Observation of an alternative ${\ensuremath{\chi}}_{c0}(2P)$ candidate in ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}D\overline{D}$

Observation of an alternative $χ_{c 0} (2 P)$ candidate in $e^{+} e^{-} \to J / ψ D \bar{D}$

K. Chilikin et al. (Belle Collaboration)

Phys. Rev. D 95, 112003 – Published 16 June 2017

Abstract

We perform a full amplitude analysis of the process $e^{+} e^{-} \to J / ψ D \bar{D}$ , where $D$ refers to either $D^{0}$ or $D^{+}$ . A new charmoniumlike state $X^{*} (3860)$ that decays to $D \bar{D}$ is observed with a significance of $6.5 σ$ . Its mass is $(3862_{- 32}^{+ 26}_{- 13}^{+ 40}) MeV / c^{2}$ , and its width is $(201_{- 67}^{+ 154}_{- 82}^{+ 88}) MeV$ . The $J^{P C} = 0^{+ +}$ hypothesis is favored over the $2^{+ +}$ hypothesis at the level of $2.5 σ$ . The analysis is based on the $980 {fb}^{- 1}$ data sample collected by the Belle detector at the asymmetric-energy $e^{+} e^{-}$ collider KEKB.