Generalization of θ vacuum and parity-odd domain structure

Heavy ion experiments have shown the possibility of creating parity-odd domains related to the nontrivial solution of quantum chromodynamic (QCD) vacuum known as the θ vacuum. In the parity-odd domains, the value of θ is taken to be a function depending on spacetime coordinates. The spacetime dependence of θ can be transferred into that of gluon condensates, and we can interprete this result as a change in the viewpoints on the definition of the QCD vacuum. In this paper, we suggest a method to generalize the θ vacuum by exploiting the dimension-2 condensates and to calculate the parity-odd domain structure formed by 9 quarks as the union of gauge slices defined by the constant value of the dimension-2 condensate.