No abstract

We construct the worldline superfield massive superparticle actions which preserve 1/4 portion of the underlying higher-dimensional supersymmetry. We consider the cases of N = 4 → N = 1 and N = 8 → N = 2 partial breaking. In the first case we present the corresponding Green-Schwarz type target superspace action with one κ-supersymmetry. In the second case we find out two possibilities, one of which is a direct generalization of the N = 4 → N = 1 case, while another is essentially different.

We study classical N=2 super W3 algebra and its interplay with N=2 supersymmetric extensions of the Boussinesq equation in the framework of the nonlinear realization method and the inverse Higgs-covariant reduction approach. These techniques have been previously used by us in the bosonic W3 case to give a new geometric interpretation of the Boussinesq hierarchy. Here we deduce the most general N=2 super Boussinesq equation and two kinds of the modified N=2 super Boussinesq equations, as well as the super Miura maps relating these systems to each other, by applying the covariant reduction to certain coset manifolds of linear [Formula: see text] symmetry associated with N=2 super W3. We discuss the integrability properties of the equations obtained and their correspondence with the formulation based on the notion of the second Hamiltonian structure.

We discuss chirality-preserving nilpotent deformations of the four-dimensional N =(1, 1) Euclidean harmonic superspace and their implications in N =(1, 1) supersymmetric gauge and hypermultiplet theories. For the SO(4)×SU(2)-invariant deformation, we present nonanticommutative Euclidean analogues of the N =2 gauge multiplet and hypermultiplet off-shell actions. As a new result, we consider a specific nonanticommutative hypermultiplet model with the N =(1, 0) supersymmetry. It involves free scalar fields and interacting right-handed spinor fields.

We extend the coset space formulation of the one-field realization of w 1+∞ to include more fields as the coset parameters. This can be done either by choosing a smaller stability subalgebra in the nonlinear realization of w 1+∞ symmetry, or by considering a nonlinear realization of some extended symmetry, or by combining both options. We show that all these possibilities give rise to the multi-field realizations of w 1+∞ . We deduce the twofield realization of w 1+∞ proceeding from a coset space of the symmetry groupG which is an extension of w 1+∞ by the second self-commuting set of higher spin currents. Next, starting with the unextended w 1+∞ but placing all its spin 2 generators into the coset, we obtain a new two-field realization of w 1+∞ which essentially involves a 2D dilaton. In order to construct the invariant action for this system we add one more field and so get a new three-field realization of w 1+∞ . We re-derive it within the coset space approach, by applying the latter to an extended symmetry groupĜ which is a nonlinear deformation ofG. Finally we present some multi-field generalizations of our three-field realization and discuss several intriguing parallels with N = 2 strings and conformal affine Toda theories. * BITNET: BELLUCCI@IRMLNF † BITNET: EIVANOV@ENSLAPP.ENS-LYON.FR ‡ BITNET: KRIVONOS@LTP.JINR.DUBNA.SU