LEP Indications for Two Light Higgs Bosons and U(1)' Model

Reanalyses of LEP data have shown preference to two light CP-even Higgs bosons. We discuss implications of such a Higgs boson spectrum for the minimal supersymmetric model extended by a Standard Model singlet chiral superfield and an additional Abelian gauge invariance (the U(1)' model). We, in particular, determine parameter regions that lead to two light CP-even Higgs bosons while satisfying existing bounds on the mass and mixings of the extra vector boson. In these parameter regions, the pseudoscalar Higgs is found to be nearly degenerate in mass with either the lightest or next-to-lightest Higgs boson. Certain parameters of the U(1)' model such as the effective mu parameter are found to be significantly bounded by the LEP two-light-Higgs signal.Comment: 20 pp, 7 figs, 2 table

Generalized Soft Breaking Leverage for the MSSM

In this work we study implications of additional non-holomorphic soft breaking terms (mu', A'_t, A'_b and A'_tau) on the MSSM phenomenology. By respecting the existing bounds on the mass measurements and restrictions coming from certain B-decays, we probe reactions of the MSSM to these additional soft breaking terms. We provide examples in which some slightly excluded solutions of the MSSM can be made to be consistent with the current experimental results. During this, even after applying additional fine-tuning constraints the non-holomorphic terms are allowed to be as large as hundreds of GeV. Such terms prove that they are capable of enriching the phenomenology and varying the mass spectra of the MSSM heavily, with a reasonable amount of fine-tuning. We observe that higgsinos, the lightest stop, the heavy Higgs boson states A, H, charged H, sbottom and stau exhibit the highest sensitivity to the new terms. We also show how the light stop can become nearly degenerate with top quark using these non-holomorphic terms.Comment: 21 pages, 9 figure

Generalized soft breaking leverage for the MSSM

In this work we study implications of additional nonholomorphic soft breaking terms (mu', A(t)', A(b)', and A(t)') on the minimal supersymmetric extension of the standard model (MSSM) phenomenology. By respecting the existing bounds on the mass measurements and restrictions coming from certain B-decays, we probe reactions of the MSSM to these additional soft breaking terms. We provide examples in which some slightly excluded solutions of the MSSM can be made to be consistent with the current experimental results. During this, even after applying additional fine-tuning constraints, the nonholomorphic terms are allowed to be as large as hundreds of GeV. Such terms prove that they are capable of enriching the phenomenology and varying the mass spectra of the MSSM heavily, with a reasonable amount of finetuning. We observe that Higgsinos, the lightest stop, the heavy Higgs boson states A; H; H-+/-, sbottom and stau exhibit the highest sensitivity to the new terms. We also show how the light stop can become nearly degenerate with top quark using these nonholomorphic terms.Russian Foundation for Basic Research (RFBR) (14-02-00494-a

Electric Dipole Moments in U(1)' Models

We study electric dipole moments (EDM) of electron and proton in E(6)--inspired supersymmetric models with an extra U(1) invariance. Compared to the Minimal Supersymmetric Standard Model (MSSM), in addition to offering a natural solution to the mu problem and predicting a larger mass for the lightest Higgs boson, these models are found to yield suppressed EDMs.Comment: 24 pages, 9 figures, 1 tabl

Vektör mezonların ışınsal bozunmalarında skaler mezon etkileri

The role of scalar mesons in radiative vector meson decays is investigated. The effects of scalar-isoscalar f_{0}(980) and scalar-isovector a_{0}(980) mesons are studied in the mechanism of the radiative Phi->pi{+}pi{-}gamma and phi->pi{0}eta gamma decays, respectively. A phenomenological approach is used to study the radiative phi->pi{+}p{-}gamma decay by considering the contributions of sigma-meson, rho-meson and f_{0}-meson. The interference effects between different contributions are analyzed and the branching ratio for this decay is calculated. The radiative phi->pi{0}eta gamma decay is studied within the framework of a phenomenological approach in which the contributions of rho-meson, chiral loop and a_{0}-meson are considered. The interference effects between different contributions are examined and the coupling constants g_{phi a_{0} gamma} and g_{a_{0}K{+}K{-}} are estimated using the experimental branching ratio for the phi->pi{0}eta gamma decay. Furthermore, the radiative rho{0}pi{+}pi{-}gammaÞ and rho{0}->pi{0}pi{0}gamma decays are studied to investigate the role of scalar-isoscalar sigma-meson. The branching ratios of the rho{0}->pi{+}pi{-}gamma and rho{0}->pi{0}pi{0}gamma decays are calculated using a phenomenological approach by adding to the amplitude calculated within the framework of chiral perturbation theory and vector meson dominance the amplitude of sigma-meson intermediate state. In all the decays studied the scalar meson intermediate states make important contributions to the overall amplitude.Ph.D. - Doctoral Progra