Off-shell (4,4) supersymmetric sigma models with torsion as gauge theories in harmonic superspace

Starting from the action of $(4,4)$ $2D$ twisted multiplets in the harmonic superspace with a double set of $SU(2)$ harmonic variables, we present its generalization which provides an off-shell description of a wide class of $(4,4)$ sigma models with torsion and non-commuting left and right complex structures. The distinguishing features of the action constructed are: (i) a nonabelian and in general nonlinear gauge invariance ensuring a correct number of physical degrees of freedom; (ii) an infinite tower of auxiliary fields. For a particular class of such models we explicitly demonstrate the non-commutativity of complex structures on the bosonic target