Related papers: String loop corrections to gauge and Yukawa coupli…
Gauge/gravity duality is the conjecture that string theories have dual descriptions as gauge theories. Weakly-coupled gravity is dual to strongly-coupled gauge theories, ideal for lattice calculations. I will show precision lattice…
We calculate one-loop string amplitudes of open and closed strings with N=1,2,4 supersymmetry in four and six dimensions, by compactification on Calabi-Yau and K3 orbifolds. In particular, we develop a method to combine contributions from…
We compare the predictions of the effective string description of confinement in finite temperature gauge theories to high precision Monte Carlo data for the three-dimensional Z(2) gauge theory. We show that string interaction effects…
We show that the currently experimentally preferred values of the top-quark mass (\ie, $130\lsim m_t\lsim180\GeV$) are naturally understood in the context of string models, where the top-quark Yukawa coupling at the string scale is…
We provide an overview of recent work which aims to understand patterns of vanishing Yukawa couplings that arise in models of particle physics derived from string theory. These patterns are seemingly linked to a plethora of different…
In this article we give a calculation of the two-loop $\sigma$-model corrections to the T-duality map in string theory. We use the effective action approach, and analyze two-loop corrections in a specific subtraction scheme. Focusing on…
We present the beta functions of gauge and Yukawa couplings in general four-dimensional quantum field theory, at four and three loops, respectively. The essence of our approach is fixing unknown coefficients in the most general ansatz for…
The derived modular invariant one-loop string effective coupling constant has been used to discuss the weak scale measurement constraints on minimal superstring models, minimal SUSY left-right string models and minimal left-right SUSY…
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…
Techniques based upon the string organisation of amplitudes may be used to simplify field theory calculations. We apply these techniques to perturbative gravity and calculate all one-loop amplitudes for four-graviton scattering with…
In this paper we discuss quantum modified moduli spaces in supergravity. We examine a model suggested by Izawa and Yanagida and by Intriligator and Thomas that breaks global supersymmetry by a quantum deformation of the classical moduli…
We compute one loop radiative corrections to the physical neutralino masses in the MSSM considering the dominant top-stop contributions. We present a numerical renormalization group analysis of the feasibility of the radiative gauge…
This article reviews the non-perturbative structure of certain higher derivative terms in the type II string theory effective action and their connection to one-loop effects in eleven-dimensional supergravity compactified on a torus. New…
We consider folded spinning strings in AdS_5xS^5 (with one spin component S in AdS_5 and J in S^5) corresponding to the Tr(D^S Z^J) operators in the sl(2) sector of the N=4 SYM theory in the special scaling limit in which both the string…
We consider the space-time variation of gauge couplings in brane-world models induced by the coupling to a bulk scalar field. A variation is generated by the running of the gauge couplings with energy and a conformal anomaly while going…
Many N=1 heterotic string compactifications exhibit physically mysterious singularities at codimension one in the moduli space of vacua. At these singularities, Yukawa couplings of charged fields develop poles as a function of the moduli.…
We calculate the moduli dependent part of string one-loop threshold corrections to gauge couplings for the heterotic string theory compactified on abelian toroidal orbifolds, allowing for arbitrary discrete Wilson lines. We show that the…
The connection between Superstring theory and the low--energy world is analyzed. In particular, the soft Supersymmetry--breaking terms arising in Supergravity theories coming from Superstrings are computed. Several solutions proposed to…
The structure of stringy quantum corrections to four-dimensional effective theories is particularly interesting for string phenomenology and attempts to stabilize moduli. We consider the heterotic string compactified on a Calabi-Yau space.…
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…