Incorporating the weak mixing angle dependence to reconcile the neutron skin measurement on 208Pb by PREX-II

Abstract

The only available electroweak measurement of the ${}^{208}\mathrm{Pb}$ neutron skin, $\Delta R_{\mathrm{np}}$, performed by the PREX-II Collaboration through polarized electron-lead scattering, shows a mild tension with respect to both the theoretical nuclear-model predictions and a host of measurements. However, the dependence on the weak mixing angle should be incorporated in the calculation, since its low-energy value is experimentally poorly known. We first repeat the PREX-II analysis confirming their measurement by fixing the weak mixing angle to its standard model value. Then, we show the explicit dependence of the PREX-II measurement on the weak mixing angle, obtaining that it is fully degenerate with the neutron skin. To break this degeneracy, we exploit the weak mixing angle measurement from atomic parity violation on lead, obtaining a slightly thinner neutron skin but with about doubled uncertainties, possibly easing the PREX tension. Relying on the theoretical prediction, $\Delta R_{\mathrm{np}}^{\mathrm{th}}\approx 0.13-0.19\mathrm{fm}$, and using it as a prior in the fit, we find a weak mixing angle value about $1.2\sigma$ smaller than the standard model prediction. Thus, we suggest a possible solution of the PREX-II tension by showing that, considering its underlying dependence on the weak mixing angle, the PREX-II neutron skin determination could be in agreement with the other available measurements and predictions if the weak mixing angle at the proper energy scale is smaller than the standard model prediction.

arXiv comment5 pages, 4 figures. Matches published version

References in corpus (48)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• GW170817: Measurements of Neutron Star Radii and Equation of State
• GW190425: Observation of a Compact Binary Coalescence with Total Mass $\sim 3.4M_{\odot }$
• A NICER View of the Massive Pulsar PSR J0740+6620 Informed by Radio Timing and XMM-Newton Spectroscopy
• Accurate Determination of the Neutron Skin Thickness of ${}^{208}$Pb through Parity-Violation in Electron Scattering
• Measurement of the Neutron Radius of 208Pb Through Parity-Violation in Electron Scattering
• Implications of PREX-II on the equation of state of neutron-rich matter
• Neutron skins and neutron stars in the multi-messenger era
• Measurement of the 6S-7S transition polarizablility in atomic cesium and an improved test of the standard model
• Charge, neutron, and weak size of the atomic nucleus
• Parity Violating Measurements of Neutron Densities
• Electric dipole polarizability and the neutron skin
• Precision Measurement of the Weak Mixing Angle in Moller Scattering
• "Dark" Z implications for Parity Violation, Rare Meson Decays, and Higgs Physics
• Precision determination of electroweak coupling from atomic parity violation and implications for particle physics
• The neutron skin thickness from the measured electric dipole polarizability in ${}^{68}$Ni, ${}^{120}$Sn, and ${}^{208}$Pb
• Neutron skin of ${}^{208}$Pb from Coherent Pion Photoproduction
• Astrophysical Constraints on the Symmetry Energy and the Neutron Skin of ${}^{208}$Pb with Minimal Modeling Assumptions
• Revisiting parity non-conservation in cesium
• Weak charge form factor and radius of 208Pb through parity violation in electron scattering
• Precision Measurement of the Weak Charge of the Proton
• Neutron density distributions from antiprotonic 208Pb and 209Bi atoms
• Information content of the parity-violating asymmetry in ${}^{208}$Pb
• Neutron skins of atomic nuclei: per aspera ad astra
• Reconciliation of the Measurement of Parity-Nonconservation in Cs with the Standard Model
• Muon Anomaly and Dark Parity Violation
• The Weak Neutral Current
• Parity Violating Elastic Electron Scattering and Coulomb Distortions
• Atomic Parity Nonconservation: Electroweak Parameters and Nuclear Structure
• A Detailed Examination of Astrophysical Constraints on the Symmetry Energy and the Neutron Skin of ${}^{208}$Pb with Minimal Modeling Assumptions
• Electroweak Measurements of Neutron Densities in CREX and PREX at JLab, USA
• Correlated many-body treatment of Breit interaction with application to cesium atomic properties and parity violation
• Impact of PREX-II and combined Radio/NICER/XMM-Newton's mass-radius measurement of PSRJ0740+6620 on the dense matter equation of state
• The effect of spin-orbit nuclear charge density corrections due to the anomalous magnetic moment on halonuclei
• Reinterpreting the weak mixing angle from atomic parity violation in view of the Cs neutron rms radius measurement from COHERENT
• The power of two: Assessing the impact of a second measurement of the weak-charge form factor of 208Pb
• Effects of Neutron Spatial Distributions on Atomic Parity Nonconservation in Cesium
• Implications of PREX-2 on the electric dipole polarizability of neutron rich nuclei
• Muon and electron g-2 and proton and cesium weak charges implications on dark ${\mathbf{Z}}_{\mathbf{d}}$ models
• Weak Polarized Electron Scattering
• New insights into nuclear physics and weak mixing angle using electroweak probes
• New Physics Constraints from Atomic Parity Violation in ${}^{133}$Cs
• The nuclear symmetry energy from neutron skins and pure neutron matter in a Bayesian framework
• A development of the CI + all-order method and application to the parity-nonconserving amplitude and other properties of Pb
• Dependence of atomic parity-violation effects on neutron skins and new physics
• Systematic trends of neutron skin thickness versus relative neutron excess
• Searching for $Z^{\prime }$ bosons at the P2 experiment
• Weak radius of the proton

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