Absorptive corrections to the electromagnetic form factor in high-energy elastic proton-proton scattering

Abstract

Recently, it was noted that absorptive corrections to the electromagnetic form factor in high-energy proton-proton scattering are important for the theoretical interpretation of the $p^{\uparrow }p$ and $p^{\uparrow }A$ analyzing power $A_{\text{N}}(t)$ measurements with the Hydrogen Jet Target polarimeter (HJET) at RHIC. Here, a concise expression for the absorptive correction was derived within the eikonal approach. The resulting analysis reveals a systematic bias, nearly independent of the beam energy, in the experimental determination of the real-to-imaginary ratio $\rho$ when absorption effects are overlooked in the data analysis. Quantification of this bias, as ${\rho }^{\text{meas}}=\rho +(0.036\pm 0.016{)}_{\text{bias}}$, was achieved using a Regge fit applied to available proton-proton measurements of ${\rho }^{\text{meas}}(s)$ and ${\sigma }_{\text{tot}}^{\text{meas}}(s)$. Considering the potential impact of such an effect on the experimentally determined $A_{\text{N}}(t)$, one may enhance consistency between the HJET and STAR measurements of the hadronic spin-flip amplitude. While the sign of the bias in the value of $\rho$ aligns with the anticipated effective increase in the proton charge radius in $pp$ scattering due to absorption, it amplifies the observed discrepancy between ${\sigma }_{\text{tot}}^{\text{meas}}$ and ${\rho }^{\text{meas}}$ values at $\sqrt{s}=13\text{TeV}$ as measured in the TOTEM experiment. Evaluation (using published TOTEM data) of the measured proton-proton $d\sigma /dt$ dependence on the absorptive corrections indicated that possible soft photon corrections to the hadronic amplitude slope may be essential for such data analysis.

6 pages, 4 figures

References in corpus (8)

• Single Spin Asymmetry $A_N$ in Polarized Proton-Proton Elastic Scattering at $\sqrt{s}=200$ GeV
• Precision Small Scattering Angle Measurements of Elastic Proton-Proton Single and Double Spin Analyzing Powers at the RHIC Hydrogen Jet Polarimeter
• Systematic error analysis in the absolute hydrogen gas jet polarimeter at RHIC
• Probing the Pomeron spin structure with Coulomb-nuclear interference
• Corrections to the Elastic Proton-Proton Analyzing Power Parametrization at High Energies
• Coulomb-nuclear interference in elastic proton scattering in the eikonal approach
• Breakup corrections to spin asymmetries in the ${}^3$He beam polarization measurements with the Polarized Atomic Hydrogen Gas Jet Target
• Polarization Measurements of $p^{\uparrow }$ and ${}^3$He${}^{\uparrow }$ Beams at RHIC and Future EIC Using the Polarized Atomic Hydrogen Gas Jet Target

Cited by in corpus (1)

• Numerical Calculation of Coulomb Corrections in Forward Elastic $p^{\uparrow }p$ and $p^{\uparrow }A$ Scattering