Central exclusive diffractive production of $p \bar{p}$ pairs in proton-proton collisions at high energies

TL;DR

This paper models the central exclusive production of proton-antiproton pairs in high-energy proton-proton collisions using the tensor-pomeron approach, predicting distinctive distributions and interference effects, and compares results with existing data and future experiment prospects.

Contribution

It introduces a detailed tensor-pomeron model for $par{p}$ production, including resonance effects and spin considerations, providing new predictions for rapidity distributions and interference phenomena.

Findings

Dip at ${ m y}_{diff} = 0$ for $p ar{p}$ production contrasts with meson pairs.

Predicted $p ar{p}$ invariant mass distribution is less steep than for pseudoscalar mesons.

Resonance presence could alter the dip, enabling resonance studies.

Abstract

We consider the central exclusive production of the $p\bar{p}$ in the continuum and via resonances in proton-proton collisions at high energies. We discuss the diffractive mechanism calculated within the tensor-pomeron approach including pomeron, odderon, and reggeon exchanges. The theoretical results are discussed in the context of existing WA102 and ISR experimental data and predictions for planned or current experiments at the RHIC and the LHC are presented. The distribution in ${\rm y}_{diff}$, the rapidity distance between proton and antiproton, is particularly interesting. We find a dip at ${\rm y}_{diff} = 0$ for the $p \bar{p}$ production, in contrast to the $\pi^{+}\pi^{-}$ and $K^{+}K^{-}$ production. We predict also the $p \bar{p}$ invariant mass distribution to be less steep than for the pairs of pseudoscalar mesons. We argue that these specific differences for the $p \bar{p}$ production with respect to the pseudoscalar meson pair production can be attributed to the proper treatment of the spin of produced particles. We discuss asymmetries that are due to the interference of $C=+1$ and $C=-1$ amplitudes of $p \bar{p}$ production. We have also calculated the cross section for the $pp \to pp \Lambda \overline{\Lambda}$ reaction. Here, the cross section is smaller but the characteristic feature for $d\sigma/d{\rm y}_{diff}$ is predicted to be similar to $p \bar{p}$ production. The presence of resonances in the $p \bar p$ channel may destroy the dip at ${\rm y}_{diff} = 0$. This opens the possibility to study diffractively produced resonances. We discuss the observables suited for this purpose.