Constraining Extra Neutral Gauge Bosons with Atomic Parity Violation Measurements
Abstract
The discovery of a new neutral gauge boson, Z', could provide the first concrete evidence of physics beyond the standard model. We explore how nuclear weak charge measurements in atomic parity violation (APV) experiments can be used to constrain Z' bosons. We use the recent measurement of the 133Cs nuclear weak charge to estimate lower bounds on the mass of Z' bosons for a number of representative models and to put constraints on the couplings of a newly discovered Z' boson. We also consider how these constraints might be improved by future APV experiments that will measure nuclear weak charges of multiple isotopes. We show how measurements of a single isotope, and combining measurements into ratios and differences, can be used to constrain the couplings of a Z' and discriminate between models. We find that current and future APV experiments could potentially play an important role in unravelling new physics if a Z' were discovered.