Resolution of the LHCb ηc anomaly

• Published in: The journal of high energy physics 2023-05, Vol.2023 (5), p.120-8, Article 120
• Main Authors: Biswal, Sudhansu S., Mishra, Sushree S., Sridhar, K.
• Format: Article
• Language: English
• Subjects: Agreements; Classical and Quantum Gravitation; Effective Field Theories of QCD; Elementary Particles; High energy physics; Large Hadron Collider; Physics; Physics and Astronomy; Predictions; Quantum chromodynamics; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Quarkonium; Quarks; Regular Article - Theoretical Physics; Relativity Theory; String Theory; Symmetry
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP05(2023)120

A bstract Due to the heavy-quark symmetry of Non-Relativistic Quantum Chromodynamics (NRQCD), the cross-section for the production of η c can be predicted . This NRQCD prediction when confronted with data from the LHCb is seen to fail miserably. We address this LHCb η c anomaly in this paper using a new approach called modified NRQCD, an approach that has been shown to work extremely well for studying J/ψ , ψ ′ and χ c production at the LHC. We show, in the present paper, that the predictions for η c production agrees very well with LHCb measurements at the three different values of energy that the experiment has presented data for. Modified NRQCD also explains the intriguing agreement of the LHCb η c data with the colour-singlet prediction. The remarkable agreement of the theoretical predictions with the LHCb data suggests that modified NRQCD is closer to apprehending the true dynamics of quarkonium production.