Model-Independent Bounds on Squarks from Monophoton Searches

TL;DR

This paper demonstrates that monophoton searches at the LHC provide strong, model-independent bounds on squark masses in compressed supersymmetry scenarios, surpassing previous collider limits.

Contribution

It introduces a novel, model-independent method using monophoton events to set bounds on squark masses in compressed spectra, improving upon prior limits.

Findings

LHC monophoton searches set a 150 GeV bound on up-type squarks.

A 110 GeV bound is established for down-type squarks.

2012 LHC data is expected to tighten these bounds further.

Abstract

Supersymmetry with a compressed spectrum could be responsible for the negative results from supersymmetric searches at LHC. Squarks and gluinos well below the TeV scale could have escaped detection since all search channels lose sensitivity when the mass splitting between supersymmetric particles becomes small. Even in this stealthy situation, production of colored particles is probed in processes with supersymmetric particles produced in association with a high-pT photon. We show that searches for missing energy with a monophoton are a powerful tool, and that the 2011 LHC data already surpasses the limits set by LEP and TeVatron in the compressed case. We set a model-independent bound on the mass of any up (down) type squark of 150 (110) GeV, and stronger model-dependent bounds can be set. We also comment on the expected improvement on those bounds in the 2012 LHC run.