Meson loop singularity, exotic states' productions and decays near threshold

Abstract

We investigate in detail the "triangle singularity" regions of meson loops where the corresponding intermediate mesons are nearly-on-shell and have relatively small momenta, and the two heavy mesons strongly interact with each other in an $S$ wave. This $S$-wave interaction will make such kind of meson loops always enhanced and can explain experimental observations of threshold enhancements. We show that the production of the $Y(4260)$ and the recently observed $Z_c(3900)$ can be related to each other by this mechanism which will allow for a possible understanding of the nature of these threshold enhancements.

to appear in the proceedings of The 6th International Workshop on Charm Physics (CHARM 2013)

References in corpus (5)

• Observation of a charged charmoniumlike structure Z_c(4020) and search for the Z_c(3900) in e+e- to pi+pi-h_c
• Observation of a charged charmoniumlike structure in $e^{+}{e}^{-}\to (D^{\ast }{\bar{D}}^{\ast }{)}^{\pm }{\pi }^{\mp }$ at $\sqrt{s}=4.26$GeV
• $Y(4260)$ as the first $S$-wave open charm vector molecular state?
• Confirming the molecular nature of the $Z_b(10610)$ and the $Z_b(10650)$
• Evidence for a Zb0(10610) in Dalitz analysis of Y(5S) -> Y(nS) pi0 pi0

Cited by in corpus (1)

• Mass spectra and decay properties of $D$ Meson in a relativistic Dirac formalism