  In this paper we study the effects of the coupling constant of the
Chern-Simons modified gravity on some physical properties of black holes. The
Hawking mass is one of the proposed definitions of quasilocal mass. We find
that, for slowly rotating Chern-Simons black holes, the Hawking mass is
independent of the coupling constant. Next, we show the dependence on the
centre of mass energy, for two neutral colliding particles, of coupling
constant and the rotation parameter. We also investigate energy extraction
through Penrose process and find that the energy gain and efficiency of the
Penrose process are independent of this coupling constant. Rotation of the
polarization vector is also studied for dependence on the Chern-Simons coupling
constant.
