%0 Generic
%A Welter, Johannes Maria René
%D 2017
%F heidok:23871
%R 10.11588/heidok.00023871
%T phenomenology of neutrino magnetic moments
%U https://archiv.ub.uni-heidelberg.de/volltextserver/23871/
%X The neutrino magnetic moment (NMM) in the Standard Model, minimally extended  allowing for massive neutrinos, is many orders of magnitude below current and expected  experimental sensitivities. A potential measurement would therefore strongly  hint to new physics beyond the Standard Model. It raises the question how a positive  NMM signal in future experiments could be explained in a theoretically consistent  way. After a brief theoretical introduction, we summarize existing experimental  bounds and systematically analyze the possibilities of model building for accommodating  large NMMs in beyond the Standard Model frameworks. As a by-product, we  derive new limits on millicharged particles from the non-observation of NMMs. The  tight connection of NMMs and neutrino masses generically leads to a fine-tuning  problem in typical models that predict sizable NMMs. We explicitly demonstrate  this problem using a model in which NMMs are proportional to neutrino masses.  Finally, we investigate mechanisms that provide large NMMs and at the same time  avoid the fine-tuning problem. As a result, we find only two such mechanisms that  are not yet excluded and in which large transition magnetic moments can be realized  for Majorana neutrinos only.