Inclusive production of $f_2(1270)$ tensor mesons at the LHC via gluon-gluon fusion in the $k_t$-factorization approach

TL;DR

This paper calculates the inclusive production cross section of the $f_2(1270)$ meson at the LHC, considering gluon-gluon fusion and pion-pion rescattering, and compares the results with experimental data.

Contribution

It introduces a $k_t$-factorization approach with modern unintegrated gluon distributions to model $f_2(1270)$ production, including vertex parameter extraction from $ o ext{gamma gamma}$ reactions.

Findings

Gluon-gluon fusion dominates at higher transverse momenta.

Rescattering explains low-$p_t$ region.

Model comparison with ALICE data shows partial agreement.

Abstract

The cross section for inclusive production of $f_2(1270)$ meson is calculated. We include both the mechanism of gluon-gluon fusion as well as the $\pi \pi$ final-state rescattering. The contribution of the gluon-gluon fusion is calculated within the $k_t$-factorization approach with modern unintegrated gluon distribution functions (UGDFs). Some parameters for the $g^* g^* \to f_2$ vertex are extracted from the $\gamma \gamma \to f_2(1270) \to \pi \pi$ reactions. The results strongly depend on the parametrization of the $g^* g^* \to f_2(1270)$ form factor. Results of our model are compared to the ALICE preliminary data. The gluon-gluon fusion does not explain low-$p_t$ data but could be the dominant mechanism at somewhat larger meson transverse momenta. By adjusting some parameters the pion-pion rescattering can explain the low-$p_t$ region.