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∓: ηc(3945), hc(4000), χc1(4010), and hc(4300), with quantum numbers JPC 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 Tc¯s¯0∗(2870)0 and Tc¯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.