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Title: Sterile neutrinos

Abstract

We characterize statistically the indications of a presence of one or more light sterile neutrinos from MiniBooNE and LSND data, together with the reactor and gallium anomalies, in the global context. The compatibility of the aforementioned signals with null results from solar, atmospheric, reactor, and accelerator experiments is evaluated. We conclude that a severe tension is present in the global fit, and therefore the addition of eV-scale sterile neutrinos does not satisfactorily explain the anomalies.

Authors:
 [1];  [2];  [3];  [4];  [5]
  1. PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics, Johannes Gutenberg University, 55099 Mainz (Germany)
  2. Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco E-28049 Madrid (Spain)
  3. (Spain)
  4. Instituto de Física Teórica UAM/CSIC, Calle Nicolás Cabrera 13-15, Cantoblanco E-28049 Madrid (Spain)
  5. Institute for Nuclear Physics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021 Karlsruhe (Germany)
Publication Date:
OSTI Identifier:
22609093
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1743; Journal Issue: 1; Conference: CETUP 2015: Workshop on dark matter, neutrino physics and astrophysics, Deadwood, SD (United States), 15 Jun - 17 Jul 2015, PPC 2015: 9. international conference on interconnections between particle physics and cosmology, Deadwood, SD (United States), 15 Jun - 17 Jul 2015; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COSMIC NEUTRINOS; DATA PROCESSING; NEUTRINOS; SOLAR NEUTRINOS; STERILE NEUTRINOS

Citation Formats

Kopp, J., Machado, P. A. N., E-mail: pedro.machado@uam.es, Instituto de Física Teórica UAM/CSIC, Calle Nicolás Cabrera 13-15, Cantoblanco E-28049 Madrid, Maltoni, M., and Schwetz, T.. Sterile neutrinos. United States: N. p., 2016. Web. doi:10.1063/1.4953310.
Kopp, J., Machado, P. A. N., E-mail: pedro.machado@uam.es, Instituto de Física Teórica UAM/CSIC, Calle Nicolás Cabrera 13-15, Cantoblanco E-28049 Madrid, Maltoni, M., & Schwetz, T.. Sterile neutrinos. United States. doi:10.1063/1.4953310.
Kopp, J., Machado, P. A. N., E-mail: pedro.machado@uam.es, Instituto de Física Teórica UAM/CSIC, Calle Nicolás Cabrera 13-15, Cantoblanco E-28049 Madrid, Maltoni, M., and Schwetz, T.. 2016. "Sterile neutrinos". United States. doi:10.1063/1.4953310.
@article{osti_22609093,
title = {Sterile neutrinos},
author = {Kopp, J. and Machado, P. A. N., E-mail: pedro.machado@uam.es and Instituto de Física Teórica UAM/CSIC, Calle Nicolás Cabrera 13-15, Cantoblanco E-28049 Madrid and Maltoni, M. and Schwetz, T.},
abstractNote = {We characterize statistically the indications of a presence of one or more light sterile neutrinos from MiniBooNE and LSND data, together with the reactor and gallium anomalies, in the global context. The compatibility of the aforementioned signals with null results from solar, atmospheric, reactor, and accelerator experiments is evaluated. We conclude that a severe tension is present in the global fit, and therefore the addition of eV-scale sterile neutrinos does not satisfactorily explain the anomalies.},
doi = {10.1063/1.4953310},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1743,
place = {United States},
year = 2016,
month = 6
}
  • Here, we report results of a search for oscillations involving a light sterile neutrino over distances of 1.04 and 735 km in a ν μ-dominated beam with a peak energy of 3 GeV. The data, from an exposure of 10.56 × 10 20 protons on target, are analyzed using a phenomenological model with one sterile neutrino. We constrain the mixing parameters θ 24 and Δm 41 2 and set limits on parameters of the four-dimensional Pontecorvo-Maki-Nakagawa-Sakata matrix, |U μ4| 2 and |U τ4| 2, under the assumption that mixing between νe and νs is negligible (|U e4| 2=0). No evidence for νmore » μ → ν s transitions is found and we set a world-leading limit on θ 24 for values of Δm 41 2 ≲ 1 eV 2.« less
  • Here, we report results of a search for oscillations involving a light sterile neutrino over distances of 1.04 and 735 km in a ν μ-dominated beam with a peak energy of 3 GeV. Furthermore, the data, from an exposure of 10.56 × 10 20 protons on target, are analyzed using a phenomenological model with one sterile neutrino. We constrain the mixing parameters θ 24 and Δ mmore » $$2\atop{41}$$ and set limits on parameters of the four-dimensional Pontecorvo-Maki-Nakagawa-Sakata matrix, |U μ4| 2 and |U τ 4| 2, under the assumption that mixing between ν e and ν s is negligible (|U e 4| 2 = 0). No evidence for ν μ → ν s transitions is found and we set a world-leading limit on θ 24 for values of Δm$$2\atop{41}$$ ≲ 1 eV 2.« less
  • We reexamine the big bang nucleosynthesis (BBN) bounds on the mixing of neutrinos with sterile species. These bounds depend on the assumption that the relic neutrino asymmetry {ital L}{sub {nu}} is very small. We show that for {ital L}{sub {nu}} large enough (greater than about 10{sup {endash}5}) the standard BBN bounds do not apply. We apply this result to the sterile neutrino solution to the atmospheric neutrino anomaly and show that for {ital L}{sub {nu}}{approx_gt}7{times}10{sup {minus}5} it is consistent with BBN. The BBN bounds on sterile neutrinos mixing with electron neutrinos can also be weakened considerably. {copyright} {ital 1995 Themore » American Physical Society.}« less
  • By combining data from cosmic microwave background (CMB) experiments (including the recent BOOMERANG-2K2 results), large scale structure (LSS) and Lyman-{alpha} forest observations, we constrain the hypothesis of a fourth, sterile, massive neutrino. For the 3 massless + 1 massive neutrino case we bound the mass of the sterile neutrino to m{sub s} < 0.55eV at 95% c.l.. These results exclude at high significance the sterile neutrino hypothesis as an explanation of the LSND anomaly. We then generalize the analysis to account for active neutrino masses (which tightens the limit to m{sub s} < 0.51eV) and the possibility that the sterilemore » abundance is not thermal. In the latter case, the constraints in the (mass, density) plane are non-trivial. For a mass of > 1eV or < 0.05eV the cosmological energy density in sterile neutrinos is always constrained to be {omega}{sub {nu}} < 0.005 at 95% c.l.. However, for a sterile neutrino mass of {approx} 0.25 eV, {omega}{sub {nu}} can be as large as 0.015.« less