrey expressed the incredulity of many in the field when he said that if the findings "prove to be correct and neutrinos have broken the speed of light, I will eat my boxer shorts on live TV".

In their original experiment scientists fired beams of neutrinos from Cern to the Gran Sasso lab and the neutrinos seemed to arrive sixty billionths of a second earlier than they should if travelling at the speed of light in a vacuum.

One potential source of error pointed out by other scientists was that the pulses of neutrinos sent by Cern were relatively long, around 10 microseconds each, so measuring the exact arrival time of the particles at Gran Sasso could have relatively large errors. To account for this potential problem in the latest version of the test, the beams sent by Cern were thousands of times shorter – around three nanoseconds – with large gaps of 524 nanoseconds between them. This allowed scientists to time the arrival of the neutrinos at Gran Sasso with greater accuracy.

Writing on his blog when the fine-tuned experiment started last month, Matt Strassler, a theoretical physicist at Rutgers University, said the shorter pulses of neutrinos being sent from Cern to Gran Sasso would remove the need to measure the shape and duration of the beam. "It's like sending a series of loud and isolated clicks instead of a long blast on a horn," he said. "In the latter case you have to figure out exactly when the horn starts and stops, but in the former you just hear each click and then it's already over. In other words, with the short pulses you don't need to know the pulse shape, just the pulse time."

"And you also don't need to measure thousands of neutrinos in order to reproduce the pulse shape, getting the leading and trailing edges just right; you just need a small number – maybe even as few as 10 or so – to check the timing of just those few pulses for which a neutrino makes a splash in Opera."

Around 20 neutrino events have been measured at the Gran Sasso lab in the fine-tuned version of the experiment in the past few weeks, each one precisely associated with a pulse leaving Cern. The scientists concluded from the new measurements that the neutrinos still appeared to be arriving earlier than they should.

"With the new type of beam produced by Cern's accelerators we've been able to to measure with accuracy the time of flight of neutrinos one by one," said Dario Autiero of the French National Centre for Scientific Research (CNRS). "The 20 neutrinos we recorded provide comparable accuracy to the 15,000 on which our original measurement was based. In addition their analysis is simpler and less dependent on the measurement of the time structure of the proton pulses and its relation to the neutrinos' production mechanism."

In a statement released on Friday, Fernando Ferroni, president of the Italian Institute for Nuclear Physics, said: "A measurement so delicate and carrying a profound implication on physics requires an extraordinary level of scrutiny. The experiment at Opera, thanks to a specially adapted Cern beam, has made an important test of consistency of its result. The positive outcome of the test makes us more confident in the result, although a final word can only be said by analogous measurements performed elsewhere in the world."

Since the Opera (Oscillation Project with Emulsion-tRacking Apparatus) team at Gran Sasso announced its results, physicists around the world have published scores of online papers trying to explain the strange finding as either the result of a trivial mistake or evidence for new physics.

Dr Carlo Contaldi of Imperial College London suggested that different gravitational effects at Cern and Gran Sasso could have affected the clocks used to measure the neutrinos. Others have come up with ideas about new physics that modify special relativity by taking the unexpected effects of higher dimensions into account.

Despite the latest result, said Autiero, the observed faster-than-light anomaly in the neutrinos' speed from Cern to Gran Sasso needed further scrutiny and independent tests before it could be refuted or confirmed definitively. The Opera experiment will continue to take data with a new muon detector well into next year, to improve the accuracy of the results.

The search for errors is not yet over, according to Jacques Martino, director of the National Institute of Nuclear and Particle Physics at CNRS. He said that more checks would be under way in future, including ensuring that the clocks at Cern and Gran Sasso were properly synchronised, perhaps by using an optical fibre as opposed to the GPS system used at the moment.

This would remove any potential errors that might occur due to the effects of Einstein's theory of general relativity, which says that clocks tick at different rates depending on the amount of gravitational force they experience – clocks closer to the surface of the Earth tick slower than those further away.

Even a tiny discrepancy between the clocks at Cern and Gran Sasso could be at the root of the faster-than-light results seen in September.
Click to expand...

I guess all we can do for now is for wait more and more results. Hopefully we have some kind of consensus by end of next year.
 
F

fanboi

Banned
JoeTheBlow said:
Why?
Say particles push a wave-front ahead of them thats slightly faster than the particle itself, that doesn't change anything other than our universes top-speed limit going up a bit.
Doesn't change a thing, or have any practical use, no matter what all the inevitable "time travel!!" stories try to push.
Click to expand...

The speed of light is such a fundamental part of scienece (in that area)... now it isn't correct anymore which is huge.
 
X

XMonkey

lacks enthusiasm.
fanboi said:
The speed of light is such a fundamental part of scienece (in that area)... now it isn't correct anymore which is huge.
Click to expand...
Slow down there. That's not how science works.
 
S

shuyin_

Banned
Nothing to get excited about. They just recreated the initial experiment with the same results. It's still probably wrong anyway.

edit: and what's with the time travel posts... if a particle travels faster than c what does that have to do with time travel?!?
 
M

Meadows

Banned
Physics degrees given out before 2012 should now become invalid and those with degrees predating this year should lose their jobs.

Science: The Meadows way
 
T

ThoseDeafMutes

Member
shuyin_ said:
edit: and what's with the time travel posts... if a particle travels faster than c what does that have to do with time travel?!?
Click to expand...

When an object is traveling at a high speed, it sees stationary observers as experiencing time at a slower rate than the object itself is. For the stationary observer, they see the reverse - that the object in motion is experiencing time at a slower rate. This is time dilation. This is experimentally verified, in case you're wondering.

When Einstein constructed Relativity, it was built on two postulates (things that were taken as true, the rest of the theory derived from them). One of these postulates is the "principle of relativity" - that is to say, the laws of physics are the same everywhere, and there aren't any places in space that are "special" or "privileged". What this means is that observations made at any point in space are just as valid as any other.

If you can travel at speeds exceeding the speed of light, with the two above things taken into account, problems occur. An idealized example to explain this is known as the "Tachyon Pistol Duel" thought experiment. It is as follows:

Two space ships (A and B) meet at a point in space, and are armed with weapons that instantly hit their targets (infinite speed). They agree to turn around, fly away from each other at 0.866 times the speed of light, count down 8 seconds, then turn and shoot each other. So, they begin counting down. Ship A counts down to 0, turns and then fires. Because of the enormous speed of both craft, there is a time dilation factor of 2 between them. What this means is that from each craft's perspective, the other craft is moving at half-speed (divided by a factor of 2). Because of this, the weapon strikes when B has counted down to 4, even though A has counted down to 0.The weapon from ship A glances ship B, but does not destroy it.

Ship B immediately returns fire, destroying ship A. Because ship B was at 4 seconds, and ship A is moving at half speed from ship B's perspective, the shot that kills A arrives at A when it has counted down to 6, a full six seconds before it fired it's original shot.

Now, this is already a problem, but it gets worse. This situation occurred because we started from ship A's perspective. If we had started from ship B's perspective, the exact opposite situation should have occurred. So not only do we have a phenomena that prevents it's own cause, but there are two outcomes that should occur (because both perspectives are equally valid) but which are mutually exclusive!
 
V

Vagabundo

Member
JoeTheBlow said:
Why?
Say particles push a wave-front ahead of them thats slightly faster than the particle itself, that doesn't change anything other than our universes top-speed limit going up a bit.
Doesn't change a thing, or have any practical use, no matter what all the inevitable "time travel!!" stories try to push.
Click to expand...

Well then we might be able to "push" that wave front harder to make FTL faster or we could discover something fundamental about space/time that might provide a new energy source.

That's the point; it opens up a new avenue for research and that might bring some new, very useful, technology.
 
T

Timedog

good credit (by proxy)
The speed of light always seemed arbitrary to me anyways. The interesting part would be that something travels faster than the speed of light and we can measure it.
 
S

shuyin_

Banned
@ThoseDeafMutes: I know about time dillation and the experiment is inherently wrong as it violates causality.

Not to mention Tachyons are fictional particles. Not to mention anything that has a mass cannot ever reach c. Not to mention Stephen Hawking proved in his chronology protection conjecture that according to general relativity it's impossible to time travel, as the laws of physics are made in such way to oppose time travel.
 
T

The Technomancer

card-carrying scientician
shuyin_ said:
@ThoseDeafMutes: I know about time dillation and the experiment is inherently wrong as it violates causality.

Not to mention Tachyons are fictional particles. Not to mention anything that has a mass cannot ever reach c. Not to mention Stephen Hawking proved in his chronology protection conjecture that according to general relativity it's impossible to time travel, as the laws of physics are made in such way to oppose time travel.
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Yes, but if we find neutrinos move faster then light and we have any way at all of generating/deflecting neutrinos and detecting them then presumably we could find a way to transmit information faster then the speed of light, which raises similar paradoxes.
 
Z

Zzoram

Member
Timedog said:
The speed of light always seemed arbitrary to me anyways. The interesting part would be that something travels faster than the speed of light and we can measure it.
Click to expand...

Why?

We know how fast the speed of light is. We can sync clocks at two distant locations. We can measure the departure time at point A and arrival time at point B. If distance/time results in a speed greater than light, we've measured faster than light speed.

It's the same way to measure anything's speed.
 
H

Hurricane_Chris

DDK
Smellycat said:
No, no and no. Time travel is simply not possible and it doesn't make sense. As Chinner said, if time travel is possible then it should have happened by now. Ex: hitler would have stopped, 9/11 would have been prevented, etc...

Or maybe, just maybe...IT HAS ALREADY HAPPENED. What if atheist scientists went back in time planted fossils that look like humans, so that they can add proof to evolution???

:O
Click to expand...


Actually, we do know that time travel (into the future) is possible via time dilation. While general and special relativity give hope for traveling into the future, traveling into the past is murkier using known theories. However, if wormholes exist then perhaps we can connect the two points and accelerate one of them (time dilation) thus creating a way to jump back and forth between reference frames (into the future and into the past). Perhaps the reason why we have not seen time travelers from the past is that we require wormhole technology first, since for such time travel to happen we'd need the machine to create the wormhole first....
 
L

Lord Error

Insane For Sony
Did they ever even commented on that GPS satellite clock movement relativity, which when calculated by someone, accounted for exactly the measured difference?
 
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