Observation of New Charmonium or Charmoniumlike States in 𝐵+→𝐷*±⁢𝐷∓⁢𝐾+ Decays

A study of resonant structures in 𝐵⁺→𝐷^*+⁢𝐷⁻⁢𝐾⁺ 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^∓: 𝜂_𝑐⁡(3945), ℎ_𝑐⁡(4000), 𝜒_𝑐⁢1⁡(4010), and ℎ_𝑐⁡(4300), with quantum numbers 𝐽^𝑃⁢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.