Production of f0(980) meson at the LHC: Color evaporation versus color-singlet gluon-gluon fusion

Abstract

The production of the f0(980) meson at high energies is not well understood. We investigate two different potential mechanisms for inclusive scalar meson production in the kt-factorization approach: color-singlet gluon-gluon fusion and color evaporation model. The γ⁎γ⁎→f0(980) form factor(s) can be constraint from the f0(980) radiative decay width. The g⁎g⁎→f0(980) form factors are obtained by a replacement of αem electromagnetic coupling constant by αs strong coupling constant and appropriate color factors. The form factors for the two couplings are parametrized with a function motivated by recent results for scalar quarkonia. The differential cross sections are calculated in the kt-factorization approach with modern unintegrated gluon distributions. Unlike for quarkonia it seems rather difficult to describe a preliminary ALICE data for inclusive production of f0(980) exclusively by the color singlet gluon-gluon fusion mechanism. Two different scenarios for flavor structure of f0(980) are considered in this context. We consider also mechanism of fusion of quark-antiquark associated with soft gluon emission in a phenomenological color evaporation model (CEM) used sometimes for quarkonium production. Here we use kt-factorization version of CEM to include higher-order contributions. In addition, for comparison we consider also NLO collinear approach with qq¯q and qq¯g color octet partonic final states. Both approaches lead to a similar result. However, very large probabilities are required to describe the preliminary ALICE data. The pomeron-pomeron fusion mechanism is also discussed and results are quantified.