306 research outputs found
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
Upper bounds on signals due to WIMP self--annihilation: comments on the case of the synchrotron radiation from the galactic center and the WMAP haze
Two recent papers reconsider the possibility that the excess of microwave
emission from a region within of the galactic center (the {\it WMAP
haze}), measured by WMAP, can be due to the synchrotron emission originated by
neutralino self-annihilation; on the basis of this possible occurrence, also
upper bounds on the neutralino self-annihilation cross--section are suggested.
In the present note, we show that in the common case of thermal WIMPs in a
standard cosmological model, when the rescaling of the galactic WIMP density is
duly taken into account for subdominant WIMPs, the upper bound applicable
generically to {\it any} signal due to self-conjugate WIMPs is more stringent
than the ones obtained from analysis of the WMAP haze. We also argue that an
experimental upper bound, which can compete with our generic upper limit, can
rather be derived from measurements of cosmic antiproton fluxes, for some
values of the parameters of the astrophysical propagation model. Finally, we
comment on the possible impact of our generic upper bound on the interpretation
of the WMAP haze in terms of thermal neutralinos in a standard cosmological
scheme.Comment: 3 pages, comments and 1 figure adde
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