Complex fermion mass term, regularization and CP violation

P Mitra
2007 Journal of Physics A: Mathematical and Theoretical  
It is well known that the CP violating theta term of QCD can be converted to a phase in the quark mass term. However, a theory with a complex mass term for quarks can be regularized so as not to violate CP, for example through a zeta function. The contradiction is resolved through the recognition of a dependence on the regularization or measure. The appropriate choice of regularization is discussed and implications for the strong CP problem are pointed out.
doi:10.1088/1751-8113/40/26/f03 fatcat:f7ajnfs7kfffnmlor3yjkrvtmm