Quasi-stable neutralinos at the LHC

TL;DR

This paper investigates the detectability of small R-parity and lepton number violating couplings in supersymmetric models at the LHC, focusing on neutralino decays and their implications for particle physics and cosmology.

Contribution

It provides a detailed analysis of LHC sensitivity to R-parity breaking parameters in supergravity models with gravitino dark matter, extending previous studies with simulations including finite NLSP decay length.

Findings

LHC can probe zeta values 10-100 times smaller than current astrophysical bounds.

Simulation results show detectable signals for gluino and squark masses within LHC reach.

Finite NLSP decay length effects are significant in signal detection.

Abstract

We study supersymmetric extensions of the Standard Model with small R-parity and lepton number violating couplings which are naturally consistent with primordial nucleosynthesis, thermal leptogenesis and gravitino dark matter. We consider supergravity models where the gravitino is the lightest superparticle followed by a bino-like next-to-lightest superparticle (NLSP). Extending previous work we investigate in detail the sensitivity of LHC experiments to the R-parity breaking parameter zeta for various gluino and squark masses. We perform a simulation of signal and background events for the generic detector DELPHES for which we implement the finite NLSP decay length. We find that for gluino and squark masses accessible at the LHC, values of zeta can be probed which are one to two orders of magnitude smaller than the present upper bound obtained from astrophysics and cosmology.