* Astronomy

Blobrana · L

RE: OPERA neutrino experiment

Blobrana · L

Title: A simple explanation of OPERA results without strange physics
Authors: Gilles Henri

We 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.

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Blobrana · L

Title: Constraints and tests of the superluminal neutrinos at OPERA
Authors: Xiao-Jun Bi, Peng-Fei Yin, Zhao-Huan Yu, Qiang Yuan

The 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.

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Blobrana · L

Title: Astrophysical consequences of the OPERA superluminal neutrino
Authors: Luis Gonzalez-Mestres

A 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.

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Blobrana · L

Title: The OPERA neutrino velocity result and the synchronisation of clocks
Authors: Carlo R. Contaldi

The 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.

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Blobrana · L

OPERA experiment

Blobrana · L

OPERA neutrino experiment

Blobrana · L

Title: Measurement of the neutrino velocity with the OPERA detector in the CNGS beam
Authors: OPERA

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 ±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.

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