31st International Symposium on Lepton Photon Interactions at High Energies

Latest results and precision measurements from the NA62 experiment

18 Jul 2023, 13:30

15m

Monash University

Talk Flavour physics Flavour

Speaker

Francesco Brizioli (CERN)

Description

The NA62 experiment at CERN collected the world’s largest dataset of charged kaon decays in 2016-2018, leading to the first measurement of the branching ratio of the ultra-rare $K^{+}\to {\pi }^{+}\nu \overline{\nu }$ decay, based on 20 candidates, and presented in 2021.
In this talk the NA62 experiment reports new results from analyses of $K^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$ and $K^{+}\to {\pi }^{+}\gamma \gamma$ decays, using a data sample recorded in 2017--2018. The $K^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$ sample comprises about 27k signal events with negligible background contamination, and the presented analysis results include the most precise determination of the branching ratio and the form factor. The $K^{+}\to {\pi }^{+}\gamma \gamma$ sample contains about 4k signal events with $10\mathrm{\%}$ background contamination, and the analysis improves the precision of the branching ratio measurement by a factor of 3 with respect to the previous measurements.
The NA62 experiment can also be run as a "beam-dump experiment" by removing the Kaon production target and moving the upstream collimators into a "closed" position. More than ${10}^{17}$ protons on target have been collected in this way during a week-long data-taking campaign by the NA62 experiment. We report on new results from analysis of this data, with a particular emphasis on Dark Photon and Axion-like particle Models.

Presentation materials

LP2023Melbourne_NA62_Brizioli.pdf