sin$^2 \theta_W$ theory and new physics

TL;DR

This paper explores how a light dark Z boson could influence low-Q^2 parity tests, emphasizing the importance of precise measurements of the weak mixing angle for detecting new physics beyond the Standard Model.

Contribution

It introduces the concept of a dark Z boson affecting low-energy parity experiments and discusses its implications for new physics searches.

Findings

Dark Z can modify parity test results at low Q^2

Precise measurements of the weak mixing angle are crucial for new physics detection

Dark Z couples to electromagnetic and weak neutral currents

Abstract

After briefly discussing the importance of the precise measurement of the weak mixing angle, we discuss the implication of the dark Z on the low-Q^2 parity tests. The dark Z is a very light (roughly, MeV - GeV scale) gauge boson, which couples to the electromagnetic current as well as the weak neutral current.