A recent study has investigated the production of heavy quarkonium pairs in high-energy collisions, focusing on the contribution of fragmentation mechanisms. Traditionally, particle production has been modeled via single-hadron fragmentation or parton scattering. This work introduces a new perspective by considering dihadron fragmentation, a process where two hadrons form from a single high-energy quark or gluon. The results suggest that this mechanism could be significantly more relevant than previously thought, especially under the energy conditions of the Large Hadron Collider (LHC).

The researchers developed a microscopic perturbative model for the dihadron fragmentation function, valid for quarkonium pairs with large invariant masses. They utilized the Color Glass Condensate (CGC) framework to calculate the production amplitude of quark-antiquark (Q$\bar{Q}$) pairs. Their findings indicate that single fragmentation of heavy quarks into quarkonium is only a minor correction, whereas dihadron fragmentation can provide a sizable contribution. In fact, this contribution is comparable to that of single- and double-parton scattering, mechanisms already established in the description of hadron production.

This advance is crucial for a more complete understanding of quantum chromodynamics (QCD) and hadronization processes in high-energy collisions. The ability to accurately describe quarkonium pair production is fundamental for probing the properties of the quark-gluon plasma and for searching for new physics beyond the Standard Model. The inclusion of dihadron fragmentation in theoretical models could improve agreement with experimental data from the LHC and open new avenues for interpreting observations in future experiments.