No abstract

A connection between weak and strong tension limits and their perturbative corrections is discussed. New twistor-like models based on D = 4, N = 1 tensionless superstring and superbrane with tensor central charges are studied. The presence of three, two or less preserved fractions of κ−symmetry in the actions free of the Wess-Zumino terms is shown. A correlation of extra κ−symmetry with the R−symmetry is established. The equations of the superstring and superbrane models preserving 3/4 supersymmetry are exactly solved. The general solution for the Goldstone fermion is pure static, but for the Goldstone bosons it also includes a term describing string/brane motions along the fixed directions given by the initial data. These solutions correspond to the partial spontaneous breaking of the D = 4, N = 1 global supersymmetry and can be associated with a static closed magnetic Nielsen-Olesen vortex or a p-dimensional vortex.

The Lagrangian formulation of the D = 4 bosonic string and superstring in terms of the (super)twistors is considered. The (super)twistor form of the equations of motion is derived and the κ−symmetry transformation for the supertwistors is given. It is shown that the covariant κ−symmetry gauge fixation results in the action quadratic in the (super)twistor variables.

No abstract

Starting with the first-order formulation of the massless superparticle model on the AdS 5 × S 5 superbackground and presenting the momentum components tangent to AdS 5 and S 5 subspaces as bilinear combinations of the constrained SU (2)-Majorana spinors allows to bring the superparticle's Lagrangian to the form quadratic in supertwistors. The SU (2, 2|4) supertwistors are assembled into a pair of SU (2) doublets, one of which has even SU (2, 2) and odd SU (4) components, while the other has odd SU (2, 2) and even SU (4) components. They are subject to the first-class constraints that generate the psu(2|2) ⊕ u(1) gauge algebra. This justifies previously proposed group-theoretic definition of the AdS 5 × S 5 supertwistors and allows to derive the incidence relations with the (10|32) supercoordinates of the AdS 5 × S 5 superspace. Whenever superparticle moves within the AdS 5 subspace of the AdS 5 × S 5 space-time, twistor formulation of its Lagrangian involves just one SU (2) doublet of SU (2, 2|4) supertwistors with even SU (2, 2) and odd SU (4) components. If in addition particle's 5-momentum is null, four first-class constraints which are the su(2) ⊕ u(1) generators single out upon quantization the states of D = 5 N = 8 gauged supergravity multiplet in the superambitwistor formulation.