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
  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.
