Constraints on the dark photon from parity violation and the $W$ mass

TL;DR

This paper analyzes how a dark photon could explain parity violation measurements and the W-boson mass anomaly, suggesting a heavy dark photon above the Z boson mass fits the data well.

Contribution

It provides new constraints on dark photon parameters from parity violation experiments and the W mass anomaly, highlighting a preference for a heavy dark photon.

Findings

Favored dark photon mass above Z boson mass

Relieves tension in neutron skin thickness measurements

Explains W-boson mass anomaly

Abstract

We present an analysis of the experimental data for parity-violating electron scattering (PVES) and atomic parity-violation, including the effects of a dark photon. We derive the favored region of dark photon parameter space, which provides a good description of the experimental data from the Qweak Collaboration and the Jefferson Lab PVDIS Collaboration and simultaneously relieves the tension between the neutron skin thickness determined in the PREX-II experiment and nuclear-model predictions. In addition, we extract the parameter region required to explain the latest W-boson mass anomaly. Our results indicate that a heavy dark photon with mass above the Z boson mass is favored, while other sources of new physics beyond the Standard Model in addition to the dark photon would also be expected.