Embedding the 125 GeV Higgs boson measured at the LHC in an effective MSSM: possible implications for neutralino dark matter

We analyze the phenomenological consequences of assuming that the 125 GeV boson measured at the LHC coincides with one of the two CP-even Higgs bosons of an effective Minimal Supersymmetric extension of the Standard Model at the electroweak scale. We consider the two ensuing scenarios and discuss critically the role of the various experimental data (mainly obtained at colliders and at B-factories) which provide actual or potential constraints to supersymmetric properties. Within these scenarios, properties of neutralinos as dark matter particles are analyzed from the point of view of their cosmological abundance and rates for direct and indirect detections.Comment: 14 pages, 14 figures, typeset with ReVTeX4. A version of the paper with full resolution figures can be found at http://www.to.infn.it/~scopel/embedding.pd

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.Comment: 6 pages, 6 figures, typeset with ReVTeX4. A version of the paper with full resolution figures can be found at http://www.to.infn.it/~scopel/cms_mssm2.pd

Relic neutralinos and the two dark matter candidate events of the CDMS II experiment

The CDMS Collaboration has presented its results for the final exposure of the CDMS II experiment and reports that two candidate events for dark matter would survive after application of the various discrimination and subtraction procedures inherent in their analysis. We show that a population of relic neutralinos, which was already proved to fit the DAMA/LIBRA data on the annual modulation effect, could naturally explain the two candidate CDMS II events, if these are actually due to a dark matter signal.Comment: 3 pages, 3 figure

Phenomenology of light neutralinos in view of recent results at the CERN Large Hadron Collider

We review the status of the phenomenology of light neutralinos in an effective Minimal Supersymmetric extension of the Standard Model (MSSM) at the electroweak scale, in light of new results obtained at the CERN Large Hadron Collider. First we consider the impact of the new data obtained by the CMS Collaboration on the search for the Higgs boson decay into a tau pair, and by the CMS and LHCb Collaborations on the branching ratio for the decay $B_s \rightarrow {\mu}^{+} + {\mu}^{-}$. Then we examine the possible implications of the excess of events found by the ATLAS and CMS Collaborations in a search for a SM--like Higgs boson around a mass of 126 GeV, with a most likely mass region (95% CL) restricted to 115.5--131 GeV (global statistical significance about 2.3 $\sigma$). From the first set of data we update the lower bound of the neutralino mass to be about 18 GeV. From the second set of measurements we derive that the excess around $m^{SM}_H$ = 126 GeV, which however needs a confirmation by further runs at the LHC, would imply a neutralino in the mass range 18 GeV \lsim m_{\chi} \lsim 38 GeV, with neutralino--nucleon elastic cross sections fitting well the results of the dark matter direct search experiments DAMA/LIBRA and CRESST.Comment: 10 pages, 6 figures, typeset with ReVTeX4. v2:discussion on LHC Higgs excess extended and one figure added. Matches version accepted for publication on Phys.Rev.D. A version of the paper with full resolution figures can be found at http://www.to.infn.it/~scopel/phenom_v2.pd