J. Lopez-Pavon, S. Pascoli, Chan-fai Wong
Neutrinoless double beta decay can be induced by various mechanisms, involving both light and heavy exchange particles such as light Majorana neutrinos, nearly-sterile neutrinos, R-parity violating supersymmetric particles, to name a few. It has been pointed out that, typically, the contribution due to the exchange of heavy particles between the two nuclei, with masses much larger than the typical exchange momentum $\sim 100$ MeV, is subdominant with respect to the light neutrino one. In fact, the former is severely constrained if the same interaction induces light neutrino masses. A relevant exception to this generic conclusion is when the contribution to the light neutrino masses cancels out. Here, we focus on this case, specifically in the context of seesaw models. We perform a general analysis without restricting the study to any particular region of the parameter space, although interesting limits associated to inverse and extended seesaw-like models are discussed in more detail. It turns out that, once the relevant experimental constraints and one-loop corrections to neutrino masses are taken into account, the heavy neutrinos can dominate the process only in one of those two limits. For the inverse seesaw we find a very constrained allowed region of the parameter space, with heavy neutrino masses around 5 GeV. In general, the extended seesaw allows for a larger region, with a very hierarchical heavy spectrum which has neutrinos above and below $\sim 100$ MeV.
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http://arxiv.org/abs/1209.5342
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