Long-lived B−L symmetric SSM particles at the LHC

W Abdallah,A Hammad,A Kasem,S Khalil

doi:10.1103/physrevd.98.095019

Abstract

We investigate the collider signatures of neutral and charged long-lived particles (LLPs), predicted by the supersymmetric $B\ensuremath{-}L$ extension of the Standard Model (BLSSM), at the Large Hadron Collider (LHC). The BLSSM is a natural extension of the minimal supersymmetric Standard Model (MSSM) that can account for nonvanishing neutrino masses. We show that the lightest right-handed sneutrino can be the lightest supersymmetric particle (LSP), while the next-to-the LSP (NLSP) is either the lightest left-handed sneutrino or the left-handed stau, which are natural candidates for the LLPs. We analyze the displaced vertex signature of the neutral LLP (the lightest left-handed sneutrino) and the charged tracks associated with the charged LLP (the left-handed stau). We show that the production cross sections of our neutral and charged LLPs are relatively large, namely of order $\mathcal{O}(1)\text{ }\text{ }\mathrm{fb}$. Thus, probing these particles at the LHC is quite plausible. In addition, we find that the displaced dilepton associated with the lightest left-handed sneutrino has a large impact parameter that discriminates it from other SM leptons. We also emphasize that the charged track associated with the left-handed stau has a large momentum with slow moving charged tracks, hence it is distinguished from the SM background, and therefore it can be accessible at the LHC.

Highlights

Searches for new physics at the Large Hadron Collider (LHC) are largely based on probing the direct decay of the associated new particles into SM particles; i.e., particles are produced and decayed at the interaction point
We investigate the collider signatures of neutral and charged long-lived particles (LLPs), predicted by the supersymmetric B − L extension of the Standard Model (BLSSM), at the Large Hadron Collider (LHC)
The BLSSM is a natural extension of the minimal supersymmetric Standard Model (MSSM) that can account for nonvanishing neutrino masses

Summary

INTRODUCTION

Searches for new physics at the Large Hadron Collider (LHC) are largely based on probing the direct decay of the associated new particles into SM particles; i.e., particles are produced and decayed at the interaction point. An interesting possibility of revealing new physics is to detect the collider signatures of heavy long-lived particles (LLPs) This type of particles has a long lifetime, it can travel for a sizable distance inside the detector and decay at a point (secondary vertex) different from its production point (primary vertex). In the minimal supersymmetric Standard Model (MSSM), the lightest supersymmetric particle (LSP) is usually the lightest neutralino and the following particles are possible candidates for the next-tothe LSP (NLSP), with quite close mass to the mass of the LSP: next-to-the lightest neutralino, the lightest chargino, the lightest stau, and the lightest stop All these particles couple to the LSP with either gauge or Yukawa couplings, which are not very suppressed.

LONG-LIVED PARTICLES IN THE BLSSM

BLSSM LONG-LIVED PARTICLE SEARCHES AT THE CMS

BLSSM LONG-LIVED SIGNATURES AT THE CMS

Long-lived sneutrino signature at the CMS

Long-lived stau signature at the CMS

CONCLUSIONS