Searching the sbottom in the four lepton channel at the LHC

Abstract

Direct searches at the Large Hadron Collider (LHC) have pushed the lower limits on the masses of the gluinos ($\tilde{g}$) and the squarks of the first two generations ($\tilde{q}$) to the TeV range. On the other hand, the limits are rather weak for the third generation squarks and masses around a few hundred GeV are still allowed. A comparatively light third generation of squarks is also consistent with the lightest Higgs boson with mass $\sim$ 125 GeV. In view of this, we consider the direct production of a pair of sbottom quarks ($\tilde{b}_1$) at the LHC and study their collider signatures. We focus on the scenario where the $\tilde{b}_1$ is not the next-to-lightest supersymmetric particle (NLSP) and hence can also decay to channels other than the commonly considered decay mode to a bottom quark and the lightest neutralino ($\tildeχ^0_1$). For example, we consider the decay modes containing a bottom quark and the second neutralino ($\tilde{b}_1 \to b \tildeχ^0_2$) and/or a top quark and the lightest chargino ($\tilde{b}_1 \to t \tildeχ^{\pm}_1$) following the leptonic decays of the neutralino, chargino and the top quark giving rise to a 4 leptons ($\ell$) + 2 $b$-jets + missing transverse momentum ($\PMET$) final state. We show that an sbottom mass $\lesssim$ 550 GeV can be probed in this channel at the 14 TeV LHC energy with integrated luminosity $\lesssim$ 100 fb$^{-1}$.