Universality of gauge thresholds in non-supersymmetric heterotic vacua
- Publisher: Elsevier
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
(issn: 0370-2693, vol:
Physics | High Energy Physics - Theory | QC1-999 | Nuclear and High Energy Physics
arxiv: High Energy Physics::Theory | High Energy Physics::Phenomenology
We compute one-loop threshold corrections to non-abelian gauge couplings in four-dimensional heterotic vacua with spontaneously broken $\cal N = 2 \to \cal N = 0$ supersymmetry, obtained as Scherk-Schwarz reductions of six-dimensional K3 compactifications. As expected, the gauge thresholds are no-longer BPS protected, and receive contributions also from the excitations of the RNS sector. Remarkably, the difference of thresholds for non-abelian gauge couplings is BPS saturated and exhibits a universal behaviour independently of the orbifold realisation of K3. Moreover, the thresholds and their difference develop infra-red logarithmic singularities whenever charged BPS-like states, originating from the twisted RNS sector, become massless at special loci in the classical moduli space.