Skip to main content
eScholarship
Open Access Publications from the University of California

Phenomenological consequences of an enhanced top-quark Yukawa coupling

  • Author(s): Sher, Marc
  • Silverman, Dennis
  • et al.
Abstract

In models with more than one Higgs doublet, the Yukawa couplings of the d-type (u-type) quarks are changed by a factor Ad (Au), which is often a ratio of vacuum expectation values. Abbott, Sikivie, and Wise showed that the KL-KS mass difference places stringent constraints on Au (Au10 for a charged-Higgs-boson mass of mW); however, this bound is very sensitive to the charged-Higgs-boson mass and to small Kobayashi-Maskawa mixing angles. We note that if the enhancement is greater than 4-5, then the top quark’s Yukawa coupling will exceed its strong coupling, even if mt∼35 GeV. The effects of this enhancement on the e+e- cross section, on energy levels, leptonic widths, and decay rate of t-quarkonium, and on top-quark decays are discussed; the former two effects are sensitive to neutral-scalar masses only, the latter to the charged-Higgs-boson mass; all of the effects are insensitive to small mixing angles. We also note that the best limit on Ad comes from recent data on the semileptonic branching ratio of b quarks. © 1985 The American Physical Society.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Main Content
Current View