Parity nonconservation in thallium - art. no. 052107

We report a calculation of the parity nonconserving (PNC) E1 amplitude for the 6p(1/2)-->6p(3/2) transition in Tl-205. Our result for the reduced matr ix element is (E1)(PNC)= -(66.7 +/- 1.7) x 10(-11)(-Q(w)/N) a.u. Comparison with the experiment of Vetter et al. [Phys. Rev. Lett. 74, 2658 (1995)] gi ves the following result for the weak charge of Tl-205: Q(w)/Q(w)(SM)= 0.97 (+/-0.01)(expt)(+/-0.03)(theor), where Q(w)(SM)= - 116.7+/-0.1 is the stand ard-model prediction. This result confirms an earlier conclusion based on t he analysis of a Cs experiment that atomic PNC experiments are in agreement with the standard model.