English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We analyze N=2 (perturbative and non-perturbative) corrections to theeffective theory in type I orbifold models where a dual heterotic descriptionis available. These corrections may play an important role in phenomenologicalscenarios. More precisely, we consider two particular compactifications: theBianchi-Sagnotti-Gimon-Polchinski orbifold and a freely-acting Z_2 x Z_2orbifold with N=1 supersymmetry and gauge group SO(q) x SO(32-q). By exploitingperturbative calculations of the physical gauge couplings on the heteroticside, we obtain multi-instanton and one-loop string corrections to the K\"ahlerpotential and the gauge kinetic function for these models. The non-perturbativecorrections appear as sums over relevant Hecke operators, whereas the one-loopcorrection to the K\"ahler potential matches the expression proposed in [1,2].We argue that these corrections are universal in a given class of models wheretarget-space modular invariance (or a subgroup of it) holds.

Multi-instanton and string loop corrections in toroidal orbifold models