String Form Factors

TL;DR

This paper calculates scattering cross sections of light probes by excited closed strings, defining effective form factors that reveal the shape and size of strings, with connections to plasma physics.

Contribution

It introduces a method to define form factors for excited strings without infinite subtractions, linking string properties to plasma dispersion functions.

Findings

Form factors characterize string shape and size.

High-energy scattering cross sections factorize.

Elastic form factors relate to plasma dispersion functions.

Abstract

We compute the cross section for scattering of light string probes by randomly excited closed strings. For high energy probes, the cross section factorizes and can be used to define effective form factors for the excited targets. These form factors are well defined without the need for infinite subtractions and contain information about the shape and size of typical strings. For highly excited strings the elastic form factor can be written in terms of the `plasma dispersion function', which describes charge screening in high temperature plasmas.