Abstract
The NA62 experiment reports an investigation of the K+→ π+νν¯ mode from a sample of K+ decays collected in 2017 at the CERN SPS. The experiment has achieved a single event sensitivity of (0.389 ± 0.024) × 10−10, corresponding to 2.2 events assuming the Standard Model branching ratio of (8.4 ± 1.0) × 10−11. Two signal candidates are observed with an expected background of 1.5 events. Combined with the result of a similar analysis conducted by NA62 on a smaller data set recorded in 2016, the collaboration now reports an upper limit of 1.78 × 10−10 for the K+→ π+νν¯ branching ratio at 90% CL. This, together with the corresponding 68% CL measurement of (0.48−0.48+0.72) × 10−10, are currently the most precise results worldwide, and are able to constrain some New Physics models that predict large enhancements still allowed by previous measurements.
Original language | English |
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Article number | 42 |
Journal | Journal of High Energy Physics |
Volume | 2020 |
Issue number | 11 |
DOIs | |
Publication status | Published - Nov 2020 |
Bibliographical note
Publisher Copyright:© 2020, The Author(s).
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
Keywords
- Fixed target experiments
- Flavor physics
- Flavour Changing Neutral Currents
- Rare decay
ASJC Scopus subject areas
- Nuclear and High Energy Physics