TY  - JOUR
AU  - Dong, Xiang-Kun
AU  - Baru, Vadim
AU  - Guo, Feng-Kun
AU  - Hanhart, Christoph
AU  - Nefediev, Alexey
TI  - Coupled-Channel Interpretation of the LHCb Double- J / ψ Spectrum and Hints of a New State Near the J / ψ J / ψ Threshold
JO  - Physical review letters
VL  - 126
IS  - 13
SN  - 1079-7114
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2021-01580
SP  - 132001
PY  - 2021
AB  - Recently, the LHCb Collaboration reported pronounced structures in the invariant mass spectrum of J/ψ pairs produced in proton-proton collisions at the Large Hadron Collider. In this Letter, we argue that the data can be very well described within two variants of a coupled-channel approach employing T matrices consistent with unitarity: (i) with just two channels, J/ψJ/ψ and ψ(2S)J/ψ, as long as energy-dependent interactions in these channels are allowed, or (ii) with three channels J/ψJ/ψ, ψ(2S)J/ψ, and ψ(3770)J/ψ with just constant contact interactions. Both formulations hint at the existence of a near-threshold state in the J/ψJ/ψ system with the quantum numbers JPC=0++ or 2++, which we refer to as X(6200). We suggest experimental tests to check the existence of this state and discuss what additional channels need to be studied experimentally to allow for distinctive tests between the two mechanisms proposed. If the molecular nature of X(6200), as hinted by the three-channel approach, is confirmed, many other double-quarkonium states should exist driven by the same binding mechanism. In particular, there should be an ηcηc molecule with a similar binding energy.
LB  - PUB:(DE-HGF)16
C6  - 33861129
UR  - <Go to ISI:>//WOS:000652826300004
DO  - DOI:10.1103/PhysRevLett.126.132001
UR  - https://juser.fz-juelich.de/record/891527
ER  -