Searching the sbottom in the four lepton channel at the LHC

Diptimoy Ghosh; Dipan Sengupta

doi:10.1140/epjc/s10052-013-2342-9

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Particles and Fields

Eur. Phys. J. C (2013) 73: 2342
https://doi.org/10.1140/epjc/s10052-013-2342-9

Regular Article - Theoretical Physics

Searching the sbottom in the four lepton channel at the LHC

Diptimoy Ghosh¹ and Dipan Sengupta²^*

¹ Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, India
² Department of High Energy Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, India

^* e-mail: dipan@tifr.res.in

Received: 22 November 2012
Revised: 4 February 2013
Published online: 27 March 2013

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 ∼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 ( $\tilde{\chi}^{0}_{1}$ ). For example, we consider the decay modes containing a bottom quark and the second neutralino ( $\tilde{b}_{1} \to b \tilde{\chi}^{0}_{2}$ ) and/or a top quark and the lightest chargino ( $\tilde{b}_{1} \to t \tilde{\chi}^{\pm}_{1}$ ) following the leptonic decays of the neutralino, chargino and the top quark giving rise to a four leptons (ℓ) + two b-jets + missing transverse momentum ([Equation not available: see fulltext.] ) final state. We show that a sbottom mass ≲550 GeV can be probed in this channel at the 14 TeV LHC energy with integrated luminosity ≲100 fb⁻¹.