  Recently it has been shown that in two dimensions is possible to add new
Lorentz invariant terms built with fractions containing the null vector $n= (1,
1)$. In this work, we have computed the meson spectrum following the 't Hooft
model in $QCD_2$ incorporating these new kinds of terms. We found these new
terms does not affect the meson spectrum. We have computed the 't Hooft model
with a new regulator. We have introduced a gluon mass and we have recovered the
't Hooft result when this parameter is set to zero.
