Propagating Degrees of Freedom in ( ) Gravity

We have computed the number of polarization modes of gravitational waves propagating in the Minkowski background in ( ) gravity. These are three of two from transverse-traceless tensor modes and one from a massive trace mode, which confirms the results found in the literature. There is no massless breathing mode and the massive trace mode corresponds to the Ricci scalar. A newly defined metric tensor in ( ) gravity satisfies the transverse-traceless (TT) condition as well as the TT wave equation