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Exclusive scalar $f_0(1500)$ meson production

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.