Events

Mehregan Doroudiani (Southampton U.)

Centre for Theoretical Physics and Astronomy 
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Date: 23 April 2026   Time: 14:00 - 15:00

Location: Room 610, G. O. Jones Building

Title: Scattering amplitude of massless closed strings at genus one


Abstract: Perturbative calculations of string amplitudes are twofold: an expansion in the string coupling (the genus expansion of the worldsheet) and a low-energy expansion in the momenta. In this talk, I will focus on the low-energy expansion of closed string amplitudes at genus one, specifically for four- and five-point massless states of type IIB superstrings in flat spacetime. Evaluating these amplitudes involves integrating over the moduli space of punctured tori. I will demonstrate how the formalism of equivariant iterated Eisenstein integrals can be used to systematically calculate these integrals. Additionally, I will discuss the implications of these results for the S-duality of type IIB.

Updated by: Kymani Armstrong-Williams