Read the paper for yourself:
Measurement of the neutrino velocity with the OPERA detector in the CNGS beam
The OPERA neutrino experiment at the underground Gran Sasso Laboratory has measured the velocity of neutrinos from the CERN CNGS beam over a baseline of about 730 km with much higher accuracy than previous studies conducted with accelerator neutrinos. The measurement is based on high-statistics data taken by OPERA in the years 2009, 2010 and 2011. Dedicated upgrades of the CNGS timing system and of the OPERA detector, as well as a high precision geodesy campaign for the measurement of the neutrino baseline, allowed reaching comparable systematic and statistical accuracies. An early arrival time of CNGS muon neutrinos with respect to the one computed assuming the speed of light in vacuum of (60.7 \pm 6.9 (stat.) \pm 7.4 (sys.)) ns was measured. This anomaly corresponds to a relative difference of the muon neutrino velocity with respect to the speed of light (v-c)/c = (2.48 \pm 0.28 (stat.) \pm 0.30 (sys.)) \times 10-5.
The summary:
The results of the study indicate for CNGS muon neutrinos with an average energy of 17
GeV an early neutrino arrival time with respect to the one computed by assuming the speed of
light in vacuum:
δt = (60.7 ± 6.9 (stat.) ± 7.4 (sys.)) ns.
The corresponding relative difference of the muon neutrino velocity and the speed of light
is:
(v-c)/c = δt /(TOF’c – δt) = (2.48 ± 0.28 (stat.) ± 0.30 (sys.)) ×10-5.
with an overall significance of 6.0 σ.
17 Responses to ““Measurement of the neutrino velocity…””
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So, let me get this straight…it’s the speed of neutrinos, not the speed of photons, that is the limiting factor (maybe) in maximum velocities in this universe?
Holy Shit.
Pat
I may not be reading this right… but the neutrinos move at _six times_ the speed of light?
Holy shit!
Holy, holy, shit!
Pat
You’re not reading it right. The six-sigma (6.0 σ) means that the data indicates six standard deviations… in this case, the measured anomaly (60 nanoseconds) is about six times as long as the uncertainty in the measurement. This means that the 60 nanosecond difference was not some minor blip in the data, but a very common event.
However, there is an opposing view:
http://johncostella.webs.com/neutrino-blunder.pdf
He argues that the CERN group made statistical errors which drop the “six sigma” event to a “two sigma” event, transforming it from “discovery” to “interesting,” and very likely meaning that the neutrinos are *not* going faster than light. Sadly, measurement and math errors are far more likely than superluminal particles.
Conversation in UCR atomic physics seminar circa 1986:
Me:”I hear Dr. XXX at Stanford has reported finding a magnetic monopole”.
Department chair: “How close was he to tenure?”
And, of course: http://xkcd.com/955/
I’m not getting excited about this yet, I have yet to see any evidence that this real and not just a math, measurement, GPS, or some other error like someone didn’t account for earth’s rotational velocity or something.
I reckon they’ve measured the distance from the neutrino source to the detector along the surface of the earth, and forgot to allow for the fact that the neutrinos go through the earth, not around it……
Hi,
I am not familiar with this advanced notation for writing the speed of light. The last time I read about it, it used to be simply written as c = 3X10^8 m/s.
Can some please break this expression down and explain what each figure means?
speed of light in vacuum of (60.7 \pm 6.9 (stat.) \pm 7.4 (sys.)) ns
Yes, i tried to google it but just couldn’t get it and since this blog happened to be one of the top hits in google, I am hoping you or one of the other commenters can help me unravel this notation.
Thanks
What those numbers refer to:
60.7 ns (nanoseconds) faster than lightspeed trip time
6.9 ns statistical variation
7.4 nanoseconds systemic variation
What they’re suggesting is that if you take into account both statistical and systemic variation in measurements (which amounts to the total possible error), you’re still far below the 60.7 nanosecond anomaly. If, on the other hand, they’re variations were *greater* than 60.7 ns, then it could be *easily* explained as simple measurement error. The paper by John Costella referenced in one of my comments above suggests that the CERN group got their statistics wrong, and that the variation is a lot closer to 60.7 ns, and thus the likelihood of this being a measurement error is much more likely.
What I find significant is not that this neutrino may have exceeded the speed of light, and whether it did is perhaps debatable, but the fact it got so close to it. Even if the speed was actually that far on the other side of light speed, then the mass is approaching infinite according to relativity, in which case some other special effects might be noticed, but so far there has been no comment of which I am aware. (Perhaps my ignorance?) The principle that no velocity can exceed light speed presumably originates through no action being mediated faster than light speed. That is definitely true for electromagnetic forces in three spatial dimensions and one time dimension, but it is only assumed thereafter, and a neutrino is presumably not affected by electromagnetism.
> , then the mass is approaching infinite according to relativity,
Mass approaches infinity as velocity approaches c. But to actually get to c, the mass must be zero. To go *beyond* c, mass must be *negative.* Theoretically, anyway.
The energy and therefore the mass^2 must be negative. The mass must be imaginary, or complex if the neutrino also has a small positive real mass (which it seems to).
My thought was, the mass might be zero at light speed, but to get there it has to go through “almost infinity” which does not seem plausible. (I also feel uncomfortable with outcomes where the result might be infinite or zero, depending on how you look at it.) There is also a question of what accelerates it? In the event that creates the neutrino, what makes it go so fast, irrespective of whether it actually broke light speed? It will not be electromagnetic in nature, and energy/momentum partitioning should not get through this “infinite mass restriction” so that raises the question, is there another force we know nothing about? (Is this our first wake-up call?) If there were to be another force, and if it were mediated at a velocity greater than c, then presumably standard relativity would remain true for all electromagnetic interactions, but there would be a modification where this new force was involved.
Could this just mean that the universal speed limit isn’t the speed of light, but just a little above. C is thus the speed no particle, quanta–what have you–can travel. Thus, the neutrino is a little below this, but a bit ahead of the photon. The anti-matter photon drive has more “push” than a ‘neutrino drive’ could have assuming it could be wrangled.
After the ‘arsenic for phosphorus-alien-life’ debacle, I worry about the woo-woo factor. Not long ago someone suggested that solar flares accelerated decay rates, and out the young-earthers popped again. In the same way that a major Carrington event melted telegraph wires, maybe minor solar events cause dectectors themselves to pick something up–not melt mind you, but cause a blip. I would think anything with wires could act as waveguides. Maybe CERN was warming up, and before each event something else preceeded the effect that is the signature of some type of equipment output needed for each burst–the blip was produced ahead of time. Gut instinct is that this is still an artifact.
Perhaps these new all graphene chips, and assembling circuits with actual patterns, might reduce this.
OT– I wonder if the WOW signal was just a powerful cosmic ray that hit equipment.
OT– I wonder if the WOW signal was just a powerful cosmic ray that hit equipment.
I doubt it — the duration was too long.
http://en.wikipedia.org/wiki/Wow_signal
[…] few days back, in the comments section to THIS POST, I posted a link to a PDF paper refuting the statistical method underlying the claim of […]
The answer to this SN1987A riddle could be as follows:-
Photons travel at ultimate speed but get slowed by electromagnetic friction over vast distances (tired light) whereas neutrinos being neutral are not slowed down over vast distance and although they travel slightly slower than photons, eventually pass them by. If the neutrinos had a head start that would contribute to the 3hr arrival time difference. The Opera finding will probably be shown to be due to an error.
What we need is more photon/neutrino arrival time readings from other supernova studies. Who is working on this?