Definition and evolution of transverse momentum dependent distribution of twist-three

A bstract We present an in-depth analysis of transverse momentum dependent (TMD) distributions twist-three. In particular, we focus on evolution equations, symmetry relations, parameterization, interpretation, small-b asymptotic behaviour and the structure singularities. The starting point discussion are correlators with definite TMD-twist. By considering suitable combinations these correlators, introduce physical TMD distribution twist-three that can be used for practical applications. also establish relations generic twist-three, demonstrate their equations autonomous in large- N c limit.