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

摘要

We discuss the impact for light neutralinos in an effective MinimalSupersymmetric extension of the Standard Model of the recent results presentedby the CMS and ATLAS Collaborations at the CERN Large Hadron Collider for asearch of supersymmetry in proton-proton collisions at a center-of-mass energyof 7 TeV with an integrated luminosity of 35 inverse pb. We find that, in thespecific case of light neutralinos, efficiencies for the specific signaturesearched by ATLAS (jets+missing transverse energy and an isolated lepton) implya lower sensitivity compared to CMS (which searches for jets +missingtransverse energy). Focusing on the CMS bound, if squark soft masses of thethree families are assumed to be degenerate, the combination of the ensuingconstraint on squark and gluino masses with the experimental limit on the b tos + gamma decay imply a lower bound on the neutralino mass that can reach thevalue of 11.9 GeV, depending on the gluino mass. On the other hand, when theuniversality condition among squark soft parameters is relaxed, the lower boundon the neutralino mass is not constrained by the CMS measurement and thenremains at the value 7.5 GeV derived in previous papers.