Charged charmonium-like [formula omitted] from rescattering in conventional B decays

P Pakhlov,T Uglov

doi:10.1016/j.physletb.2015.06.074

Abstract

In a previous paper we suggested an explanation for the peak designated as Z(4430)+ in the ψ′π+ mass spectrum, observed by Belle in B¯→ψ′π+K decays, as an effect of D¯⁎0D+→ψ′π+ rescattering in the decays B¯→Ds′−D, where the Ds′− is an as-yet unobserved radial excitation of the pseudoscalar ground state Ds−-meson. In this paper, we demonstrate that this hypothesis provides an explanation of the double Z+-like peaking structures, which were studied by LHCb with much higher statistics. While according to our hypothesis, the origin of the peaking structures is due to the kinematical reflection of conventional resonances in the unobserved intermediate state, the amplitude of the Z(4430)+ peak carries a Breit–Wigner-like complex phase, arising from the intermediate Ds′− resonance. Thus, our hypothesis is entirely consistent with the recent LHCb measurement of the resonant-like amplitude behavior of the Z(4430)+. We perform a toy fit to the LHCb data, which illustrates that our approach is also consistent with all the observed structure in the LHCb M(ψ′π+) spectrum. We suggest a critical test of our hypothesis that can be performed experimentally.

Highlights

In a previous paper we suggested an explanation for the peak designated as Z(4430)+ in the ψ′π+ mass spectrum, observed by Belle in B → ψ′π+K decays, as an effect of D ∗0D + → ψ′π+ rescattering in the decays B → Ds′−D, where the Ds′− is an as-yet unobserved radial excitation of the pseudoscalar ground state Ds−-meson
The first charmonium-like state, the Z(4430)+, which is entirely inconsistent with a simple charmonium interpretation, was observed by Belle [1, 2] in 2007 as a peak in the ψ′π+ mass near M ∼ 4430 MeV in B decays
In our previous paper [11], we suggested another possible explanation of the Z(4430)+ peak, resulting from D ∗0D + → ψ′π+ rescattering in the decays B → Ds′−D +

Summary

Introduction

In a previous paper we suggested an explanation for the peak designated as Z(4430)+ in the ψ′π+ mass spectrum, observed by Belle in B → ψ′π+K decays, as an effect of D ∗0D + → ψ′π+ rescattering in the decays B → Ds′−D, where the Ds′− is an as-yet unobserved radial excitation of the pseudoscalar ground state Ds−-meson. Many XYZ states above open charm threshold, and decaying into charmonium and light hadron(s) have been observed within the past decade.

Results

Conclusion