Speaker
Description
The CMS, LHCb, and ATLAS experiments have observed up to three resonances in
the X → J/ψ J/ψ → 4µ decay channel in the invariant mass spectrum between 6 and 8 GeV. These resonances are candidates for ccc¯ c¯ tetra-quark states. In order to study this hypothesis, and to understand the nature of these resonances, we perform a spin-parity study using kinematic distributions of the four muons. A matrix-element approach is employed to create optimal discriminants to distinguish pairs of hypotheses from the list of J P = 0+, 0−, 1+, 1−, 2+, 2−, where both gluon fusion and quark-antiquark production mechanisms are considered. The results of this study are presented using the full Run-2 dataset from the CMS experiment.