Comments on Higher Derivative Terms for the Tachyon Action

TL;DR

This paper computes higher derivative corrections to the open string tachyon action using a world-sheet sigma model approach, providing explicit results for bosonic and superstring cases and discussing regularization effects.

Contribution

It presents explicit calculations of higher derivative terms in the tachyon action up to order 8 for bosonic strings and order 6 for superstrings, extending previous results.

Findings

Reproduces known lower derivative terms

Provides explicit higher derivative corrections

Discusses regularization via world-sheet contact terms

Abstract

We consider the open string tachyon action in a world-sheet sigma model approach. We present explicit calculations up to order 8 in derivatives for the bosonic string, and mimic these to order 6 for the superstring, including terms with multiple derivatives acting on the tachyon field. We reproduce lower derivative terms obtained elsewhere, and speculate on the role of the world-sheet contact terms regularizing the action for the superstring tachyon.