Abstract
Abstract It is shown that substantially enhanced Higgs to diphoton rate induced by light staus with large left-right mixing in MSSM requires at the GUT scale non-universal gaugino masses with bino and/or wino lighter than gluino. The possibility of such enhancement is investigated in MSSM models with arbitrary gaugino masses at the GUT scale with additional restriction of top-bottom-tau Yukawa unification, as predicted by minimal SO(10) GUTs. Many patterns of gaugino masses leading to enhanced Higgs to diphoton rate and the Yukawa unification are identified. Some of these patterns can be accommodated in a well-motivated scenarios such as mirage mediation or SUSY breaking F -terms being a non- singlet of SO(10). Phenomenological implications of a scenario with non-universal gaugino masses generated by a mixture of the singlet F -term and the F -term in a 24-dimensional representation of SU(5) ⊂ SO(10) are studied in detail. Possible non-universalities of other soft terms generated by such F-terms are discussed. The enhancement of Higgs to diphoton rate up to 30% can be obtained in agreement with all phenomenological constraints, including vacuum metastability bounds. The lightest sbottom and pseudoscalar Higgs are within easy reach of the 14 TeV LHC. The LSP can be either bino-like or wino-like. The thermal relic abundance in the former case may be in agreement with the cosmological data thanks to efficient stau coannihilation.
Highlights
Model (MSSM) due to mixing between the the two CP-even Higgs bosons [9].1 this effect enhances the Higgs signal strength in the W W ∗ and ZZ∗ by the same amount as in the γγ channel unless partial Higgs decay widths are non-universally modified
It is shown that substantially enhanced Higgs to diphoton rate induced by light staus with large left-right mixing in MSSM requires at the GUT scale non-universal gaugino masses with bino and/or wino lighter than gluino
Assuming D-term splitting of scalar masses, which generically arises in spontaneously broken SO(10) models [47] and is needed to account for proper radiative electroweak symmetry breaking (REWSB) [48], we identify patterns of gaugino masses that may allow for enhanced h → γγ rate
Summary
In the SM, h → γγ is a loop mediated process with a dominant contribution from W ± and a smaller, but non-negligible, contribution from the top quark [56]: ΓSM(h. In the MSSM, non-negligible contributions can originate from very light sfermions provided that. Their Yukawa couplings are large [9]. The candidates for the modification of the Higgs diphoton rate are stops, and at large tan β sbottoms and staus. Light stops and sbottoms with large left-right mixing can enhance Γ(h → γγ) but at the cost of even larger reduction of the Higgs production cross-section via gluon fusion [57].4. Light staus with large left-right mixing can enhance Γ(h → γγ) without affecting the Higgs production rate [10, 11]. In the following subsection we describe the effects of light staus on the Higgs decay rate to two photons in some more detail
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