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Mandal, S., Rojas, N., Srivastava, R., & Valle, J. W. F. (2021). Dark matter as the origin of neutrino mass in the inverse seesaw mechanism. Phys. Lett. B, 821, 136609–15pp.
Abstract: We propose that neutrino masses are “seeded” by a dark sector within the inverse seesaw mechanism. This way we have a new, “hidden”, variant of the scotogenic scenario for radiative neutrino masses. We discuss both explicit and dynamical lepton number violation. In addition to invisible Higgs decays with majoron emission, we discuss in detail the pheneomenolgy of dark matter, as well as the novel features associated to charged lepton flavour violation, and neutrino physics.
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Sierra, D. A., De Romeri, V., & Rojas, N. (2019). CP violating effects in coherent elastic neutrino-nucleus scattering processes. J. High Energy Phys., 09(9), 069–22pp.
Abstract: The presence of new neutrino-quark interactions can enhance, deplete or distort the coherent elastic neutrino-nucleus scattering (CEvNS) event rate. The new interactions may involve CP violating phases that can potentially affect these features. Assuming light vector mediators, we study the effects of CP violation on the CEvNS process in the COHERENT sodium-iodine, liquid argon and germanium detectors. We identify a region in parameter space for which the event rate always involves a dip and another one for which this is never the case. We show that the presence of a dip in the event rate spectrum can be used to constraint CP violating effects, in such a way that the larger the detector volume the tighter the constraints. Furthermore, it allows the reconstruction of the effective coupling responsible for the signal with an uncertainty determined by recoil energy resolution. In the region where no dip is present, we find that CP violating parameters can mimic the Standard Model CEvNS prediction or spectra induced by real parameters. We point out that the interpretation of CEvNS data in terms of a light vector mediator should take into account possible CP violating effects. Finally, we stress that our results are qualitatively applicable for CEvNS induced by solar or reactor neutrinos. Thus, the CP violating effects discussed here and their consequences should be taken into account as well in the analysis of data from multi-ton dark matter detectors or experiments such as CONUS, nu-cleus or CONNIE.
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Rojas, N., Srivastava, R., & Valle, J. W. F. (2019). Simplest scoto-seesaw mechanism. Phys. Lett. B, 789, 132–136.
Abstract: By combining the simplest (3,1) version of the seesaw mechanism containing a single heavy “right-handed” neutrino with the minimal scotogenic approach to dark matter, we propose a theory for neutrino oscillations. The “atmospheric” mass scale arises at tree level from the seesaw, while the “solar” oscillation scale emerges radiatively, through a loop involving the “dark sector” exchange. Such simple setup gives a clear interpretation of the neutrino oscillation lengths, has a viable WIMP dark matter candidate, and implies a lower bound on the neutrinoless double beta decay rate.
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Aristizabal Sierra, D., De Romeri, V., & Rojas, N. (2018). COHERENT analysis of neutrino generalized interactions. Phys. Rev. D, 98(7), 075018–14pp.
Abstract: Effective neutrino-quark generalized interactions are entirely determined by Lorentz invariance, so they include all possible four-fermion nonderivative Lorentz structures. They contain neutrino-quark nonstandard interactions as a subset, but span over a larger set that involves effective scalar, pseudoscalar, axial and tensor operators. Using recent COHERENT data, we derive constraints on the corresponding couplings by considering scalar, vector and tensor quark currents and assuming no lepton flavor dependence. We allow for mixed neutrino-quark Lorentz couplings and consider two types of scenarios in which: (i) one interaction at the nuclear level is present at a time, (ii) two interactions are simultaneously present. For scenarios (i) our findings show that scalar interactions are the most severely constrained, in particular for pseudoscalar-scalar neutrino-quark couplings. In contrast, tensor and nonstandard vector interactions still enable for sizable effective parameters. We find as well that an extra vector interaction improves the data fit when compared with the result derived assuming only the standard model contribution. In scenarios (ii) the presence of two interactions relaxes the bounds and opens regions in parameter space that are otherwise closed, with the effect being more pronounced in the scalar-vector and scalar-tensor cases. We point out that barring the vector case, our results represent the most stringent bounds on effective neutrino-quark generalized interactions for mediator masses of order similar to 1 GeV. They hold as well for larger mediator masses, case in which they should be compared with limits from neutrino deep-inelastic scattering data.
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Diaz, M. A., Rojas, N., Urrutia-Quiroga, S., & Valle, J. W. F. (2017). Heavy Higgs boson production at colliders in the singlet-triplet scotogenic dark matter model. J. High Energy Phys., 08(8), 017–23pp.
Abstract: We consider the possibility that the dark matter particle is a scalar WIMP messenger associated to neutrino mass generation, made stable by the same symmetry responsible for the radiative origin of neutrino mass. We focus on some of the implications of this proposal as realized within the singlet-triplet scotogenic dark matter model. We identify parameter sets consistent both with neutrino mass and the observed dark matter abundance. Finally we characterize the expected phenomenological profile of heavy Higgs boson physics at the LHC as well as at future linear Colliders.
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