Publications
Publication Information
| Title | Normal single-spin asymmetries in electron-proton scattering: two-photon exchange with intermediate state resonances |
| Authors | Jaseer Ahmed, P.G. Blunden, W. Melnitchouk |
| JLAB number | JLAB-THY-23-3835 |
| LANL number | (None) |
| Other number | DOE/OR/23177-6260 |
| 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 C Volume 108 Page(s) 055202 Refereed | |
| Publication Abstract: | We calculate the beam ($B_n$) and target ($A_n$) normal single-spin asymmetries in electron--proton elastic scattering from two-photon exchange amplitudes with resonance intermediate states of spin-parity $1/2^\pm$ and $3/2^\pm$ and mass $W \lesssim 1.8$~GeV. The latest CLAS exclusive meson electroproduction data are used as input for the transition amplitudes from the proton to the excited resonance states. For $B_n$, the spin 3/2 resonances dominate by an order of magnitude over the spin 1/2 states. In general we observe cancellations between the negative contributions of the $\Delta(1232)$ and $N(1520)$ across both beam energy and scattering angle, and the positive contributions of the $\Delta(1700)$ and $N(1720)$, leading to a rather large overall uncertainty band in the total $B_n$. At forward angles and beam energies $E_{\rm lab} < 1$~GeV, where the $\Delta(1232)$ dominates, the calculated $B_n$ tend to overshoot the A4 and SAMPLE data. The calculated $B_n$ compare well with the measured values from the A4 and $Q_{\textrm{weak}}$ experiments with $E_{\rm lab} > 1$~GeV. |
| Experiment Numbers: | other |
| Group: | THEORY CENTER |
| Document: | |
| DOI: | https://doi.org/10.1103/PhysRevC.108.055202 |
| Accepted Manuscript: | PhysRevC.108.055202.pdf |
| Supporting Documents: | |
| Supporting Datasets: | |