Exclusive scalar $f_0(1500)$ meson production

TL;DR

This paper analyzes the production mechanisms of the scalar $f_0(1500)$ meson, a glueball candidate, comparing pion-pion meson exchange and QCD diffractive processes, with predictions relevant for PANDA experiment energies.

Contribution

It provides a detailed calculation of differential distributions for $f_0(1500)$ production, highlighting the dominance of pion-pion fusion near threshold and the negligible gluonic contribution at PANDA energies.

Findings

Pion-pion fusion dominates near threshold energies.

QCD diffractive component is negligible at PANDA energies.

Large cross sections predicted for pion-pion fusion at PANDA energies.

Abstract

We evaluate differential distributions for exclusive scalar $f_0(1500)$ meson (glueball candidate) production. Both QCD diffractive, pion-pion meson exchange current (MEC) components as well as double-diffractive mechanism with intermediate pionic loop are calculated. The pion-pion component, which can be reliably calculated, dominates close to the threshold while the diffractive component may take over only for larger energies. At the moment only upper limit for the QCD-diffractive component can be obtained. The diffractive component is calculated based on the Khoze-Martin-Ryskin approach proposed for diffractive Higgs boson production. Different unintegrated gluon distribution functions (UGDFs) from the literature are used. Rather large cross sections (due to pion-pion fusion) are predicted for PANDA energies, where the gluonic mechanism is shown to be negligible.