Radiative Upsilon decays and a light pseudoscalar Higgs in the NMSSM

TL;DR

This paper investigates how a light CP-odd Higgs in the NMSSM could influence radiative Upsilon decays, providing constraints from experiments and exploring potential signals like Higgs-eta_b mixing and lepton universality violations.

Contribution

It offers a detailed analysis of the impact of a light CP-odd Higgs on Upsilon decays, translating experimental constraints into parameter space limits and discussing observable effects.

Findings

Constraints on CP-odd Higgs mass and couplings from CLEO data.

Possible explanation of hyperfine splitting via Higgs-eta_b mixing.

Predicted signals of lepton universality violation in future experiments.

Abstract

We study possible effects of a light CP-odd Higgs boson on radiative Upsilon decays in the Next-to-Minimal Supersymmetric Standard Model. Recent constraints from CLEO on radiative Upsilon(1S) decays are translated into constraints on the parameter space of CP-odd Higgs boson masses and couplings, and compared to constraints from B physics and the muon anomalous magnetic moment. Possible Higgs - eta_b(nS) mixing effects are discussed, notably in the light of the recent measurement of the eta_b(1S) mass by Babar: The somewhat large Upsilon(1S) - eta_b(1S) hyperfine splitting could easily be explained by the presence of a CP-odd Higgs boson with a mass in the range 9.4 - 10.5 GeV. Then, tests of lepton universality in inclusive radiative Upsilon decays can provide a visible signal in forthcoming experimental data.