2011/12/14 by Gang Guo, Bo Ren, Guo, Gang +3
Computer Science · Physics and Astronomy · #Computational Physics and Python Applications #Distributed and Parallel Computing Systems #Particle physics theoretical and experimental studies #hep-ex #hep-ph
paper · pdf · doi:10.48550/arxiv.1112.3188
Latex 5 pages and 4 figures. A few references added
arxiv created 2011/12/23 · arxiv updated 2011/12/26
Searches for Higgs boson at the LHC have excluded standard model (SM) Higgs boson mass in the range between 127 GeV to 600 GeV. With a fourth generation, the excluded range is wider. To close the windows between 114 GeV to 127 GeV, the mode H → γγ plays an important role. There are evidences that the Higgs boson mass is about 126 GeV from LHC data. H→ γγ can occur at one loop level in the SM. In the SM with three generations (SM3), the dominant contribution is from W boson with some cancellation from top quark in the loop. With SM4, the large mass of the fourth generation quarks and charged lepton cancel the W boson contribution significantly, the decay width is suppressed by a factorin the range of 0.25 ∼ 0.55 for the fourth generation mass in the range of 500 to 1000 GeV. This reduction factor makes σ(pp→ H X)Br(H→ γγ) for SM4 comparable to that for SM3 for Higgs boson mass in the window allowed mentioned earlier. Using H → γγ alone, therefore, it is difficult at present to distinguish whether the Higgs boson is from SM3 or SM4. We also comments on some other detection channels.