We characterize helix surfaces (constant angle surfaces) in the special
linear group SL(2,)˚. In particular, we give an explicit local
description of these surfaces in terms of a suitable curve and a 1-parameter
family of isometries of SL(2,)˚.Comment: Minor corrections. To appear in Annali di Matematica Pura e
Applicata. arXiv admin note: substantial text overlap with arXiv:1206.127