Role of the tetraquark in the chiral phase transition

Understand

We investigate the implications of a tetraquark field on chiral symmetry restoration at nonzero temperature.

• In order for the chiral phase transition to be cross-over, as shown by lattice QCD studies, a strong mixing between scalar quarkonium and tetraquark fields is required.
• This leads to a light ($\sim0.4$ GeV), predominantly tetraquark state, and a heavy ($\sim1.2$ GeV), predominantly quarkonium state in the vacuum, in accordance with recently advocated interpretations of spectroscopy data.
• The mixing even increases with temperature and leads to an interchange of the roles of the originally heavy, predominantly quarkonium state and the originally light, predominantly tetraquark state.