Measurement of the absolute differential cross section of proton-proton elastic scattering at small angles

TL;DR

This paper reports precise measurements of proton-proton elastic scattering differential cross sections at various energies and angles, providing valuable data that influence partial wave analyses and support dispersion relation predictions.

Contribution

It presents new, high-precision differential cross section data for proton-proton elastic scattering over a range of energies and angles, improving normalization accuracy and impact on theoretical analyses.

Findings

Data significantly impact partial wave analysis

Results broadly agree with forward dispersion relation predictions

Achieved 3% normalization accuracy

Abstract

The differential cross section for proton-proton elastic scattering has been measured at a beam energy of 1.0 GeV and in 200 MeV steps from 1.6 to 2.8 GeV for centre-of-mass angles in the range from 12-16 degrees to 25-30 degrees, depending on the energy. Absolute normalisations of typically 3% were achieved by studying the energy losses of the circulating beam of the COSY storage ring as it passed repeatedly through the windowless hydrogen target of the ANKE magnetic spectrometer. It is shown that the data have a significant impact upon a partial wave analysis. After extrapolating the differential cross sections to the forward direction, the results are broadly compatible with the predictions of forward dispersion relations.