相关论文: The computation of one-loop heterotic string thres…
The modular symmetries of string loop threshold corrections for gauge coupling constants are studied in the presence of discrete Wilson lines for all examples of abelian orbifolds, where the point group is realised by the action of Coxeter…
The string one loop renormalization of the gauge coupling constants is examined in abelian orbifold models. The contributions to string threshold corrections independent of the compactification moduli fields are evaluated numerically for…
We revisit the question of gauge coupling unification at the string scale in orbifold compactifications of the heterotic string for the supersymmetric Standard Model. In the presence of discrete Wilson lines threshold corrections with…
We discuss aspects of the heterotic string effective field theories in orbifold constructions of the heterotic string. We calculate the moduli dependence of threshold corrections to gauge couplings in (2,2) symmetric orbifold…
We derive the moduli dependent threshold corrections to gauge couplings in toroidal orbifold compactifications. The underlying six dimensional torus lattice of the heterotic string theory is not assumed ---as in previous calculations--- to…
Target space modular symmetries relevant to string loop threshold corrections are studied for $Z_N$ orbifold compactified string theories containing Wilson line background fields.
We study moduli dependent threshold corrections to gravitational couplings in the case of the heterotic string compactified on a symmetric orbifold, for untwisted moduli, extending previous analysis on gauge couplings. Like in the gauge…
We present the computation of threshold functions for Abelian orbifold compactifications. Specifically, starting from the massive, moduli-dependent string spectrum after compactification, we derive the threshold functions as target space…
To compute the string one-loop correction to the Kahler potential of moduli fields of string compactifications in Einstein-frame, one must compute: the string one-loop correction to the Einstein-Hilbert action, the string one-loop…
We derive the universal threshold corrections in heterotic string theory including a continuous Wilson line. Unification of gauge and gravitational couplings is shown to be possible even within perturbative string theory. The relative…
In this note a simple calculation of one loop threshold corrections for the SO(32) heterotic string is performed. In particular the compactification on T^2 with a Wilson line breaking the gauge group to SO(16) x SO(16) is considered. Using…
In the context of a recently proposed method for computing exactly string loop corrections regularized in the infra-red, we determine and calculate the universal moduli-dependent part of the threshold corrections to the gauge couplings for…
Target space symmetries are studied for orbifold compactified string theories containing Wilson line background fields. The symmetries determined are for those moduli which contribute to the string loop threshold corrections of the gauge…
We study the R -> 0 limit for heterotic strings of either kind (Spin(32)/Z_2 or E_8 x E_8) compactified on a circle, in the presence of an arbitrary Wilson line. Though for generic Wilson line this limit leads to chaotic behaviour, there…
We identify the untwisted moduli of heterotic orbifold compactifications for the case, when the gauge twist is realized by a rotation. The Wilson lines are found to have both continuous and discrete parts. For the case of the standard Z(3)…
We work out the relation between automorphic forms on SO(s+2,2) and gauge one-loop corrections of heterotic K3 x T^2 string compactifications for the cases s=0,1. We find that one-loop gauge corrections of any orbifold limit of K3 can…
By employing the symmetries of the underlying conformal field theory, the tree-level K\"ahler potentials for untwisted moduli of the heterotic string compactifications on orbifolds with continuous Wilson lines are derived. These symmetries…
We discuss the calculation of threshold corrections to gauge coupling constants for the, only, non-decomposable class of abelian (2, 2) symmetric N=1 four dimensional heterotic orbifold models, where the internal twist is realized as a…
String theory one-loop threshold corrections are studied in a background field approach due to Kiritsis and Kounnas which uses space-time curvature as an infrared regulator. We review the conformal field theory aspects using the…
The moduli dependence of string loop threshold corrections to gauge coupling constants is investigated for those ${\bf Z}_N$ Coxeter orbifolds with the property that some twisted sectors have fixed planes for which the six-torus ${\bf T}_6$…