Long-lived higgsinos as probes of gravitino dark matter at the LHC

TL;DR

This paper explores how light higgsinos with small R-parity violation could be detected at the LHC through displaced vertices, providing a new way to probe gravitino dark matter models.

Contribution

It introduces a novel collider signature for light higgsinos in gravitino dark matter scenarios and assesses LHC sensitivity using simulation tools.

Findings

Higgsinos with 100-400 GeV mass can be detected at the 8 TeV LHC with 10-30 fb^-1.

Displaced-vertex signatures are promising for identifying small R-parity violation.

Higgsino mass can be reconstructed from dimuon mass edge if a signal is observed.

Abstract

We investigate the LHC sensitivity to supersymmetric models with light higgsinos, small R-parity breaking and gravitino dark matter. The limits on decaying gravitino dark matter from gamma-ray searches with the Fermi-LAT put a lower bound on the higgsino-like neutralino NLSP decay length, giving rise to a displaced-vertex collider signature. Using publicly available tools for simulation of signal, background and detector response, we find that higgsinos with masses of 100-400 GeV and R-parity violation of approximately 10^-8 to 10^-9 can show up in the 8 TeV LHC data with 10-30 fb^-1 of integrated luminosity. We demonstrate that in the case of a signal, the higgsino mass can be determined by reconstruction of the dimuon mass edge.