Probing new physics with charge asymmetries in 2 same-sign leptons plus jets final states at the LHC

TL;DR

This paper investigates how charge asymmetries in same-sign dilepton plus jets final states at the LHC can reveal new physics, analyzing various models and proposing differential measurements to enhance sensitivity.

Contribution

It introduces a comprehensive method to probe new physics through charge asymmetries in specific LHC final states, considering multiple models and kinematic observables.

Findings

Some new physics scenarios can be detected with current LHC data.

Charge asymmetry measurements improve sensitivity to new physics.

High-luminosity LHC can further enhance detection prospects.

Abstract

We study the impact of new physics models in the charge asymmetry defined for LHC final states consisting of two same-sign leptons (2SS$l$, with $l= e, \mu$) plus jets ($N_\text{jets}\geq2$), with a center-of-mass energy of $\sqrt{s}=13$ TeV, where the main SM contribution is $t\bar{t}W$ production. Concretely, we consider three different new physics sources for the charge asymmetries: a heavy neutral scalar/pseudoscalar arising from the general two Higgs doublet model, an effective theory with dimension-6 four-quark operators, and a simplified $R$-parity-violating supersymmetric model with electroweakino production (higgsino-like or wino-like). We propose measuring the charge asymmetries differentially with respect to several kinematic observables, and inclusively/exclusively with the number of $b$-tagged jets in the final state ($N_b\geq\{1, 2, 3\}$). Results are compared with the SM prediction using the $\chi^2$ criteria, expressing sensitivity in terms of the normal Gaussian significance. We show that some of the proposed new physics scenarios can be probed at the LHC even for the already recorded integrated luminosity of 139 fb$^{-1}$. Finally, we also estimate the prospects for the potential LHC sensitivity to the considered new physics models in its high-luminosity phase.