  We prove a global limiting absorption principle on the entire real line for
free, massless Dirac operators $H_0 = \alpha \cdot (-i \nabla)$ for all space
dimensions $n \in \mathbb{N}$, $n \geq 2$. This is a new result for all
dimensions other than three, in particular, it applies to the two-dimensional
case which is known to be of some relevance in applications to graphene.
  We also prove an essential self-adjointness result for first-order
matrix-valued differential operators with Lipschitz coefficients.
