Revisiting Combinatorial Ambiguities at Hadron Colliders with MT2

TL;DR

This paper introduces a method using kinematic variables like MT2 to effectively resolve combinatorial ambiguities in multi-particle final states at hadron colliders, improving efficiency while maintaining purity.

Contribution

The authors propose a novel approach that leverages MT2 and invariant mass to reduce combinatorial issues without significant loss of data, outperforming recent methods.

Findings

Enhanced efficiency in resolving combinatorial ambiguities

Comparable purity to existing methods

Applicable to gluino pair and top quark pair production

Abstract

We present a method to resolve combinatorial issues in multi-particle final states at hadron colliders. The use of kinematic variables such as MT2 and invariant mass significantly reduces combinatorial ambiguities in the signal, but at a cost of losing statistics. We illustrate this idea with gluino pair production leading to 4 jets $+\met$ in the final state as well as $t\bar{t}$ production in the dilepton channel. Compared to results in recent studies, our method provides greater efficiency with similar purity