Evaluating genus one superstring amplitudes

by Emiel Claasen (Max Planck Institute for Gravitational Physics)

Wednesday Oct 29, 2025, 10:30 AM → 12:30 PM Europe/Berlin

A.1.01/03 - Alps (MPP)

The low-energy expansion of closed-string genus-one amplitudes introduces non-holomorphic modular forms for SL(2, Z) known as modular graph forms (MGFs). The expansion of the amplitude can be evaluated by integrating MGFs over the moduli space of the genus-one Riemann surface. A modern, more systematic approach to tackle this problem is by writing MGFs as equivariant iterated Eisenstein integrals, which are genus-one analogues of single-valued multiple polylogarithms. Their integrals over the moduli space result in among others multiple zeta values, logarithmic derivatives of zeta values and the Euler-Mascheroni constant. In this talk, I will report on the recent four- and five-point amplitude progress.