INPAC-Seminar 115：Multiple/Degenerate 125 GeV Higgs scenarios within the NMSSM and 2HDM perspectives (Dr. Yun Jiang, Dec.14, 2012)

Title: Multiple/Degenerate 125 GeV Higgs scenarios within the NMSSM and 2HDM perspectives

Speaker: Dr. Yun Jiang, U.C. Davis

Time and place: 12:30-13:30, December 14th (Friday), 2012, Lecture Hall/INPAC

Abstract:

We assessed the extent to which various semi-constrained NMSSM(scNMSSM) scenarios with, at least, a near 125 GeV Higgs is able to describe the Higgs-like signal at the LHC and Tevatron. In light of the fact that broadened mass peaks are natural, we proposed a novel idea--“degenerate Higgs” and examined scNMSSM scenarios in which both the lightest Higgs h1 and the second lightest Higgs h2 have mass near 125 GeV. As expected, very substantially enhanced diphoton and other signals are possible. We then developed diagnostic tools that could discriminate whether this degeneracy, contributing to the LHC signals at 125 GeV, exists. In addition, two interesting multiple Higgs scenarios (i) 125 GeV+136 GeV LHC-Tevatron scenario and (ii) 98+125 LEP-LHC scenario will be presented. Both scenarios can be consistent with practically all available signal rates, including a reduced rate in the bb (tautau) channel around 98 (125) GeV in the former (latter) scenario. The former scenario has additionally the best fit to the Tevatron results in the bb channel and the mild excesses in CMS data in the diphoton channel at 136 GeV and in the tautau channel above 132 GeV. Phenomenological consequences of these multiple/degenerate Higgs scenarios are discussed. Furthermore, the level of enhancement that can be achieved in the diphoton and ZZ channels for a two-Higgs-doublet model (2HDM) Higgs boson with mass near 125 GeV will be also briefly mentioned.