Yukawa coupling unification in S O ( 10 ) with positive μ and a heavier gluino

Physical review D: Particles and fields (Impact Factor: 4.86). 06/2012; 86(3). DOI: 10.1103/PhysRevD.86.035019
Source: arXiv


The t-b-tau unification with positive Higgs mass parameter \mu\ in the
minimal supersymmetric standard model prefers "just so" Higgs splitting and a
light gluino < 500 GeV which appears to be ruled out by the recent LHC
searches. We reanalyze constraints on soft supersymmetry breaking parameters in
this scenario allowing independent splittings among squarks and Higgs doublets
at the grand unification scale and show that it is possible to obtain t-b-tau
unification and satisfy experimental constraints on gluino mass without raising
supersymmetry breaking scale to very high value ~ 20 TeV. We discuss the origin
of independent squark and Higgs splittings in realistic SO(10) models. Just so
Higgs splitting can be induced without significantly affecting the t-b-tau
unification in SO(10) models containing Higgs fields transforming as
10+\bar{126}+126+210. This splitting arises in the presence of non-universal
boundary conditions from mixing between 10 and other Higgs fields. Similarly,
if additional matter fields are introduced then their mixing with the matter
multiplet 16 is shown to generate the squark splitting required to raise the
gluino mass within the t-b-tau unified models with positive \mu.

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Available from: Ketan M Patel, Jun 28, 2014
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    • "The effects of these supersymmetric threshold corrections are important especially in the era of precision Higgs couplings and flavor physics and has been a part of many analysis. For some recent work, see [4] [5] [6] [7] [8] [9] [10] [11]. "
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    ABSTRACT: Threshold corrections to the bottom quark mass are often estimated under the approximation that tan$\beta$ enhanced contributions are the most dominant. In this work we revisit this common approximation made to the estimation of the supersymmetric threshold corrections to the bottom quark mass. We calculate the full one-loop supersymmetric corrections to the bottom quark mass and survey a large part of the phenomenological MSSM parameter space to study the validity of considering only the tan$\beta$ enhanced corrections. Our analysis demonstrates that this approximation severely breaks down in parts of the parameter space. The size of the threshold corrections has significant consequences for the estimation of fits to the bottom quark mass, couplings to Higgses, and flavor observables, and therefore the approximate expressions must be replaced with the full contributions for accurate estimations.
    Preview · Article · Nov 2014 · Journal of High Energy Physics
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    • "Although tbτ YU may be spoiled by the addition of extra fields, realistic charged fermions and neutrino masses can be obtained if we assume that the MSSM Higgs doublets H u,d are a superposition of the components that reside in distinct SO(10) representations [25] [26] [27] [28]. To preserve tbτ YU alongside with correct fermion masses, the contributions to H u,d from the extra Higgs fields must be small (see [29] and references therein). However, if those contributions are sizable we can still have tbτ Quasi-Yukawa unification (QYU) [30]. "
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    ABSTRACT: We study models of supersymmetric grand unification based on the SO(10) gauge group. We investigate scenarios of non-universal gaugino masses including models containing a mixture of two representations of hidden sector chiral superfields. We analyse the effect of excluding mu from the fine-tuning measure, and confront the results with low energy constraints, including the Higgs boson mass, dark matter relic density and supersymmetry bounds. We also determine high scale Yukawa coupling ratios and confront the results with theoretical predictions. Finally, we present two additional benchmarks that should be explored at the LHC and future colliders.
    Preview · Article · Aug 2014 · Journal of High Energy Physics
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    • "Large values of tan β can explain the observed hierarchy between the top and bottom masses [30] and are predicted in minimal SO(10) models since they impose unification of top, bottom and tau Yukawa couplings at the GUT scale ([31] [32]; for some more recent works see e.g. [33] [34] [35] [36] [37] [38] [39]). Therefore, these models are perfect candidates to accommodate enhanced h → γγ rate. "
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    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) $\subset$ 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.
    Preview · Article · Jul 2013 · Journal of High Energy Physics
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