Hot Topics From BABAR Experiment

TL;DR

This paper reports on searches for a hypothetical light CP-odd Higgs boson in radiative decays of Upsilon resonances, using large datasets collected by the BaBar experiment to look for invisible or muon/tau decay modes.

Contribution

It presents the first search for a light scalar particle in single-photon decays of Upsilon(3S) and for invisible Upsilon(1S) decays recoiling against dipions, expanding the search for non-Standard Model Higgs bosons.

Findings

No evidence of the light Higgs boson was found.

Sets new upper limits on branching fractions for these decay modes.

Constrains parameter space for non-Standard Model Higgs models.

Abstract

We search for a new light non-Standard Model CP-odd Higgs boson, $A^0$, decaying to $\tau^+\tau^-$, $\mu^+\mu^-$, and invisible in radiative decays of the $\Upsilon(2S)$ and $\Upsilon(3S)$. We search for the light scalar particle produced in single-photon decays of the $\Upsilon(3S)$ resonance through the process $\Upsilon(3S) \to \gamma A^0, A^0 \to$ invisible. We also search for evidence of an undetectable $\Upsilon(1S)$ decay recoiling against the dipion system. The data samples contain $99 \times 10^6 \Upsilon(2S)$ and $122 \times 10^6 \Upsilon(3S)$ decays collected by the \babar\ detector at the SLAC PEP-II $B$ factory.