Amplitude analysis of $B^{+}\to \ddot{I}ˆ(2S)K^{+}\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ decays

Abstract

The first full amplitude analysis of $B^{+}\to \ddot{I}ˆ(2S)K^{+}\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ decays is performed using proton-proton collision data corresponding to an integrated luminosity of $9{\text{fb}}^{-1}$ recorded with the LHCb detector. The rich $K^{+}\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ spectrum is studied and the branching fractions of the resonant substructure associated with the prominent $K_1(1270{)}^{+}$ contribution are measured. The data cannot be described by conventional strange and charmonium resonances only. An amplitude model with 53 components is developed comprising 11 hidden-charm exotic hadrons. New production mechanisms for charged charmonium-like states are observed. Significant resonant activity with spin-parity $J^P=1^{+}$ in the $\ddot{I}ˆ(2S)\ddot{I}{€}^{+}$ system is confirmed and a multi-pole structure is demonstrated. The spectral decomposition of the $\ddot{I}ˆ(2S)\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ invariant-mass structure, dominated by $X^0\to \ddot{I}ˆ(2S)\ddot{I}(770{)}^0$ decays, broadly resembles the $J/\ddot{I}ˆ\ddot{I}•$ spectrum observed in $B^{+}\to J/\ddot{I}ˆ\ddot{I}•K^{+}$ decays. Exotic $\ddot{I}ˆ(2S)K^{+}\ddot{I}{€}^{-}$ resonances are observed for the first time.

All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://lbfence.cern.ch/alcm/public/analysis/full-details/1601 (LHCb public pages)