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

Chen, Dian-Yong (Aff1, 0000 0004 1761 0489, School of Physics, Southeast University, 210094, Nanjing, China) ; Liu, Xiang (Aff2, 0000 0000 8571 0482, School of Physical Science and Technology, Lanzhou University, 730000, Lanzhou, China) (Aff3, 0000 0000 8571 0482, Research Center for Hadron and CSR Physics, Institute of Modern Physics of CAS, Lanzhou University, 730000, Lanzhou, China) ; Matsuki, Takayuki (Aff4, Tokyo Kasei University, 1-18-1 Kaga, Itabashi, 173-8602, Tokyo, Japan) (Aff5, 0000000094465255, Theoretical Research Division, Nishina Center, RIKEN, Wako, 351-0198, Saitama, Japan)

17 February 2018

Abstract: In this letter, we decode the newly observed charmoniumlike states, Y (4320) and Y (4390), by introducing interference effect between ψ(4160) and ψ(4415) , 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 ψ(4160) and ψ(4415) are missing in the cross sections of e+e-→π+π-J/ψ and π+π-hc simultaneously. To well describe the detailed data of these cross sections around s=4.2 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 e+e-→D0π+D∗- , which provides an extra support to ψ(4S) 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.

Published in: EPJC 78 (2018) 136
Published by: Springer/Società Italiana di Fisica
DOI: 10.1140/epjc/s10052-018-5635-1
License: CC-BY-3.0

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