How tetraquarks can affect the chiral phase transition

摘要

We discuss the possible role which scalar mesons composed of tetraquarks can play in the chiral phase transition for three colors and two or three light flavors. For two flavors the tetraquark is an isoscalar, and isn't expected to significantly affect the chiral transition. For three flavors, however, one can naturally form a tetraquark field which in the same representation as the usual chiral field. Having two fields can alter the chiral transition significantly: for light fields, they may produce two chiral phase transitions. For QCD, in the plane of temperature and chemical potential we argue that a crossover line for the tetraquark condensate naturally connects to a line of phase transitions for color superconductivity.