Impact of the recent results by the CMS and ATLAS Collaborations at the CERN Large Hadron Collider on an effective Minimal Supersymmetric extension of the Standard Model

TL;DR

This paper examines how recent CMS and ATLAS collider results impact light neutralino scenarios within an effective Minimal Supersymmetric Standard Model, highlighting differences in sensitivity and deriving bounds on neutralino mass.

Contribution

It provides an analysis of collider constraints on light neutralinos in a specific supersymmetric model, considering different assumptions on squark masses and their implications.

Findings

CMS bounds impose a lower neutralino mass limit of 11.9 GeV with degenerate squark masses.

ATLAS sensitivity is lower for light neutralinos due to specific signature efficiencies.

Relaxing squark universality removes the neutralino mass constraint, maintaining a lower bound of 7.5 GeV.

Abstract

We discuss the impact for light neutralinos in an effective Minimal Supersymmetric extension of the Standard Model of the recent results presented by the CMS and ATLAS Collaborations at the CERN Large Hadron Collider for a search of supersymmetry in proton-proton collisions at a center-of-mass energy of 7 TeV with an integrated luminosity of 35 inverse pb. We find that, in the specific case of light neutralinos, efficiencies for the specific signature searched by ATLAS (jets+missing transverse energy and an isolated lepton) imply a lower sensitivity compared to CMS (which searches for jets +missing transverse energy). Focusing on the CMS bound, if squark soft masses of the three families are assumed to be degenerate, the combination of the ensuing constraint on squark and gluino masses with the experimental limit on the b to s + gamma decay imply a lower bound on the neutralino mass that can reach the value of 11.9 GeV, depending on the gluino mass. On the other hand, when the universality condition among squark soft parameters is relaxed, the lower bound on the neutralino mass is not constrained by the CMS measurement and then remains at the value 7.5 GeV derived in previous papers.