We review and analyze the available information on the nuclear-fusion cross sections that are most important for solar energy generation and solar neutrino production. We provide best values for the low-energy cross-section factors and, wherever possible, estimates of the uncertainties. We also describe the most important experiments and calculations that are required in order to improve our knowledge of solar fusion rates. [S0034-6861(98)00704-1]

The NOvA experiment has seen a 4.4σ signal ofν e appearance in a 2 GeVν μ beam at a distance of 810 km. Using 12.33 × 10 20 protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27ν μ →ν e candidates with a background of 10.3 and 102ν μ →ν μ candidates. This new antineutrino data are combined with neutrino data to measure the parameters jΔm 2 32 j ¼ 2.48 þ0.11 −0.06 × 10 −3 eV 2 =c 4 and sin 2 θ 23 in the ranges from (0.53-0.60) and (0.45-0.48) in the normal neutrino mass hierarchy. The data exclude most values near δ CP ¼ π=2 for the inverted mass hierarchy by more than 3σ and favor the normal neutrino mass hierarchy by 1.9σ and θ 23 values in the upper octant by 1.6σ.

We present in detail a formulation of the shell model as a path integral and Monte Carlo techniques for its evaluation. The formulation, which linearizes the two-body interaction by an auxiliary field, is quite general, both in the form of the effective `one-body' Hamiltonian and in the choice of ensemble. In particular, we derive formulas for the use of general (beyond monopole) pairing operators, as well as a novel extraction of the canonical (fixed-particle number) ensemble via an activity expansion. We discuss the advantages and disadvantages of the various formulations and ensembles and give several illustrative examples. We also discuss and illustrate calculation of the imaginary-time response function and the extraction, by maximum entropy methods, of the corresponding strength function. Finally, we discuss the "sign-problem" generic to fermion Monte Carlo calculations, and prove that a wide class of interactions are free of this limitation.Comment: 38 pages, RevTeX v3.0, figures available upon request; Caltech Preprint #MAP-15

We investigate the low-lying spectra of many-body systems with random two-body interactions, specifying that the ensemble be invariant under particle-hole conjugation. Surprisingly we find patterns reminiscent of more orderly interactions, such as a predominance of J = 0 ground states separated by a gap from the excited states, and evidence of phonon vibrations in the low-lying spectra.c 1998 American Physical Society PACS: 05.45, 21.60.Cs, 24.60.Lz In the spectra of molecules, atomic nuclei, and other many-body systems, the low-lying excitations often display a pattern suggestive of group symmetries, such as rotational or vibrational bands, even though the many-body spectrum is in principle complex and the interactions themselves have no trace of the symmetry groups displayed. This raises the question, to what extent does the low-lying spectrum acquire order simply from the most basic properties of the Hamiltonian? These properties include rotational invariance, possibly other symmetries such as isospin, and the fundamental nature of the interaction, which is predominantly two-body in character. Given an ensemble of Hamiltonians of this form, some properties might occur often, while others would occur rarely and would depend sensitively upon the detailed form of the two-body interactions. An example might be a rotational spectrum: one could imagine that a typical ground state might behave as a solid. Then many members of the ensemble would have a rotational band built on the ground state. Stated another way, many-body calculations often rely upon model interactions, such as pseudopotentials in atomic and molecular physics, and the Skyrme, quadrupole-quadrupole, and other interactions in nuclear physics, that despite being drastic simplifications reproduce many key properties. We ask the logical extension: what properties remain as the Hamiltonian gets more and more arbitrary?In this letter, we begin exploratory studies of these questions, choosing ensembles of two-body random Hamiltonians and computing their many-body spectra. Although our own reference point is nuclear physics, we believe these issues may be relevant to generic many-body systems, such as molecules, atomic clusters, etc., and so our explorations should be considered in a broad an arena as possible. Obviously the choice of ensemble is crucial. In standard random matrix theory [1], a powerful principle for specifying the ensemble is to require that it be invariant under a change of basis. We shall use this principle at the level of the two-body Hamiltonian to construct our ensembles. We first choose a single-particle basis labeled by angular momentum j and two-particle states of good total angular momentumStates of the same angular momentum can be transformed into each other, so the ensemble is specified by the average of the matrix elements and their fluctuations for each J. For the symmetric matrix ensemble, invariant under orthogonal transformations, the mean square variance in matrix elements V α,α ′ isHere α and α ′ label two-body states ...

The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber with an active volume of 7.2× 6.1× 7.0 m3. It is installed at the CERN Neutrino Platform in a specially-constructed beam that delivers charged pions, kaons, protons, muons and electrons with momenta in the range 0.3 GeV/c to 7 GeV/c. Beam line instrumentation provides accurate momentum measurements and particle identification. The ProtoDUNE-SP detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment, and it incorporates full-size components as designed for that module. This paper describes the beam line, the time projection chamber, the photon detectors, the cosmic-ray tagger, the signal processing and particle reconstruction. It presents the first results on ProtoDUNE-SP's performance, including noise and gain measurements, dE/dx calibration for muons, protons, pions and electrons, drift electron lifetime measurements, and photon detector noise, signal sensitivity and time resolution measurements. The measured values meet or exceed the specifications for the DUNE far detector, in several cases by large margins. ProtoDUNE-SP's successful operation starting in 2018 and its production of large samples of high-quality data demonstrate the effectiveness of the single-phase far detector design.