Central exclusive diffractive production of axial-vector $f_{1}(1285)$ and $f_{1}(1420)$ mesons in proton-proton collisions

TL;DR

This paper models the central exclusive production of $f_1(1285)$ and $f_1(1420)$ mesons in proton-proton collisions using tensor-pomeron theory, fitting parameters to experimental data and predicting cross sections for RHIC and LHC energies.

Contribution

It introduces a tensor-pomeron approach with specific couplings to describe $f_1$ meson production and compares it with the Sakai-Sugimoto model, providing predictions for high-energy colliders.

Findings

Both tensorial couplings fit WA102 data separately.

Predicted cross section for $f_1(1285)$ at 13 TeV is about 38 μb.

Larger production cross section for $f_1(1285)$ than $f_2(1270)$ at LHC.

Abstract

We present a study of the central exclusive diffractive production of the $f_{1}(1285)$ and $f_{1}(1420)$ resonances in proton-proton collisions. The theoretical results are calculated within the tensor-pomeron approach. Two pomeron-pomeron-$f_{1}$ tensorial couplings labeled by $(l,S) = (2,2)$ and $(4,4)$ are derived. We adjust the model parameters (coupling constants, cutoff constant) to the WA102 experimental data taking into account absorption effects. Both the $(l,S) = (2,2)$ and $(4,4)$ couplings separately allow one to describe the WA102 differential distributions. We compare these predictions with those of the Sakai-Sugimoto model, where the pomeron-pomeron-$f_{1}$ couplings are determined by the mixed axial-gravitational anomaly of QCD. We derive an approximate relation between the pomeron-pomeron-$f_{1}$ coupling constants of this approach and the $(l,S) = (2,2)$ and $(4,4)$ couplings. Then we present our predictions for the energies available at the RHIC and LHC. The total cross sections and several differential distributions are presented. Analysis of the distributions in the azimuthal angle $\phi_{pp}$ between the transverse momenta of the outgoing protons may be used to disentangle $f_{1}$- and $\eta$-type resonances contributing to the same final channel. We find for the $f_{1}(1285)$ a total cross section $\sim 38$ $\mu$b for $\sqrt{s} = 13$ TeV and a rapidity cut on the $f_{1}$ of $|{\rm y_{M}}| < 2.5$. We predict a much larger cross section for production of $f_{1}(1285)$ than for production of $f_{2}(1270)$ in the $\pi^{+}\pi^{-}\pi^{+}\pi^{-}$ decay channel for the LHC energies. This opens a possibility to study the $f_{1}(1285)$ meson in experiments planned at the LHC.