Search for Low-mass Dark-Sector Gauge Boson with the BABAR Detector

Abstract

We report searches for a new muonic dark force mediated by a gauge boson ($Z^{\prime }$) coupling only to the second and third lepton families. The existence of the $Z^{\prime }$ boson is probed in $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}{Z}^{\prime }$, $Z^{\prime }\to {\mu }^{+}{\mu }^{-}$ events, with an analysis based on the full data sample collected with the BABAR detector at the PEP-II $e^{+}{e}^{-}$ collider. No significant signal is observed. Limits on dark-sector coupling constants are derived; these improve upon current bounds, and further constrain the allowed parameter space.

arXiv commentComments: Contributed to the Proceedings of the 38th International Conference on High Energy Physics, Chicago, USA. This work was supported by the U.S. Department of Energy. arXiv admin note: substantial text overlap with arXiv:1611.07934