Joern Kersten

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We systematically analyze quantum corrections in see-saw scenarios, including effects from above as well as below the see-saw scales. We derive approximate renormalization group equations for neutrino masses, lepton mixings and CP phases, yielding an analytic understanding and a simple estimate of the size of the effects. Even for hierarchical masses, they(More)
One of the most interesting results in recent particle physics is the evidence for large generation mixing in the lepton sector, which has been established by neutrino oscillation experiments. Two of the three mixing angles θ12, θ23, θ13 commonly used to parameterize the lepton mixing matrix are large: the “solar” mixing angle θ12 is approximately 33◦,(More)
We consider the running of the neutrino mass matrix in the Standard Model and the Minimal Supersymmetric Standard Model, extended by heavy singlet Majorana neutrinos. Unlike previous studies, we do not assume that all of the heavy mass eigenvalues are degenerate. This leads to various effective theories when the heavy degrees of freedom are integrated out(More)
We re-derive the renormalization group equation for the effective coupling of the dimension five operator which corresponds to a Majorana mass matrix for the Standard Model neutrinos. We find a result which differs somewhat from earlier calculations, leading to modifications in the evolution of leptonic mixing angles and CP phases. We also present a general(More)
In a recent re-analysis of the Standard Model (SM) β-function for the effective neutrino mass operator, we found that the previous results were not entirely correct. Therefore, we consider the analogous dimension five operators in a class of Two Higgs Doublet Models (2HDM’s) and the Minimal Supersymmetric Standard Model (MSSM). Deriving the renormalization(More)
We show that in see-saw models with bimaximal lepton mixing at the GUT scale and with zero CP phases, the solar mixing angle θ12 generically evolves towards sizably smaller values due to Renormalization Group effects, whereas the evolution of θ13 and θ23 is comparatively small. The currently favored LMA solution of the solar neutrino problem can thus be(More)
We derive simple analytical formulae for the renormalization group running of neutrino masses, leptonic mixing angles and CP phases, which allow an easy understanding of the running. Particularly for a small angle θ13 the expressions become very compact, even when non-vanishing CP phases are present. Using these equations we investigate: (i) the influence(More)
After a brief overview of the present knowledge of neutrino masses and mixing, we summarize what can be learned about physics beyond the standard model from the various proposed neutrino experiments. We also comment on the impact of the experiments on our understanding of the origin of the matter–antimatter asymmetry of the Universe as well as what can be(More)
We consider the impact of Catalyzed Big Bang Nucleosynthesis on theories with a gravitino LSP and a charged slepton NLSP. In models where the gravitino to gaugino mass ratio is bounded from below, we derive a lower bound on the gaugino mass parameter m1/2. As a concrete example, we determine the parameter space of gaugino mediation that is compatible with(More)