Sparticles at the LHC

TL;DR

This paper studies the possible mass hierarchies of the four lightest sparticles in supergravity models, analyzing their signatures at the LHC to distinguish different patterns and identify the source of supersymmetry breaking.

Contribution

It identifies viable sparticle mass hierarchies under experimental constraints and develops a comprehensive analysis method for their signatures at the LHC.

Findings

Only a small subset of hierarchies survive constraints.

Significant discrimination among mass patterns is possible.

Analysis techniques are applicable beyond supergravity models.

Abstract

Sparticle mass hierarchies will play an important role in the type of signatures that will be visible at the Large Hadron Collider. We analyze these hierarchies for the four lightest sparticles for a general class of supergravity unified models including nonuniversalities in the soft breaking sector. It is shown that out of nearly $10^4$ possibilities of sparticle mass hierarchies, only a small number survives the rigorous constraints of radiative electroweak symmetry breaking, relic density and other experimental constraints. The signature space of these mass patterns at the Large Hadron Collider is investigated using a large set of final states including multi-leptonic states, hadronically decaying $\tau$s, tagged $b$ jets and other hadronic jets. In all, we analyze more than 40 such lepton plus jet and missing energy signatures along with several kinematical signatures such as missing transverse momentum, effective mass, and invariant mass distributions of final state observables. It is shown that a composite analysis can produce significant discrimination among sparticle mass patterns allowing for a possible identification of the source of soft breaking. While the analysis given is for supergravity models, the techniques based on mass pattern analysis are applicable to wide class of models including string and brane models.