We implement the Fock-space perturbed relativistic coupled-cluster (FSPRCC) theory to compute the electric dipole polarizability of ground and low-lying excited states and nuclear spin-dependent (NSD) parity nonconservation (PNC) transition amplitudes in Cs. Further, by combining our computed NSD-PNC transition amplitudes with a Cs experiment [C. S. Wood et al., Science 275, 1759 (1997)], we extract the value of the nuclear anapole moment and pion-mediated meson-nucleon coupling constant $f_{\pi }$. The deviation in our $f_{\pi }$ from the standard model value could be attributed to the existence of new particles such as $Z^{\prime }$ bosons. By combining our nuclear spin-independent PNC calculation with experiment [Science 275, 1759 (1997)], we extract the mass of the $Z^{\prime }$ boson to be $M_{Z^{\prime }}>1.6$ TeV/${\mathrm{c}}^2$. To check the accuracy of the wave functions used in the calculations, we compute the excitation energies, $E1$ transition amplitudes, and magnetic dipole hyperfine constants for ground and low-lying excited states. To improve the accuracy of the computed properties, we incorporate the corrections from the relativistic and QED effects in our calculations. The contributions from triple excitations are accounted for perturbatively. Our results on excitation energies, $E1$ transition amplitudes, and hyperfine constants are in good agreement with the available experimental results. Our polarizability results using the FSPRCC theory match well with the experimental values. The values of parity-violating transition amplitudes from our calculations are in general on the lower side of the previous values. From a detailed analysis of electron correlations, we find that the corrections from the Breit interaction and QED effects are important to get accurate results of NSD-PNC amplitudes in Cs. The largest cumulative contribution from the Breit and QED corrections is found to be approximately equal to 3.2% of the total value. The upper bound on the theoretical uncertainty in our calculated NSD-PNC amplitudes is estimated to be about 1%.

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• Electron correlation calculations for atoms & ions
• Electronic structure of atoms & molecules
• Relativistic & quantum electrodynamic effects in atoms, molecules,& ions