Higgs boson-mu-tau coupling at high and low energy colliders

There is no tree-level flavor changing neutral current (FCNC) in the standard model (SM) which contains only one Higgs doublet. If more Higgs doublets are introduced for various reasons, the tree-level FCNC would be inevitable, except that extra symmetry was imposed. Therefore, FCNC processes are an excellent probe for physics beyond the SM (BSM). In this paper, we study the lepton flavor violated decay processes h -> mu tau and tau -> mu gamma induced by the Higgs boson-mu-tau vertex. For tau -> mu gamma its branching ratio is also related to the ht (t) over bar, h tau(+)tau(-), and hW(+)W(-) vertices. We categorize the BSM into two scenarios for the Higgs boson coupling strengths near or away from the SM. For the latter scenario, we take the spontaneously broken two Higgs doublet model (the Lee model) as an example. We consider the constraints by recent data from the LHC and B factories, and we find that the measurements give weak constraints. At LHC run II, h -> mu tau will be confirmed or will have a stricter limit set on its branching ratio. Accordingly, Br(tau -> mu gamma) less than or similar to O (10(-10) - 10(-8)) for general chosen parameters. For the positive case, tau -> mu gamma can be discovered with O(10(10)) tau pair samples at the SuperB factory, the Super tau-charm factory, and the new Z factory. The future measurements for Br(h -> mu tau) and Br(tau -> mu tau) will be used to distinguish these two scenarios or set strict constraints on the correlations among different Higgs couplings.Natural Science Foundation of China [11135003, 11375014]SCI(E)ARTICLE39