Measuring superparticle masses at hadron collider using the transverse mass kink

TL;DR

This paper explores the use of the $m_{T2}$ variable in collider experiments to measure superparticle masses, revealing a kink feature at the true LSP mass that allows simultaneous determination of superparticle and LSP masses.

Contribution

It provides analytic expressions for $m_{T2}^{ m max}$ and demonstrates how the kink structure can be used to measure superparticle and LSP masses simultaneously.

Findings

Analytic formulas for $m_{T2}^{ m max}$ derived.

Kink structure identified at true LSP mass.

Monte Carlo analysis confirms the method's effectiveness.

Abstract

We present a detailed study of the collider observable $m_{T2}$ applied for pair-produced superparticles decaying to visible particles and a pair of invisible lightest supersymmetric particles (LSPs). Analytic expressions of the maximum of $m_{T2}$ over all events ($m_{T2}^{\rm max}$) are derived. It is noticed that if the decay product of each superparticle involves more than one visible particles, $m_{T2}^{\rm max}$ being a function of the {\it trial} LSP mass ${m}_\chi$ has a kink structure at ${m}_\chi=$ true LSP mass, which can be used to determine the mother superparticle mass and the LSP mass simultaneously. To see how well $m_{T2}^{\rm max}$ can be constructed from collider data, a Monte-Carlo analysis of the gluino $m_{T2}$ is performed for some superparticle spectra.