Neutrinos caught speeding at CERN??

[JohnH]

See:

http://www.telegraph.co.uk/science/8...-of-light.html

Seems we get this story from time to time - another funding ploy or ....

[CraigS]

More here …

Looks like they're taking it seriously … Fermilab is ramping up to see if they can replicate the readings and they're requesting T2K (Japan) to step up to the mark, also … a call to arms !

Caution is warranted, I would think especially in the light of:

The Chicago team had similar faster-than-light results in 2007, but those came with a giant margin of error that undercut its scientific significance.
…
{Min you, with this news however, back at CERN ...} Scientists calculated the margin of error at just 10 nanoseconds, making the difference statistically significant.
...
He cautioned that the neutrino researchers would have to explain why similar results weren't detected before.

The plot thickens !

Fermilab is in need of some publicity and T2K are still cleaning up after the earthquake damage.

We'll see, I guess. This kind of thing has happened before.

In a way, this reminds me of the 'unaccountable noise' measured in the GEO600 gravity wave detector in Germany. A scientist called Hogan has been attempting to explain the noise in terms of the Holographic Principle. We covered this in this thread).

It'll be interesting to watch the reactions to this within scientific community, though !

Cheers
PS: The team reporting this are no slouches in Particle Physics, either. It is a big team and they have published many peer-reviewed papers. Accusations centred around the credibility of the team, would seem unfounded.

[CraigS]

Its interesting … neutrinos oscillate from one flavour to another (this was observed last year in May). This means they have a small, but non-zero mass. The MINOS experiment then measured oscillation differences between mass eigenstates, (2 and 3, according to Wiki), which means that there is at least one neutrino with a mass of at least 0.04eV.

That's pretty tiny !

One has to wonder about the uncertainty/error bars of the newly measured velocity. I guess all we can do is wait and let other 'pros' review the analysis and replicate the results. (Which is what the CERN team are requesting … a normal part of the process .. and the media will hype this up beyond belief, I'm sure of that !)

Cheers

[CraigS]

There is a huge amount of precision imposed on all the instrumentation needed to make this measurement accurate.

Seeing as neutrinos don't interact with normal matter, knowing when they are emitted and being able to eliminate any latency effects in the detectors at the receiving end, is critical. One needs a very, very accurate clock to measure the time time taken. The precision of the distance measurement is also critical, especially over a tiny distance like 730 kms !

They are also up against astronomical neutrino measurements to date from Supernovae. Mind you, the distances the little beasties have to have traveled in space, might allow for a good chance that they could change flavours in transit .. thereby rendering these measurements a little suspect, as well.

I don't think the results (and the paper .. if there is one, yet) have been peer-reviewed (??). They seem to be requesting this, at this stage.

My take on this, is that this is more than likely another media hype-up which taps into the middle of the normal science review process, in order to get 'the scoop'.

I look forward to some real science scrutiny on the results.

Cheers

[sjastro]

Interesting. Didn't the same Gran Sasso laboratory announce the presence of dark matter to a 4 sigma confidence level, despite the fact no one else on the planet has been able to verify this?

Regards

Steven

[renormalised (Carl)]

Did they book them??

Neutrino 1: "Hey Steve, this is fun!!!. Racing around here at 0.99999c"

Neutrino 2: "Sure is.....might get booked for speeding, you know"

Neutrino 1: "Nah....not likely"

Neutrino 2: "Hey, there's one of those 'physics cops' behind the detector over there!!!"

Neutrino 1: "Him...dopey Dora in the lab coat, no worries!!!. He's useless"

[bojan]

Wikipedia has already an article on the subject (actually, the details will follow shortly):
http://en.wikipedia.org/wiki/Tachyon

[renormalised (Carl)]

Being serious for now.....it's a very interesting result. But like Craig said, it's most likely just media hype grabbing onto the coattails of an unusual result that's turned up. If it holds up to experimental scrutiny and the peer review process, then that is a different matter altogether, but I think it's a little premature to have "announced" such a result on the basis of an apparent detection. Especially with neutrinos...considering for all intents and purposes the little blighters would normally just shoot straight through the detectors and keep on going without even touching the sides. Then you have those coming in externally from cosmic sources contaminating the experiment, as Craig mentioned.

However, if it does turn out to be repeatable experimentally and the paper passes the peer review, then that will most certainly throw a very large spanner into the works. SR will have to be heavily modified if this is the case.

[renormalised (Carl)]

Originally Posted by sjastro

Interesting. Didn't the same Gran Sasso laboratory announce the presence of dark matter to a 4 sigma confidence level, despite the fact no one else on the planet has been able to verify this?

Regards

Steven

I believe so. I think Fermilab thought they (Gran Sasso) shot themselves in the foot with that one because they weren't able to go much beyond about 2/2.5 sigma at the very best.

[bojan]

60ns time delay is very easy to measure on the bench even with standard oscilloscope.
However, I am not sure if this is within the un-certainty of the synchronisation of clocks between two labs.
Perhaps there was an error made somewhere.

[CraigS]

Originally Posted by sjastro

Interesting. Didn't the same Gran Sasso laboratory announce the presence of dark matter to a 4 sigma confidence level, despite the fact no one else on the planet has been able to verify this?

Regards

Steven

Good point Steven.
I had assumed that this Antonio Ereditato guy was credible as he has been part of the Laguna Design Study .. the 'L Collaboration', which has been working on the development of neutrino detectors throughout Europe.

I had assumed because of his membership within this team and because of his role within that team, there was more to this than just a single scientist coming up with some spurious study results.

Perhaps the quality of testing done by that particular team (from Gran Sasso) should be subject to a little more scrutiny, particularly if they were the originators of the DM 4 sigma issue (??)

Cheers

[renormalised (Carl)]

Originally Posted by bojan

60ns time delay is very easy to measure on the bench even with standard oscilloscope.
However, I am not sure if this is within the un-certainty of the synchronisation of clocks between two labs.
Perhaps there was an error made somewhere.

That's what they're trying to determine. Although they believe they have it right.

[bojan]

I remember the neutrinos detected that was thought to originate from SN1987A.... They arrived almost at the same time as light signal, and the distance was much, much larger.. compared to only 760km in this case.
Now either neutrinos change the propagation speed along with their flavour (so that the arrival time from SN averaged out) or there is something very fishy with this recent measurement

Or the detection of those 7 neutrinos from SN1987A was erroneous and coincidental.

EDIT.
I just made a quick calculation.. if the time delay between two labs (760kn away from each other) was 60ns, the time delay from Magellanic Cloud (assumed distance of 150.000ly away) should be 4 years.
Something is VERY wrong here.

[xelasnave]

IF we were able to detect all nuetrinos how many would we find?

I get the impression we would find a thick soup all rushing by at near C I expect.

Thinking about nothing I thought about how many (nuetrinoes) you could observe on an almost infinite number of tradjectories and it would seem reasonable to think there are a few...same for HB really but just because we cant observe them takes away from imagining how full space must be of with each of these or if not those another particle doing the same job.
Even full destrustion of the standard model will still leave that fact remaining..
How does a nuetrino interact with matter?I will look it up.

alex

[xelasnave]

From Wiki... taking this statement as being reasonable

http://en.wikipedia.org/wiki/Neutrino

Most neutrinos passing through the Earth emanate from the Sun. Every second, in the region of the Earth, about 65 billion (6.5×1010) solar neutrinos pass through every square centimeter perpendicular to the direction of the sun.[4]

Wow and that is from just one Sun.

alex

[ngcles]

Hi All,

Yes I am apprehensive -- as commented by others, the time gap seems unreasonably large for such a small distance between the detectors (in context). The comparison Bojan mentioned re the neutrinos from 1987A and the short gap (three-odd hours from memory) between their arrival and the light's arrival over a distance of 50 Kpc for me rings alarm bells.

I hope it isn't something as basic as the speed of light in a vacuum -v- the speed of light through the medium(s) between the detectors. Will be interesting to see if the result is able to be duplicated independently elsewhere. [Edit: Nope, just realized this can't be the error -- my dopey mistake].


Best,

Les D

[Suzy]

Science is starting to get scary now.
But will also take on board what Craig said about possible media hype., But still, if it's open to public scrutiny- it makes me think they are really on to something here.

I've been doing lots of reading this morning on the various media releases regarding this subject- they are flying all over the place on facebook.
So I thought I'd share some here...

http://www.universetoday.com/89135/b...ign=WordSocial



http://www.bbc.co.uk/news/science-environment-15017484

The result - which threatens to upend a century of physics - will be put online for scrutiny by other scientists.
In the meantime, the group says it is being very cautious about its claims.
"We tried to find all possible explanations for this," said report author Antonio Ereditato of the Opera collaboration.
"We wanted to find a mistake - trivial mistakes, more complicated mistakes, or nasty effects - and we didn't," he told BBC News.
"When you don't find anything, then you say 'Well, now I'm forced to go out and ask the community to scrutinise this.'"

http://http://www.nature.com/news/2011/110922/full/news.2011.554.html

Ereditato says that he is confident enough in the new result to make it public. The researchers claim to have measured the 730-kilometre trip between CERN and its detector to within 20 centimetres. They can measure the time of the trip to within 10 nanoseconds, and they have seen the effect in more than 16,000 events measured over the past two years. Given all this, they believe the result has a significance of six-sigma — the physicists' way of saying it is certainly correct. The group will present their results tomorrow at CERN, and a preprint of their results will be posted on the physics website ArXiv.org.

And regarding SN1987A (from above article)....

Ellis, however, remains sceptical. Many experiments have looked for particles travelling faster than light speed in the past and have come up empty-handed, he says. Most troubling for OPERA is a separate analysis of a pulse of neutrinos from a nearby supernova known as 1987a. If the speeds seen by OPERA were achievable by all neutrinos, then the pulse from the supernova would have shown up years earlier than the exploding star's flash of light; instead, they arrived within hours of each other. "It's difficult to reconcile with what OPERA is seeing," Ellis says.


Ereditato says that he welcomes scepticism from outsiders, but adds that the researchers have been unable to find any other explanation for their remarkable result. "Whenever you are in these conditions, then you have to go to the community," he says.

[michaellxv (Michael)]

How do you determine that the particle you're measuring at the far end is the same one that you sent?
It's not like you can put a number on them.

[CraigS]

Originally Posted by xelasnave

From Wiki... taking this statement as being reasonable

http://en.wikipedia.org/wiki/Neutrino

Most neutrinos passing through the Earth emanate from the Sun. Every second, in the region of the Earth, about 65 billion (6.5×1010) solar neutrinos pass through every square centimeter perpendicular to the direction of the sun.[4]

Wow and that is from just one Sun.

alex

Alex;
I think that figure, or its interpretation by Wiki authors, might be dodgy (Wiki's problem .. not yours)?
I checked the reference linked paper (Dec 2004) and I can't find anywhere where it cites this figure. (Someone can check me on this).

From the Ice Cube observatory with 22 strings (25% of planned total detectors), as at July 2009), they say:

The average upper limit over the northern sky for point sources of muon-neutrinos with E^−2 spectrum is:
E^2 Φ(νμ) < 1.4 × 10^−11 TeV cm−2 s−1,
in the energy range from 3 TeV to 3 PeV, improving the previous best average upper limit by the AMANDA-II detector by a factor of two.

So, it seems the presently accepted flux density (as measured) is:
14x10^-11 GeV per square cm per sec.

If the combined mass of all three neutrinos is say, 0.28 eV, then using the Ice Cube figures, (& by my quick calcs … if someone can check me) .. comes out to be about 0.05 combined neutrinos per square cm per sec.
Mind you, I'm not quite sure what the E^-2 spectrum means. (I think this is just scientific speak for straight flux density).

Its a big difference if I'm right (which might also be a first on this sort of stuff .. I'm happy to be corrected ...).

Cheers

[bojan]

Originally Posted by michaellxv

How do you determine that the particle you're measuring at the far end is the same one that you sent?
It's not like you can put a number on them.

Usually they are generated in individual experiments (in bursts), and they know when the experiment (burst) took place - so they (neutrinos) are actually tagged.