Nuclear Theory·nucl-th

Thursday·May 30, 2024

7 papers—3 primary·4 cross-listed

01
Ab-initio electroweak corrections to superallowed $β$ decays and their impact on $V_{u d}$
Vincenzo Cirigliano🇺🇸 · Wouter Dekens🇺🇸 · Jordy de Vries🇳🇱 · Stefano Gandolfi🇺🇸 · Martin Hoferichter🇨🇭 · Emanuele Mereghetti🇺🇸
Radiative corrections are essential for an accurate determination of $V_{u d}$ from superallowed $β$ decays. In view of recent progress in the single-nucleon sector, the uncertainty is dominated by the theoretical description of nucleus-dependent effects, limiting the precision that can currently be achieved for $V_{u d}$ . In this work, we provide a detailed account of the electroweak corrections to superallowed $β$ decays in effective field theory (EFT), including the power counting, potential and ultrasoft contributions, and factorization in the decay rate. We present a first numerical evaluation of the dominant corrections in light nuclei based on Quantum Monte Carlo methods, confirming the expectations from the EFT power counting. Finally, we discuss strategies how to extract from data the low-energy constants that parameterize short-distance contributions and whose values are not predicted by the EFT. Combined with advances in ab-initio nuclear-structure calculations, this EFT framework allows one to systematically address the dominant uncertainty in $V_{u d}$ , as illustrated in detail for the $^{14}$ O $\to$ $^{14}$ N transition.
nucl-thhep-exhep-lathep-ph+1PRC(2024)·42 citations
02
Neutron skin impurity from Coulomb core polarization in $^{208} Pb$ : Insights from PREX-II and validation via the $(^{3} He, t)$ isobaric analog state reaction
Phan Nhut Huan
I investigate the effect of Coulomb core-polarization in $^{208} Pb$ , highlighting its impact on uncertainties in neutron distribution measurements due to the discrepancy between neutron excess and neutron skin regions at the surface. This effect is validated using the $(^{3} He, t)$ isobaric analog state (IAS) reaction at 420 MeV. My findings reveal that the Coulomb boundary radius, where core-polarization becomes negligible, is critical for accurately probing the neutron skin region in the target nucleus. Consequently, I propose extending the $^{208} Pb (^{3} He, t)$ IAS reaction experiment conducted by Zegers et al. [Phys. Rev. Lett. 99, 202501 (2007)] to measure cross sections up to 3 $^{\circ}$ angles to more precisely determine the neutron skin thickness in $^{208} Pb$ from theoretical reaction analysis. Additionally, I observe that, under the assumption of a large neutron skin in $^{208} Pb$ , as suggested by the PREX-II result, the core-polarization effect introduces impurity into the neutron skin region.
nucl-thnucl-exPRC(2024)·2 citations
03
An $ab initio$ strategy for taming nuclear-structure dependence of $V_{u d}$ extractions: the $^{10} C \to^{10} B$ superallowed transition
Michael Gennari🇨🇦 · Mehdi Drissi🇨🇦 · Mikhail Gorchtein🇩🇪 · Petr Navratil🇨🇦 · Chien-Yeah Seng🇺🇸
We report the first \textit{ab initio} calculation of the nuclear-structure-dependent radiative correction $δ_{NS}$ to the $^{10} C \to^{10} B$ superallowed transition, computed with the no-core shell model and chiral effective field theory. We obtain $δ_{NS} = - 0.422 (29)_{nuc} (12)_{n, el}$ with a $1.6$ -times reduction in the total uncertainty when compared to the current literature estimate based on the shell model and Fermi gas picture. This work paves the way for a precise determination of $V_{u d}$ from superallowed beta decays within a systematically improvable framework.
nucl-thhep-exhep-phnucl-exPRL(2025)·41 citations

Affiliations

first authorsco-authorsvia INSPIRE

Ab-initio electroweak corrections to superallowed β decays and their impact on Vud​

Neutron skin impurity from Coulomb core polarization in 208Pb: Insights from PREX-II and validation via the (3He,t) isobaric analog state reaction

An ab initio strategy for taming nuclear-structure dependence of Vud​ extractions: the 10C→10B superallowed transition

Affiliations

Ab-initio electroweak corrections to superallowed $β$ decays and their impact on $V_{u d}$

Neutron skin impurity from Coulomb core polarization in $^{208} Pb$ : Insights from PREX-II and validation via the $(^{3} He, t)$ isobaric analog state reaction

An $ab initio$ strategy for taming nuclear-structure dependence of $V_{u d}$ extractions: the $^{10} C \to^{10} B$ superallowed transition