D. Kalashnikov | Searcharxiv

arXiv2026

Sgoldstino Phenomenology at SND@HL-LHC

We study the phenomenology of light scalar sgoldstinos, with masses from the dimuon threshold up to a few GeV, focusing on their production and detection prospects at the SND@HL-LHC experiment. We review the effective sgoldstino interactions with Standard Model particles, the dominant meson-decay production channels, and the relevant experimental constraints on the model parameter space. We also outline the recently proposed SND@HL-LHC detector configuration and discuss the kinematics and track separation of the muon pair produced in sgoldstino decays inside the detector volume. For two representative sets of supersymmetry-breaking parameters, we present sensitivity estimates and show that the muon-antimuon separation efficiency should be taken into account in searches for the dimuon signal.

hep-ph↗

arXiv2020

Search for the rare decays $\pi^+ \to \mu^+\nu_\mu\nu\bar\nu$ and $\pi^+ \to e^+\nu_e\nu\bar\nu$

The rare pion decays ${\pi}^+{\rightarrow}{\mu}^+{\nu}_{\mu}{\nu}\bar{\nu}$ and ${\pi}^+{\rightarrow}e^+{\nu}_{e}{\nu}\bar{\nu}$ are allowed in the Standard Model but highly suppressed. These decays were searched for using data from the PIENU experiment. A first result for ${\Gamma}({\pi}^+{\rightarrow}{\mu}^+{\nu}_{\mu}{\nu}\bar{\nu})/{\Gamma}({\pi}^+{\rightarrow}{\mu}^+{\nu}_{\mu})<8.6{\times}10^{-6}$, and an improved measurement ${\Gamma}({\pi}^+{\rightarrow}{e}^+{\nu}_{e}{\nu}\bar{\nu})/{\Gamma}({\pi}^+{\rightarrow}{\mu}^+{\nu}_{\mu})<1.6{\times}10^{-7}$ were obtained.

hep-ex↗