A light CP-odd Higgs boson and the muon anomalous magnetic moment

TL;DR

This paper investigates whether a light CP-odd Higgs boson can account for the muon g-2 discrepancy, analyzing experimental constraints within various models and finding it plausible in some extended supersymmetric frameworks.

Contribution

It provides a comprehensive analysis of experimental limits on a light CP-odd Higgs and assesses its potential to explain the muon g-2 anomaly across different theoretical models.

Findings

A light CP-odd Higgs can significantly contribute to muon g-2 in general two-Higgs-doublet models.

The minimal supersymmetric model constraints prevent it from explaining the muon g-2 discrepancy.

Next-to-minimal supersymmetric models can accommodate a light CP-odd Higgs to explain or contribute to muon g-2.

Abstract

We amalgamate the many experimental limits on the $ab\anti b$ coupling of a light CP-odd Higgs boson, $a$, including model-dependence coming from the ratio of the $at\anti t$ to the $a b\anti b$ coupling. We then employ these limits to analyze the extent to which a light $a$ can make a significant contribution to the discrepancy, $\Delta a_\mu$, between the experimentally observed $a_\mu$ and that predicted by the standard model. In a "model-independent" framework and in the context of a general two-Higgs-doublet model this is a significant possibility. In contrast, the minimal supersymmetric model is too strongly constrained (after combining experimental and theoretical input) to allow a CP-odd-$a$ explanation of $\Delta a_\mu$. The next-to-minimal supersymmetric model allows more freedom and the light $a$ of the model could explain the full $\Delta a_\mu$ if $9.2\gev<\ma<12\gev $, or contribute substantially for larger $\ma$, if $\tanb$ is large.