Amplification of endpoint structure for new particle mass measurement at the LHC

TL;DR

The paper introduces MCT2, a new collider variable that amplifies endpoint structures in particle decay distributions, improving the measurement of new particle masses at the LHC despite background noise.

Contribution

It proposes MCT2, a novel variable combining features of MT2 and MCT, to enhance endpoint visibility for mass measurements in collider experiments.

Findings

MCT2 amplifies endpoint structures in decay distributions.

MCT2 improves the observability of mass constraints.

The method reduces background and systematic uncertainties.

Abstract

We introduce a new collider variable, MCT2, named as constransverse mass. It is a mixture of `stransverse mass(MT2)' and `contransverse mass(MCT)' variables, where the usual endpoint structure of MT2 distribution can be amplified in the MCT2 basis by large Jacobian factor which is controlled by trial missing particle mass. Thus the MCT2 projection of events increases our observability to measure several important endpoints from new particle decays, which are usually expected to be buried by irreducible backgrounds with various systematic uncertainties at the LHC. In this paper we explain the phenomenology of endpoint amplification in MCT2 projection, and describe how one may employ this variable to measure several meaningful mass constraints of new particles.