The Veneziano Amplitude via Mostly BRST Exact Operator
Abstract
The Veneziano amplitude is derived from fixing one degree of freedom of $PSL(2,\mathbb{R})$ symmetry by the insertion of a mostly BRST exact operator. Evaluating the fivepoint function which consists of four open string tachyons and this gauge fixing operator, we find it equals the Veneziano amplitude up to a sign factor. The sign factor is interpreted as a signed intersection number.The result implies that the mostly BRST exact operator, which is originally used to provide twopoint string amplitudes, correctly fixes the $PSL(2,\mathbb{R})$ gauge symmetry for general amplitudes. We conjecture an expression for general $n$point tree amplitudes with an insertion of this gauge fixing operator.
 Publication:

arXiv eprints
 Pub Date:
 September 2021
 arXiv:
 arXiv:2109.08433
 Bibcode:
 2021arXiv210908433K
 Keywords:

 High Energy Physics  Theory
 EPrint:
 1+18 pages, 8 figures