In:
Nature Physics, Springer Science and Business Media LLC, Vol. 18, No. 2 ( 2022-02), p. 160-166
Abstract:
Since the discovery of neutrino oscillations, we know that neutrinos have non-zero mass. However, the absolute neutrino-mass scale remains unknown. Here we report the upper limits on effective electron anti-neutrino mass, m ν , from the second physics run of the Karlsruhe Tritium Neutrino experiment. In this experiment, m ν is probed via a high-precision measurement of the tritium β -decay spectrum close to its endpoint. This method is independent of any cosmological model and does not rely on assumptions whether the neutrino is a Dirac or Majorana particle. By increasing the source activity and reducing the background with respect to the first physics campaign, we reached a sensitivity on m ν of 0.7 eV c –2 at a 90% confidence level (CL). The best fit to the spectral data yields $${{\mbox{}}}{m}_{\nu }^{2}{{\mbox{}}}$$ m ν 2 = (0.26 ± 0.34) eV 2 c –4 , resulting in an upper limit of m ν 〈 0.9 eV c –2 at 90% CL. By combining this result with the first neutrino-mass campaign, we find an upper limit of m ν 〈 0.8 eV c –2 at 90% CL.
Type of Medium:
Online Resource
ISSN:
1745-2473
,
1745-2481
DOI:
10.1038/s41567-021-01463-1
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2022
detail.hit.zdb_id:
2206346-8
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