Testing Lorentz Invariance with Neutrinos

Physical Review D, 1997

We point out that the assumption of Lorentz noninvariance examined recently by Coleman and Glashow leads to neutrino flavor oscillations which are phenomenologically equivalent to those obtained by assuming the neutrinos violate the principle of equivalence. We then comment on the limits on Lorentz noninvariance which can be derived from solar, atmospheric, and accelerator neutrino experiments.

Physical Review D, 2018

Experimental tests of Lorentz symmetry in systems of all types are critical for ensuring that the basic assumptions of physics are well founded. Data from all phases of the Sudbury Neutrino Observatory, a kiloton-scale heavy water Cherenkov detector, are analyzed for possible violations of Lorentz symmetry in the neutrino sector. Such violations would appear as one of eight possible signal types in the detector: six seasonal variations in the solar electron neutrino survival probability differing in energy and time dependence and two shape changes to the oscillated solar neutrino energy spectrum. No evidence for such signals is observed, and limits on the size of such effects are established in the framework of the standard model extension, including 38 limits on previously unconstrained operators and improved limits on 16 additional operators. This makes limits on all minimal, Dirac-type Lorentz violating operators in the neutrino sector available for the first time.

Physical Review D, 2014

The recent observation of high-energy astrophysical neutrinos can be used to constrain violations of Lorentz invariance emerging from a quantum theory of gravity. We perform threshold anď Cerenkov analyses that improve existing bounds by factors ranging from about a million to 10 20 .

Physical Review D, 2015

A search for neutrino oscillations induced by Lorentz violation has been performed using 4,438 live-days of Super-Kamiokande atmospheric neutrino data. The Lorentz violation is included in

Physical Review D, 2000

Working in the context of a Lorentz-violating extension of the standard model we show that estimates of Lorentz symmetry violation extracted from ultra-high energy cosmic rays beyond the Greisen-Kuzmin-Zatsepin (GZK) cutoff allow for setting bounds on parameters of that extension. Furthermore, we argue that a correlated measurement of the difference in the arrival time of gamma-ray photons and neutrinos emitted from active galactic nuclei or gamma-ray bursts may provide a signature of possible violation of Lorentz symmetry. We have found that this time delay is energy independent, however it has a dependence on the chirality of the particles involved. We also briefly discuss the known settings where the mechanism for spontaneous violation of Lorentz symmetry in the context of string/M-theory may take place.

We discuss the issue of Lorentz invariance for neutrino oscillations by resorting to the properties of flavor charges and currents. It turns out that oscillation formulas are sensitive to the effects of a boost on the source (detector), resulting in a possibly measurable effect.

Nature Physics

Lorentz symmetry is a fundamental space-time symmetry underlying both the Standard Model of particle physics and general relativity. This symmetry guarantees that physical phenomena are observed to be the same by all inertial observers. However, unified theories, such as string theory, allow for violation of this symmetry by inducing new space-time structure at the quantum gravity scale. Thus, the discovery of Lorentz symmetry violation could be the first hint of these theories in Nature. Here we report the results of the most precise test of space-time symmetry in the neutrino sector to date. We use high-energy atmospheric neutrinos observed at the IceCube Neutrino Observatory to search for anomalous neutrino oscillations as signals of Lorentz violation. We find no evidence for such phenomena. This allows us to constrain the size of the dimension-four

2014

The time dilation predicted by Special Relativity Theory is completely determined by the Lorentz Factor. The Invariance Principle, expressed in γ, puts two categorical constraints on the velocity β: 1. β< 1, and 2. γ(β) = γ(-β). The findings of recent neutrino velocity experiments, which tested the first constraint, reveal that the velocity of neutrinos is not statistically different from the velocity of light. Surprisingly, in all these experiments, the second constraint, γ(β) = γ(-β), which constitutes the essence of the Lorentz Invariance, was not tested. Here I explain why the design of the neutrino velocity experiments qualifies them as "severe" tests of the Lorentz invariance. I further show that Special Relativity fails colossally in predicting all the reported (v-c)/c values. I also show that for all the discussed experiments, abandoning the Lorentz Invariance yields accurate predictions.

Astroparticle Physics, 2011

We have previously shown that a very small amount of Lorentz invariance violation (LIV), which suppresses photomeson interactions of ultrahigh energy cosmic rays (UHECRs) with cosmic background radiation (CBR) photons, can produce a spectrum of cosmic rays that is consistent with that currently observed by the Pierre Auger Observatory (PAO) and HiRes experiments. Here, we calculate the corresponding flux of high energy neutrinos generated by the propagation of UHECR protons through the CBR in the presence of LIV. We find that LIV produces a reduction in the flux of the highest energy neutrinos and a reduction in the energy of the peak of the neutrino energy flux spectrum, both depending on the strength of the LIV. Thus, observations of the UHE neutrino spectrum provide a clear test for the existence and amount of LIV at the highest energies. We further discuss the ability of current and future proposed detectors make such observations.

CPT and Lorentz Symmetry, 2014

High-energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance, such as may be related to the structure of spacetime near the Planck scale. I will discuss the possible signatures of Lorentz invariance violation that can be manifested by observing the spectra, polarization, and timing of γ-rays from active galactic nuclei and γ-ray bursts. Other sensitive tests are provided by observations of the spectra of ultrahighenergy cosmic rays and very high-energy neutrinos. I will also discuss a new time-of-flight analysis of observations of GRB 090510 by the Fermi γ-ray Space Telescope. These results, based on high-energy astrophysical observations, have fundamental implications for spacetime physics and quantum gravity models.