Process Z -> h(A)+gamma in the 2HDM and the experimental constraints from LEP

Citation
M. Krawczyk et al., Process Z -> h(A)+gamma in the 2HDM and the experimental constraints from LEP, EUR PHY J C, 8(3), 1999, pp. 495-505
Citations number
54
Categorie Soggetti
Physics
Journal title
EUROPEAN PHYSICAL JOURNAL C
ISSN journal
14346044 → ACNP
Volume
8
Issue
3
Year of publication
1999
Pages
495 - 505
Database
ISI
SICI code
1434-6044(199905)8:3<495:PZ-HIT>2.0.ZU;2-A
Abstract
The one-loop branching ratios for the process Z-->h(A)+ gamma are calculate d in the general two Higgs doublet model (Model II), taking into account ex isting constraints on the model parameters. For Higgs boson masses below 50 GeV and tan beta of O(1 - 10) the fraction of such Z decays are at the lev el of 10(-7), but can be significantly stronger for very low or high tan be ta, where the dependence of these results on other model parameters like si n(beta - alpha) and the mass of the charged Higgs boson is found to be of l ittle importance. The results are compared to the LEP measurements, which a re sensitive to branching ratios of Z-->h(A)+ gamma of the order 10(-5) for masses greater than or equal to 20 GeV, but approach 10(-6) for low masses . By relating the expectation to the experimental limits, constraints on th e parameter space of the 2HDM are derived.