Precision determination of weak charge of $^{133}$Cs from atomic parity violation

Abstract

We discuss results of the most accurate to-date test of the low-energy electroweak sector of the standard model of elementary particles. Combining previous measurements with our high-precision calculations we extracted the weak charge of the 133Cs nucleus, Q_W = -73.16(29)_exp (20)_th [S.G. Porsev, K. Beloy, and A. Derevianko, Phys. Rev. Lett. {\bf 102}, 181601 (2009)]. The result is in perfect agreement with Q_W^{SM} predicted by the standard model, Q_W^{SM} =-73.16(3), and confirms energy-dependence (or running) of the electroweak interaction and places constraints on a variety of new physics scenarios beyond the standard model. In particular, we increase the lower limit on the masses of extra Z-bosons predicted by models of grand unification and string theories. This paper provides additional details to the Letter. We discuss large-scale calculations in the framework of the coupled-cluster method, including full treatment of single, double, and valence triple excitations. To determine the accuracy of the calculations we computed energies, electric-dipole amplitudes, and hyperfine-structure constants. An extensive comparison with high-accuracy experimental data was carried out