Parity violating measurements of neutron densities

Accurate calibration of relativistic mean-field models: Correlating observables and providing meaningful theoretical uncertainties

“…Such a strong correlation is consistent with two recent studies that employ a large number of accurately-calibrated relativistic and non-relativistic interactions to uncover the correlation [47,48]. Also consistent with recent studies [6,48], is the fact that the proposed 1% measurement of the neutron radius of 208 Pb by the PREx collaboration [42,43] may not be able to place a significant constrain on L. For example, our covariance analysis suggests that the 20% uncertainty assumed for L translates into a theoretical error in the neutron skin of 0.037 fm-or about a 0.7% uncertainty in the neutron radius of 208 Pb. Conversely, if L is to be determined to within 10% (i.e., L ≈ 60 ± 6 MeV) then the neutron skin must be constrained to about 0.018 fm so the neutron radius must be measured with close to a 0.3% accuracy-a fairly daunting task.…”

Neutron skin and giant resonances in nuclei

“…Also, from the experimentally known charge density distribution the Coulomb mean field U C (r) can be calculated rather accurately, and hence one can determine the small difference between Eqs. (9) and (8). But at the level of 1% accuracy several theoretical effects discarded in Eq.…”

“…The weak charge is mainly determined by neutrons ρ W (r) = (1 − 4 sin 2 θ W )ρ p (r) − ρ n (r), with sin 2 θ W ≈ 0.23. In a scattering experiment using polarized electrons one can determine the cross section asymmetry [8] which comes from the interference between the A and V contributions. Using the measured neutron form factor at small finite value of Q 2 and the existing information on the charge distribution one can uniquely extract the neutron skin.…”

“…Parity violating electron scattering off nuclei is probably the least model dependent approach to probe the neutron distribution [8]. The weak electron-nucleus potential isṼ (r) = V (r) + γ 5 A(r), where the axial potential A(r) = G F 2 3/2 ρ W (r).…”

Precision hfs of 126Cs() by ABMR

“…This is important in the interpretation of studies of isotopic variations of parity nonconservation (PNC) in atomic interactions [3] [4], an alternative to precise single isotope studies but in different atomic transitions [5]. PNC has in fact been suggested [6] as a possible source of information on neutron distributions. Neutron star structure and its relation to neutron radii and distributions [7] has also been pointed out as an area of application of BW.…”