345 research outputs found

    Branching Ratio and CP-asymmetry for B-> 1^{1}P_{1}gamma decays

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    We calculate the branching ratios for B_{d}^{0}->(b_{1},h_{1})gamma at next-to-leading order (NLO) of alpha_{s} where b_{1} and h_{1} are the corresponding radially excited axial vector mesons of rho and omega respectively. Using the SU(3)symmetry for the form factor, the branching ratio for B_{d}^{0}->(b_{1},h_{1})gamma is expressed in terms of the branching ratio of the B_{d}^{0}-> K_{1}gamma and it is found to be B(B_{d}^{0}->b_{1}gamma)=0.71* 10^{-6} and B(B_{d}^{0}-> h_{1}gamma) =0.74*10^{-6}. We also calculate direct CP asymmetry for these decays and find, in confirmity with the observations made in the literature, that the hard spectator contributions significantely reduces the asymmetry arising from the vertex corrections alone. The value of CP-asymmetry is 10% and is negative like rho and omega in the Standard Model.Comment: 10 pages, 2 figure

    Two-Higgs-Doublet type-II and -III models and tcht\to c h at the LHC

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    We study the constraints of the generic two-Higgs-doublet model (2HDM) type-III and the impacts of the new Yukawa couplings. For comparisons, we revisit the analysis in the 2HDM type-II. To understand the influence of all involving free parameters and to realize their correlations, we employ χ\chi-square fitting approach by including theoretical and experimental constraints, such as S, T, and U oblique parameters, the production of standard model Higgs and its decay to γγ\gamma\gamma, WW/ZZWW^*/ZZ^*, τ+τ\tau^+\tau^-, etc. The errors of analysis are taken at 68%68\%, 95.5%95.5\%, and 99.7%99.7\% confidence levels. Due to the new Yukawa couplings being associated with cos(βα)\cos(\beta-\alpha) and sin(βα)\sin(\beta -\alpha), we find that the allowed regions for sinα\sin\alpha and tanβ\tan\beta in the type-III model can be broader when the dictated parameter χF\chi_F is positive; however, for negative χF\chi_F, the limits are stricter than those in the type-II model. By using the constrained parameters, we find that the deviation from the SM in the hZγh\to Z\gamma can be of O(10%){\cal O}(10\%). Additionally, we also study the top-quark flavor-changing processes induced at the tree level in the type-III model and find that when all current experimental data are considered, we get Br(tc(h,H))<103Br(t\to c(h, H) )< 10^{-3} for mh=125.36m_h=125.36 and mH=150m_H=150 GeV and Br(tcA)Br(t\to cA) slightly exceeds 10310^{-3} for mA=130m_A =130 GeV.Comment: 22 pages, 11 figures. v3: Slight change in the abstract, Figure.1 added and commented, the conclusion remains unchange
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