Perfect DD* Molecular Prediction Matching the T cc Observation at LHCb

In 2012, we investigated the possible molecular states composed of two charmed mesons [Phys. Rev. D 88 (2013) 114008; 2012 arXiv:1211.5007 [hep-ph]]. The DD system with the quantum numbers of I(JP ) = 0(1+) was found to be a good candidate of the loosely bound molecular state. This state is very close to the DD threshold with a binding energy around 0.47 MeV. This prediction was confirmed by the new LHCb observation of Tcc+ [see Franz Muheim’s talk at the European Physical Society conference on high energy physics 2021].