In models with an extended Higgs sector there exists an alignment limit, in which the lightest CP-even Higgs boson mimics the Standard Model Higgs. The alignment limit is commonly associated with the decoupling limit, where all non-standard scalars are significantly heavier than the Z boson. However, alignment can occur irrespective of the mass scale of the rest of the Higgs sector. In this work we discuss the general conditions that lead to "alignment without decoupling", therefore allowing for the existence of additional non-standard Higgs bosons at the weak scale. The values of tan β for which this happens are derived in terms of the effective Higgs quartic couplings in general twoHiggs-doublet models as well as in supersymmetric theories, including the MSSM and the NMSSM. Moreover, we study the information encoded in the variations of the SM Higgsfermion couplings to explore regions in the m A − tan β parameter space.

We consider the possibility of a Standard Model (SM)-like Higgs in the context of the Minimal Supersymmetric Standard Model (MSSM), with a mass of about 125 GeV and with a production times decay rate into two photons which is similar or somewhat larger than the SM one. The relatively large value of the SM-like Higgs mass demands stops in the several hundred GeV mass range with somewhat large mixing, or a large hierarchy between the two stop masses in the case that one of the two stops is light. We find that, in general, if the heaviest stop mass is smaller than a few TeV, the rate of gluon fusion production of Higgs bosons decaying into two photons tends to be somewhat suppressed with respect to the SM one in this region of parameters. However, we show that an enhancement of the photon decay rate may be obtained for light third generation sleptons with large mixing, which can be naturally obtained for large values of tan β and sizable values of the Higgsino mass parameter.

Abstract:Recently, an excess of events consistent with a Higgs boson with mass of about 125 GeV was reported by the CMS and ATLAS experiments. This Higgs boson mass is consistent with the values that may be obtained in minimal supersymmetric extensions of the Standard Model (SM), with both stop masses less than a TeV and large mixing. The apparently enhanced photon production rate associated with this potential Higgs signal may be the result of light staus with large mixing. Large stau mixing and large coupling of the staus to the SM-like Higgs boson may be obtained for large values of tan β and moderate to large values of the Higgsino mass parameter, µ. We study the phenomenological properties of this scenario, including precision electroweak data, the muon anomalous magnetic moment, Dark Matter, and the evolution of the soft supersymmetry-breaking parameters to high energies. We also analyze the possible collider signatures of light third generation sleptons and demonstrate that it is possible to find evidence of their production at the 8 TeV and the 14 TeV LHC. The most promising channel is stau and tau sneutrino associated production, with the sneutrino decaying into a W boson plus a light stau.

We compute the Coleman Weinberg effective potential for the Higgs field in RS Gauge-Higgs unification scenarios based on a bulk SO(5) × U (1) X gauge symmetry, with gauge and fermion fields propagating in the bulk and a custodial symmetry protecting the generation of large corrections to the T parameter and the coupling of the Z to the bottom quark. We demonstrate that electroweak symmetry breaking may be realized, with proper generation of the top and bottom quark masses for the same region of bulk mass parameters that lead to good agreement with precision electroweak data in the presence of a light Higgs. We compute the Higgs mass and demonstrate that for the range of parameters for which the Higgs boson has Standard Model-like properties, the Higgs mass is naturally in a range that varies between values close to the LEP experimental limit and about 160 GeV. This mass range may be probed at the Tevatron and at the LHC. We analyze the KK spectrum and briefly discuss the phenomenology of the light resonances arising in our model. High energy physics experiments in recent years have confirmed the predictions of the Standard Model (SM), a renormalizable, chiral gauge theory based on the group SUIn particular, the low energy dynamics of fermions and gauge bosons of the theory have been tested with great accuracy. The origin of masses of these fundamental particles, however, remains a mystery. In the SM, masses arise through the vacuum expectation value (vev) of a scalar field doublet, which spontaneously breaks the electroweak (EW) symmetryA physical, neutral scalar field, the so called Higgs field, appears in the spectrum. Information on the mass of this scalar particle may be obtained through the quantum corrections that it induces to the masses and couplings of the EW gauge bosons. Consistency of the SM predictions with experimental observations is improved for small values of the Higgs mass, m H , close to the current experimental bound, m H ≥ 114.4 GeV [1].There are several aspects of the mechanism of the origin of mass that demand explanation. On one hand, the scale of the spontaneous symmetry breaking is governed by the size of the scalar mass parameter appearing in the Higgs field effective potential, and is much smaller than the Planck scale, the only known mass scale in nature, besides the dynamical generated QCD scale Λ QCD . Moreover, this scale is associated with a negative value of the squared Higgs mass. There is, however, no dynamical explanation for the origin of the Higgs effective potential, or for the associated breakdown of the EW symmetry. Finally, the hierarchy of the fermion masses of the different generations remains unexplained.Warped extra dimensions provide a theoretically attractive framework for the solution of the hierarchy problem of the SM. For one extra spatial dimension as in RS1 [2], the curvature k in the extra dimension induces a warp factor on the four dimensional metric, which depends on the position in the extra dimension. The coordinate point, x 5 = 0, is associated with a t...