In the context of a five dimensional N=1 Kaluza Klein model compactified on S1/Z2 × Z2 we compute the one-loop gauge corrections to the self energy of the (zero-mode) scalar field. The result is… (More)

On Gauge couplings, " Large " extra-dimensions and the limit α ′ → 0 of the String. Abstract Using an effective field theory (EFT) approach for a generic model with two additional dimensions… (More)

An effective field theory approach is introduced to compute one-loop radiative corrections to the gauge couplings due to Kaluza-Klein states associated with a two-torus compactification. The results… (More)

Generic D-brane string models of particle physics predict the existence of extra U(1) gauge symmetries beyond hypercharge. These symmetries are not of the E6 class but rather include the gauging of… (More)

Higher Derivative Operators as loop counterterms in one-dimensional field theory orbifolds. Abstract Using a 5D N=1 supersymmetric toy-model compactified on S 1 /(Z 2 × Z ′ 2), with a "… (More)

For one and two dimensional field theory orbifolds we compute in the DR scheme the full dependence on the momentum scale (q) of the one-loop radiative corrections to the 4D gauge coupling. Imposing… (More)

A field theory approach to summing threshold effects to the gauge couplings in a two-torus compactification is presented and the link with the (heterotic) string calculation is carefully… (More)

We investigate the amount of fine tuning of the electroweak scale in the presence of new physics beyond the MSSM, parametrized by higher dimensional operators. We show that these significantly reduce… (More)

We perform a general analysis of the R-parity conserving dimension-five operators that can be present beyond the Minimal Supersymmetric Standard Model. Not all these operators are actually… (More)

In 4D renormalisable theories, integrating out massive states generates in the low energy effective action higher dimensional operators (derivative or otherwise). Using a superfield language it is… (More)