An investigation of the very rare Kpinn decay
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Colleges, School and Institutes
The NA62 experiment reports an investigation of the Kpinn 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 Kpinn branching ratio at 90% CL. This, together with the corresponding 68% CL measurement, 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.
|Publication status||Published - 10 Nov 2020|