Cornering (quasi) degenerate neutrinos with cosmology
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Received: July 23, 2020 Accepted: September 18, 2020 Published: October 30, 2020
Cornering (quasi) degenerate neutrinos with cosmology
a
Istituto Nazionale di Fisica Nucleare, sezione di Ferrara, Polo Scientifico e Tecnologico, Edificio C, Via Saragat, 1, Ferrara I-44122, Italy b High Energy Division, Argonne National Laboratory, 9700 S. Cass Avenue, Building 362, Lemont, IL 60439, U.S.A. c Physics Department, University of Texas, 2515 Speedway, C1600, Austin, TX 78712, U.S.A. d The Oskar Klein Centre for Cosmoparticle Physics, Department of Physics, Stockholm University, Roslagstullsbacken 21, Stockholm SE-106 91, Sweden e The Nordic Institute for Theoretical Physics (NORDITA), Roslagstullsbacken 23, Stockholm SE-106 91, Sweden f Leinweber Center for Theoretical Physics, Department of Physics, University of Michigan, 3444 Randall Lab, 450 Church Street, Ann Arbor, MI 48109, U.S.A. g AHEP Group, Institut de F´ısica Corpuscular (CSIC-Universitat de Val`encia), Parc Cient´ıfic de Paterna, C/ Catedr´ atico Jos´e Beltr´ an, 2, Paterna E-46980, Valencia, Spain
E-mail: [email protected], [email protected], [email protected], [email protected], [email protected] Abstract: In light of the improved sensitivities of cosmological observations, we examine the status of quasi-degenerate neutrino mass scenarios. Within the simplest extension of the standard cosmological model with massive neutrinos, we find that quasi-degenerate neutrinos are severely constrained by present cosmological data and neutrino oscillation experiments. We find that Planck 2018 observations of cosmic microwave background (CMB) anisotropies disfavour quasi-degenerate neutrino masses at 2.4 Gaussian σ’s, while adding baryon acoustic oscillations (BAO) data brings the rejection to 5.9σ’s. The highest statistical significance with which one would be able to rule out quasi-degeneracy would P arise if the sum of neutrino masses is mν = 60 meV (the minimum allowed by neutrino oscillation experiments); indeed a sensitivity of 15 meV, as expected from a combination of future cosmological probes, would further improve the rejection level up to 17σ. We discuss the robustness of these projections with respect to assumptions on the underlying cosmological model, and also compare them with bounds from β decay endpoint and neutrinoless double beta decay studies. Keywords: Cosmology of Theories beyond the SM, Neutrino Physics ArXiv ePrint: 2007.01650
c The Authors. Open Access, Article funded by SCOAP3 .
https://doi.org/10.1007/JHEP10(2020)213
JHEP10(2020)213
Massimiliano Lattanzi,a Martina Gerbino,a,b Katherine Freese,c,d,e Gordon Kanef and Jos´ e W.F. Valleg
Contents 1
2 Preliminaries
2
3 Theory setup 3.1 Simplest mass matrix 3.2 The full mass matrix
4 4 5
4 Cosmological data
7
5 Results of cosmological analysis 5.1 Results in the simplest mass matrix model 5.2 Cosmological bounds on neutrino mass in the full mass matrix approach 5.3 Neutrinoless double beta decay
9 10 10 13
6 Conclusions and discussion
15
A Statistical analy
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