2,519 research outputs found
Relic density and future colliders: inverse problem(s)
Relic density calculations are often used to constrain particle physics
models, and in particular supersymmetry. We will show that the presence of
additional energy or entropy before the Big-Bang nucleosynthesis can however
completely change the relic density constraints on the SUSY parameter space.
Therefore one should be extremely careful when using the relic density to
constrain supersymmetry as it could give misleading results, especially if
combined with the future collider data. Alternatively, we will also show that
combining the discoveries of the future colliders with relic density
calculations can shed light on the inaccessible pre-BBN dark time physics.
Finally we will present SuperIso Relic, a new relic density calculator code in
Supersymmetry, which incorporates alternative cosmological models, and is
publicly available.Comment: 8 pages, 5 figures, contribution to the proceedings of the conference
"Invisible Universe", Paris, June 29 - July 3, 2009, Franc
LHC and ILC Data and the Early Universe Properties
With the start-up of the LHC, we can hope to find evidences for new physics
beyond the Standard Model, and particle candidates for dark matter. Determining
the parameters of the full underlying theory will be a long process requiring
the combination of LHC and ILC data, flavor physics constraints, and
cosmological observations. However, the Very Early Universe properties, from
which the relic particles originate, are poorly known, and the relic density
calculation can be easily falsified by hidden processes. We consider
supersymmetry and show that determining the underlying particle physics
parameters will help understanding the Very Early Universe properties.Comment: 6 pages, 2 figures, contribution to the proceedings of the workshop
"LC09: e+e- Physics at the TeV Scale and the Dark Matter Connection",
Perugia, September 21 - 24, 2009, Italy. v2: reference adde
Complementarity of direct and indirect searches in the pMSSM
We explore the pMSSM parameter space in view of the constraints from SUSY and
monojet searches at the LHC, from Higgs data and flavour physics observables,
as well as from dark matter searches. We show that whilst the simplest SUSY
scenarios are already ruled out, there are still many possibilities left over
in the pMSSM. We discuss the complementarity between different searches and
consistency checks which are essential in probing the pMSSM and will be even
more important in the near future with the next round of data becoming
available.Comment: 6 pages, 9 figures. Contribution to the proceedings of the Fifth
Capri Workshop on the interplay of flavour physics with electroweak symmetry
breaking and dark matter, Capri, May 201
Light neutralino dark matter in MSSM
Three dark matter direct detection experiments, DAMA, COGENT and CRESST, have
reported a possible signal of WIMP interaction corresponding to very light
particles, close to the edge of the XENON 100 and CDMS sensitivity. Imposing
the latest constraints from colliders, flavour physics, electroweak precision
tests and direct and indirect dark matter searches, we show that viable MSSM
scenarios with a light neutralino, in agreement with all the present data, are
feasible. An analysis of the characteristics of the resulting scenarios will be
presented.Comment: 6 pages, 2 figures, contribution to the ICHEP 2012 Conference
proceedings, 4-11 July 2012, Melbourne, Australi
Implications of LHC Higgs and SUSY searches for MSSM
The implications of the LHC SUSY searches as well as the discovery of a new
bosonic state compatible with the lightest Higgs boson will be discussed in the
context of constrained and general MSSM scenarios. Exploring the MSSM through
the Higgs sector is an alternative and complementary path to direct searches,
and tight constraints on the MSSM parameter space can be obtained.Comment: 7 pages, 5 figures, contribution to the ICHEP 2012 Conference
proceedings, 4-11 July 2012, Melbourne, Australi
On split products of quaternion algebras with involution in characteristic two
The question of whether a split tensor product of quaternion algebras with
involution over a field of characteristic two can be expressed as a tensor
product of split quaternion algebras with involution, is shown to have an
affirmative answer
Exploring CP Violation in the MSSM
We explore the prospects for observing CP violation in the minimal
supersymmetric extension of the Standard Model (MSSM) with six CP-violating
parameters, three gaugino mass phases and three phases in trilinear soft
supersymmetry-breaking parameters, using the CPsuperH code combined with a
geometric approach to maximize CP-violating observables subject to the
experimental upper bounds on electric dipole moments. We also implement
CP-conserving constraints from Higgs physics, flavour physics and the upper
limits on the cosmological dark matter density and spin-independent scattering.
We study possible values of observables within the constrained MSSM (CMSSM),
the non-universal Higgs model (NUHM), the CPX scenario and a variant of the
phenomenological MSSM (pMSSM). We find values of the CP-violating asymmetry
A_CP in b -> s gamma decay that may be as large as 3%, so future measurements
of A_CP may provide independent information about CP violation in the MSSM. We
find that CP-violating MSSM contributions to the B_s meson mass mixing term
Delta M_Bs are in general below the present upper limit, which is dominated by
theoretical uncertainties. If these could be reduced, Delta M_Bs could also
provide an interesting and complementary constraint on the six CP-violating
MSSM phases, enabling them all to be determined experimentally, in principle.
We also find that CP violation in the h_{2,3} tau+ tau- and h_{2,3} tbar t
couplings can be quite large, and so may offer interesting prospects for future
pp, e+ e-, mu+ mu- and gamma gamma colliders.Comment: 36 pages, 32 figure
Gene molecular study of biofilm of Staphylococcus aureus isolated from fresh milk using multiplex polymerase chain reaction
Background: Staphylococcus aureus is one of the main causes of food poisoning in the world. This pathogen has the ability to create biofilms that can lead to food contamination. The presence of biofilm genes in bacteria is very important. The aim of this study was to identify sticky genes (eno, cna, ebp, bbp) that play an important role in virulence and pathogenicity of the bacteria and even prevent the penetration of antibiotics in pathogenicity time. Materials and Methods: A total of 100 samples of fresh milk were collected from live animals and 60 isolates were selected to identify sticky genes (eno, cna, ebp, bbp) in the production of biofilm of S. aureus using the multiplex polymerase chain reaction method. In addition, the frequency rates of S. aureus strains resistant and susceptible to antibiotics such as methicillin, vancomycin, and clindamycin were determined among the samples. Results: From a total of 60 isolates of fresh milk, 43.4 of the colonies had laminin-binding protein gene or eno gene. Also, 90 of the isolates were sensitive to vancomycin, 50 sensitive to clindamycin and 43.4 sensitive to methicillin. Distribution rates of other sticky genes including ebp, cna, bbp were 11.6, 20 and 25, respectively. Molecular study results showed that the highest and lowest percentages of genes were related to the eno and bbp genes, respectively. Conclusion: The present study shows that the maximum sensitivity of the samples (90) was related to vancomycin and the least amount of sensitivity (43.3) was related to methicillin
Anomaly mediated SUSY breaking scenarios in the light of cosmology and in the dark (matter)
Anomaly mediation is a popular and well motivated supersymmetry breaking
scenario. Different possible detailed realisations of this set-up are studied
and actively searched for at colliders. Apart from limits coming from flavour,
low energy physics and direct collider searches, these models are usually
constrained by the requirement of reproducing the observations on dark matter
density in the universe. We reanalyse these bounds and in particular we focus
on the dark matter bounds both considering the standard cosmological model and
alternative cosmological scenarios. These scenarios do not change the
observable cosmology but relic dark matter density bounds strongly depend on
them. We consider few benchmark points excluded by standard cosmology dark
matter bounds and suggest that loosening the dark matter constraints is
necessary in order to avoid a too strong (cosmological) model dependence in the
limits that are obtained for these models. We also discuss briefly the
implications for phenomenology and in particular at the Large Hadron Collider.Comment: 37 pages, 20 figures, 1 tabl
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