摘要
The recent measurement of the muon anomalous magnetic moment (Formula presented) shows a (Formula presented) deviation from the standard model value. We show that it puts strong constraints on the parameter space of the two-Higgs-doublet model (2HDM) II. The dominant contribution of the Higgs bosons comes at the two-loop level, and in order to explain the data it favors a pseudoscalar A with a light mass range and a large (Formula presented) At 95% C.L., the upper limit for (Formula presented) is 29 (55) (85) GeV for (Formula presented) (45) (60), and (Formula presented) is bounded below at 17. This is in sharp contrast to the conclusion one draws from considering one-loop Higgs contributions alone. Finally, we also discuss the role of the Higgs contributions in the minimal supersymmetric standard model. © 2001 The American Physical Society.