Precision muon g-2 results and light Higgs bosons in the 2HDM(II)

TL;DR

Recent muon g-2 measurements suggest a deviation from the Standard Model, allowing constraints on light Higgs bosons in the 2HDM(II), excluding some scenarios and permitting others within specific parameter ranges.

Contribution

This paper derives constraints on light Higgs bosons in the 2HDM(II) using the latest muon g-2 results, highlighting which scenarios are excluded or allowed.

Findings

Light-scalar scenario excluded at 95% CL.

Light-pseudoscalar scenario viable with 25-70 GeV mass and tan beta between 25 and 115.

Constraints tighten the parameter space for light Higgs bosons in 2HDM(II).

Abstract

We discuss the implications of the recent evaluations of the SM contribution to a_mu=(g-2)_mu/2 in the light of the latest E821 measurement, which indicate \~ 3 sigma deviation. We derive the 95 % CL interval, delta a_mu, to be used to constrain any additional contribution to a_mu, beyond the SM ones; it has to have a positive sign. We apply the delta a_mu to constrain the light Higgs-boson scenarios in a Two-Higgs-Doublet-Model (``Model II''). If the constraints from the new (g-2)_mu results are combined with the other existing constraints, one can exclude a light-scalar scenario at 95 % CL, while a light-pseudoscalar scenario can be realized, for a pseudoscalar mass between 25 and 70 GeV, with tan beta in the range 25 < tan beta < 115.