Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN
© 2019 authors. Published by the American Physical Society. 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 a...
| Format: | Article |
|---|---|
| Language: | English |
| Published: |
American Physical Society (APS)
2021
|
| Online Access: | https://hdl.handle.net/1721.1/136554 |
| Summary: | © 2019 authors. Published by the American Physical Society. 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) eV2. 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. |
|---|