407 research outputs found
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 . 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 ). 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 = 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
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