Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 24Citation - Scopus: 25Sneutrino Dark Matter: Symmetry Protection and Cosmic Ray Anomalies(American Physical Society, 2010) Demir, Durmuş Ali; Everett, Lisa L.; Frank, Mariana; Selbuz, Levent; Turan, İsmailWe present an R-parity conserving model of sneutrino dark matter within a Higgsphilic U(1)′ extension of the minimal supersymmetric standard model. In this theory, the μ parameter and light Dirac neutrino masses are generated naturally upon the breaking of the U(1)′ gauge symmetry. One of the right-handed sneutrinos is the lightest supersymmetric particle. The leptonic and hadronic decays of another sneutrino, taken to be the next-to-lightest superpartner, allow for a natural fit to the recent results reported by the PAMELA experiment. We perform a detailed calculation of the dark matter relic density in this scenario, and show that the model is consistent with the ATIC and Fermi LAT experiments. © 2010 The American Physical Society.Article Citation - WoS: 7Citation - Scopus: 8Search for Gauge Extensions of the Mssm at the Lhc(American Physical Society, 2009) Ahmed, Ali; Demir, Durmuş Ali; Frank, Mariana; Turan, İsmailThe extensions of the minimal supersymmetric model (MSSM), driving mainly from the need to solve the μ problem, involve novel matter species and gauge groups. These extended MSSM models can be searched for at the LHC via the effects of the gauge and Higgs bosons or their fermionic partners. Traditionally, the focus has been on the study of the extra forces induced by the new gauge and Higgs bosons present in such models. An alternative way of studying such effects is through the superpartners of matter species and the gauge forces. We thus consider a U(1)′ gauge extension of the MSSM, and perform an extensive study of the signatures of the model through the production and decays of the scalar quarks and gluino, which are expected to be produced copiously at the LHC. After a detailed study of the distinctive features of such models with regard to the signatures at the LHC, we carry out a detailed Monte-Carlo analysis of the signals from the process pp→nleptons+mjets+E T, and compare the resulting distributions with those predicted by the MSSM. Our results show that the searches for the extra gauge interactions in the supersymmetric framework can proceed not only through the forces mediated by the gauge and Higgs bosons but also through the superpartner forces mediated by the gauge and Higgs fermions. Analysis of the events induced by the squark/gluino decays presented here is complementary to the direct Z′ searches at the LHC.Article Citation - WoS: 18Citation - Scopus: 18Squark Pair Production in the Mssm With Explicit Cp Violation(American Physical Society, 2007) Alan, Ahmet T.; Cankoçak, Kerem; Demir, Durmuş AliWe analyze effects of the CP-odd soft phases in the MSSM on the pair productions of colored superpartners in pp collisions at the LHC energies. We find that, among all pair-production processes, those of the scalar quarks in the first and second generations are particularly sensitive to the CP-odd phases, more precisely, to the phases of the gluinos and neutralinos. We compute pair-production cross sections, classify various production modes according to their dependencies on the gluino and neutralino phases, perform a detailed numerical analysis to determine individual as well as total cross sections, and give a detailed discussion of 2. electric dipole moment (EDM) bounds. We find that pair productions of first and second generation squarks serve as a viable probe of the CP violation sources in the gaugino sector of the theory even if experiments cannot determine chirality, flavor and electric charge of the squarks produced.Article Citation - WoS: 10Citation - Scopus: 12Neutralino Dark Matter in the Left-Right Supersymmetric Model(American Physical Society, 2006) Demir, Durmuş Ali; Frank, Mariana; Turan, İsmailWe study the neutralino sector of the left-right supersymmetric model. In addition to the possibilities available in the minimal supersymmetric model, the neutralino states can be superpartners of the U(1)B-L gauge boson, the neutral SU(2)R gauge boson, or of the Higgs triplets. We analyze neutralino masses and determine the parameter regions for which the lightest neutralino can be one of the new pure states. We then calculate the relic density of the dark matter for each of these states and impose the constraints coming from the ρ parameter, the anomalous magnetic moment of the muon, b→sγ, as well as general supersymmetric mass bounds. The lightest neutralino can be the bino, or the right-wino, or the neutral triplet Higgsino, all of which have different couplings to the standard model particles from the usual neutralinos. A light bino satisfies all the experimental constraints and would be the preferred dark matter candidate for light supersymmetric scalar masses, while the right-wino would be favored by intermediate supersymmetric mass scales. The neutral triplet Higgs fermion satisfies the experimental bounds only in a small region of the parameter space, for intermediate to heavy supersymmetric scalar masses.