Total, elastic, and inclusive single-diffractive cross sections in alpha-alpha collisions at the cern intersecting storage rings

Abstract

We present measurements of the total interaction cross section and of the single-diffractive dissociation cross section in αα collisions at √s = 126 GeV. The result obtained for the total cross section, σ_tot = (315±18) mb, is a substantial improvement on the precision of earlier measurements. Earlier elastic data were re-analysed, incorporating, through the optical theorem, the present σ_tot measurement, resulting in improved determinations of the forward slope, b_−t<0.07 = (87±4) GeV⁻², and of the integrated elastic cross section, σ_el = (58±6) mb. The single-diffractive differential cross section falls exponentially with momentum transfer at small values of t with a slope b_sd = (19.3 ± 0.6) GeV⁻². The integrated single-diffractive cross section is σ_sd = (16.6±2.5) mb. The topology of charged tracks resulting from the disintegration of the α in single-diffractive events reveals a two-component distribution. The cross section data are compared with multiple-scattering models.