The hypothesis of superluminal neutrinos: Comparing OPERA with other data

Drago, A.; Masina, Isabella; Pagliara, Giuseppe; Tripiccione, R.

doi:10.1209/0295-5075/97/21002

Cited by 14 publications

(7 citation statements)

References 27 publications

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“…Direct observations of the neutrinos from supernova 1987A [37,38] allowed Stodolsky [39] and Longo [40] to set bounds on any excess speed of neutrinos over that of light at the $10 À8 level, a significant improvement over early results at accelerators [41]. In the context of OPERA experiments [41][42][43][44][45][46][47][48][49][50] several ideas of interest have been put forward, and we reference a few for completeness [20,29,33,41,[51][52][53][54][55][56][57][58][59][60][61][62][63][64].…”

Section: Introductionmentioning

confidence: 99%

Testing violations of Lorentz invariance with cosmic rays

Cowsik¹,

Madziwa-Nussinov²,

Nussinov

et al. 2012

Phys. Rev. D

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Cosmic rays are the highest energy particles available for our study, and as such serve as excellent probes of the effects of Lorentz invariance violations which are expected to increase with energy. This general paradigm is investigated in this paper by studying the effects of such violations within the Coleman-Glashow model in which each particle species may have its own maximum attainable velocity, even exceeding that of light in vacuo. The particular focus here is that the muon neutrino may have the maximum speed exceeding that of light. We show that such an assumption leads to the elongation of the decay lifetime of the pion which increases with energy over and above the time dilation effects. We provide a transparent analytical derivation of the spectral intensities of muon neutrinos and muons generated in the Earth's atmosphere by cosmic rays. In this derivation we not only account for elongation of the pion lifetime, but also for the loss of energy by the neutrinos by radiation of the electron-positron pairs through the Cohen-Glashow process during their propagation. We then compare the theoretical spectra with observations of neutrinos and muons from large instruments like IceCube and BUST to set a limit of $10 À13 on the fractional excess speed of neutrinos over that of light. We also show that the ratio of the spectral intensities of downward and upward moving neutrinos at various angles constitute an exclusive diagnostic for the Cohen-Glashow process, which may be searched for in the IceCube data set. We conclude the paper with several comments, including those related to improvements of these tests when definite signals of Griesen-Zatsepin-Kuzmin neutrinos will be observed.

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Section: Introductionmentioning

confidence: 99%

Testing violations of Lorentz invariance with cosmic rays

Cowsik¹,

Madziwa-Nussinov²,

Nussinov

et al. 2012

Phys. Rev. D

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“…As far as the interpretation of this result is concerned, see Refs. [3][4][5][6][7][8] for general comments, Refs. [9][10][11][12][13][14][15][16] for theoretical ideas indicating Lorentz invariance violation and Ref.…”

Section: Introductionmentioning

confidence: 99%

“…[36,37], or a flavor-or mass-eigenstate dependence, see Refs. [5,8,12,16,38,39] for related discussions. A particular mass-eigenstatedependent case is sterile neutrinos, such as taking a shortcut through an extra dimension [40][41][42][43][44], see also Ref.…”

Section: Introductionmentioning

confidence: 99%

Constraints on the interpretation of the superluminal motion of neutrinos at OPERA

Winter

2012

Phys. Rev. D

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Various approaches aim to describe the recent analysis by the OPERA experiment, which indicates that neutrinos travel faster than the speed of light. We demonstrate that any such theoretical or experimental explanation must not destroy the complicated (nonlinear) structure of the proton waveform recovered in the neutrino signal. As one example, consider that only a fraction of the neutrinos travels faster than the speed of light, such as sterile neutrinos. We fit the OPERA data including this fraction as a free variable, assuming that the OPERA result is correct. In our analysis, the best-fit values are 50% of the neutrinos being superluminal and ðv À cÞ=c ¼ 4:5 Á 10 À5 , where the neutrino velocity increases as the fraction of superluminal neutrinos decreases. The minimal fraction of superluminal neutrinos is found to be 17% (3), which is constrained by the nonlinearity of the proton waveform. This minimal fraction challenges the hypothesis that only sterile neutrinos travel faster than the speed of light. In addition, we demonstrate that an experimental effect introducing a smearing between the proton waveform and neutrino signal, as expected for some systematical errors, is also limited by the shape of the waveform. Finally, we illustrate that even stronger constraints may be obtained from the recent analysis with a short-bunch beam, in spite of the low statistics.

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“…If the OPERA results are confirmed, theorists will face a formidable challenge (see Refs. [8,18,[29][30][31][32][33][34] for some of the attempts to deal with this challenge.) These challenges include developing quantum field theories consistent with relative locality; efforts to do so are underway.…”

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confidence: 99%

Opera Neutrinos and Deformed Special Relativity

et al. 2012

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In a recent study, Cohen and Glashow argue that superluminal neutrinos of the type recently reported by OPERA should be affected by anomalous Cherenkov-like processes. This causes them to loose much of their energy before reaching the OPERA detectors. Related concerns were reported also by Gonzalez-Mestres, Bi et al, and Cowsik et al, who argued that pions cannot decay to superluminal neutrinos over part of the energy range studied by OPERA. We observe here that these arguments are set within a framework in which Lorentz symmetry is broken, by the presence of a preferred frame. We further show that these anomalous processes are forbidden if Lorentz symmetry is instead "deformed", preserving the relativity of inertial frames. These deformations add non-linear terms to energy momentum relations, conservation laws and Lorentz transformations in a way that is consistent with the relativity of inertial observers.The OPERA collaboration recently reported [1] evidence of superluminal behavior for µ neutrinos with energies of a few tens of GeVs: v − 1 ≃ 2.4 · 10 −5 , with a significance of six standard deviations (we use units such that the speed of light is c = 1). As usual in science, when a particularly striking experimental result is first reported, the most likely hypothesis is that some unknown bias or source of uncertainty affects these OPERA data. However, the result would be of such potential importance that it behoves us to at least investigate what is the second most likely hypothesis that is consistent with all the relevant data, including OPERA, and gives a reasonable path for physics to go ahead. In the event that the OPERA data is right, we must, by the development of such an hypothesis, come to understand special relativity as an approximation to deeper physics. This is of no small importance because a particular hypothesis that can explain all the relevant data can serve to predict other experiments. These predictions, if confirmed, would strengthen the case that there really are departures from special relativity.However, a recent letter by Cohen and Glashow [2] appears to indicate that there cannot be such a second hypothesis, since it claims that the OPERA results are self-contradictory. Cohen and Glashow argue that neutrinos in OPERA's CNGS beam, if superluminal as described in Ref.[1], would loose much of their energy via Cherenkov-like processes on their way from CERN to Gran Sasso. They then could not be detected with energy in excess of 12GeV , contrary to what is also reported [1] by OPERA. And a similar message is contained in studies by , by Bi et al [4], and by Cowsik et al [5], which argued that the reported superluminality of µ neutrinos would even prevent, over part of the energy range studied by OPERA, the pion-decay processes at CERN, which are partly responsible for the flux of neutrinos reaching Gran Sasso. If these arguments are correct, then it seems unavoidable that the OPERA results are mistaken.But, as we show here, there is a loophole 1 in the arguments reported in Refs. [2-5], ...

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The hypothesis of superluminal neutrinos: Comparing OPERA with other data

Cited by 14 publications

References 27 publications

Testing violations of Lorentz invariance with cosmic rays

Testing violations of Lorentz invariance with cosmic rays

Constraints on the interpretation of the superluminal motion of neutrinos at OPERA

Opera Neutrinos and Deformed Special Relativity

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