Measurement of proton-proton elastic scattering into the Coulomb region at $\text{P}_\text{beam}$ = 2.5, 2.8 and 3.2 GeV/c

TL;DR

This study precisely measured proton-proton elastic scattering at small angles across three energies, providing new data on the Coulomb-nuclear interference region to improve understanding of proton interactions.

Contribution

The paper presents the first precise measurements of the differential cross section in the Coulomb region at these energies, filling a gap in existing data and aiding dispersion analyses.

Findings

Total cross section $\sigma_ ext{tot}$ consistent with previous data

Determined slope parameter $B$ with improved accuracy

Measured real amplitude ratio $ ho$ to support theoretical models

Abstract

The proton--proton elastic differential cross section at very small four momentum transfer squared has been measured at three different incident proton momenta in the range of 2.5 to 3.2 GeV/c by detecting the recoil proton at polar angles close to $90^\circ$. The measurement was performed at COSY with the KOALA detector covering the Coulomb-nuclear interference region. The total cross section $\sigma_\text{tot}$, which has been determined precisely, is consistent with previous measurements. The values of the slope parameter $B$ and the relative real amplitude ratio $\rho$ determined in this experiment alleviate the lack of data in the relevant energy region. This precise data on $\rho$ might be an important check for a new dispersion analysis.