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Di Valentino, E., Gariazzo, S., Giare, W., & Mena, O. (2023). Impact of the damping tail on neutrino mass constraints. Phys. Rev. D, 108(8), 083509–11pp.
Abstract: Model-independent mass limits assess the robustness of current cosmological measurements of the neutrino mass scale. Consistency between high-multipole and low-multiple cosmic microwave background observations measuring such scale further valuates the constraining power of present data. We derive here up-to-date limits on neutrino masses and abundances exploiting either the Data Release 4 of the Atacama Cosmology Telescope (ACT) or the South Pole Telescope polarization measurements from SPT-3G, envisaging different nonminimal background cosmologies and marginalizing over them. By combining these high-l observations with supernova Ia, baryon acoustic oscillations (BAO), redshift space distortions (RSD) and a prior on the reionization optical depth fromWMAP data, we find that the marginalized bounds are competitive with those from Planck analyses. We obtain Sigma m(nu) < 0.139 eV and N-eff = 2.82 +/- 0.25 in a dark energy quintessence scenario, both at 95% CL. These limits translate into Sigma m(nu) < 0.20 eV and N-eff = 2.79(-0.28)(+0.30) after marginalizing over a plethora of well-motivated fiducial models. Our findings reassess both the strength and the reliability of cosmological neutrino mass constraints.
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Hajjar, R., Mena, O., & Palomares-Ruiz, S. (2023). Earth tomography with supernova neutrinos at future neutrino detectors. Phys. Rev. D, 108(8), 083011–24pp.
Abstract: Earth neutrino tomography is a realistic possibility with current and future neutrino detectors, complementary to geophysics methods. The two main approaches are based on either partial absorption of the neutrino flux as it propagates through Earth (at energies about a few TeV) or on coherent Earth matter effects affecting the neutrino oscillations pattern (at energies below a few tens of GeV). In this work, we consider the latter approach, focusing on supernova neutrinos with tens of MeV. Whereas at GeVenergies, Earth matter effects are driven by the atmospheric mass-squared difference, at energies below similar to 100 MeV, it is the solar mass-squared difference that controls them. Unlike solar neutrinos, which suffer from significant weakening of the contribution to the oscillatory effect from remote structures due to the neutrino energy reconstruction capabilities of detectors, supernova neutrinos can have higher energies and, thus, can better probe Earth's interior. We shall revisit this possibility, using the most recent neutrino oscillation parameters and up-to-date supernova neutrino spectra. The capabilities of future neutrino detectors, such as DUNE, Hyper-Kamiokande, and JUNO, are presented, including the impact of the energy resolution and other factors. Assuming a supernova burst at 10 kpc, we show that the average Earth's core density could be determined within less than or similar to 10% at 1 sigma confidence level, Hyper-Kamiokande being, with its largest mass, the most promising detector to achieve this goal.
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Tagliente, G. et al, Babiano-Suarez, V., Domingo-Pardo, C., Ladarescu, I., & Tain, J. L. (2024). High-resolution cross section measurements for neutron interactions on 89Y with incident neutron energies up to 95 keV. Eur. Phys. J. A, 60(1), 21–18pp.
Abstract: The cross section of the Y-89(n,gamma) reaction has important implications in nuclear astrophysics and for advanced nuclear technology. Given its neutron magic number N = 50 and a consequent small neutron capture crosssection,89Y represents one of the key nuclides for the stellars-process. It acts as a bottleneck in the neutron capture chain between the Fe seed and the heavier elements. Moreover, it is located at the overlapping region, where both the weak and mains-process components take place.Y-89, the only stable yttrium isotope, is also used in innovative nuclear reactors. Neutron capture and transmission measurements were per-formed at the time-of-flight facilities n_TOF at CERN and GELINA at JRC-Geel. Resonance parameters of individual resonances were extracted from a resonance analysis of the experimental transmission and capture yields, up to a neutron incident energy of 95 keV. Even though a comparison with results reported in the literature shows differences in resonance parameters, the present data are consistent with the Maxwellian averaged cross section suggested by the astro-physical database KADoNiS.
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Pompa, F., & Mena, O. (2024). How long do neutrinos live and how much do they weigh? Eur. Phys. J. C, 84(2), 134–12pp.
Abstract: The next-generation water Cherenkov Hyper-Kamiokande detector will be able to detect thousands of neutrino events from a galactic Supernova explosion via Inverse Beta Decay processes followed by neutron capture on Gadolinium. This superb statistics provides a unique window to set bounds on neutrino properties, as its mass and lifetime. We shall explore the capabilities of such a future detector, constraining the former two properties via the time delay and the flux suppression induced in the Supernovae neutrino time and energy spectra. Special attention will be devoted to the statistically sub-dominant elastic scattering induced events, normally neglected, which can substantially improve the neutrino mass bound via time delays. When allowing for a invisible decaying scenario, the 95% CL lower bound on tau/m\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau /m$$\end{document} is almost one order of magnitude better than the one found with SN1987A neutrino events. Simultaneous limits can be set on both m nu\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$m\nu $$\end{document} and tau nu\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau {\nu }$$\end{document}, combining the neutrino flux suppression with the time-delay signature: the best constrained lifetime is that of nu 1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\nu 1$$\end{document}, which has the richest electronic component. We find tau nu 1 greater than or similar to 4x105\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau {\nu _1}\gtrsim 4\times 10<^>5$$\end{document} s at 95% CL. The tightest 95% CL bound on the neutrino mass we find is 0.34 eV, which is not only competitive with the tightest neutrino mass limits nowadays, but also comparable to future laboratory direct mass searches. Both mass and lifetime limits are independent on the mass ordering, which makes our results very robust and relevant.
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Angles-Castillo, A., Perez, A., & Roldan, E. (2024). Bright and dark solitons in a photonic nonlinear quantum walk: lessons from the continuum. New J. Phys., 26(2), 023004–16pp.
Abstract: We propose a nonlinear quantum walk model inspired in a photonic implementation in which the polarization state of the light field plays the role of the coin-qubit. In particular, we take profit of the nonlinear polarization rotation occurring in optical media with Kerr nonlinearity, which allows to implement a nonlinear coin operator, one that depends on the state of the coin-qubit. We consider the space-time continuum limit of the evolution equation, which takes the form of a nonlinear Dirac equation. The analysis of this continuum limit allows us to gain some insight into the existence of different solitonic structures, such as bright and dark solitons. We illustrate several properties of these solitons with numerical calculations, including the effect on them of an additional phase simulating an external electric field.
Keywords: quantum walks; soliton; non-linear optics
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