Publications
Publication Information
| Title | Electroweak axial structure functions and improved extraction of the $V_{ud}$ CKM matrix element |
| Authors | Kyle Shiells, Peter Blunden, Wolodymyr Melnitchouk |
| JLAB number | JLAB-THY-20-3289 |
| LANL number | arXiv:2012.01580 |
| Other number | DOE/OR/23177-5082 |
| Document Type(s) | (Journal Article) |
| Associated with EIC: | No |
| Supported by Jefferson Lab LDRD Funding: | No |
| Funding Source: | Nuclear Physics (NP) |
|
Journal Compiled for Physical Review D Volume 104 Page(s) 033003 Refereed | |
| Publication Abstract: | We present a comprehensive analysis of the $\gamma W$ interference radiative correction to the neutron $\beta$-decay matrix element. Within a dispersion relations approach, we compute the axial-vector part of the $\gamma W$ box amplitude $\Box^{\gamma W}_A$ in terms of the isoscalar part of the $F_3^{\gamma W}$ interference structure function. Using the latest available phenomenology for $F_3^{\gamma W}$ from the nucleon elastic, resonance, deep-inelastic, and Regge regions, we find the real part of the box correction to be \mbox{$\Box^{\gamma W}_A = 3.90(9) \times 10^{-3}$}. This improved correction gives a theoretical estimate of the CKM matrix element $|V_{ud}|^2=0.94796(25)$, which represents a 4$\sigma$ violation of unitarity. |
| Experiment Numbers: | other |
| Group: | THEORY CENTER |
| Document: | |
| DOI: | https://doi.org/10.1103/PhysRevD.104.033003 |
| Accepted Manuscript: | PhysRevD.104.033003.pdf |
| Supporting Documents: | |
| Supporting Datasets: | |