Thresholds for Intersecting D-branes Revisited

TL;DR

This paper reevaluates gauge threshold corrections in intersecting D6-brane models on toroidal orbifolds, incorporating infrared divergences and light state contributions to improve the understanding of gauge coupling running.

Contribution

It introduces a refined regularisation approach for one-loop diagrams, accounting for massless and light states in gauge threshold calculations.

Findings

Consistent regularisation methods for open string one-loop diagrams.

Inclusion of light state contributions in threshold corrections.

Enhanced understanding of gauge coupling evolution in D-brane models.

Abstract

Gauge threshold corrections for intersecting D6-brane string models on toroidal orbifold backgrounds are reconsidered. Both by dimensionally regularising the appearing open string one-loop diagrams in tree-channel as well as by zeta-function regularisation of the corresponding loop-channel one-loop diagrams, we arrive at a result which takes into account the infrared divergence from the contribution of the massless states in the running of the gauge coupling constant as well as the contribution of states, which become light in certain regions of the moduli space.