Observation and investigation of the $T_{c\bar{c}1}(4430{)}^{+}$ structure in $B^{+}\to \psi (2S)K_{\text{S}}^0{\pi }^{+}$ decays

Abstract

The first four-dimensional amplitude analysis of the $B^{+}\to \psi (2S)K_{\text{S}}^0{\pi }^{+}$ decay is performed with proton-proton collision data collected by the LHCb experiment at $\sqrt{s}=13\mathrm{TeV}$, corresponding to an integrated luminosity of $5.4\mathrm{f}{\mathrm{b}}^{-1}$. The data cannot be fully explained by $B^{+}\to \psi (2S)K^{\ast +}$ contributions alone. A significantly better description of the data is obtained by adding a $T_{c\bar{c}}^{+}$ contribution decaying to $\psi (2S){\pi }^{+}$. The properties of the $T_{c\bar{c}}^{+}$ structure are consistent with the exotic state $T_{c\bar{c}1}(4430{)}^{+}$ reported in the isospin-related ${\bar{B}}^0\to \psi (2S)K^{-}{\pi }^{+}$ decay. Effects of a possible $T_{c\bar{c}1}(4430{)}^{+}\to {\bar{D}}_1^{\ast }(2600{)}^0{D}^{+}$ decay mode on the $T_{c\bar{c}1}(4430{)}^{+}\to \psi (2S){\pi }^{+}$ mass distribution are investigated through a Flatté parametrization, providing constraints on the relative decay strength. A description of the $T_{c\bar{c}1}(4430{)}^{+}$ structure using the triangle singularity mechanism is studied and also found to be consistent with the data.

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/3755/ (LHCb public pages)

References in corpus (12)

• Pentaquark and Tetraquark states
• An updated review of the new hadron states
• Observation of a resonance-like structure in the pi^+- psi' mass distribution in exclusive B-->K pi^+- psi' decays
• Observation of the resonant character of the $Z(4430{)}^{-}$ state
• Threshold cusps and triangle singularities in hadronic reactions
• The Z(4430) and a New Paradigm for Spin Interactions in Tetraquarks
• Is Z^+(4430) a loosely bound molecular state?
• Analysis of the $Z(4430)$ as the first radial excitation of the $Z_c(3900)$
• Treating $Z_c(3900)$ and $Z(4430)$ as the ground-state and first radially excited tetraquarks
• Review of the QCD sum rules for exotic states
• ${\mathrm{Z}}^{+}(4430)$ and Analogous Heavy Flavor States
• Exotic Hadrons at LHCb