Exclusive diffractive production of $\pi^+ \pi^-$ pairs within tensor pomeron approach

TL;DR

This paper models exclusive diffractive production of pion pairs in high-energy proton collisions using a tensor pomeron approach, analyzing resonance contributions, interference effects, and comparing with experimental data to inform future experiments.

Contribution

It introduces a tensor pomeron model for describing exclusive dipion production, including resonance and continuum contributions, and provides predictions for current and future collider experiments.

Findings

Resonance and continuum contributions depend on proton transverse momentum cuts.

Interference effects influence the observed dipion spectra.

Model aligns with existing STAR, CDF, and CMS data.

Abstract

We discuss exclusive central diffractive production of $\pi^{+} \pi^{-}$ in proton-(anti)proton collisions at high energies. Based on a tensor pomeron model we present results of the purely diffractive dipion continuum, the scalar $f_{0}(500)$, $f_{0}(980)$ and tensor $f_{2}(1270)$ resonances decaying into the $\pi^{+} \pi^{-}$ pairs as well as the photoproduction mechanism ($\rho^{0}$, Drell-S\"oding). We discuss how two pomerons couple to the tensor meson $f_{2}(1270)$ and the interference effects of resonance and dipion continuum contributions. The theoretical results are compared with existing STAR, CDF, and CMS experimental data. Predictions for planned or being carried out experiments (ALICE, ATLAS) are presented. We find that the relative contribution of resonant $f_2(1270)$ and dipion continuum strongly depend on the cut on proton transverse momenta (or four-momentum transfer squared $t_{1,2}$) which may explain some controversial observations made by different ISR experiments in the past. The cuts may play then the role of a $\pi \pi$ resonance filter.