Chen, P., Centelles Chulia, S., Ding, G. J., Srivastava, R., & Valle, J. W. F. (2019). CP symmetries as guiding posts: Revamping tribimaximal mixing. II. Phys. Rev. D, 100(5), 053001–15pp.
Abstract: In this follow up of arXiv:1812.04663 we analyze the generalized CP symmetries of the charged lepton mass matrix compatible with the complex version of the tribimaximal (TBM) lepton mixing pattern. These symmetries are used to “revamp” the simplest TBM Ansatz in a systematic way. Our generalized patterns share some of the attractive features of the original TBM matrix and are consistent with current oscillation experiments. We also discuss their phenomenological implications both for upcoming neutrino oscillation and neutrinoless double beta decay experiments.
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Kang, S. K., Popov, O., Srivastava, R., Valle, J. W. F., & Vaquera-Araujo, C. A. (2019). Scotogenic dark matter stability from gauged matter parity. Phys. Lett. B, 798, 135013–10pp.
Abstract: We explore the idea that dark matter stability results from the presence of a matter-parity symmetry, arising naturally as a consequence of the spontaneous breaking of an extended SU(3) circle times SU(3)(L) circle times U(1)(X) circle times U(1)(N) electroweak gauge symmetry with fully gauged B-L. Using this framework we construct a theory for scotogenic dark matter and analyze its main features.
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Bonilla, C., Centelles Chulia, S., Cepedello, R., Peinado, E., & Srivastava, R. (2020). Dark matter stability and Dirac neutrinos using only standard model symmetries. Phys. Rev. D, 101(3), 033011–5pp.
Abstract: We provide a generic framework to obtain stable dark matter along with naturally small Dirac neutrino masses generated at the loop level. This is achieved through the spontaneous breaking of the global U(1)(B-L) symmetry already present in the standard model. The U(1)(B-L) symmetry is broken down to a residual even Z(n) (n >= 4) subgroup. The residual Z(n) symmetry simultaneously guarantees dark matter stability and protects the Dirac nature of neutrinos. The U(1)(B-L) symmetry in our setup is anomaly free and can also be gauged in a straightforward way. Finally, we present an explicit example using our framework to show the idea in action.
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Leite, J., Popov, O., Srivastava, R., & Valle, J. W. F. (2020). A theory for scotogenic dark matter stabilised by residual gauge symmetry. Phys. Lett. B, 802, 135254–10pp.
Abstract: Dark matter stability can result from a residual matter-parity symmetry, following naturally from the spontaneous breaking of the gauge symmetry. Here we explore this idea in the context of the SU(3)(c) circle times SU(3)L circle times U(1)(x) circle times U(1)(N) electroweak extension of the standard model. The key feature of our new scotogenic dark matter theory is the use of a triplet scalar boson with anti-symmetric Yukawa couplings. This naturally implies that one of the light neutrinos is massless and, as a result, there is a lower bound for the O nu beta beta decay rate.
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Mandal, S., Srivastava, R., & Valle, J. W. F. (2020). Consistency of the dynamical high-scale type-I seesaw mechanism. Phys. Rev. D, 101(11), 115030–15pp.
Abstract: We analyze the consistency of electroweak breaking within the simplest high-scale SU(3)(c) circle times SU(2)(L) circle times U(1)(Y) type-I seesaw mechanism. We derive the full two-loop renormalization group equations of the relevant parameters, including the quartic Higgs self-coupling of the Standard Model. For the simplest case of bare “right-handed” neutrino mass terms we find that, with large Yukawa couplings, the Higgs quartic self-coupling becomes negative much below the seesaw scale, so that the model may be inconsistent even as an effective theory. We show, however, that the “dynamical” type-I high-scale seesaw with spontaneous lepton number violation has better stability properties.
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