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

A study of resonant structures in Bþ → DþD−Kþ and Bþ → D−DþKþ decays is performed, using proton-proton collision data at center-of-mass energies of ffiffi s p ¼ 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−Dþ and DþD− states linked by C parity. This procedure allows the C parities of resonances in the DD∓ mass spectra to be determined. Four charmonium or charmoniumlike states are observed decaying into DD∓: ηcð3945Þ, hcð4000Þ, χc1ð4010Þ, and hcð4300Þ, with quantum numbers JPC equal to 0−þ, 1þ−, 1þþ, and 1þ−, respectively. At least three of these states have not been observed previously. In addition, the existence of the T c¯ s¯ 0ð2870Þ0 and T c¯ s¯ 1ð2900Þ0 resonances in the D−Kþ mass spectrum, already observed in the Bþ → DþD−Kþ decay, is confirmed in a different production channel.