Superpartner mass measurements with 1D decomposed MT2

TL;DR

This paper introduces a new model-independent method for measuring particle masses in missing energy events at hadron colliders, using 1D decompositions of the MT2 variable to determine sneutrino mass.

Contribution

The paper presents a novel technique employing 1D decompositions of MT2, enabling direct mass measurements in challenging short decay chains without relying on specific models.

Findings

The method accurately measures sneutrino mass from MT2 endpoint analysis.

The 1D decompositions simplify the analysis of missing energy events.

The approach is applicable to supersymmetry scenarios with short decay chains.

Abstract

We propose a new model-independent technique for mass measurements in missing energy events at hadron colliders. We illustrate our method with the most challenging case of a short, single-step decay chain. We consider inclusive same-sign chargino pair production in supersymmetry, followed by leptonic decays to sneutrinos. We introduce two one-dimensional decompositions of the Cambridge MT2 variable: MT2_\parallel and MT2_\perp, on the direction of the upstream transverse momentum PT and the direction orthogonal to it, respectively. We show that the sneutrino mass can be measured directly by minimizing the number of events N in which MT2 exceeds a certain threshold, conveniently measured from the endpoint MT2^max_\perp.