分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-06-28
摘要： After the discovery of a standard model (SM)-like Higgs boson, naturalness strongly favors the next-to-minimal supersymmetric SM. In this letter, we point out that the natural next-to-minimal supersymmetric SM usually predicts the following CP-even Higgs H-i sector: (A) H-2 is the SM-like Higgs boson with mass pushed upward by a lighter H-1 with mass overwhelmingly within [m(H2)/2, m(H2)]; (B) m(H3) similar or equal to 2 mu/sin 2 beta greater than or similar to 300 GeV; (C) H-3 has a significant coupling to the top quark and can decay to H1H2 with a large branching ratio. Using a jet substructure we show that these three Higgs bosons can be discovered via gg -> H-3 -> H1H2 -> b (b) over barl nu jj at the 14 TeV LHC. In particular, the LEP-LHC scenario with H-1 similar or equal to 98 GeV has a very good discovery potential.
分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-06-27
摘要： We perform a detailed semianalytical analysis of the electroweak phase transition (EWPT) property in the Next-to-Minimal Supersymmetric standard model, which serves as a good benchmark model in which the 126 GeV Higgs mixes with a singlet. In this case, a strongly first-order electroweak phase transition (SFOEWPT) is achieved by the tree-level effects, and the phase transition strength gamma(c) is determined by the vacua energy gap at T = 0. We make an anatomy of the energy gap at both tree level and loop level and extract out a dimensionless phase transition parameter R-kappa equivalent to 4 kappa v(s)/A(kappa), which can replace A(kappa) in the parameterization and affect the light CP-odd/even Higgs spectra. We find that SFOEWPT only occurs in R-kappa similar to -1 and positive R-kappa less than or similar to O(10), which in the non-PQ limit case would prefer either a relatively light CP-odd or CP-even Higgs boson similar to(60, 100) GeV, and therefore serves as a smoking gun signal and requires new search strategies at the LHC.
分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-05-15
摘要： We propose a realistic flipped SU(5) model derived from a five-dimensional orbifold SO(10) model. The Standard Model (SM) fermion masses and mixings are explained by combining the traditional Froggatt-Nielsen mechanism with the five-dimensional wave function profiles of the SM fermions. Employing tree-level spontaneous R-symmetry breaking in the hidden sector and extra( ordinary) gauge mediation, we obtain realistic supersymmetry breaking soft mass terms with non-vanishing gaugino masses. Including the messenger fields at the intermediate scale and Kaluza-Klein states at the compactification scale, we study gauge coupling unification. We show that the SO(10) unified gauge coupling is very strong and the unification scale can be much higher than the compactification scale. We briefly discuss proton decay as well.
分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-05-14
摘要： To obtain a standard model-like Higgs boson around 125 GeV in the minimal supersymmetric standard model with minimal gauge mediation of supersymmetry breaking (GMSB), a heavy stop at multi-TeV level is needed and incurs severe fine-tuning, which can be ameliorated in the framework of the deformed GMSB with visible-hidden direct Yukawa interactions (YGMSB). We examine some general features of the YGMSB and focus on the scenario with Higgs-messenger couplings (HYGMSB) which can automatically maintain the minimal flavor violation. It turns out that such a Yukawa mediation scenario can give a large -Lambda(t) and -m((t) over tildeL,R)(2), leading to a maximal stop mixing, and thus can readily give a light stop ((t) over tilde (1)) below the TeV scale. However, we find that in the minimal HYGMSB scenario, m(Hu)(2) is too large and then the electroweak symmetry breaking is inconsistent with the large stop mixing. To solve this problem, we modify the hidden sectors in two ways, adding a new strong gauge dynamics or introducing the (10, (10) over bar) messengers. For each case we present some numerical studies.
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