Baryogenesis in a flat direction with neither baryon nor lepton charge

We present a new mechanism of spontaneous baryogenesis. Usually such mechanisms require a derivative coupling between a scalar field and baryon current. In our model, the scalar field instead derivatively couples to a current associated with some global symmetry U(1)(Q). In this case, baryogenesis is still possible provided that an interaction exists, which violates the baryon and U(1)(Q) symmetries simultaneously. As a concrete example, we discuss baryogenesis in a flat direction with neither baryon nor lepton charge.