PoS - Proceedings of Science
Volume 462 - 16th International Conference on Heavy Quarks and Leptons (HQL2023) - Kaon Physics
Precision Measurements and Prospects with Kaons at CERN
Z. Hives*  on behalf of the NA62 Collaboration
Full text: pdf
Pre-published on: March 28, 2024
Published on:
The NA62 experiment at the CERN SPS collected the world’s largest dataset of charged kaon decays during 2016-2018.
The dataset was used for the most precise measurement of the branching fraction of the ultra-rare decay $K^+ \rightarrow \pi^+\nu\bar{\nu}$.
In this proceedings, the NA62 experiment reports recent results from analyses of decays $K^+ \rightarrow \pi^0e^+\nu\gamma$ $(K_{e3\gamma})$, $K^+ \rightarrow \pi^+\mu^+\mu^-$ $(K_{\pi\mu\mu})$ and $K^+ \rightarrow \pi^+\gamma\gamma$ $(K_{\pi\gamma\gamma})$.
The radiative $K_{e3\gamma}$ decay has a data sample of $\mathcal{O}(100k)$ candidates with sub-percent background contamination.
Published results with the most precise measurement of the branching fraction and T-asymmetry are presented.
The $K_{\pi\mu\mu}$ sample comprises about 27k signal events with negligible background contamination, and the results include the most precise determination of the branching ratio and the form factor.
The $K_{\pi\gamma\gamma}$ sample contains about 4k signal events with \qty{10}{\percent} background contamination, and the analysis improves the precision of the branching ratio measurement by a factor of 3 with respect to the previous measurements.

Recent results from the NA48/2 experiment from the analysis of the decay $K^{\pm} \rightarrow \pi^0\pi^0\mu^{\pm}\nu$ $(K_{\mu4}^{00})$ are also reported in this proceedings.
The sample consists of 2437 events with \qty{15}{\percent} background contamination.
The result is compared with a newly calculated theoretical prediction to 1-loop level, including previously neglected $R_1$ form factor.

The NA62 experiment is approved to take data until the CERN Long Shutdown 3.
A proposal for next-generation kaon experiments at CERN, called HIKE, was submitted to the SPSC in November 2023 and is also presented in this proceedings.
In its first phase, HIKE will continue to study decays of charged kaons at significantly higher beam intensities than NA62 using a new detector system.
Neutral kaon decays will be then studied in the second phase of HIKE.
DOI: https://doi.org/10.22323/1.462.0003
How to cite

Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.

Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.