New Constraint on the Local Relic Neutrino Background Overdensity with the First KATRIN Data Runs

0559940 - ÚJF 2023 RIV US eng J - Journal Article
Aker, M. - Batzler, D. - Beglarian, A. - Behrens, J. - Dragoun, Otokar - Kovalík, Alojz - Lebeda, Ondřej - Ráliš, Jan - Ryšavý, Miloš - Šefčík, Michal - Vénos, Drahoslav … Total 131 authors
New Constraint on the Local Relic Neutrino Background Overdensity with the First KATRIN Data Runs.
Physical Review Letters. Roč. 129, č. 1 (2022), č. článku 011806. ISSN 0031-9007. E-ISSN 1079-7114
R&D Projects: GA MŠMT LTT19005
Research Infrastructure: CANAM II - 90056
Institutional support: RVO:61389005
Keywords : KATRIN experiment * neutrino
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 8.6, year: 2022
Method of publishing: Open access
https://doi.org/10.1103/PhysRevLett.129.011806

We report on the direct search for cosmic relic neutrinos using data acquired during the first two science campaigns of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity molecular tritium gas source are analyzed by a high-resolution MAC-E filter around the end point at 18.57 keV. The analysis is sensitive to a local relic neutrino overdensity ratio of eta < 9.7 x 10(10)/alpha (1.1 x 10(11)/alpha) at a 90% (95%) confidence level with alpha = 1 (0.5) for Majorana (Dirac) neutrinos. A fit of the integrated electron spectrum over a narrow interval around the end point accounting for relic neutrino captures in the tritium source reveals no significant overdensity. This work improves the results obtained by the previous neutrino mass experiments at Los Alamos and Troitsk. We furthermore update the projected final sensitivity of the KATRIN experiment to eta < 1 x 10(10)/alpha at 90% confidence level, by relying on updated operational conditions.
Permanent Link: https://hdl.handle.net/11104/0333060