41 hep - ph / 9507375 IMPACT OF ATOMIC PARITY VIOLATION MEASUREMENTS

The impact of atomic parity violation experiments on determination of the weak mixing parameter sin θ and the Peskin-Takeuchi parameters S and T is reassessed in the light of recent electroweak measurements at LEP, SLAC, and Fermilab. Since the weak charge QW provides unique information on S, its determination with a factor of four better accuracy than present levels can have a noticeable effect on global fits. However, the measurement of ∆QW/QW for two different isotopes provides primarily information on sin θ. To specify this quantity to an accuracy of ±0.0004, comparable to that now provided by other electroweak experiments, one would have to determine ∆QW/QW in cesium to about 0.1% of its value, with comparable demands for other nuclei. The relative merits of absolute measurements ofQW and isotope ratios for discovering effects of new gauge bosons are noted briefly. To be submitted as a Brief Report to Phys. Rev. D. Permanent address.