Eur. Phys. J. C (2018) 78: 136
https://doi.org/10.1140/epjc/s10052-018-5635-1

Regular Article - Theoretical Physics

Interference effect as resonance killer of newly observed charmoniumlike states Y(4320) and Y(4390)

¹ School of Physics, Southeast University, Nanjing, 210094, China
² School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China
³ Research Center for Hadron and CSR Physics, Institute of Modern Physics of CAS, Lanzhou University, Lanzhou, 730000, China
⁴ Tokyo Kasei University, 1-18-1 Kaga, Itabashi, Tokyo, 173-8602, Japan
⁵ Theoretical Research Division, Nishina Center, RIKEN, Wako, Saitama, 351-0198, Japan

^* e-mail: chendy@seu.edu.cn

Received: 25 November 2017
Accepted: 10 February 2018
Published online: 17 February 2018

Abstract

In this letter, we decode the newly observed charmoniumlike states, Y(4320) and Y(4390), by introducing interference effect between and , which plays a role of resonance killer for Y(4320) and Y(4390). It means that two newly reported charmoniumlike states are not genuine resonances, according to which we can naturally explain why two well-established charmonia and are missing in the cross sections of and simultaneously. To well describe the detailed data of these cross sections around GeV, our study further illustrates that a charmoniumlike structure Y(4220) must be introduced. As a charmonium, Y(4220) should dominantly decay into its open-charm channel , which provides an extra support to assignment to Y(4220). In fact, this interference effect introduced to explain Y(4320) and Y(4390) gives a typical example of non-resonant explanations to the observed XYZ states, which should be paid more attention especially before identifying the observed XYZ states as genuine resonances.