Type of Document	Dissertation
Author	Mustafayev, Azar
URN	etd-06142006-123342
Title	Phenomenology of Supergravity Models with Non-universal Scalar Masses
Degree	Doctor of Philosophy
Department	Physics, Department of
Advisory Committee	Advisor Name Title Howard Baer Committee Chair Ettore Aldrovandi Committee Member Horst D. Wahl Committee Member Jorge Piekarewicz Committee Member Laura Reina Committee Member
Keywords	NUHM mSUGRA Higgs Mass SUGRA SUSY NMH Dark Matter
Date of Defense	2006-05-02
Availability	unrestricted
Abstract Supersymmetry (SUSY) is one of the most compelling theoretical extensions of the Standard Model. Many physicists believe that the discovery of SUSY may be imminent and that current and upcoming experiments will finally be able to observe it. Because of the large number of parameters and limited information about physics at very high energy, one should combine all available experimental results with cosmological data in order to determine viable models. One of the major unknowns in SUSY is the origin and pattern of the supersymmetry breaking scalar masses. For the sake of simplicity, they are usually taken to be universal at the grand unification (GUT) scale. In this study, we discuss theoretical motivations for scalar mass non-universality and explore its experimental signatures. We show that the seemingly innocuous deviation from universality in scalar masses can significantly alter our expectations in terms of dark matter as well as (s)particle physics phenomenology. This dissertation is devoted to the analysis of scalar mass non-universality in supergravity models and consists of two parts. After a brief review of phenomenology of models with universality, in the first part, we relax universality of scalar mass terms between generations at GUT scale. This should be done with great care - breaking generational universality of the GUT-scale soft masses induces flavor-violating processes at the weak scale. We find that recent constraints from $b ightarrow sgamma$, $(g-2)_mu$ and relic density of neutralino Dark Matter can be simultaneously satisfied if one makes the third generation scalar masses heavier than the degenerate first and second generation scalar masses. This scenario has light sleptons that yield large rates for multilepton processes that, as we have shown in our study, make it testable at the LHC, LC and possibly at the Tevatron. In the second part, we have examined the possibility that the soft SUSY breaking mass parameters in the Higgs sector are unrelated to the matter scalar masses $m_0$. We conducted extensive investigation of one and two parameter models of this type. Previously it was known that making Higgs mass squared parameters independent of $m_0$ and positive can lower relic density for almost any mSUGRA point. In this study we have found for the first time the particular correlation of Higgs mass squared parameters with other SUSY parameters and experimental observables in the viable parameter space. For example, we have found that allowing Higgs mass squared parameters to take negative values can decrease the axial Higgs boson mass to the A-funnel ($2m_{ z_1}simeq m_A$) with a neutralino relic density in accord with WMAP results even at low $taneta$. This wasn't possible for positive Higgs mass squared parameters. We also study implications of these models for Dark Matter detection experiments and collider searches.
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