The Single Photon Signature of a Light Long-lived Neutralino at Remote Detectors at the LHC

Abstract

We investigate the phenomenology of light long-lived neutralinos in R-parity violating supersymmetric models, focusing on the proposed remote detectors $\texttt{ANUBIS}$, $\texttt{CODEX-b}$, $\texttt{FACET}$, $\texttt{FASER}$, $\texttt{FASER2}$, $\texttt{MAPP}$, $\texttt{MAPP2}$, and $\texttt{MATHUSLA}$ at the LHC. We assume the production of the neutralinos at the ATLAS or CMS interaction points via rare scalar meson decays induced by R-parity violating couplings. We study six supersymmetric R-parity violating benchmark scenarios in which the dominant neutralino decay is $\tildeχ^0_1 \rightarrow γ+ ν$. For each scenario, we determine the projected search sensitivity at the above listed detectors. Extending previous work focused primarily on $\texttt{FASER}$ and $\texttt{FASER2}$, we improve the simulation by taking into account the extended flight path of the parent meson. We find that $\texttt{ANUBIS}$ provides the best sensitivity to our benchmark scenarios and $\texttt{FASER}$ the least among the considered experiments, while of course $\texttt{FASER}$ has already taken data.