Exclusive diffractive resonance production in proton\u2013proton collisions at high energies

R Fiore,L Jenkovszky,R Schicker

doi:10.1140/epjc/s10052-018-5907-9

Abstract

A model for exclusive diffractive resonance production in proton–proton collisions at high energies is presented. This model is able to predict double differential distributions with respect to the mass and the transverse momentum of the produced resonance in the mass region sqrt{M^2}lesssim 5 GeV. The model is based on convoluting the Pomeron distribution in the proton with the Pomeron–Pomeron–meson total cross section. The Pomeron–Pomeron–meson cross section is saturated by direct-channel contributions from the Pomeron as well as from two different f trajectories, accompanied by the isolated f_0(500) resonance dominating the sqrt{M^{2}}lesssim 1 GeV region. A slowly varying background is taken into account.

Highlights

Central production in proton–pro√ton collisions has been analysed from the low energy range s = 12.7 − 63 GeV of the I√SR at CERN up to the presently highest energy available of s = 13 TeV achieved in Run II at the LHC
The contribution of the f0(500) resonance results from the Breit–Wigner parameterisation of Eq (8), taken with the resonance mass M0 = 0.475 GeV and the width = 0.55 GeV, and is shown by the dashed cyan line. Even though this state is the lowest mass resonance contributing to the spectrum shown in Fig. 11, the f0(500) with the chosen central values for the mass M0 and the width dominates the distribution in the high mass region
A model is presented for calculating double differential distributions in mass and transverse momentum for exclusive diffractive meson production at high energies

Summary

Introduction

This pair distribution is derived from events where there are exactly two oppositely charged pions in the event and significant energy in the forward shower counter HeRSCel, suggesting proton dissociation. This histogram is dominated by the photoproduction of the ρ-resonance, with

Dual resonance model of Pomeron–Pomeron scattering

Total meson cross section at hadron level

Double differential meson cross section

Summary and outlook