Pion-pion cross section from proton-proton collisions at the LHC

Abstract

The zero-degree calorimeters (ZDC) installed in the ALICE, ATLAS and CMS experiments at the LHC, make possible simultaneous detection of forward-backward leading neutrons, pp=>nXn. Such data with sufficiently high statistics could be a source of information about the pion-pion total cross section at high energies, provided that the absorption corrections, which are expected to be strong, are well understood. Otherwise, making a plausible assumption about the magnitude of the pion-pion cross section, one can consider such measurements as a way to study the absorption effects, which is the main focus of the present paper. These effects introduced at the amplitude level, are found to be different for the pion fluxes, which either conserve or flip the nucleon helicity. The pion fluxes from both colliding protons are essentially reduced by absorption, moreover, there is a common absorption suppression factor, which breaks down the factorized form of the cross section. We also evaluate the feed-down corrections related to the initial/final state inelastic processes possessing a rapidity gap, and found them to be small in the kinematic range under consideration. The contribution of other iso-vector Reggeons, spin-flip natural parity rho and a2, and spin non-flip unnatural parity a1 are also evaluated and found to be rather small.

arXiv comment15 pages, 14 figures, an essentially extended version to be published in PRD

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Cited by in corpus (6)

• System size dependence of the hadronic rescattering effect at energies available at the CERN Large Hadron Collider
• Total ${\pi }^{+}p$ cross section extracted from the leading neutron spectra at the LHC
• Total pion-proton cross-section from the new LHCf data on leading neutrons spectra
• Leading neutron production at the EIC and LHeC: estimating the impact of the absorptive corrections
• Diffractive dijet production: breakdown of factorization
• Leading Neutrons From Polarized Proton-Nucleus Collisions