Possible solution of the J/psi production puzzle

Area of Science:

• High Energy Physics
• Quantum Chromodynamics
• Particle Phenomenology

Background:

• J/psi hadroproduction measurements at colliders like the Fermilab Tevatron and BNL Relativistic Heavy Ion Collider (RHIC) are underestimated by the standard color-singlet mechanism.
• Understanding the production mechanisms of heavy quarkonium states is crucial for probing fundamental interactions.

Purpose of the Study:

• To propose a new theoretical framework for J/psi hadroproduction that accurately reproduces experimental data.
• To investigate the role of intermediate cc[over ] interactions in J/psi production.
• To determine the polarization characteristics of J/psi particles produced within this new framework.

Main Methods:

• Calculation of the s-channel cut contribution to J/psi hadroproduction.
• Development of a theoretical model incorporating intermediate cc[over ] interactions.
• Comparison of theoretical predictions with experimental data from the Tevatron and RHIC.

Main Results:

• The s-channel cut contribution is found to be significantly larger than previously considered.
• The proposed model successfully reproduces J/psi production data across a range of transverse momenta (P_(T)).
• The J/psi particles produced via this mechanism are predominantly longitudinally polarized.

Conclusions:

• The s-channel cut mechanism, including intermediate cc[over ] interactions, provides a more accurate description of J/psi hadroproduction.
• This improved understanding has implications for interpreting heavy quarkonium production in high-energy collisions.
• The predicted longitudinal polarization of J/psi offers a testable prediction for future experiments.