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Aristizabal Sierra, D., Degee, A., Dorame, L., & Hirsch, M. (2015). Systematic classification of two-loop realizations of the Weinberg operator. J. High Energy Phys., 03(3), 040–41pp.
Abstract: We systematically analyze the d = 5 Weinberg operator at 2-loop order. Using a diagrammatic approach, we identify two different interesting categories of neutrino mass models: (i) Genuine 2-loop models for which both, tree-level and 1-loop contributions, are guaranteed to be absent. And (ii) finite 2-loop diagrams, which correspond to the 1-loop generation of some particular vertex appearing in a given 1-loop neutrino mass model, thus being effectively 2-loop. From the large list of all possible 2-loop diagrams, the vast majority are infinite corrections to lower order neutrino mass models and only a moderately small number of diagrams fall into these two interesting classes. Moreover, all diagrams in class (i) are just variations of three basic diagrams, with examples discussed in the literature before. Similarly, we also show that class (ii) diagrams consists of only variations of these three plus two more basic diagrams. Finally, we show how our results can be consistently and readily used in order to construct two-loop neutrino mass models.
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Barry, J., Dorame, L., & Rodejohann, W. (2012). Linear collider test of a neutrinoless double beta decay mechanism in left-right symmetric theories. Eur. Phys. J. C, 72(5), 2023–11pp.
Abstract: There are various diagrams leading to neutrinoless double beta decay in left-right symmetric theories based on the gauge group SU(2)(L) x SU(2)(R). All can in principle be tested at a linear collider running in electron-electron mode. We argue that the so-called lambda-diagram is the most promising one. Taking the current limit on this diagram from double beta decay experiments, we evaluate the relevant cross section e(-)e(-) -> WL-WR-, where W-L(-) is the Standard Model W-boson and W-R(-) the one from SU(2)(R). It is observable if the life-time of double beta decay and the mass of the W-R are close to current limits. Beam polarization effects and the high-energy behaviour of the cross section are also analyzed.
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Dorame, L., Meloni, D., Morisi, S., Peinado, E., & Valle, J. W. F. (2012). Constraining neutrinoless double beta decay. Nucl. Phys. B, 861(3), 259–270.
Abstract: A class of discrete flavor-symmetry-based models predicts constrained neutrino mass matrix schemes that lead to specific neutrino mass sum-rules (MSR). We show how these theories may constrain the absolute scale of neutrino mass, leading in most of the cases to a lower bound on the neutrinoless double beta decay effective amplitude.
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Dorame, L., Morisi, S., Peinado, E., Valle, J. W. F., & Rojas, A. D. (2012). New neutrino mass sum rule from the inverse seesaw mechanism. Phys. Rev. D, 86(5), 056001–9pp.
Abstract: A class of discrete flavor-symmetry-based models predicts constrained neutrino mass matrix schemes that lead to specific neutrino mass sum rules. One of these implies a lower bound on the effective neutrinoless double beta mass parameter, even for normal hierarchy neutrinos. Here we propose a new model based on the S-4 flavor symmetry that leads to the new neutrino mass sum rule and discuss how to generate a nonzero value for the reactor angle theta(13) indicated by recent experiments, and the resulting correlation with the solar angle theta(12).
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