Superstring Threshold Corrections to Yukawa Couplings

TL;DR

This paper develops a method to compute one-loop string corrections to Yukawa couplings and the Kähler metric in heterotic superstring compactifications, including explicit formulas for symmetric orbifolds.

Contribution

It introduces a general technique for calculating string threshold corrections to Yukawa couplings and the Green-Schwarz term at one-loop in heterotic string theory.

Findings

Derived explicit formulas for symmetric orbifold compactifications.

Identified the infrared divergent part related to anomalous dimensions.

Connected matter metric corrections to physical Yukawa couplings.

Abstract

A general method of computing string corrections to the K\"ahler metric and Yukawa couplings is developed at the one-loop level for a general compactification of the heterotic superstring theory. It also provides a direct determination of the so-called Green-Schwarz term. The matter metric has an infrared divergent part which reproduces the field-theoretical anomalous dimensions, and a moduli-dependent part which gives rise to threshold corrections in the physical Yukawa couplings. Explicit expressions are derived for symmetric orbifold compactifications.