Searching for New Physics with $b\bar{b}{\ell }^{+}{\ell }^{-}$ Contact Interactions

Abstract

We study the impact of contact interactions involving two leptons (electrons or muons) and two $b$-quarks ($b\bar{b}{\ell }^{+}{\ell }^{-}$) on the high-mass di-lepton region at the LHC. We consider different selections of $b$-tagged jet multiplicities in the di-lepton final states: inclusive (no selection), 0, 1 and 2 $b$-tagged jets, and show that the single $b$-jet selection significantly improves the sensitivity to New Physics (NP) in the form of the $b\bar{b}{\ell }^{+}{\ell }^{-}$ contact term. We obtain a better sensitivity compared to the currently existing searches of NP in the di-lepton inclusive channel. In particular, the expected limits go beyond competitive bounds set by LEP (for electrons) on the scale of NP, $\hat{I}›$, by a factor of $1.2-3.1$, depending on the chirality structure of the operator. In addition, the expected limits on $\hat{I}›$, set by using a non-resonant LHC di-lepton inclusive search, are expected to be improved by a factor of $1.3-1.4$ for both electrons and muons.

12 pages, 6 Figures, 2 Tables