# Fermionic superstring loop amplitudes in the pure spinor formalism

## TL;DR

This paper advances the calculation of superstring loop amplitudes using the pure spinor formalism, providing new methods to evaluate integrals and computing specific one-loop and two-loop amplitudes involving Ramond states.

## Contribution

It introduces novel techniques for evaluating pure spinor superspace integrals and computes explicit one-loop and two-loop four-point amplitudes with Ramond states.

## Key findings

- Developed methods for evaluating pure spinor superspace integrals.
- Calculated one-loop and two-loop massless four-point amplitudes.
- Provided explicit expressions for amplitudes involving Ramond states.

## 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.