Implications of QCD radiative corrections on high-pT Higgs searches

We discuss the effect of next-to-leading order (NLO) QCD corrections to the Higgsstrahlung process, where the Higgs boson decays to bottom quarks, using a partonic-level fully differential code. First we evaluate the impact of initial- and final-state gluon radiation on the reconstruction of a mass peak with the fat-jet analysis in the boosted regime at the LHC with sqrt(s) = 14 TeV as proposed in Butterworth et al. (2008) [1]. Finally we study the current CMS search strategy for this channel and compare it to the fat-jet procedure at the LHC with sqrt(s) = 8 TeV. Both show that final-state QCD radiation has a sizable effect and should be taken properly into account.Comment: 16 pages, 5 figures, version accepted for publicatio

Implications of Higgs Searches on the Four Generation Standard Model

Within the four generation Standard Model, the Higgs couplings to gluons and to photons deviate in a significant way from the predictions of the three generation Standard Model. As a consequence, large departures in several Higgs production and decay channels are expected. Recent Higgs search results, presented by ATLAS, CMS and CDF, hint on the existence of a Higgs boson with a mass around 125 GeV. Using these results and assuming such a Higgs boson, we derive exclusion limits on the four generation Standard Model. For m_H = 125 GeV, the model is excluded at 99.9% confidence level. For 124 GeV <= m_H <= 127 GeV, an exclusion limit above 95% confidence level is found.Comment: 4 pages, 2 figures; v2: updated LHC results, refined sca

MSSM with mh=125m_{h}=125 GeV in High-Scale Gauge Mediation

After the discovery of SM-like Higgs with $m_{h}=125$ GeV, it is increasingly urgent to explore a solution to the hierarchy problem. In the context of MSSM from gauge-mediated SUSY breaking, the lower bound on gluino mass suggests that the messenger scale $M$ is probably large if the magnitude of $\Lambda\sim 100$ TeV. In this paper, we study $\overline{\mathbf{5}}+ \mathbf{5}$ model with $M\sim 10^{8}-10^{12}$ GeV and $\Lambda\simeq 100$ TeV. For moderate Higgs-messenger coupling, it will be shown a viable model with moderate fine tuning. In this model, $\mu\sim 800$ GeV and $B_{\mu}$ nearly vanishes at input scale, which can be constructed in microscopic model.Comment: 12pp, more discussions adde

The generalised NMSSM at one loop: fine tuning and phenomenology

We determine the degree of fine tuning needed in a generalised version of the NMSSM that follows from an underlying Z4 or Z8 R symmetry. We find that it is significantly less than is found in the MSSM or NMSSM and extends the range of Higgs mass that have acceptable fine tuning up to Higgs masses of mh ~ 130 GeV. For universal boundary conditions analogous to the CMSSM the phenomenology is rather MSSM like with the singlet states typically rather heavy. For more general boundary conditions the singlet states can be light, leading to interesting signatures at the LHC and direct detection experiments.Comment: 20 pages, 9 figures, matches published versio

The Higgs decay rate to two photons in a model with two fermiophobic-Higgs doublets

We consider a three Higgs doublet model with an $S_3$ symmetry in which beside the SM-like doublet there are two fermiophobic doublets. Due to the new charged scalars there is an enhancement in the two-photon decay while the other channels have the same decay widths that the SM neutral Higgs. The fermiophobic scalars are mass degenerated unless soft terms breaking the $S_3$ symmetry are added.Comment: typos were corrected, the figures have been modified and the conclusions were increased. Still contains 15 pages, 2 figure