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NEXT Collaboration(Renner, J. et al), Kekic, M., Martinez-Lema, G., Alvarez, V., Benlloch-Rodriguez, J. M., Carcel, S., et al. (2019). Energy calibration of the NEXT-White detector with 1% resolution near Q(beta beta) of Xe-136. J. High Energy Phys., 10(10), 230–13pp.
Abstract: Excellent energy resolution is one of the primary advantages of electroluminescent high-pressure xenon TPCs. These detectors are promising tools in searching for rare physics events, such as neutrinoless double-beta decay (beta beta 0 nu), which require precise energy measurements. Using the NEXT-White detector, developed by the NEXT (Neutrino Experiment with a Xenon TPC) collaboration, we show for the first time that an energy resolution of 1% FWHM can be achieved at 2.6 MeV, establishing the present technology as the one with the best energy resolution of all xenon detectors for beta beta 0 nu searches.
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Davesne, D., Pastore, A., & Navarro, J. (2019). Linear response theory in asymmetric nuclear matter for Skyrme functionals including spin-orbit and tensor terms. II. Charge exchange. Phys. Rev. C, 100(6), 064301–10pp.
Abstract: We present the formalism of linear response theory both at zero and finite temperature in the case of asymmetric nuclear matter excited by an isospin flip probe. The particle-hole interaction is derived from a general Skyrme functional that includes spin-orbit and tensor terms. Response functions are obtained by solving a closed algebraic system of equations. Spin strength functions are analyzed for typical values of density, momentum transfer, asymmetry, and temperature. We evaluate the role of statistical errors related to the uncertainties of the coupling constants of the Skyrme functional and thus determine the confidence interval of the resulting response function.
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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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Alcaide, J., Banerjee, S., Chala, M., & Titov, A. (2019). Probes of the Standard Model effective field theory extended with a right-handed neutrino. J. High Energy Phys., 08(8), 031–18pp.
Abstract: If neutrinos are Dirac particles and, as suggested by the so far null LHC results, any new physics lies at energies well above the electroweak scale, the Standard Model effective field theory has to be extended with operators involving the right-handed neutrinos. In this paper, we study this effective field theory and set constraints on the different dimension-six interactions. To that aim, we use LHC searches for associated production of light (and tau) leptons with missing energy, monojet searches, as well as pion and tau decays. Our bounds are generally above the TeV for order one couplings. One particular exception is given by operators involving top quarks. These provide new signals in top decays not yet studied at colliders. Thus, we also design an LHC analysis to explore these signatures in the tt production. Our results are also valid if the right-handed neutrinos are Majorana and long-lived.
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Gariazzo, S., de Salas, P. F., & Pastor, S. (2019). Thermalisation of sterile neutrinos in the early universe in the 3+1 scheme with full mixing matrix. J. Cosmol. Astropart. Phys., 07(7), 014–30pp.
Abstract: In the framework of a 3+1 scheme with an additional inert state, we consider the thermalisation of sterile neutrinos in the early Universe taking into account the full 4 x 4 mixing matrix. The evolution of the neutrino energy distributions is found solving the momentum-dependent kinetic equations with full diagonal collision terms, as in previous analyses of flavour neutrino decoupling in the standard case. The degree of thermalisation of the sterile state is shown in terms of the effective number of neutrinos, N-eff, and its dependence on the three additional mixing angles (theta(14), theta(24), theta(34)) and on the squared mass difference Delta m(41)(2) is discussed. Our results are relevant for fixing the contribution of a fourth light neutrino species to the cosmological energy density, whose value is very well constrained by the final Planck analysis. For the preferred region of active-sterile mixing parameters from short-baseline neutrino experiments, we find that the fourth state is fully thermalised (N-eff similar or equal to 4).
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