skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: How unequal fluxes of high energy astrophysical neutrinos and antineutrinos can fake new physics

Abstract

Flavor ratios of very high energy astrophysical neutrinos, which can be studied at the Earth by a neutrino telescope such as IceCube, can serve to diagnose their production mechanism at the astrophysical source. The flavor ratios for neutrinos and antineutrinos can be quite different as we do not know how they are produced in the astrophysical environment. Due to this uncertainty the neutrino and antineutrino flavor ratios at the Earth also could be quite different. Nonetheless, it is generally assumed that flavor ratios for neutrinos and antineutrinos are the same at the Earth, in fitting the high energy astrophysical neutrino data. This is a reasonable assumption for the limited statistics for the data we currently have. However, in the future the fit must be performed allowing for a possible discrepancy in these two fractions in order to be able to disentangle different production mechanisms at the source from new physics in the neutrino sector. To reinforce this issue, in this work we show that a wrong assumption about the distribution of neutrino flavor ratios at the Earth may indeed lead to misleading interpretations of IceCube results.

Authors:
 [1]; ;  [2]
  1. Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, C.P. 38071, 22452-970, Rio de Janeiro (Brazil)
  2. Instituto de Física, Universidade de São Paulo, C.P. 66.318, 05315-970 São Paulo (Brazil)
Publication Date:
Sponsoring Org.:
SCOAP3, CERN, Geneva (Switzerland)
OSTI Identifier:
22572169
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2016; Journal Issue: 10; Other Information: PUBLISHER-ID: JCAP10(2016)036; OAI: oai:repo.scoap3.org:17595; cc-by Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANTINEUTRINOS; ASTROPHYSICS; COSMIC NEUTRINOS; FLAVOR MODEL; NEUTRINO DETECTION; PARTICLE PRODUCTION; TELESCOPE COUNTERS; ICECUBE NEUTRINO DETECTOR; NEUTRINO DETECTORS

Citation Formats

Nunokawa, Hiroshi, Panes, Boris, and Funchal, Renata Zukanovich. How unequal fluxes of high energy astrophysical neutrinos and antineutrinos can fake new physics. United States: N. p., 2016. Web. doi:10.1088/1475-7516/2016/10/036.
Nunokawa, Hiroshi, Panes, Boris, & Funchal, Renata Zukanovich. How unequal fluxes of high energy astrophysical neutrinos and antineutrinos can fake new physics. United States. doi:10.1088/1475-7516/2016/10/036.
Nunokawa, Hiroshi, Panes, Boris, and Funchal, Renata Zukanovich. 2016. "How unequal fluxes of high energy astrophysical neutrinos and antineutrinos can fake new physics". United States. doi:10.1088/1475-7516/2016/10/036.
@article{osti_22572169,
title = {How unequal fluxes of high energy astrophysical neutrinos and antineutrinos can fake new physics},
author = {Nunokawa, Hiroshi and Panes, Boris and Funchal, Renata Zukanovich},
abstractNote = {Flavor ratios of very high energy astrophysical neutrinos, which can be studied at the Earth by a neutrino telescope such as IceCube, can serve to diagnose their production mechanism at the astrophysical source. The flavor ratios for neutrinos and antineutrinos can be quite different as we do not know how they are produced in the astrophysical environment. Due to this uncertainty the neutrino and antineutrino flavor ratios at the Earth also could be quite different. Nonetheless, it is generally assumed that flavor ratios for neutrinos and antineutrinos are the same at the Earth, in fitting the high energy astrophysical neutrino data. This is a reasonable assumption for the limited statistics for the data we currently have. However, in the future the fit must be performed allowing for a possible discrepancy in these two fractions in order to be able to disentangle different production mechanisms at the source from new physics in the neutrino sector. To reinforce this issue, in this work we show that a wrong assumption about the distribution of neutrino flavor ratios at the Earth may indeed lead to misleading interpretations of IceCube results.},
doi = {10.1088/1475-7516/2016/10/036},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 10,
volume = 2016,
place = {United States},
year = 2016,
month =
}
  • Measurements of the ..nu.. and nu-bar weak hadronic neutral-current total cross sections and hadron energy distributions are consistent with a V - A form for this current. They are three standard deviations from pure V, pure A, or a pure T form and unambiguously exclude V + A and any linear combination of S and P.
  • We present results on flux-normalized neutrino and antineutrino cross sections near y = 0 from data obtained in the Fermilab narrow-band beam. We conclude that they are consistent with rising linearly with energy over the range 45 < or = E/sub ..nu../GeV. The separate averages of ..nu.. and nu-bar each measured to 4%, are equal to well within the errors. The best fit for the combined data gives sigma/sub 0//E = (0.719 +- 0.035) x 10/sup -38/ cm/sup 2//GeV at an average E/sub ..nu../of 100 GeV.
  • We present data on dimuon-production rates from neutrinos and antineutrinos in the energy range 45-205 GeV. The measurements were made using the Fermilab narrow-band beam. At higher energies (> or approx. = 100 GeV), the dimuon-production rates relative to single-muon production for events within our kinematic cuts are about 1%. The numbers are consistent with calculations of Glawshow-Iliopoulos-Maiani (four-quark) models and do not require the introduction of additional quarks.
  • High-energy neutrinos are expected to be produced in a variety of astrophysical sources as well as in optically thick hidden sources. We explore the matter-induced oscillation effects on emitted neutrino fluxes of three different flavors from the latter class. We use the ratio of electron and tau induced showers to muon tracks, in upcoming neutrino telescopes, as the principal observable in our analysis. This ratio depends on the neutrino energy, density profile of the sources, and on the oscillation parameters. The largely unknown flux normalization drops out of our calculation and only affects the statistics. For the current knowledge ofmore » the oscillation parameters we find that the matter-induced effects are non-negligible and the enhancement of the ratio from its vacuum value takes place in an energy range where the neutrino telescopes are the most sensitive. Quantifying the effect would be useful to learn about the astrophysics of the sources as well as the oscillation parameters. If the neutrino telescopes mostly detect diffuse neutrinos without identifying their sources, then any deviation of the measured flux ratios from the vacuum expectation values would be most naturally explained by a large population of hidden sources for which matter-induced neutrino oscillation effects are important.« less