When we define the operators $P_{L,R}=\frac{1\mp\gamma_{5}}{2}$, we are able to define right- and left-handed Dirac fields:
$$\psi=(P_{L}\psi+ P_{R}\psi)=:\psi_{L}+\psi_{R}$$
The corresponding Dirac-adjoints are therefore defined through $$\overline{\psi}_{L,R}:=\overline{\psi}P_{L,R}$$
Plugging $\psi=\psi_{L}+\psi_{R}$ and $\overline{\psi}=\overline{\psi}_{L}+\overline{\psi}_{R}$ into the definitions of the Dirac Lagrangian $$\mathcal{L}=i\overline{\psi}\gamma^{\mu}\partial_{\mu}\psi - m\overline{\psi}\psi$$ and using $P_{L}P_{R}=P_{R}P_{L}=0$, one gets
$$\mathcal{L}=i\overline{\psi}_{L}\gamma^{\mu}\partial_{\mu}\psi_{L}+i\overline{\psi}_{R}\gamma^{\mu}\partial_{\mu}\psi_{R} - m(\overline{\psi}_{R}\psi_{L}+\overline{\psi}_{L}\psi_{R})$$
This expression can be found in many QFT books.....
Now to my question...Isn't the mass term zero? Because
$$\overline{\psi}_{R}\psi_{L}=\overline{\psi}\underbrace{P_{R}P_{L}}_{=0}\psi=0$$ and the same for the other term....