Study of charmonium decays to 𝐾0 S⁢𝐾⁢𝜋 in the 𝐵→(𝐾0 S⁢𝐾⁢𝜋)⁢𝐾 channels

A study of the 𝐵+→𝐾0S⁢𝐾+⁢𝐾−⁢𝜋+ and 𝐵+→𝐾0S⁢𝐾+⁢𝐾+⁢𝜋− decays is performed using proton-proton collisions at center-of-mass energies of 7, 8 and 13 TeV at the LHCb experiment. The 𝐾0
S⁢𝐾⁢𝜋 invariant mass spectra from both decay modes reveal a rich content of charmonium resonances. New precise measurements of the 𝜂𝑐 and 𝜂𝑐⁡(2⁢𝑆) resonance parameters are performed and branching fraction measurements are obtained for 𝐵+ decays to 𝜂𝑐, 𝐽/𝜓, 𝜂𝑐⁡(2⁢𝑆) and 𝜒𝑐⁢1 resonances. In particular, the first observation and branching fraction measurement of 𝐵+→𝜒𝑐⁢0⁢𝐾0⁢𝜋+ is reported as well as first measurements of the 𝐵+→𝐾0⁢𝐾+⁢𝐾−⁢𝜋+ and 𝐵+→𝐾0⁢𝐾+⁢𝐾+⁢𝜋− branching fractions. Dalitz plot analyses of 𝜂𝑐→𝐾0
S⁢𝐾⁢𝜋 and 𝜂𝑐⁡(2⁢𝑆)→𝐾0S⁢𝐾⁢𝜋 decays are performed. A new measurement of the amplitude and phase of the 𝐾⁢𝜋 𝑆-wave as functions of the 𝐾⁢𝜋 mass is performed, together with measurements of the 𝐾*0⁡(1430), 𝐾*0⁡(1950) and 𝑎0⁡(1700) parameters. Finally, the branching fractions of 𝜒𝑐⁢1 decays to 𝐾* resonances are also measured.