| Preprint | |
| Report number | CERN-EP-2024-343 |
| Title | Observation of the $K^+ \to \pi^+ \nu \bar\nu$ decay and measurement of its branching ratio |
| Author(s) | Cortina Gil, E |
| Corporate author(s) | The NA62 collaboration |
| Publication | 2024 |
| Imprint | 13 Dec 2024 |
| Number of pages | 29 |
| Subject category | Particle Physics - Experiment |
| Accelerator/Facility, Experiment | CERN SPS ; NA62 |
| Keywords | electroweak interaction ; flavor physics ; branching fraction ; rare decay ; experimental results ; very rare kaon decay ; New Physics sensitivity |
| Abstract | A measurement of the $K^+ \to \pi^+ \nu \bar\nu$ decay by the NA62 experiment at the CERN SPS is presented, using data collected in 2021 and 2022. This dataset was recorded, after modifications to the beamline and detectors, at a higher instantaneous beam intensity with respect to the 2016–2018 data taking. Combining NA62 data collected in 2016–2022, a measurement of B($K^+ \to \pi^+ \nu \bar\nu$) = $(13.0^{+3.3}_{-3.0}) \times 10^{−11} $ is reported. With 51 signal candidates observed and an expected background of $18^{+3}_{−2}$ events, B($K^+ \to \pi^+ \nu \bar\nu$) becomes the smallest branching ratio measured with a signal significance above 5 $\sigma$. |
| Copyright/License | Preprint: © 2024 CERN (License: CC-BY-4.0) |
| Submitted by | brigitte.bloch-devaux@cern.ch |
记录创建於2024-10-28，最後更新在2024-12-17