This article reviews our current understanding of how the internal quark structure of a nucleon bound in nuclei differs from that of a free nucleon. We focus on the interpretation of measurements of the EMC effect for valence quarks, a reduction in the Deep Inelastic Scattering (DIS) cross-section ratios for nuclei relative to deuterium, and its possible connection to nucleon-nucleon Short-Range Correlations (SRC) in nuclei. Our review and new analysis (involving the amplitudes of non-nucleonic configurations in the nucleus) of the available experimental and theoretical evidence shows that there is a phenomenological relation between the EMC effect and the effects of SRC that is not an accident. The influence of strongly correlated neutron-proton pairs involving highly virtual nucleons is responsible for both effects. These correlated pairs are temporary high-density fluctuations in the nucleus in which the internal structure of the nucleons is briefly modified. This conclusion needs to be solidified by the future experiments and improved theoretical analyses that are discussed herein.

This paper describes the design and construction of the MicroBooNE liquid argon time projection chamber and associated systems. MicroBooNE is the first phase of the Short Baseline Neutrino program, located at Fermilab, and will utilize the capabilities of liquid argon detectors to examine a rich assortment of physics topics. In this document details of design specifications, assembly procedures, and acceptance tests are reported.

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The nuclear symmetry energy (Esym(ρ)) is a vital ingredient of our understanding of many processes, from heavy-ion collisions to neutron stars structure. While the total nuclear symmetry energy at nuclear saturation density (ρ0) is relatively well determined, its value at supranuclear densities is not. The latter can be better constrained by separately examining its kinetic and potential terms and their density dependencies. The kinetic term of the symmetry energy, E kin sym (ρ0), equals the difference in the per-nucleon kinetic energy between pure neutron matter (PNM) and symmetric nuclear matter (SNM), often calculated using a simple Fermi gas model. However, experiments show that tensor force induced short-range correlations (SRC) between proton-neutron pairs shift nucleons to high-momentum in SNM, but have almost no effect in PNM. We present an approximate analytical expression for E kin sym (ρ) of correlated nucleonic matter. In our model, E kin sym (ρ0) = −10 MeV, which differs significantly from +12.5 MeV for the widely-used free Fermi gas model. This result is consistent with our analysis of recent data on the free proton-to-neutron ratios measured in intermediate energy nucleus-nucleus collisions as well as with microscopic many-body calculations, and previous phenomenological extractions. We then use our calculated E kin sym (ρ) in combination with the known total symmetry energy and its density dependence at saturation density to constrain the value and density dependence of the potential part and to extrapolate the total symmetry energy to supranuclear densities. The nuclear symmetry energy, E sym (ρ), where ρ is the nuclear density, is related to the difference in the energy per nucleon of pure neutron matter (PNM) and symmetric nuclear matter (SNM). It determines many nuclear and astrophysical properties, such as the cooling of proto-neutron stars [1], the mass-radius relations of neutron stars [2], properties of nuclei involved in r-process nucleosynthesis [3], and heavy-ion collisions [4-6].Much effort is being invested in improving our knowledge of E sym (ρ). In particular, several major radioactive beam facilities being built around the world have all listed constraining the symmetry energy as one of their major science drivers, see, e.g., Ref. [7]. Moreover, observations of neutron stars from current missions such as the Chandra X-ray and XMM-Newton observatories, and upcoming missions such as the Neutron star Interior Composition ExploreR (NICER) [8] will provide high precision data to infer more accurately neutron star radii which are very sensitive to the symmetry energy [9][10][11][12] Significant progress has been made in recent years in constraining E sym (ρ) especially around ρ ≈ ρ 0 , the nuclear saturation density, using data from both terrestrial laboratory experiments and astrophysical observations [13][14][15][16][17][18]. Recent surveys of model analyses of world data found that the mean values of the symmetry energy and its density dependence at ρ 0 are consistent with 29 ≤ E sym...

Recently published measurements of the two-nucleon short range correlation (NN-SRC) scaling factors, a 2 (A/d), strengthen the previously observed correlation between the magnitude of the EMC effect measured in electron deep inelastic scattering at 0.35 x B 0.7 and the SRC scaling factor measured at x B 1. The new results improve precision and include previously unmeasured nuclei. The measurements of a 2 (A/d) for 9 Be and 197 Au agree with published predictions based on the EMC-SRC correlation. This Brief Report examines the effects of the new data and of different corrections to the data on the slope and quality of the EMC-SRC correlation, the size of the extracted deuteron in-medium correction effect, and the free-neutron structure function. The results show that the linear EMC-SRC correlation is robust and that the slope of the correlation is insensitive to most combinations of corrections examined in this work. This strengthens the interpretation that both NN-SRC and the EMC effect are related to high-momentum nucleons in the nucleus.