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The Hunt for the Tachyon

The Hunt for the Tachyon. (a “biased” view?). Robert Ehrlich George Mason University mason.gmu.edu/~ rehrlich.

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The Hunt for the Tachyon

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  1. The Hunt for the Tachyon (a “biased” view?) Robert Ehrlich George Mason University mason.gmu.edu/~rehrlich ABSTRACT: Despite the apparent conflict with relativity, some physicists have continued to seek evidence for the existence of  hypothetical faster-than-light particles dubbed tachyons.  In the past all claims of tachyons have, however, later been shown to be incorrect, or at least not reproducible.  Nevertheless, the speaker believes that the tachyon is not some mythical beast, and that we may be on the verge of proving its existence.  Specifically, he believes that the ever-surprising neutrino, or its electron flavor, is actually a tachyon.   It might be useful to check out the speaker’s youtube video or a press release describing his latest research on the subject, both of which can be found on his web site: http://mason.gmu.edu/~rehrlich/ Sound check

  2. The OPERA experiment (2011) “The phantom of the OPERA” Sent “bunches” of neutrinos from CERN to a detector 730 km away Compared their time of flight to that of light, c Measured neutrino speed higher than c by 0.0000237 % NOT the way experiment was done! photon photon Experiment has been redone by OPERA and others, and all now show a departure from c within the experimental uncertainty -- just the latest of a number of false sightings. This is not the greatest time to make the case for superluminal (FTL) neutrinos!

  3. Conclusions from tachyon searches Many false sightings: all speed measurements so far consistent with v = c within experimental uncertainties, but we know that neutrinos (unlike photons) cannot have exactly v = c.Never settled: Negative results on speed measurements cannot rule out neutrinos being tachyons – they only set more stringent limits, i.e., v closer to c. Pointless? Many people believe there is no point in even looking since Einstein said v > c is impossible!

  4. Nothing can go faster than light … if it travels in in vacuum … if it carries energy or information … if it is measured locally within the space … if it started out slower than light

  5. Why were tachyons first proposed? (1962) Rest mass Relativistic mass How can you define the rest mass of tachyons which can never be at rest!?! m is imaginary! Bilaniuk, O.-M. P.; Deshpande, V. K.; Sudarshan, E. C. G. "'Meta' Relativity". American Journal of Physics30 718 (1962).

  6. Tachyons would fill a vacant nicheTachyon luxon tardyon 3 world lines Future light cone Else- where Else- where Past light cone Spacetime diagram (c = 1.0 here)

  7. Tachyons from A to B Tachyon kinematics is consistent with special relativity For v > c particles relativity says M2 < 0 No passing through the light barrier from either side 3 distinct classes: tachyons, tardyons & luxons Neither required nor forbidden by theory They violate “causality” -- sending messages back in time???

  8. The only known candidates for being tachyons are one of the 3 types of neutrinos. How are the neutrino masses found? Why? ANSWER: Only neutrinos have masses so close to zero that within the experimental uncertainty we do not know if m2 > 0 or m2 <0, but we do know that m2 is non-zero. -- For some reaction where neutrino is emitted measure the “missing” (unobserved) energy E & momentum p -- Calculate the missing mass from: m2 = E2 – p2 (relation assumes c = 1)

  9. Measuring the neutrino mass Assume pion initially at rest Neutrino (nu) not detected E = mc2 pion nu muon Muon detector Muon & neutrino have equal magnitude momenta so we can find the neutrino mass by observing the muon energy Measure the muon kinetic energy (KE)

  10. Using pion decay to find the neutrino mass # muons -1149 +1149 Mass2 meter 0 4.12 Result for muon neutrino: Result for electron neutrino

  11. How could we tell if neutrinos are tachyons? STATUS Least Sensitive test 1. Find one type that can outrace light (v > c). 2. Find one type that has an imaginary rest mass, i.e., 3. Look for low energy neutrinos created in a brief pulse arrive before high energy ones Supernovae are the only way it could be done – why? Wait until 2020 (Katrin) Need enormous distance to see spread in times due to energy variation. A. Chodos, and V. A. Kostelecky, Phys. Lett. B 150, 431 (1985;

  12. SN 1987A – 1st supernova whose neutrinos were observed

  13. Super-Kamiokande Neutrino detector:Currently the World’s largest Super –K is hundred’s of times more sensitive than what was available in 1987

  14. What can SN tell us about the neutrino mass, m?How does arrival time ordinarily correlate with energy, E? 1/E2 1/E2 Slope ~ 1/m2 Is arrival time relative to light & T is light travel time from SN Leads light Lags light Infinite energy neutrino

  15. How about a tachyonic mass? (m2 < 0) 1/E2 1/E2 The limited data on SN 1987 neutrinos hinted at a tachyonic neutrino. Ehrlich, R. “Tachyonic neutrinos and the neutrino masses,” Astropart. Phys., 41 (2013) 1–6, http://arxiv.org/pdf/1204.0484.pdf Infinite energy neutrino

  16. The actual data: 24 neutrinos from SN 1987A supports 2 mass values m1 = 4 eV neutrinos m2 = 21 eV neutrinos v > c neutrinos -- none observed R. Ehrlich, Evidence for two neutrino mass eigenstates from SN 1987A and the possibility of superluminal neutrinos, Robert Ehrlich, Astroparticle Physics 35 , 625–628 (2012)

  17. A 3rd superluminal (v > c) neutrino to the rescue • The flavor state masses can be very close to zero (and even negative) if one of the mass states has m2 < 0

  18. Would lie on line shown!!! 4 Dots are simulated data The one real data point available Both slope and intercept predicted & no background Chances of the one event being due to random background? What if they found 2 more in looking at the data for the rest of the one hour? SN 1987A data for 17 min interval Including burst 12 MeV

  19. How could we tell if neutrinos are tachyons? STATUS Least Sensitive test 1. Find one type that can outrace light (v > c). 2. Find one type that has an imaginary rest mass, i.e., 3. Look for low energy neutrinos created in a brief pulse arrive before high energy ones Supernovae are the only way it could be done – why? 4. Find an energetically forbidden decay in which one is emitted!!! Wait until 2020 (Katrin) Next SN in galaxy will tell Need enormous distance to see spread in times due to energy variation. Maybe seen already!!! New results A. Chodos, and V. A. Kostelecky, Phys. Lett. B 150, 431 (1985;

  20. Recent work is based on experiment on high energy cosmic rays What is known about them Acceleration mechanism? Composition? Points of origin? Shape of spectrum, dN/dE? NASA Drawing of showers of charged particles created by incoming high energy cosmic rays

  21. A Radical proposal: Missing protons?

  22. Missing protons interpreted as being due to the onset of proton beta decay at an energy E = Eknee Proton beta decay (normally energetically forbidden) why? Inverse beta decay (allowed if proton has enough E & neutrino is a tachyon) Tachyons violate causality, or reverse their direction in time and the sign of their energy in certain reference frames, i.e., an emitted neutrino of energy E appears as an absorbed (anti) neutrino to a sufficiently rapidly moving observer moving with the proton at speed: Follows from the Lorentz Transformation From energy of knee deduce neutrino has: m2 ~ -- 0.25 eV2 1Ehrlich, R., "Implications for the Cosmic Ray Spectrum of a Negative Electron Neutrino Mass2, Phys. Rev. D, 60, 17302 (1999)

  23. The pnpnp … Decay chain p ne+v pe-v ne+v pe-v ne+v Assume n  p much slower than p  n. Chain continues with energy loss at each step until p drops below the energy of the knee. The result is a “pile up” of neutrons at an energy a bit above the knee – a small peak at around 4.5 PeV (+ 2.2 PeV) After 1999 prediction a 2nd paper written in same year found a 4.5 PeV peak for CR’s pointing back to Cygnus X-3. Chain Offers a way cosmic rays could “mostly” point back to their sources

  24. Cygnus X-3 paper1 in which peak claimed Animation Counts above background vs energy Signal based on counts in 2.5% wide interval of phase, background based on the other 97.5% -- factor of 40 background suppression 1 PeV 10 PeV 100 PeV 4.5 1. R. Ehrlich, Phys. Rev. D 60, 073005 (1999) using published data from: J. Lloyd-Evans et al., Nature, 305 (1983) 784.

  25. Reception to 4.5 PeV paper (1999) Any guesses? Was cited by 23 people over the years, but by the wrong ones! Great skepticism (extending to whether all reports of Cygnus X-3 claimed CR signals were genuine), in light of several high statistics subsequent experiments having negative results: The “coffin nail” CASA-MIA (1996) In addition, conventional wisdom is that except at very high energies , CR’s being charged protons or nuclei are randomized sufficiently by galactic B-field so that none point back to sources. Also, neutrons could not survive the trip from any sources

  26. Why 4.5 PeV signal from Cygnus X-3 only seen in some experiments? Obviously signal cannot show up in experiments that lack enough CR’s with E ~ 4 PeV. CASA-MIA had only 0.09% of its data with E > 1.2 PeV Plus, being a weak signal 4.5 PeV peak only shows up when background suppressed by: -- cut on times of very rare major flares (Tibet & Marshak) -- cut on 2.5% phase window (Lloyd-Evans)

  27. Data is from the Tunka Collaboration (35 physicists, mainly Russians) (1 PeV) Data analyzed: 1.8 M events collected over 3 years 2009 -2012; energy resolution 15% & energy threshold 1 PeV. Tunka continues to take data. The Tunka experiment 133 Cherenkov detectors Cherenkov Effect

  28. My connection to Tunka? Absolutely none! I am not aware if Tunka has taken a position on my results. Around Jan 2013 I connected with Mikhail Zotov at MSU about some cosmic ray work he had done MZ had access to the Tunka data though he was not a member of the group. He provided me with his analysis of the data – though he declined to be a coauthor on the paper based on it.

  29. New paper supporting 4.5 PeV peak Don’t look at any one suspected source, but do a blind search for “candidate sources” anywhere in the sky, i.e, statistically significant excess of counts above what calculated background See how the excess number of “candidate sources” depends on energy & look for a peak near E = 4.5 + 2.2 PeV Data Suggests a peak in CR spectrum at 5.86 PeV consistent with previous claim of peak at 4.5 + 2.2 PeV

  30. For E = 5.86 PeV energy bin many more large S > 0 excesses than chance predicts & no excess for S < 0 Standard Gaussian (sigma = 1) N 68 candidate sources -- 48 above Gaussian S “Candidate sources” taken to have S > 3.3 sigma excess above background Basis of this definition?

  31. Numbers of excess candidate sources in each energy bin N Candidate sources S > 3.3 E (PeV) No excess seen for “candidate sinks” Not physically possible Candidate sinks S < - 3.3 N E (PeV)

  32. Summary of the new evidence No single source identified, but the number of candidate sources (68) is much greater than chance would predict (20) in the energy bin centered on 5.86 PeV. Consistent with 1999 result (peak at 4.5 + 2.2 PeV) for Cygnus X-3, and with previous prediction of peak Number of candidate “sinks” consistent with chance (20) at all energies & none are physically possible Main Problem: Is the result replicable?

  33. Now some fun stuff:Why v > c neutrinos might imply the ability to send signals back in timeFirst, one-way signaling

  34. Tachyons violate causalityNo absolute distinction between cause & effect! Consider a warning signal sent between approaching saucers to avoid a collision. Assume that the warning signal is sent using v > c tachyons . How would this appear on a spacetime diagram?

  35. time distance

  36. Sending a message to your earlier self?Requires round trip signaling Which famous physicist first showed this could be done if faster-than-light particles existed & could be used to send signals? In what year? Paul Ehrenfest (1911) See wikipedia entry on tachyon anti-telephone for details

  37. Sending a message to your earlier selfwith the aid of a friend u > c v < c Return signal from ship reaches you on Earth before you sent the original message provided: How much in your past? E.g., if u = 2c, v = 0.9c, L = 220 ly, get: T = -50 y

  38. A bit of philosophy on different ways to make big discoveries

  39. Pack hunters (1,046 Higgsians) Lone wolves or crackpots Two types of physicists seeking to make fundamental discoveries Massive expensive apparatus & many years spent in preparation Analyze existing data in a novel way & takes little time to complete Lone wolves may be stronger, more aggressive and far more dangerous than the average wolf that is a member of a pack. However, lone wolves have difficulty hunting, as wolves’ favorite prey, large ungulates, are nearly impossible for a single wolf to bring down alone. Instead, lone wolves will generally hunt smaller animals and scavenge carrion. Wikipedia entry Problems: getting funding & you won’t get the Nobel prize Problems: getting access to someone else’s raw data & most of the time you will be wrong Advantage of getting advice from many highly knowledgeableexperts Advantage of not getting advice from many experts “It’s better to be lucky than smart.”

  40. “Jumping from failure to failure with undying enthusiasm is the secret of success.” SavasDimopoulos, a particle physicist, quoted in the 2/25/14 NY Times in connection with the discovery of the Higgs Ehrlich corollary (courtesy of Kenny Rogers): “You've got to know when to hold them & Know when to fold them.”

  41. Special thanks to:Leonid Kuzmichev of Moscow State University, Head of the Tunka Collaboration & to Mikhail Zotov also of MSU for providing his analysis of the Tunka data. My web site http://mason.gmu.edu/~rehrlich has a link to a press release, a link to this presentation, and to the scientific paper on which it is based.

  42. Tardy- centrism mason.gmu.edu/~rehrlich

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