Abstract: Liquid argon time projection chamber detector technology provides high spatial and calorimetric resolutions on the charged particles traversing liquid argon. As a result, the technology has been used in a number of recent neutrino experiments, and is the technology of choice for the Deep Underground Neutrino Experiment (DUNE). In order to perform high precision measurements of neutrinos in the detector, final state particles need to be effectively identified, and their energy accurately reconstructed. This article proposes an algorithm based on a convolutional neural network to perform the classification of energy deposits and reconstructed particles as track-like or arising from electromagnetic cascades. Results from testing the algorithm on experimental data from ProtoDUNE-SP, a prototype of the DUNE far detector, are presented. The network identifies track- and shower-like particles, as well as Michel electrons, with high efficiency. The performance of the algorithm is consistent between experimental data and simulation.

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.

Abstract: The simplest ΛCDM model provides a good fit to a large span of cosmological data but harbors large areas of phenomenology and ignorance. With the improvement of the number and the accuracy of observations, discrepancies among key cosmological parameters of the model have emerged. The most statistically significant tension is the 4 sigma to 6 sigma disagreement between predictions of the Hubble constant, H (0), made by the early time probes in concert with the 'vanilla' ΛCDM cosmological model, and a number of late time, model-independent determinations of H (0) from local measurements of distances and redshifts. The high precision and consistency of the data at both ends present strong challenges to the possible solution space and demands a hypothesis with enough rigor to explain multiple observations-whether these invoke new physics, unexpected large-scale structures or multiple, unrelated errors. A thorough review of the problem including a discussion of recent Hubble constant estimates and a summary of the proposed theoretical solutions is presented here. We include more than 1000 references, indicating that the interest in this area has grown considerably just during the last few years. We classify the many proposals to resolve the tension in these categories: early dark energy, late dark energy, dark energy models with 6 degrees of freedom and their extensions, models with extra relativistic degrees of freedom, models with extra interactions, unified cosmologies, modified gravity, inflationary models, modified recombination history, physics of the critical phenomena, and alternative proposals. Some are formally successful, improving the fit to the data in light of their additional degrees of freedom, restoring agreement within 1-2 sigma between Planck 2018, using the cosmic microwave background power spectra data, baryon acoustic oscillations, Pantheon SN data, and R20, the latest SH0ES Team Riess, et al (2021 Astrophys. J. 908 L6) measurement of the Hubble constant (H (0) = 73.2 +/- 1.3 km s(-1) Mpc(-1) at 68% confidence level). However, there are many more unsuccessful models which leave the discrepancy well above the 3 sigma disagreement level. In many cases, reduced tension comes not simply from a change in the value of H (0) but also due to an increase in its uncertainty due to degeneracy with additional physics, complicating the picture and pointing to the need for additional probes. While no specific proposal makes a strong case for being highly likely or far better than all others, solutions involving early or dynamical dark energy, neutrino interactions, interacting cosmologies, primordial magnetic fields, and modified gravity provide the best options until a better alternative comes along.

Abstract: The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg(2), and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg(2) and probes a volume of 3 h(-3) Gpc(3), making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high-precision cosmological constraints can be obtained given careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at four redshift slices with an accuracy of similar to 15%, with a bin size of delta(l) = 10 on scales of the baryon acoustic oscillations (BAOs; at l similar to 40-400). We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. For a flat Lambda CDM model, when combined with cosmic microwave background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H-0 constraints from using 600 Cepheids observed by Wide Field Camera 3 (WFC3; HST), we find Omega(Lambda) = 0.73 +/- 0.019 and H-0 to be 70.5 +/- 1.6 s(-1) Mpc(-1) km. For an open Lambda CDM model, when combined with WMAP7 + HST, we find Omega(K) = 0.0035 +/- 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+ SN, we find w = -1.071 +/- 0.078, and H-0 to be 71.3 +/- 1.7 s(-1) Mpc(-1) km, which is competitive with the latest large-scale structure constraints from large spectroscopic surveys such as the SDSS Data Release 7 (DR7) and WiggleZ. We also find that systematic-corrected power spectra give consistent constraints on cosmological models when compared with pre-systematic correction power spectra in the angular scales of interest. The SDSS-III Data Release 8 (SDSS-III DR8) Angular Clustering Data allow a wide range of investigations into the cosmological model, cosmic expansion (via BAO), Gaussianity of initial conditions, and neutrino masses. Here, we refer to our companion papers for further investigations using the clustering data. Our calculation of the survey selection function, systematics maps, and likelihood function for the COSMOMC package will be released at http://portal.nersc.gov/project/boss/galaxy/photoz/.

Abstract: As part of the European LAGUNA design study on a next-generation neutrino detector, we propose the liquid-scintillator detector LENA (Low Energy Neutrino Astronomy) as a multipurpose neutrino observatory. The outstanding successes of the Borexino and KamLAND experiments demonstrate the large potential of liquid-scintillator detectors in low-energy neutrino physics. Low energy threshold, good energy resolution and efficient background discrimination are inherent to the liquid-scintillator technique. A target mass of 50 kt will offer a substantial increase in detection sensitivity. At low energies, the variety of detection channels available in liquid scintillator will allow for an energy and flavor-resolved analysis of the neutrino burst emitted by a galactic Supernova. Due to target mass and background conditions, LENA will also be sensitive to the faint signal of the Diffuse Supernova Neutrino Background. Solar metallicity, time-variation in the solar neutrino flux and deviations from MSW-LMA survival probabilities can be investigated based on unprecedented statistics. Low background conditions allow to search for dark matter by observing rare annihilation neutrinos. The large number of events expected for geoneutrinos will give valuable information on the abundances of Uranium and Thorium and their relative ratio in the Earth's crust and mantle. Reactor neutrinos enable a high-precision measurement of solar mixing parameters. A strong radioactive or pion decay-at-rest neutrino source can be placed close to the detector to investigate neutrino oscillations for short distances and sub-MeV to MeV energies. At high energies, LENA will provide a new lifetime limit for the SUSY-favored proton decay mode into kaon and antineutrino, surpassing current experimental limits by about one order of magnitude. Recent studies have demonstrated that a reconstruction of momentum and energy of GeV particles is well feasible in liquid scintillator. Monte Carlo studies on the reconstruction of the complex event topologies found for neutrino interactions at multi-GeV energies have shown promising results. If this is confirmed. LENA might serve as far detector in a long-baseline neutrino oscillation experiment currently investigated in LAGUNA-LBNO.