Esteves, J. N., Joaquim, F. R., Joshipura, A. S., Romao, J. C., Tortola, M., & Valle, J. W. F. (2010). A(4)-based neutrino masses with Majoron decaying dark matter. Phys. Rev. D, 82(7), 073008–8pp.
Abstract: We propose an A(4) flavor-symmetric SU(3) circle times SU(2) circle times U(1) seesaw model where lepton number is broken spontaneously. A consistent two-zero texture pattern of neutrino masses and mixing emerges from the interplay of type-I and type-II seesaw contributions, with important phenomenological predictions. We show that, if the Majoron becomes massive, such seesaw scenario provides a viable candidate for decaying dark matter, consistent with cosmic microwave background lifetime constraints that follow from current WMAP observations. We also calculate the subleading one-loop-induced decay into photons which leads to a monoenergetic emission line that may be observed in future x-ray missions such as Xenia.
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Adhikari, R. et al, Pastor, S., & Valle, J. W. F. (2017). A White Paper on keV sterile neutrino Dark Matter. J. Cosmol. Astropart. Phys., 01(1), 025–247pp.
Abstract: We present a comprehensive review of keV-scale sterile neutrino Dark Matter, collecting views and insights from all disciplines involved – cosmology, astrophysics, nuclear, and particle physics – in each case viewed from both theoretical and experimental/observational perspectives. After reviewing the role of active neutrinos in particle physics, astrophysics, and cosmology, we focus on sterile neutrinos in the context of the Dark Matter puzzle. Here, we first review the physics motivation for sterile neutrino Dark Matter, based on challenges and tensions in purely cold Dark Matter scenarios. We then round out the discussion by critically summarizing all known constraints on sterile neutrino Dark Matter arising from astrophysical observations, laboratory experiments, and theoretical considerations. In this context, we provide a balanced discourse on the possibly positive signal from X-ray observations. Another focus of the paper concerns the construction of particle physics models, aiming to explain how sterile neutrinos of keV-scale masses could arise in concrete settings beyond the Standard Model of elementary particle physics. The paper ends with an extensive review of current and future astrophysical and laboratory searches, highlighting new ideas and their experimental challenges, as well as future perspectives for the discovery of sterile neutrinos.
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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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Reig, M., Valle, J. W. F., Vaquera-Araujo, C. A., & Wilczek, F. (2017). A model of comprehensive unification. Phys. Lett. B, 774, 667–670.
Abstract: Comprehensive – that is, gauge and family – unification using spinors has many attractive features, but it has been challenged to explain chirality. Here, by combining an orbifold construction with more traditional ideas, we address that difficulty. Our candidate model features three chiral families and leads to an acceptable result for quantitative unification of couplings. A potential target for accelerator and astronomical searches emerges.
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Deppisch, F. F., Hati, C., Patra, S., Sarkar, U., & Valle, J. W. F. (2016). 331 models and grand unification: From minimal SU(5) to minimal SU(6). Phys. Lett. B, 762, 432–440.
Abstract: We consider the possibility of grand unification of the SU(3)(c) circle times SU(3)(L) circle times U(1)(X) model in an SU(6) gauge unification group. Two possibilities arise. Unlike other conventional grand unified theories, in SU(6) one can embed the 331 model as a subgroup such that different multiplets appear with different multiplicities. Such a scenario may emerge from the flux breaking of the unified group in an E(6) F-theory GUT. This provides new ways of achieving gauge coupling unification in 331 models while providing the radiative origin of neutrino masses. Alternatively, a sequential variant of the SU(3)(c) circle times SU(3)(L) circle times U(1)(X) model can fit within a minimal SU(6) grand unification, which in turn can be a natural E(6) subgroup. This minimal SU(6) embedding does not require any bulk exotics to account for the chiral families while allowing for a TeV scale SU(3)(c) circle times SU(3)(L) circle times U(1)(X) model with seesaw-type neutrino masses.
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