Some time ago the bosonic and fermionic 4-field terms of the non-abelian low energy effective action of the open superstring were obtained, to all order in α. This was done at tree level by directly generalizing the abelian case, treated some time before, and considering the known expressions of all massless superstring 4-point amplitudes (at tree level). In the present work we obtain the boson...

We describe the constraints imposed on quantum maximal supergravity theories in perturbation theory by the two duality frameworks: S-duality in superstring theory and the AdS/CFT holographic correspondence between IIB superstring theory and N = 4 super Yang-Mills theory. E-mail address: [email protected]

Using the manifestly spacetime-supersymmetric version of open superstring field theory , we construct the free action for the first massive states of the open superstring com-pactified to four dimensions. This action is in N=1 D=4 superspace and describes a massive spin-2 multiplet coupled to two massive scalar multiplets.

For a calculation of divergent fermion string amplitudes a regularization procedure invariant under the supermodular group is constructed. By this procedure superstring amplitudes of an arbitrary genus are calculated using both partition functions and superfield vacuum correlators computed early. A finiteness of superstring amplitudes and related topics are discussed. E-mail address: danilov@th...

We show that the M-theory/IIA and IIA/IIB superstring dualities together with the diffeomorphism invariance of the underlying theories require the presence of certain p-brane bound states in IIA and IIB superstring theories preserving 1/2 of the spacetime supersymmetry. We then confirm the existence of IIA and IIB supergravity solutions having the appropriate p-brane bound states interpretation.

We discuss the bihamiltonian structure of the Metsaev-Tseytlin superstring in AdS5 ×S 5. We explicitly write down the boost-invariant symplectic structure for the superstring in AdS5 × S 5 and explain its relation to the standard (canonical) symplectic structure. We discuss the geometrical meaning of the boost-invariant symplectic structure for the bosonic string.

We discuss the bihamiltonian structure of the Metsaev-Tseytlin superstring in AdS5 ×S 5. We explicitly write down the boost-invariant symplectic structure for the superstring in AdS5 × S 5 and explain its relation to the standard (canonical) symplectic structure. We discuss the geometrical meaning of the boost-invariant symplectic structure for the bosonic string.

The free action for the massless sector of the Type II superstring was recently constructed using closed RNS superstring field theory. The supersymmetry transformations of this action are shown to satisfy an N=2 D=10 SUSY algebra with Ramond-Ramond

We give a model-independent discussion of fermion masses in four-dimensional het-erotic superstring theories. We discuss the tree level contributions and quantum corrections, including one-loop threshold effects and masses generated as a result of non-perturbative supersymmetry breaking. We also point out that superstring models give rise to a generic µ-term in the effective low energy Lagrangi...

We explore geometrical properties of fermionic vertex operators for a NSR superstring in order to establish connection between worldsheet and target space supersymmetries.The mechanism of picture-changing is obtained as a result of imposing certain constraints on a world-sheet gauge group of the NSR Superstring Theory. We find that picture-changing operators of different integer ghost numbers f...