The effective action for the 4-point functions in abelian open superstring theory

We construct the derivative corrections to the four-point vertices in the abelian open string effective action to all orders in alpha'. The result is based on the structure of the string four-point function. Supersymmnetry of these vertices is guaranteed by the supersymmetry of the F^4 term in the effective action. By this construction we establish the existence of an infinite number of supersymmetry invariants, the number of invariants at order alpha'^n grows linearly with n.Comment: 11 pages, 1 figure, v2: additional remarks in Section 5, added references, v3: additional remarks in Section 4 and minor correction

Supersymmetric Yang-Mills theory at order alpha'^3

We construct the order alpha'^3 terms in the supersymmetric Yang-Mills action in ten dimensions for an arbitrary gauge group. The result can be expressed in terms of the structure constants of the Yang-Mills group, and is therefore independent of abelian factors. The alpha'^3 invariant obtained here is independent of the alpha'^2 invariant, and we argue that additional superinvariants will occur at all odd orders of alpha'.Comment: 15 pages LaTe

Testing the fermionic terms in the non-abelian D-brane effective action through order α′3\alpha'{}^3

Recently the construction of the non-abelian effective D-brane action was performed through order $\alpha'{}^3$ including the terms quadratic in the gauginos. This result can be tested by calculating the spectrum in the presence of constant magnetic background fields and comparing it to the string theoretic predictions. This test was already performed for the purely bosonic terms. In this note we extend the test to the fermionic terms. We obtain perfect agreement.Comment: 10 pages, LaTe

Derivative corrections in 10-dimensional super-Maxwell theory

We construct the supersymmetric effective action at order alpha'(4) of the abelian open superstring. It includes the alpha'4 terms in the abelian Born-Infeld action, and in particular the leading derivative correction of the form partial derivative(4)F(4). Besides linear supersymmetry this sector of the open string effective action also has a nonlinear supersymmetry. The terms partial derivative(4)F(4) and their fermionic partners have an arbitrary coefficient, and we discuss the possible fate of such coefficients when higher orders in alpha' are included