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Date:
 RE: OPERA neutrino experiment Permalink Title: Neutrino speed anomaly as a signal of Lorentz violationAuthors: Zhou Lingli, Bo-Qiang Ma(Version v2)The OPERA experiment just reported that the muon neutrino speed is larger than the vacuum light speed, and such result puts up a challenge to Einstein's theory of relativity and the basic principle of Lorentz invariance. We exam the possibility to attribute Lorentz violation as a source for the neutrino speed anomaly, and relate the OPERA result with Lorentz violation parameters in a new framework of standard model supplement (SMS), in which the Lorentz violation terms are brought about by a new basic principle of physical independence or physical invariance, stating that the equations describing the laws of physics have the same form in all admissible mathematical manifolds.Read more  (8kb, PDF) __________________

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Posts: 131433
Date:
 Permalink Title: A simple explanation of OPERA results without strange physicsAuthors: Gilles HenriWe show that OPERA recent results showing an apparent superluminal velocity of muonic neutrinos can find a very simple explanation without any measurement error or any strange physics. Namely, it is enough that the beam composition varies during the leading and the trailing edges to explain an apparent time shift in the detected neutrinos. The order of magnitude of the shift will be the relative variation of the average cross-section times the rising/decaying time, and even a modest change in the composition of the beam could produce the observed effect.Read more  (76kb, PDF) __________________

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Posts: 131433
Date:
 Permalink Title: Constraints and tests of the superluminal neutrinos at OPERAAuthors: Xiao-Jun Bi, Peng-Fei Yin, Zhao-Huan Yu, Qiang YuanThe superluminal neutrinos detected by OPERA may indicate Lorentz invariance violation (LIV) of the neutrino sector at order 10^{-5}. In this paper we study a few phenomenologies related to neutrinos with LIV. We find that the neutrino generation processes of \pi \to \mu + \nu_\mu and \mu \to e + \nu_\mu +\bar{\nu_e} may become kinematically forbidden for neutrino energies higher than ~ 10 GeV for LIV parameter \xi ~10^{-5}. The observation of atmospheric muons in cosmic rays at a few TeV gives much stronger constraints on the superluminal neutrino LIV parameter. Furthermore the neutrinos with LIV may lose energy by radiative emission or three body decay quickly. By taking a smaller LIV parameter we study how the LIV changes the spectra of astrophysical neutrinos. Observations of the astrophysical neutrino spectra can be a way to test the superluminal neutrino scenario.Read more  (39kb, PDF) __________________

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Posts: 131433
Date:
 Permalink Title: Astrophysical consequences of the OPERA superluminal neutrinoAuthors: Luis Gonzalez-MestresA simple discussion of the recent OPERA result on the apparent critical speed of the muon neutrino is presented. We point out in particular some of the possible consistency problems of such an interpretation of the OPERA data with respect to well-established astrophysical observations.Read more  (4kb, PDF) __________________

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Posts: 131433
Date:
 Permalink Title: The OPERA neutrino velocity result and the synchronisation of clocksAuthors: Carlo R. ContaldiThe CERN-OPERA experiment claims to have measured a one-way speed of neutrinos that is apparently faster than the speed of light c. One-way speed measurements such as these inevitably require a convention for the synchronisation of clocks in non-inertial frames since the Earth is rotating. We argue that the effect of the synchronisation convention is not properly taken into account in the analysis of and may well invalidate their interpretation of superluminal neutrino velocity.Read more  (6kb, PDF) __________________

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Posts: 131433
Date:
 OPERA experiment Permalink The OPERA experiment has been designed to perform the most straightforward test of the phenomenon of neutrino oscillations. This experiment exploits the CNGS high-intensity and high-energy beam of muon neutrinos produced at the CERN SPS in Geneva pointing towards the LNGS underground laboratory at Gran Sasso, 730 km away in central Italy. OPERA is located in the Hall C of LNGS and it is aimed at detecting for the first time the appearance of tau-neutrinos from the transmutation (oscillation) of muon-neutrinos during their 3 millisecond travel from Geneva to Gran Sasso. In OPERA, tau-leptons resulting from the interaction of tau-neutrinos will be observed in "bricks" of photographic emulsion films interleaved with lead plates. The apparatus contains about 150000 of such bricks for a total mass of 1300 tons and is complemented by electronic detectors (trackers and spectrometers) and ancillary infrastructure. Its construction has been completed in spring 2008 and the experiment is currently in data taking. Read more  __________________

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Posts: 131433
Date:
 OPERA neutrino experiment Permalink Brian Cox on Cern's baffling light-speed findPuzzling results from Cern, home of the Large Hadron Collider, have confounded physicists - because it seems subatomic particles have beaten the speed of light.Neutrinos sent through the ground from Cern toward the Gran Sasso laboratory 732km away in Italy seemed to show up a tiny fraction of a second early.Physicist Brian Cox talks to Shaun Keaveny on BBC 6 Music about this baffling find - he says that if it is right, it could require a complete rewriting of our understanding of the laws of the Universe.See more Ed ~ There is the straightforward possibility that the distance measured is wrong... __________________

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Posts: 131433
Date:
 Permalink Title: Measurement of the neutrino velocity with the OPERA detector in the CNGS beamAuthors: OPERAThe 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 ±6.9 (stat.) ±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 ±0.28 (stat.) ± 0.30 (sys.)) x  10^-5. Read more  (4763kb, PDF) __________________
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