Search for a Light Higgs Boson at BaBar

TL;DR

This study searches for a light Higgs boson in Upsilon(3S) decays, finding no evidence but setting upper limits on its production and decay rates, which constrains extensions of the Standard Model.

Contribution

First search for a light Higgs boson in Upsilon(3S) radiative decays with new upper limits on branching fractions and eta_b di-muon decay.

Findings

No evidence for light Higgs in data

Set 90% C.L. upper limits on branching fractions

Established a limit on eta_b di-muon decay

Abstract

We search for evidence of a light Higgs boson (A0) in the radiative decays of the narrow Upsilon(3S) resonance: Upsilon(3S) -> gamma A0, where A0 -> invisible or A0 -> mu+mu-. Such an object appears in extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. We find no evidence for such processes in a sample of 122 million Upsilon(3S) decays collected by the BaBar collaboration at the PEP II B-factory, and set 90% C.L. upper limits on the product of the corresponding branching fractions. We also set a limit on the di-muon branching fraction of the recently discovered eta_b meson.