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Comments on the two-point string amplitudes

High Energy Physics - Theory 2023-06-14 v3

Abstract

The two-point string amplitude at tree level in flat spacetime reproduces the expected expression for free particles. This has been proven by Erbin, Maldacena and Skliros in [JHEP 07 (2019) 139] by two methods. Here, we provide an alternative proof of this result. Our method consists in considering a timelike Liouville direction as a regularization parameter, which suffices to break time translation invariance and, at the same time, to stabilize the residual conformal symmetry in the worldsheet. This allows taking a limit and restoring Poincare symmetry in a controlled way, thus reproducing the correct expression of the two-point amplitude.

Keywords

Cite

@article{arxiv.2303.15658,
  title  = {Comments on the two-point string amplitudes},
  author = {Gaston Giribet and Nicholas Labranche and Joan La Madrid},
  journal= {arXiv preprint arXiv:2303.15658},
  year   = {2023}
}

Comments

13 pages. v3 references and comments added. Version accepted for publication

R2 v1 2026-06-28T09:36:59.452Z