Paired composite fermion phase of quantum Hall bilayers at nu=1/2+1/2.

We provide numerical evidence for composite fermion pairing in quantum Hall bilayer systems at filling v = 1/2 + 1/2 for intermediate spacing between the layers. We identify the phase as p x + ip y pairing, and construct high accuracy trial wave functions to describe the ground state on the sphere. For large distances between the layers, and for finite systems, a competing "Hund's rule" state, or composite fermion liquid, prevails for certain system sizes.