OPERA not contradicted by SN1987a

September 23, 2011 at 8:06 pm 15 comments

Everyone is talking about the exciting results from OPERA on the superluminal velocities of neutrinos (arXiv:1109.4897, 23-Sep-2011), which were explained in an excellent CERN EP Seminar given this afternoon. The speaker was Dario Autiero (Institut de Physique Nucleaire de Lyon):

Dario Autiero (Institut de Physique Nucleaire de Lyon)

(For excellent accounts of the measurement and implications, see, for example, viXra log and Matt Strassler, among others.)

Many people point out that the OPERA result:

δv/c = (2.48 ± 0.28(stat) ± 0.30(syst)) × 10-5,

would seem to be contradicted by constraints coming from Supernove 1987a. viXra quotes this constraint as δv/c < 2 × 10-9 for typical neutrino energies of 10 MeV.

The OPERA analysis was essentially described in a paper by John Ellis, Nicholas Harries, Anselmo Meregaglia, Andre Rubbia, Alexander Sakharov
(arXiv:0805.0253, May 2008) who are motivated by considerations of Quantum Gravity. They consider two scenarios, in which the deviations from c depend linearly or quadratically on the neutrino energy.

Motivated by this idea, and the number quoted on viXra log, I made the following plot. It shows the upper limit on δv/c as a function of the neutrino energy, for the quadratic and the linear assumptions. These limits are drawn as continuous curves (straight lines on a double-log plot). The region above the curve is excluded.

SN1987a limits on δv/c and the OPERA measurements

As you can see, the OPERA points are not exluded by the SN1987a limit as cited by viXra log, in the quadratic case. In the linear case, there is apparently a contradiction.

Of course, this does not mean that the OPERA results are right. Only confirmation by an independent experiment, preferably with different metrology techniques, will convince me and everyone else that this astounding result is correct.

Entry filed under: Particle Physics.

Top background shapes and the CDF MJJ Anomaly Fitting OPERA’s Result

15 Comments Add your own

  • 1. Kea  |  September 23, 2011 at 8:24 pm

    Excellent. But what I wonder is why nobody points out (also) that neutrinos are not antineutrinos. Many experiments have indicated differences …

  • 2. Kea  |  September 23, 2011 at 8:30 pm

    OK, so if we include the OPERA and MINOS data points … how many experiments do we need before people stop laughing?

    • 3. John Ståhle  |  September 25, 2011 at 12:26 pm

      We are not laughing, we only demonstrate the scepticism the community MUST show towards an unusual claim, which challenges one of the most basic theories in cosmology/…

      Assume 2 experiments showed within 6σ that electrons are massles.

      Would we clap our little fat hands in awe? or demand extremely solid proof and an extremely carefull analysis of any imaginable (even unimaginable) systematic error? (rethoric Qs)

  • 4. Daniel  |  September 23, 2011 at 8:48 pm

    Many already mentioned a controversy between the superluminal fraction observed in the Opera experiment (2×10^-5) and what has been observed in the 1987 supernova. If that fraction is applied to the supernova, the time delay must be about a year, but actually it was just 2 hours. Interesting, that the controversy could be resolved if one suggest that the neutrino, when it “virtually” goes through the electron, somehow manages make it instantly. It is interesting, because the required cross section of such virtual interaction (let call it “swap”) have to be about the typical neutrino-electron cross section 10^-48 m^2. With that assumption, we would have that the neutrinos in the supernova become superluminal just when they go through the matter, as well as across the rocks in the Opera experiment. In vacuum their velocity is equal to the speed of light. What remains with that model, that one should prove that the causality didn’t suffer from “swap”.

  • 5. Jester  |  September 24, 2011 at 4:24 am

    The quadratic case is also excluded, imo. Scaling the OPERA result down to MeV assuming the quadratic energy dependence you’d predict a \sim 10 min delay between the highest (39 MeV) and the lowest (6 MeV) energy SN neutrinos detected by K2 and IMB, whereas they arrived within 15 sec.

    • 6. marc  |  September 24, 2011 at 4:57 am

      Jester—your argument is quite important, and rules out a quadratic fit (as do the two OPERA points). Since there is no dispersion in the arrival times of the SN neutrinos, the difference in speeds between 39 MeV and 6 MeV must be less than a part per trillion. Even a cubic fit might not work. The solution is clear–the dispersion relation is flat between 6 and 39 MeV, rises quadratically to 10 GeV, and then flattens out again!!!

  • 7. Fitting OPERA’s Result « Collider Blog  |  September 25, 2011 at 10:59 am

    […] Yesterday I tried to point out that the results from OPERA are not necessarily contradicted by the SN1987a results. […]

  • 8. zephirawt  |  September 26, 2011 at 4:22 am

    Before some time I analyzed the similar problem. The relatively close gamma ray burst of Mkn 501 galaxy exhibited relatively large delay of gamma ray photons behind the visible light flash.


    But the observation of more distant gamma ray burst didn’t exhibited such large delay, so it has been neglected with mainstream physics.


    Now the situation just repeats with neutrinos and IMO it could have the same explanation.


    IMO the photons are forming massive clusters, which can encapsulate neutrinos and as the result, only small portion of neutrinos will come before the flash of visible light flash. The same, just from opposite side of speed of light barrier applies to gamma ray photons, which are always moving with subluminal speed in AWT. At short distances the formation of clusters cannot apply, so that the difference in speed of visible light and neutrinos/gamma ray photons can manifest freely.

    • 9. John Ståhle  |  September 26, 2011 at 9:19 pm

      I have been working on and off on the same subject since 2007.

      Exactly the same (as Markarian 501) happened at the GRB 080916C event in September 2008.

      In both cases the more energetic photons arrived before the more energetic.

      From the highly active galactic core in the Markarian 501 event, the lowenergetic particles (0,5 TeV) arrived ≈ 240 sec. before the highenergetic (5 TeV), having travelled ≈ 135 Mpc, i.e. (v(High) ≈ (v(Low) * (1 – 1,73E-14))).

      One can assume that more highenergetic photons (equivalent to higher mass) moves slightly slower than the lowenergetic ones.

      A less exiting explanation is that the lowenergetic photons in both cases simply originates from a more distant part of the emitter, in the Markarian 501 then
      1. ≈ 120 lightseconds further away or
      2. at the same distance from Earth, but some 240 lightseconds (72 mio. km) from the first burst or
      3. any combination of distances from Earth and first burst, and
      4. thus possibly a result of processes initiated when the first burst hit.

      See also: “These tests have looked for delays in the arrival times of energetic photons relative to low-energy photons …”:
      Abstract: http://arxiv.org/abs/0805.0253 (hep-ph) (paper: http://arxiv.org/pdf/0805.0253 and
      Abstract: http://arxiv.org/abs/0903.5048 (hep-ph) (paper: http://arxiv.org/pdf/0805.0253v2

      • 10. John Ståhle  |  September 26, 2011 at 9:30 pm


        Read “In both cases the LESS energetic photons arrived before the more energetic.”

    • 11. John Ståhle  |  September 26, 2011 at 9:24 pm

      Why do you use tinyurl as a redirect instead of direct links to arxiv?

      tinyurl known to host some infamous attack-pages.

    • 12. John Ståhle  |  September 27, 2011 at 3:48 pm

      The separate-photon-speed idea seems to be “observationally challenged”, by “Limiting properties of light and the universe with high energy photons from Fermi-detected Gamma Ray Bursts”, 23 SEP 2011, http://arxiv.org/abs/1109.5191

      Goodbye to a favorite hypothesis?

  • 13. Pavel Murat  |  September 27, 2011 at 3:29 pm

    Hi Michael,

    as I was pointed out, the leading edge of the OPERA timing distributions doesn’t seem to be very sensitive to a ~60ns offset, while the trailing edge seems to be much more sensitive. This can be seen on slide 47 of their CERN seminar talk. At the same time, I’d guess that the leading edge should provide more reliable information than the trailing edge. It would be interesting to see how consistent are results defined by the fits to the leading edge and trailing edge of the timing distributions separately.

    • 14. Pavel Murat  |  September 27, 2011 at 3:34 pm

      sorry, the URL to look at is http://tony5m17h.net/OPERAx1x2.png – I’m not entirely sure about the origin of the plots, but they show the fits to the leading and trailing edge with and without the 60ns offset

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September 2011

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