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Form Factors from String Amplitudes

Qu Cao*

  • *Contact author: qucao@zju.edu.cn
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Phys. Rev. Lett. 135, 021603 – Published 10 July, 2025

DOI: https://doi.org/10.1103/svb5-mhpc

Abstract

In this Letter, we propose a stringy model for n-point tree-level form factor with the off-shell operator in the scalar and gluon theories from the bosonic string disk amplitude: n open string states and one closed string state scatter on the disk. In the field-theory limit (α′→0), the “stringy form factor” reduces to the form factor, which helps us to investigate the hidden properties of the field-theory form factors, manifest the factorization and soft behaviors, and uncover more nontrivial relations between form factors and scattering amplitudes.

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Phys. Rev. Lett. 135, 021603– Published 10 July, 2025
  • Received 1 May 2025
  • Accepted 24 June 2025
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