Newly observed exotic doubly charmed meson Tcc+

In this work, we treat the newly observed doubly charmed four-quark state T-cc(+) as an axial-vector tetraquark with content cc (u) over bar(d) over bar, and calculate its spectroscopic parameters and width. The mass and current coupling of the tetraquark T-cc(+) are found by means of the QCD two-point sum rule method by taking into account quark, gluon and mixed condensates up to dimension 10. The width of the T-cc(+) is evaluated using partial widths of decay processes T-cc(+) -> (T) over tilde pi(0) and T-cc(+) -> T-cc;(uu) over bar(0)pi(+), where (T) over tilde = cc (u) over bar(d) over bar and T-cc;(uu) over bar(0) are scalar tetraquarks. To compute the partial width of the first process, we apply the QCD three-point sum rule approach and exact numerical value of the strong coupling g that corresponds to the vertex T-cc(+) (T) over tilde pi(0). The width of the second decay is estimated using isospin symmetry and the prediction obtained for the first channel. Our results for the mass m = (3868 +/- 124) MeV and width Gamma = (489 +/- 92) keV of the tetraquark T-cc(+) are in a nice agreement with recent measurements of the LHCb collaboration. (C) 2022 The Author(s). Published by Elsevier B.V.

Automated summary

In this work, the newly observed doubly charmed four-quark state T-cc(+) is treated as an axial-vector tetraquark and its spectroscopic parameters and width are calculated. Various methods, including the QCD two-point sum rule method and QCD three-point sum rule method, are used to determine the mass, current coupling, and width of the tetraquark T-cc(+).