A central question in exotic-hadron physics is their internal structure whether these states are loosely bound hadronic molecules or compact multiquark configurations. To shed light on this issue, we develop a model that incorporates mixing between hadronic-molecular and compact multiquark components. We then apply this framework to the specific case of the T c c ( 3875 ) + and analyze the peak structure in the D 0 D 0 π + invariant-mass spectrum reported by LHCb. We find that the model admits three solutions of comparable fit quality that can account for the T c c ( 3875 ) + . One solution corresponds to a predominantly compact tetraquark configuration. The other two solutions imply a molecular T c c ( 3875 ) + : (1) the T c c ( 3875 ) + is a D * + D 0 molecule and an additional D * 0 D + molecular state appears; (2) the T c c ( 3875 ) + is a D * 0 D + molecule and an additional D * + D 0 molecular state is found below the D 0 D 0 π + threshold. These molecular states are not simple I = 0 states, but mixtures of I = 0 and I = 1 states. We show that all three scenarios are also consistent with the experimentally observed near-threshold D 0 D 0 and D 0 D + invariant-mass distributions.
Anonymous et al. (Thu,) studied this question.