Resolving the PREX-CREX puzzle in covariant density functional theory

TL;DR

This paper resolves the PREX-CREX puzzle in nuclear physics by modifying covariant density functional theory to include an enhanced isovector tensor coupling, reconciling experimental discrepancies in lead and calcium isotopes.

Contribution

It introduces an enhanced isovector tensor coupling in covariant density functional theory to solve the PREX-CREX puzzle, a longstanding challenge in nuclear structure analysis.

Findings

The puzzle can be resolved within covariant density-dependent point-coupling density functional theory.

Enhanced isovector tensor coupling leads to a stronger isovector spin-orbit interaction.

The approach reconciles parity-violating electron-scattering results for $^{208}$Pb and $^{48}$Ca.

Abstract

The PREX-CREX puzzle, an apparent tension between parity-violating electron-scattering results for $^{208}$Pb and $^{48}$Ca revealed by modern density functional analyses, has posed a major challenge for nuclear theory. We show that this puzzle can be resolved within covariant density-dependent point-coupling density functional theory by introducing an enhanced isovector tensor coupling. A nonrelativistic reduction identifies the resulting strong isovector spin-orbit interaction as the key mechanism that reconciles the PREX and CREX measurements.