Testing top-quark Yukawa interactions in e+e--->tt¯Z
Abstract
The determination of the top-quark Yukawa couplings in the process e+e--->tt¯Z is studied for the high luminosity option (∫L=500 fb-1) of a linear e+e- collider. Polarization of the electron beam is considered. The method of optimal observables is adopted to determine the couplings and to disentangle different models. It is found that it could be possible to discriminate between the standard model scalar Higgs boson, a pure pseudoscalar, and the Higgs boson of mixed CP at about the 12σ level for s=1. TeV for a Higgs boson mass slightly above twice the top-quark mass both for the leptonic and hadronic top-quark decay channels. However, the s=0.5 TeV collider turns out to have too small energy for tests of the top-quark Yukawa coupling because of its limited production rate (at most a 2.5σ effect). Possible tests of CP violation in the scalar sector are considered.
- Publication:
-
Physical Review D
- Pub Date:
- December 1999
- DOI:
- 10.1103/PhysRevD.60.115018
- arXiv:
- arXiv:hep-ph/9907206
- Bibcode:
- 1999PhRvD..60k5018G
- Keywords:
-
- 14.80.Cp;
- 14.65.Ha;
- Non-standard-model Higgs bosons;
- Top quarks;
- High Energy Physics - Phenomenology
- E-Print:
- 17 pages, references added, typos and a few minor imprecise comments corrected