Quarkonium production and decays

TL;DR

This paper reviews quarkonium production and decay processes, incorporating relativistic, perturbative, and non-perturbative effects, and provides theoretical predictions aligned with experimental data across various collision types.

Contribution

It offers a comprehensive analysis of quarkonium production models, including new calculations of cross sections and decay rates with higher-order QCD corrections and relativistic effects.

Findings

Relativistic and non-perturbative effects are crucial for accurate quarkonium decay predictions.

The ${}^1S_0$ cross section is calculated at next-to-leading order.

High-energy behavior of quarkonium cross sections is characterized by asymptotic QCD corrections.

Abstract

Quarkonium decays are studied in the charmonium model. Relativistic corrections, higher-order perturbative QCD corrections and non- perturbative contributions are discussed. Recent measurements of charmonium annihilation rates are used to evaluate the strong coupling constant $\alpha_s$ simultaneously with the wave functions (and their derivatives) at the origin. Further predictions are made for yet unobserved decay rates. The various models for quarkonium production in hadronic collisions are critically reviewed. Based on the charmonium model, the cross sections of different quarkonium states are given in a well-defined QCD perturbation series, including quark--antiquark, quark--gluon, and gluon--gluon scatterings. Numerical estimates are given for charmonium production in $\p\p$, $\ppbar$, and $\pi\p$ collisions. The role of indirect $\JP$ production via $\chi_{\c J}(1P)$, $\eta_{\c}(2S)$, $\psi(2S)$ and $\b$-decays is pointed out. Relativistic effects and non-perturbative contributions are found to be important. Existing measurements are compiled and shown to be well explained if all contributions are included. The ${}^1S_0$ cross section is calculated in complete next-to-leading order. Finally, a study of the high-energy behaviour of quarkonium cross sections is made, based on the asymptotical behaviour of higher-order QCD corrections.