Determination of the top quark mass from leptonic observables

TL;DR

This paper introduces a leptonic observable-based method for precisely determining the top quark mass at the LHC, minimizing modeling biases and avoiding top reconstruction.

Contribution

It presents a novel approach using Mellin moments of kinematic distributions that reduces sensitivity to long-distance effects and addresses theoretical biases in top mass measurements.

Findings

Achieves a theoretical error of about 0.8 GeV on the top mass

Does not require top quark reconstruction

Provides a strategy to minimize theoretical biases

Abstract

We present a procedure for the determination of the mass of the top quark at the LHC based on leptonic observables in dilepton $t\bar{t}$ events. Our approach utilises the shapes of kinematic distributions through their few lowest Mellin moments; it is notable for its minimal sensitivity to the modelling of long-distance effects, for not requiring the reconstruction of top quarks, and for having a competitive precision, with theory errors on the extracted top mass of the order of 0.8 GeV. A novel aspect of our work is the study of theoretical biases that might influence in a dramatic way the determination of the top mass, and which are potentially relevant to all template-based methods. We propose a comprehensive strategy that helps minimise the impact of such biases, and leads to a reliable top mass extraction at hadron colliders.