Probing R-parity violating models of neutrino mass at the LHC via top squark decays

TL;DR

This paper demonstrates that R-parity violating decays of the lighter top squark can be detected at the LHC through dilepton di-jet channels, even with very small couplings relevant to neutrino mass models, providing a new way to probe such models.

Contribution

It provides a model-independent estimate of the minimum observable branching ratio product at the LHC and compares it with predictions from various neutrino mass models, highlighting the detectability of R-parity violation.

Findings

R-parity violating top squark decays are observable at the LHC for small couplings.

The minimum detectable branching ratio product is estimated for 10fb$^{-1}$ luminosity.

Predicted decay rates in neutrino mass models are above the detection threshold.

Abstract

It is shown that the R-parity violating decays of the lighter top squarks (${\widetilde t}_1$) triggered by the lepton number violating couplings $\lambda^{\prime}_{i33}$, where the lepton family index i = 1-3, can be observed at the LHC via the dilepton di-jet channel even if the coupling is as small as 10$^{-4}$ or 10$^{-5}$, which is the case in several models of neutrino mass, provided it is the next lightest supersymmetric particle(NLSP) the lightest neutralino being the lightest supersymmetric particle(LSP). We have first obtained a fairly model independent estimate of the minimum observable value of the parameter ($P_{ij} \equiv BR(\widetilde t \to l_i^+ b) \times BR(\widetilde t^* \to l_j^- \bar b$)) at the LHC for an integrated luminosity of 10fb$^{-1}$ as a function of $\mlstop$ by a standard Pythia based analysis. We have then computed the parameter $P_{ij}$ in several representative models of neutrino mass constrained by the neutrino oscillation data and have found that the theoretical predictions are above the estimated minimum observable levels for a wide region of the parameter space.