Exclusive open-charm near-threshold cross sections in a coupled-channel approach

Abstract

Data on 7 open-charm channels collected by the Belle Collaboration are analyzed simultaneously using a unitary approach based on a coupled channel model in a wide energy range $ \sqrt s $ = 3.7 − 4.7 GeV. The resulting fit provides a remarkably good overall description of the line shapes in all studied channels. Parameters of 5 vector charmonium resonances are extracted from the fit. It is demonstrated, that this approach could be used account for all exclusive channels and thus solve the long-term problem of the charmonium spectra near threshold.

Production of X(3872) and a photon in e+e− annihilation

“…[28] is only about 6% smaller than their sum from the fit in Ref. [23]. However the ratio 0.81 of the spin-2 and spin-0 cross sections in Ref.…”

“…A comparison of their results with those of Ref. [23] can however give some indication of the possible size of theoretical errors. In Ref.…”

“…The cross sections are 1.52 nb and 1.23 nb, respectively, compared to 0.75 nb and 2.19 nb from the fit in Ref. [23]. The sum of the two cross sections in Ref.…”

“…The dispersive contributions have a significant effect on the shape of the narrow peak. We also predicted the normalization of the cross section for e + e − → Xγ using a fit to the cross section for e + e − → D * + D * − by Uglov et al [23].…”

“…The Belle collaboration has measured exclusive cross sections for e + e − annihilation into several pairs of charm mesons, including D * + D * − [26,27]. Uglov et al have analyzed the Belle data using a unitary approach based on a coupled channel model [23]. They included a spin-2 F-wave amplitude for e + e − → D * D * as well as spin-0 and spin-2 P-wave amplitudes.…”