de Salas, P. F., Forero, D. V., Gariazzo, S., Martinez-Mirave, P., Mena, O., Ternes, C. A., et al. (2021). 2020 global reassessment of the neutrino oscillation picture. J. High Energy Phys., 02(2), 071–36pp.
Abstract: We present an updated global fit of neutrino oscillation data in the simplest three-neutrino framework. In the present study we include up-to-date analyses from a number of experiments. Concerning the atmospheric and solar sectors, besides the data considered previously, we give updated analyses of IceCube DeepCore and Sudbury Neutrino Observatory data, respectively. We have also included the latest electron antineutrino data collected by the Daya Bay and RENO reactor experiments, and the long-baseline T2K and NO nu A measurements, as reported in the Neutrino 2020 conference. All in all, these new analyses result in more accurate measurements of theta (13), theta (12), Delta m212 and Delta m312. The best fit value for the atmospheric angle theta (23) lies in the second octant, but first octant solutions remain allowed at similar to 2.4 sigma. Regarding CP violation measurements, the preferred value of delta we obtain is 1.08 pi (1.58 pi) for normal (inverted) neutrino mass ordering. The global analysis still prefers normal neutrino mass ordering with 2.5 sigma statistical significance. This preference is milder than the one found in previous global analyses. These new results should be regarded as robust due to the agreement found between our Bayesian and frequentist approaches. Taking into account only oscillation data, there is a weak/moderate preference for the normal neutrino mass ordering of 2.00 sigma. While adding neutrinoless double beta decay from the latest Gerda, CUORE and KamLAND-Zen results barely modifies this picture, cosmological measurements raise the preference to 2.68 sigma within a conservative approach. A more aggressive data set combination of cosmological observations leads to a similar preference for normal with respect to inverted mass ordering, namely 2.70 sigma. This very same cosmological data set provides 2 sigma upper limits on the total neutrino mass corresponding to Sigma m(nu)< 0.12 (0.15) eV in the normal (inverted) neutrino mass ordering scenario. The bounds on the neutrino mixing parameters and masses presented in this up-to-date global fit analysis include all currently available neutrino physics inputs.
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Celis, A., Fuentes-Martin, J., & Serodio, H. (2014). A class of invisible axion models with FCNCs at tree level. J. High Energy Phys., 12(12), 167–53pp.
Abstract: We build a class of invisible axion models with tree-level Flavor Changing Neutral Currents completely controlled by the fermion mixing matrices. The scalar sector of these models contains three-Higgs doublets and a complex scalar gauge singlet, with the same fermionic content as in the Standard Model. A horizontal Peccei-Quinn symmetry provides a solution to the strong CP problem and predicts the existence of a very light and weakly coupled pseudo-Goldstone boson, the invisible axion or familon. A phenomenological analysis is performed taking into account familon searches in rare kaon and muon decays, astrophysical considerations and axion searches via axion-photon conversion. Drastic differences are found in the axion properties of different models due to the strong hierarchy of the CKM matrix, making some of the models considered much more constrained than others. We also obtain that a rich variety of these models avoid the domain wall problem. A possible mechanism to protect the solution to the strong CP problem against gravitational effects is also discussed.
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Fonseca, R. M., & Hirsch, M. (2016). A flipped 331 model. J. High Energy Phys., 08(8), 003–12pp.
Abstract: Models based on the extended SU(3)(C) x SU(3)(L) x U(1)(X) (331) gauge group usually follow a common pattern: two families of left-handed quarks are placed in anti triplet representations of the SU(3)(L) group; the remaining quark family, as well as the left-handed leptons, are assigned to triplets (or vice-versa). In this work we present a flipped 331 model where this scheme is reversed: all three quark families are in the same representation and it is the lepton families which are discriminated by the gauge symmetry. We discuss fermion masses and mixing, as well as Z' interactions, in a minimal model implementing this idea.
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Alcaide, J., Das, D., & Santamaria, A. (2017). A model of neutrino mass and dark matter with large neutrinoless double beta decay. J. High Energy Phys., 04(4), 049–21pp.
Abstract: We propose a model where neutrino masses are generated at three loop order but neutrinoless double beta decay occurs at one loop. Thus we can have large neutrinoless double beta decay observable in the future experiments even when the neutrino masses are very small. The model receives strong constraints from the neutrino data and lepton flavor violating decays, which substantially reduces the number of free parameters. Our model also opens up the possibility of having several new scalars below the TeV regime, which can be explored at the collider experiments. Additionally, our model also has an unbroken Z(2) symmetry which allows us to identify a viable Dark Matter candidate.
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del Aguila, F., Aparici, A., Bhattacharya, S., Santamaria, A., & Wudka, J. (2012). A realistic model of neutrino masses with a large neutrinoless double beta decay rate. J. High Energy Phys., 05(5), 133–30pp.
Abstract: The minimal Standard Model extension with the Weinberg operator does accommodate the observed neutrino masses and mixing, but predicts a neutrinoless double beta (0 nu beta beta) decay rate proportional to the effective electron neutrino mass, which can be then arbitrarily small within present experimental limits. However, in general 0 nu beta beta decay can have an independent origin and be near its present experimental bound; whereas neutrino masses are generated radiatively, contributing negligibly to 0 nu beta beta decay. We provide a realization of this scenario in a simple, well defined and testable model, with potential LHC effects and calculable neutrino masses, whose two-loop expression we derive exactly. We also discuss the connection of this model to others that have appeared in the literature, and remark on the significant differences that result from various choices of quantum number assignments and symmetry assumptions. In this type of models lepton flavor violating rates are also preferred to be relatively large, at the reach of foreseen experiments. Interestingly enough, in our model this stands for a large third mixing angle, sin(2) theta(13) greater than or similar to 0.008, when μ-> eee is required to lie below its present experimental limit.
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Hooper, D., Leane, R. K., Tsai, Y. D., Wegsman, S., & Witte, S. J. (2020). A systematic study of hidden sector dark matter: application to the gamma-ray and antiproton excesses. J. High Energy Phys., 07(7), 163–38pp.
Abstract: In hidden sector models, dark matter does not directly couple to the particle content of the Standard Model, strongly suppressing rates at direct detection experiments, while still allowing for large signals from annihilation. In this paper, we conduct an extensive study of hidden sector dark matter, covering a wide range of dark matter spins, mediator spins, interaction diagrams, and annihilation final states, in each case determining whether the annihilations are s-wave (thus enabling efficient annihilation in the universe today). We then go on to consider a variety of portal interactions that allow the hidden sector annihilation products to decay into the Standard Model. We broadly classify constraints from relic density requirements and dwarf spheroidal galaxy observations. In the scenario that the hidden sector was in equilibrium with the Standard Model in the early universe, we place a lower bound on the portal coupling, as well as on the dark matter's elastic scattering cross section with nuclei. We apply our hidden sector results to the observed Galactic Center gamma-ray excess and the cosmic-ray antiproton excess. We find that both of these excesses can be simultaneously explained by a variety of hidden sector models, without any tension with constraints from observations of dwarf spheroidal galaxies.
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Breso-Pla, V., Falkowski, A., & Gonzalez-Alonso, M. (2021). A(FB) in the SMEFT: precision Z physics at the LHC. J. High Energy Phys., 08(8), 021–27pp.
Abstract: We study the forward-backward asymmetry A(FB) in pp -> l(+)l(-) at the Z peak within the Standard Model Effective Field Theory (SMEFT). We find that this observable provides per mille level constraints on the vertex corrections of the Z boson to quarks, which close a flat direction in the electroweak precision SMEFT fit. Moreover, we show that current A(FB) data is precise enough so that its inclusion in the fit improves significantly LEP bounds even in simple New Physics setups. This demonstrates that the LHC can compete with and complement LEP when it comes to precision measurements of the Z boson properties.
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Lavoura, L., Morisi, S., & Valle, J. W. F. (2013). Accidental stability of dark matter. J. High Energy Phys., 02(2), 118–17pp.
Abstract: We propose that dark matter is stable as a consequence of an accidental Z(2) that results from a flavour symmetry group which is the double-cover group of the symmetry group of one of the regular geometric solids. Although model-dependent, the phenomenology resembles that of a generic “inert Higgs” dark matter scheme.
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Thakore, T., Devi, M. M., Agarwalla, S. K., & Dighe, A. (2018). Active-sterile neutrino oscillations at INO-ICAL over a wide mass-squared range. J. High Energy Phys., 08(8), 022–34pp.
Abstract: We perform a detailed analysis for the prospects of detecting active-sterile oscillations involving a light sterile neutrino, over a large Delta m(41)(2 )range of 10(-5) eV(2) to 10(2) eV(2), using 10 years of atmospheric neutrino data expected from the proposed 50 kt magnetized ICAL detector at the INO. This detector can observe the atmospheric nu(mu), and (nu) over bar (mu) separately over a wide range of energies and baselines, making it sensitive to the magnitude and sign of Arni i over a large range. If there is no light sterile neutrino, ICAL can place competitive upper limit on vertical bar U-mu 4 vertical bar(2) less than or similar to 0.02 at 90% C.L. for Delta m(41)(2) in the range (0.5-5) x 10(-3) eV(2). For the same vertical bar Delta m(41)(2)vertical bar range, ICAL would be able to determine its sign, exploiting the Earth's matter effect in mu(-) and mu(+) events separately if there is indeed a light sterile neutrino in Nature. This would help identify the neutrino mass ordering in the four-neutrino mixing scenario.
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Blennow, M., Dasgupta, B., Fernandez-Martinez, E., & Rius, N. (2011). Aidnogenesis via leptogenesis and dark sphalerons. J. High Energy Phys., 03(3), 014–14pp.
Abstract: We discuss aidnogenesis,(1) i.e. the generation of a dark matter asymmetry, via new sphaleron processes associated to an extra non-abelian gauge symmetry common to both the visible and the dark sectors. Such a theory can naturally produce an abundance of asymmetric dark matter which is of the same size as the lepton and baryon asymmetries, as suggested by the similar sizes of the observed baryonic and dark matter energy content, and provide a definite prediction for the mass of the dark matter particle. We discuss in detail a minimal realization in which the Standard Model is only extended by dark matter fermions which form “dark baryons” through an SU(3) interaction, and a (broken) horizontal symmetry that induces the new sphalerons. The dark matter mass is predicted to be similar to 6GeV, close to the region favored by DAMA and CoGeNT. Furthermore, a remnant of the horizontal symmetry should be broken at a lower scale and can also explain the Tevatron dimuon anomaly.
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