Muon anomaly and dark parity violation.

Area of Science:

• Particle Physics
• Astrophysics
• Cosmology

Background:

• The muon anomalous magnetic moment shows a 3.6σ deviation between experimental and theoretical values.
• A light vector boson, the dark Z (Z(d)), is a potential explanation, interacting via kinetic mixing.
• Astrophysical theories propose a U(1)(d) gauge symmetry in dark matter sectors, supporting the dark Z boson hypothesis.

Purpose of the Study:

• To investigate the implications of mass mixing between the dark Z boson (Z(d)) and the standard Z boson.
• To explore the potential for observing "dark" parity violation in atomic and polarized electron scattering experiments.
• To establish constraints on the Z(d) boson's properties and its mixing with the standard Z boson.

Main Methods:

• Analyzing the effects of mass mixing between Z(d) and Z bosons.
• Evaluating existing atomic parity violation data to constrain mixing parameters.
• Projecting the sensitivity of future polarized electron scattering experiments.

Main Results:

• Mass mixing introduces a novel source of "dark" parity violation.
• Existing atomic parity violation experiments set restrictive bounds: δ² < 2×10⁻⁵.
• Future experiments aim for sensitivity up to δ² ∼ 10⁻⁶.

Conclusions:

• The dark Z boson, if it exists, could be detected through "dark" parity violation.
• Atomic and polarized electron scattering experiments provide complementary probes to direct searches.
• This research offers a pathway to constrain or discover the dark Z boson and its interactions.