Improved upper limit on the neutrino mass from a direct kinematic method by KATRIN

M Aker, K Altenmüller, M Arenz, M Babutzka, J Barrett… - Physical review …, 2019 - APS
M Aker, K Altenmüller, M Arenz, M Babutzka, J Barrett, S Bauer, M Beck, A Beglarian…
Physical review letters, 2019APS
We report on the neutrino mass measurement result from the first four-week science run of
the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons
from a high-purity gaseous molecular tritium source are energy analyzed by a high-
resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval
around the kinematic end point at 18.57 keV gives an effective neutrino mass square value
of (-1.0-1.1+ 0.9) eV 2. From this, we derive an upper limit of 1.1 eV (90% confidence level) …
We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.57 keV gives an effective neutrino mass square value of . From this, we derive an upper limit of 1.1 eV (90% confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a factor of 2 and provides model-independent input to cosmological studies of structure formation.
American Physical Society