Gian Francesco Giudice

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Theories with gauge-mediated supersymmetry breaking provide an interesting alternative to the scenario in which the soft terms of the low-energy fields are induced by gravity. These theories allow for a natural suppression of flavour violations in the supersymmetric sector and have very distinctive phenomenological features. Here we review their basic(More)
Recently it has been pointed out that the characteristic quantum-gravity scale could be as low as the weak scale in theories with gravity propagating in higher dimensions. The observed smallness of Newton’s constant is a consequence of the large compactified volume of the extra dimensions. We investigate the consequences of this supposition for high-energy(More)
We perform a thorough study of thermal leptogenesis adding finite temperature effects, RGE corrections, scatterings involving gauge bosons and by properly avoiding overcounting on-shell processes. Assuming hierarchical right-handed neutrinos with arbitrary abundancy, successful leptogenesis can be achieved if left-handed neutrinos are lighter than 0.13 eV(More)
In models with dynamical supersymmetry breaking in the hidden sector, the gaugino masses in the observable sector have been believed to be extremely suppressed (below 1 keV), unless there is a gauge singlet in the hidden sector with specific couplings to the observable sector gauge multiplets. We point out that there is a pure supergravity contribution to(More)
We develop a simple description of models where electroweak symmetry breaking is triggered by a light composite Higgs, which emerges from a strongly-interacting sector as a pseudo-Goldstone boson. Two parameters fully characterize these models: mρ, the mass scale of the new resonances and gρ, their coupling. An effective low-energy Lagrangian approach(More)
We show that in theories in which supersymmetry breaking is communicated by renormalizable perturbative interactions, it is possible to extract the soft terms for the observable fields from wave-function renormalization. Therefore all the information about soft terms can be obtained from anomalous dimensions and β functions, with no need to further compute(More)
We present the QCD corrections to the matching conditions of the ∆B = 1 magnetic and chromo-magnetic operators in the Standard Model and in two-Higgs doublet models. We use an off-shell matching procedure which allows us to perform the computation using Taylor series in the external momenta, instead of asymptotic expansions. In the Standard Model case, we(More)
We discuss possible large contributions to B → Xsγ, which can occur at the next-to-leading order in supersymmetric models. They can originate from terms enhanced by tan β factors, when the ratio between the two Higgs vacuum expectation values is large, or by logarithm ofMsusy/MW , when the supersymmetric particles are considerably heavier than the W boson.(More)
We extend to all orders in perturbation theory a method to calculate supersymmetry-breaking effects by analytic continuation of the renormalization group into superspace. A central observation is that the renormalized gauge coupling can be extended to a real vector superfield, thereby including soft breaking effects in the gauge sector. We explain the(More)