Probing the nature of the χ c 1 (3872) state using radiative decays

Journal article

The radiative decays χc1(3872) → ψ(2S) γ and χc1(3872) → J/ψγ are used to probe the nature of the χc1(3872) state using proton-proton collision data collected with the LHCb detector, corresponding to an integrated luminosity of 9 fb−1. Using the B+ → χc1(3872)K+ decay, the χc1(3872) → ψ(2S) γ process is observed for the first time and the ratio of its partial width to that of the χc1(3872) → J/ψγ decay is measured to beΓχc13872→ψ2SγΓχc13872→J/ψγ=1.67±0.21±0.12±0.04, where the first uncertainty is statistical, the second systematic and the third is due to the uncertainties on the branching fractions of the ψ(2S) and J/ψ mesons. The measured ratio makes the interpretation of the χc1(3872) state as a pure D0D¯∗0 + D¯0 D*0 molecule questionable and strongly indicates a sizeable compact charmonium or tetraquark component within the χc1(3872) state.

Authors: Aaij, R; Abdelmotteleb, ASW; Abellan Beteta, C; Abudinén, F; Ackernley, T

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: Journal of High Energy Physics
• Volume: 2024
• Issue: 11
• Article number: 121
• Publication date: 2024-11-21
• Acceptance date: 2024-10-27
• DOI: 10.1007/jhep11(2024)121
• EISSN: 1029-8479
• ISSN: 1126-6708
• Language: English
• Keywords: Quarkonium; Hadron-Hadron Scattering; Exotics; Spectroscopy