Search for Muonic Dark Forces at BABAR

TL;DR

This paper reports on searches for light Higgs states, dark photons, and a muonic dark force using BABAR data, significantly tightening constraints on these hypothetical particles and interactions beyond the Standard Model.

Contribution

First search for a muonic dark force mediated by a $Z'$ gauge boson coupling to second and third lepton families using BABAR data.

Findings

No evidence found for the hypothesized particles or forces.

Results set new upper limits, improving previous bounds.

Remaining parameter space for these models is further constrained.

Abstract

Many models of physics beyond Standard Model predict the existence of light Higgs states, dark photons, and new gauge bosons mediating interactions between dark sectors and the Standard Model. Using a full data sample collected with the BABAR detector at the PEP-II $e^+e^-$ collider, we report searches for a light non-Standard Model Higgs boson, dark photon, and a new muonic dark force mediated by a gauge boson ($Z'$) coupling only to the second and third lepton families. Our results significantly improve upon the current bounds and further constrain the remaining region of the allowed parameter space.