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

Production and decay of gluino pairs at hadron colliders

At hadron colliders, one of the most important channels for sparticle production is expected to be the gluino pair production. In the scenario where the sbottom is lighter than the gluino, gluinos can decay into sbottom and bottom quarks. Sbottoms can subsequently decay into bottom quarks and neutralinos. Hence, one expects a rich signature consisting of four b-jets and the missing transverse energy from neutralinos. To compute the cross section of this reaction, it is important to find tools and techniques suitable for the calculation of diagrams with many particles in the final state. We present here a way to deal with such complicated reactions.Comment: Proceedings of the Conference: "QCD and High Energy Hadronic Interactions", XXXXth Rencontres de Moriond, La Thuile, Italy - March 12-19, 2005 - 4 pages. References update

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

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