Decoding the riddle of Y(4260) and Z_c(3900)

2013/03/31 by Qian Wang, Christoph Hanhart, Qiang Zhao · 3 citations
Physics and Astronomy · #hep-ex #hep-ph #nucl-ex #nucl-th

paper · pdf · doi:10.1103/physrevlett.111.132003

Version to appear in Phys. Rev. Letters

arxiv created 2013/09/12 · arxiv updated 2015/06/15

Abstract

The observation of Z_c(3900) by the BESIII collaboration in the invariant mass spectrum of J/ψπ^± in e⁺e^-→ J/ψπ⁺π^- at the center of mass 4.260 GeV suggests the existence of a charged D D^*+D D^* molecular state with I(J^P)=1(1⁺), which could be an isovector brother of the famous X(3872) and an analogue of Z_b(10610) claimed by the Belle Collaboration. We demonstrate that this observation provides strong evidence that the mysterious Y(4260) is a DD₁(2420) +DD₁(2420) molecular state. Especially, we show that the decay of this molecule naturally populates low momentum DD^* pairs and leads unavoidably to a cusp at the DD^* threshold. We discuss the signatures that distinguish such a DD^* cusp from the presence of a true resonance.

Cited by

• Pole trajectories from S- and P-wave DD^* interactions
• Dipionic transitions of Y(4500) to J/ψ
• Study of the e⁺e^-→ J/ψ π⁺π^- lineshape near the D^*D+c.c. threshold and possible signals for exotic hidden charm states