Observation of New Charmonium or Charmoniumlike States in Decays

Physical Review Letters. 2024. Vol. 133. No. 13. Article 131902.

Aaij R., Abdelmotteleb A. S., Abellan Beteta C., Abudinén F., Ackernley T., Adefisoye A. A., Adeva B., V. Bocharnikov, A. Boldyrev, M. Hushchyn, A. Ryzhikov, F. Ratnikov

A study of resonant structures in and 𝐵+→𝐷*−⁢𝐷+⁢𝐾+ decays is performed, using proton-proton collision data at center-of-mass energies of √𝑠 =7, 8, and 13 TeV recorded by the LHCb experiment, corresponding to an integrated luminosity of 9  fb−1. A simultaneous amplitude fit is performed to the two channels with contributions from resonances decaying to 𝐷*−⁢𝐷+ and 𝐷*+⁢𝐷− states linked by 𝐶 parity. This procedure allows the 𝐶 parities of resonances in the 𝐷*±⁢𝐷∓ mass spectra to be determined. Four charmonium or charmoniumlike states are observed decaying into 𝐷*±⁢𝐷∓: 𝜂𝑐⁡(3945), ℎ𝑐⁡(4000), 𝜒𝑐⁢1⁡(4010), and ℎ𝑐⁡(4300), with quantum numbers 𝐽𝑃⁢𝐶 equal to 0−+, 1+−, 1++, and 1+−, respectively. At least three of these states have not been observed previously. In addition, the existence of the 𝑇*¯𝑐⁢¯𝑠⁢0⁢(2870)0 and 𝑇*¯𝑐⁢¯𝑠⁢1⁢(2900)0 resonances in the 𝐷−⁢𝐾+ mass spectrum, already observed in the 𝐵+→𝐷+⁢𝐷−⁢𝐾+ decay, is confirmed in a different production channel.

Keywords: машинное обучение, новая физика, глубокое обучение, spin, mass, Quark models, hadronic decays, анализ данных и искусственный интеллект, Multiquark bound states

Publication based on the results of: Neuromorphic optimization of complex experimental setups at dynamically changing quality metrics and boundary conditions (2024)