Measurements of Single Diffraction at sqrt(s) = 630 GeV; Evidence for a Non-Linear alpha(t) of the Pomeron

TL;DR

This paper presents detailed measurements of single diffraction at 630 GeV, revealing a non-linear Pomeron trajectory and complex Pomeron-proton interactions, advancing understanding of diffraction phenomena in high-energy physics.

Contribution

It introduces a quadratic term in the Pomeron Regge trajectory and characterizes the Pomeron-proton cross section behavior, based on new experimental data and analysis.

Findings

Effective Pomeron Regge trajectory requires a quadratic t term.

Pomeron-proton cross section decreases then increases with diffractive mass.

Observation of beam jets in the Pomeron direction.

Abstract

We report measurements of the inclusive differential cross section for the single-diffractive reactions: p + pbar --> p + X and p + pbar --> X + pbar at sqrt(s) = 630 GeV, in the momentum transfer range, 0.8 < -t < 2.0 GeV^2 and final state Feynman-x > 0.90. Based on the assumption of factorization, several new features of the Pomeron Flux Factor are determined from simultaneous fits to our UA8 data and lower energy data from the CHLM collaboration at the CERN-Intersecting Storage Rings. Prominent among these is that the effective Pomeron Regge trajectory requires a term quadratic in t, with coefficient, a'' = 0.079 +- 0.012 GeV^{-4}. We also show that the data require a Pomeron-proton cross section that first decreases with increasing diffractive mass (corresponding to the PPR term in the triple-Regge expansion) and then increases at larger mass (the PPP term), similar to real particle total cross sections. We measure the product, (K x sigma0) = 0.72 +- 0.10 mb/GeV^2, where K is the normalization constant of the Pomeron Flux Factor in the proton and sigma0 is the scale constant in the Pomeron-proton total cross section. Finally, we report the occurence of ``beam jets'' in the Pomeron direction in the rest frame of the diffractive system.