Search for RPV Gaugino and Gravitino Production at HERA

TL;DR

This paper reports on searches for R-parity violating supersymmetry at HERA, focusing on gaugino and gravitino production, with no deviations from the Standard Model observed, leading to new exclusion limits on supersymmetric parameters.

Contribution

The study provides the first combined search results for RPV gaugino and gravitino production at HERA, setting new limits on MSSM and GMSB model parameters.

Findings

No deviations from the Standard Model observed.

Exclusion limits set on MSSM parameters.

Limits established on selectron and neutralino masses.

Abstract

In R-parity violating supersymmetry a gaugino can be produced at HERA by the t-channel exchange of a selectron between the beam positron or electron and an initial quark from the beam proton. In the generic MSSM model the gaugino can decay in a cascade into two quarks and an (anti)lepton. For this model a search in the e^{+-}-channel has been performed with the ZEUS detector using combined e^{+-}p-data of L_{int}=121pb^{-1}. No deviations from the Standard Model have been observed and exclusion limits on parameters of the MSSM have been set. Assuming the GMSB model with the gravitino as lightest supersymmetric particle and the neutralino as next-to-lightest supersymmetric particle, the neutralino decays into a gravitino and a high-energy photon. For this model searches have been performed with the H1 detector using e^+p-data of L_{int}=64.3pb^{-1} and e^-p-data of L_{int}=13.5pb^{-1} and with the ZEUS detector using e^+p-data of L_{int}=65.1pb^{-1}. No deviations from the Standard Model have been observed and limits on the selectron and neutralino masses have been set. Additionally, limits on the R-parity violating Yukawa coupling have been derived in the search performed with the H1 detector.