Speaker
Mauro Raggi
(CERN and Sapienza)
Description
Searches for the decays $K^{+}\rightarrow\pi^{+}X$ and $\pi^{+}\rightarrow e^{+}N$ are presented using data collected in 2016-2022 and 2017-2024, respectively. Results are interpreted to constrain a range of new physics scenarios covering all four portal model scenarios. Upper limits on the $K^{+}\rightarrow\pi^{+}X$ branching ratio are established at the $10^{-11}$ level, providing constraints on dark photon, scalar and ALP couplings. From the search for heavy neutral lepton production in $\pi^{+}\to e^+N$ decays of beam pions, upper limits of the extended neutrino mixing matrix element $|U_{e4}|^2$ are established at the $10^{-8}$ level over the heavy neutral lepton mass range 95--126~MeV/$c^2$.
Authors
Angela Romano
(University of Birmingham (GB))
Mauro Raggi
(CERN and Sapienza)
