Physics / Fizik
Permanent URI for this collectionhttps://hdl.handle.net/11147/6
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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: 13Citation - Scopus: 13Higgs Boson Masses in the Mssm With General Soft Breaking(Elsevier Ltd., 2008) Sabancı, Aslı; Hayreter, Alper; Solmaz, LeventThe operators that break supersymmetry can be holomorphic or non-holomorphic in structure. The latter do not pose any problem for gauge hierarchy and are soft provided that the particle spectrum does not contain any gauge singlets. In minimal supersymmetric model (MSSM) we discuss the impact of non-holomorphic soft-breaking terms on the Higgs sector. We find that non-holomorphic operators can cause significant changes as are best exhibited by the correlation between the masses of the charginos and Higgs bosonsArticle Citation - WoS: 6Citation - Scopus: 6Dilepton Signatures of Family Non-Universal U (1)'(Elsevier Ltd., 2007) Hayreter, AlperThe supersymmetric models extending the minimal supersymmetric Standard Model (MSSM) by an additional Abelian gauge factor U (1)′ in order to solve the μ problem do generically suffer from anomalies disrupting the gauge coupling unification found in the MSSM. The anomalies are absent if the minimal matter content necessitated by the μ problem is augmented with exotic matter species having appropriate quantum numbers. Recently, it has been shown that anomaly cancellation can also be accomplished by introducing family non-universal U (1)′ charges and non-holomorphic soft-breaking terms [D.A. Demir, G.L. Kane, T.T. Wang, Phys. Rev. D 72 (2005) 015012, hep-ph/0503290]. We discuss collider signatures of anomaly-free family non-universal U (1)′ model by analyzing dilepton production in future colliders. We find that, both at LHC and NLC, one can establish existence/absence of such a Z′ boson by simply comparing the number of dilepton production events for electron, muon and tau lepton. The signal is free of the SM background.Article Citation - WoS: 3Citation - Scopus: 3Electric Dipole Moments in U(1)' Models(American Physical Society, 2008) Hayreter, Alper; Sabancı, Aslı; Solmaz, Levent; Solmaz, SaimeWe study electric dipole moments of electrons and protons in E(6)-inspired supersymmetric models with an extra U(1) invariance. Compared to the Minimal Supersymmetric Standard Model, in addition to offering a natural solution to the μ problem and predicting a larger mass for the lightest Higgs boson, these models are found to yield suppressed electric dipole moments. © 2008 The American Physical Society.Article Citation - WoS: 78Citation - Scopus: 79Minimal U(1)' Extension of the Minimal Supersymmetric Standard Model(American Physical Society, 2005) Demir, Durmuş Ali; Kane, Gordon L.; Wang, Ting T.Motivated by the apparent need for extending the minimal supersymmetric standard model (MSSM) and perhaps mitigating naturalness problems associated with the μ parameter and fine-tuning of the soft masses, we augment the MSSM spectrum by a SM gauge singlet chiral superfield, and enlarge the gauge structure by an additional U(1)′ invariance, so that the gauge and Higgs sectors are relatively secluded. One crucial aspect of U(1)′ models is the existence of anomalies, the cancellation of which may require the inclusion of exotic matter which in turn disrupts the unification of the gauge couplings. In this work we pursue the question of canceling the anomalies with a minimal matter spectrum and no exotics. This can indeed be realized provided that U(1)′ charges are family dependent and the soft-breaking sector includes nonholomorphic operators for generating the fermion masses. We provide the most general solutions for U(1)′ charges by taking into account all constraints from gauge invariance and anomaly cancellation. We analyze various laboratory and astrophysical bounds ranging from fermion masses to relic density, for an illustrative set of parameters. The U(1)′ charges admit patterns of values for which family nonuniversality resides solely in the lepton sector, though this does not generate leptonic flavor-changing neutral currents due to the U(1)′ gauge invariance.