Top-quark Polarization and Asymmetries at the LHC in the Effective Description of Squark Interactions

TL;DR

This paper investigates top-quark polarization and charge asymmetries at the LHC resulting from squark decays within an effective interaction framework, aiming to distinguish supersymmetric models and improve simulation accuracy.

Contribution

It introduces an effective description of squark interactions including Yukawa couplings and supersymmetry breaking effects, suitable for Monte Carlo simulations with MadGraph.

Findings

Charge asymmetry $A_C$ can differentiate SUSY scenarios.

Top polarization observables are sensitive to SUSY parameters.

Effective interaction approach enhances simulation fidelity.

Abstract

A detailed study of top-quark polarizations and $t \bar t$ charge asymmetries, induced by top-squark-pair production at the LHC and the subsequent decays $\tilde t \to t \tilde \chi_1^0$, is performed within the effective description of squark interactions, which includes the effective Yukawa couplings and another logarithmic term encoding the supersymmetry breaking. This effective approach is more suitable for its introduction into Monte-Carlo simulations and we make use of its implementation in {\tt MadGraph} in order to investigate the possibilities of the charge asymmetry $A_\text{C}$, measured at the LHC and consistent with SM expectations, to discriminate among different SUSY scenarios and analyze the implications of these scenarios in the top polarizations and related observables.