# Effect of nuclear quadrupole moment on parity nonconservation in atoms

## TL;DR

This paper investigates how the nuclear quadrupole moment influences parity nonconservation effects in atoms, highlighting potential for measuring neutron distribution in nuclei through atomic PNC experiments.

## Contribution

It calculates the tensor contribution of nuclear quadrupole moments to atomic PNC and identifies atomic systems where this effect is significantly enhanced for experimental detection.

## Key findings

- Small quadrupole-induced PNC in Yb+, Fr, Ra+
- Strong enhancement of PNC in lanthanides and Ra near levels
- Potential to measure neutron quadrupole moments via hyperfine transitions

## Abstract

Nuclei with spin $I \ge 1$ have a weak quadrupole moment which leads to tensor contribution to the parity non-conserving interaction between nuclei and electrons. We calculate this contribution for Yb$^+$, Fr and Ra$^+$ and found it to be small. In contrast, in many lanthanides (e.g., Nd, Gd, Dy, Ho, Er, Pr, Sm) and Ra close levels of opposite parity lead to strong enhancement of the effect making it sufficiently large to be measured. Another possibility is to measure the PNC transitions between the hyperfine components of the ground state of Bi. Since nuclear weak charge is dominated by neutrons this opens a way of measuring quadrupole moments of neutron distribution in nuclei.