학술논문
Direct neutrino-mass measurement with sub-electronvolt sensitivity
Document Type
article
Author
Aker, M; Beglarian, A; Behrens, J; Berlev, A; Besserer, U; Bieringer, B; Block, F; Bobien, S; Boettcher, M; Bornschein, B; Bornschein, L; Brunst, T; Caldwell, TS; Carney, RMD; La Cascio, L; Chilingaryan, S; Choi, W; Debowski, K; Deffert, M; Descher, M; Barrero, D Diaz; Doe, PJ; Dragoun, O; Drexlin, G; Eitel, K; Ellinger, E; Engel, R; Enomoto, S; Felden, A; Formaggio, JA; Fraenkle, FM; Franklin, GB; Friedel, F; Fulst, A; Gauda, K; Gil, W; Glueck, F; Groessle, R; Gumbsheimer, R; Gupta, V; Hoehn, T; Hannen, V; Haussmann, N; Helbing, K; Hickford, S; Hiller, R; Hillesheimer, D; Hinz, D; Houdy, T; Huber, A; Jansen, A; Karl, C; Kellerer, F; Kellerer, J; Kleifges, M; Klein, M; Koehler, C; Koellenberger, L; Kopmann, A; Korzeczek, M; Kovalik, A; Krasch, B; Krause, H; Kunka, N; Lasserre, T; Le, TL; Lebeda, O; Lehnert, B; Lokhov, A; Machatschek, M; Malcherek, E; Mark, M; Marsteller, A; Martin, EL; Melzer, C; Menshikov, A; Mertens, S; Mostafa, J; Mueller, K; Neumann, H; Niemes, S; Oelpmann, P; Parno, DS; Poon, AWP; Poyato, JML; Priester, F; Ramachandran, S; Robertson, RGH; Rodejohann, W; Roellig, M; Roettele, C; Rodenbeck, C; Rysavy, M; Sack, R; Saenz, A; Schaefer, P; Pollithy, A Schaller Nee; Schimpf, L; Schloesser, K; Schloesser, M
Source
Nature Physics. 18(2)
Subject
Language
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, mν, from the second physics run of the Karlsruhe Tritium Neutrino experiment. In this experiment, mν 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 mν of 0.7 eV c–2 at a 90% confidence level (CL). The best fit to the spectral data yields mν2 = (0.26 ± 0.34) eV2 c–4, resulting in an upper limit of mν < 0.9 eV c–2 at 90% CL. By combining this result with the first neutrino-mass campaign, we find an upper limit of mν < 0.8 eV c–2 at 90% CL.