Fermionic superstring loop amplitudes in the pure spinor formalism
arXiv:0704.0015 · doi:10.1088/1126-6708/2007/05/034
Abstract
The pure spinor formulation of the ten-dimensional superstring leads to manifestly supersymmetric loop amplitudes, expressed as integrals in pure spinor superspace. This paper explores different methods to evaluate these integrals and then uses them to calculate the kinematic factors of the one-loop and two-loop massless four-point amplitudes involving two and four Ramond states.
22 pages; signs and coefficients adjusted for anticommuting superfields, section 4.3 changed accordingly, reference added