Jun 5 – 9, 2023
Genova, Italy
Europe/Rome timezone

Physics Beyond the Standard Model with NA62

Not scheduled
DAD - Room 0B (Genova, Italy)

DAD - Room 0B

Genova, Italy

Contributed Hadrons and physics beyond the standard model Hadrons and physics beyond the standard model




The NA62 experiment at CERN took data in 2016–2018 with the main goal of measuring the $K^+ \rightarrow \pi^+ \nu \bar\nu$ decay. The NA62 dataset is also exploited to search for light feebly interacting particles produced in kaon decays. Searches for $K^+\rightarrow e^+ N$, $K^+ \rightarrow \mu^+ N$ and $K^+ \rightarrow \mu^+ \nu X$ decays, where N and X are massive invisible particles, are performed by NA62. The N particle is assumed to be a heavy neutral lepton, and the results are expressed as upper limits of $O(10^{-8})$ of the neutrino mixing parameter $|U_{\mu 4}|^2$. The X particle is considered a scalar or vector hidden sector mediator decaying to an invisible final state. Upper limits of the decay branching fraction for X masses in the range 10–370 MeV/c$^2$ are reported. An improved upper limit of $1.0 \times 10^{-6}$ is established at 90$\%$ CL on the $K^+ \rightarrow \mu^+ \nu \nu \nu$ branching fraction.
Dedicated trigger lines were employed to collect di-lepton final states, which allowed establishing stringent upper limits on the rates of lepton flavor and lepton number violating kaon decays. Upper limits on the rates of several $K^+$ decays violating lepton flavour and number conservation, obtained by analysing this dataset, are presented.
The NA62 experiment can 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 recent results from the search for visible decays of exotic mediators from data taken in "beam-dump" mode, with a particular emphasis on Dark Photon and Axion-like particle Models.

Primary authors

Angela Romano (University of Birmingham) OTHER SPEAKER

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