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The fundamental building blocks of the proton—quarks and gluons—have been known for decades. However, we still have an incomplete theoretical and experimental understanding of how these particles and their dynamics give rise to the quantum bound state of the proton and its physical properties, such as its spin 1 . The two up quarks and the single down quark that comprise the proton in the simplest picture account only for a few per cent of the proton mass, the bulk of which is in the form of quark kinetic and potential energy and gluon energy from the strong force 2 . An essential feature of this force, as described by quantum chromodynamics, is its ability to create matter–antimatter quark pairs inside the proton that exist only for a very short time. Their fleeting existence makes the antimatter quarks within protons difficult to study, but their existence is discernible in reactions in which a matter–antimatter quark pair annihilates. In this picture of quark–antiquark creation by the strong force, the probability distributions as a function of momentum for the presence of up and down antimatter quarks should be nearly identical, given that their masses are very similar and small compared to the mass of the proton 3 . Here we provide evidence from muon pair production measurements that these distributions are considerably different, with more abundant down antimatter quarks than up antimatter quarks over a wide range of momenta. These results are expected to revive interest in several proposed mechanisms for the origin of this antimatter asymmetry in the proton that had been disfavoured by previous results 4 , and point to future measurements that can distinguish between these mechanisms. Quark–antiquark annihilation measurements provide a precise determination of the ratio of down and up antiquarks within protons as a function of momentum, which confirms the asymmetry between the abundance of down and up antiquarks.

Limited health literacy is associated with poor patient health outcomes and increased hospitalization rates. Patient-provider communication plays an important role in patient health literacy and the understanding of medical terminology. This study demonstrates how a collaboration between clinical, academic, and community partners was instrumental in the design and implementation of a clinic readiness assessment and a clinic-based pilot intervention to encourage patient-provider communication and improve patient health literacy. A state hospital association, academic research team, and community adult literacy center director collaborated to develop a 60-item clinic readiness assessment and an evidence-informed pilot intervention. The clinic readiness assessment captured clinics’ motivation and capacity for pilot implementation and providers’ current communication strategies. The intervention centered around AskMe3™ educational materials and involved 2 patient visits (initial and follow-up visits). Data collection instruments for the intervention were administered verbally and included questions about patient demographics and communication needs, and a single-item health literacy measure. Descriptive statistics (frequencies/percentages) were used to analyze results from the clinic readiness assessment and pilot intervention. Establishment of the partnership, and collaborative, iterative development of the clinic readiness assessment and pilot intervention are described. This pilot project resulted in important lessons learned which led to critical modifications that will inform future expansion of the intervention. Collaboration between healthcare leaders, researchers, and community partners is recommended for developing clinic-based health literacy initiatives.

The fundamental building blocks of the proton—quarks and gluons—have been known for decades. However, we still have an incomplete theoretical and experimental understanding of how these particles and their dynamics give rise to the quantum bound state of the proton and its physical properties, such as its spin1. The two up quarks and the single down quark that comprise the proton in the simplest picture account only for a few per cent of the proton mass, the bulk of which is in the form of quark kinetic and potential energy and gluon energy from the strong force2. An essential feature of this force, as described by quantum chromodynamics, is its ability to create matter–antimatter quark pairs inside the proton that exist only for a very short time. Their fleeting existence makes the antimatter quarks within protons difficult to study, but their existence is discernible in reactions in which a matter–antimatter quark pair annihilates. In this picture of quark–antiquark creation by the strong force, the probability distributions as a function of momentum for the presence of up and down antimatter quarks should be nearly identical, given that their masses are very similar and small compared to the mass of the proton3. Here we provide evidence from muon pair production measurements that these distributions are considerably different, with more abundant down antimatter quarks than up antimatter quarks over a wide range of momenta. These results are expected to revive interest in several proposed mechanisms for the origin of this antimatter asymmetry in the proton that had been disfavoured by previous results4, and point to future measurements that can distinguish between these mechanisms.

We present the results of a measurement of isotopic concentrations and atomic number ratio of a double-sided actinide target with alpha-spectroscopy and mass spectrometry. The double-sided actinide target, with primarily Pu-239 on one side and U-235 on the other, was used in the fission Time Projection Chamber (fissionTPC) for a measurement of the neutron-induced fission cross-section ratio between the two isotopes. The measured atomic number ratio is intended to provide an absolute normalization of the measured fission cross-section ratio. The Pu-239/U-235 atom number ratio was measured with a combination of mass spectrometry and alpha-spectroscopy with a planar silicon detector with uncertainties of less than 1%.

The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) is a double-sided Time Projection Chamber (TPC) with micromegas readout designed to measure the energy-dependent neutron-induced fission cross sections of the major and minor actinides with unprecedented accuracy. The NIFFTE project addresses the challenge of minimizing major sources of systematic uncertainties from previous fission chamber measurements such as: target and beam non-uniformities, misidentification of alpha and light charged particles as fission fragments, and uncertainties inherent to the reference standards used. In-beam tests of the NIFFTE TPC at the Los Alamos Neutron Science Center (LANSCE) started in 2010 and have continued in 2011, 2012 and 2013. An overview of the NIFFTE TPC status and performance at LANSCE will be presented.

The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) collaboration has performed measurements with a fission time projection chamber (fissionTPC) to study the fission process by reconstructing full three-dimensional tracks of fission fragments and other ionizing radiation. The amount of linear momentum imparted to the fissioning nucleus by the incident neutron can be inferred by measuring the opening angle between the fission fragments. Using this measured linear momentum, fission fragment angular distributions can be converted to the center-of-mass frame for anisotropy measurements. Angular anisotropy is an important experimental observable for understanding the quantum mechanical state of the fissioning nucleus and vital to determining detection efficiency for cross section measurements. Neutron linear momentum transfer to fissioning \\(^235\\)U, \\(^238\\)U, and \\(^239\\)Pu and fission fragment angular anisotropy of \\(^235\\)U and \\(^238\\)U as a function of neutron energies in the range 130 keV--250 MeV are presented.

We present experimental results on the angular distributions of Drell-Yan muons produced by a 120 GeV/\\(c\\) proton beam interacting with liquid hydrogen and deuterium targets. The dimuon angular distributions in both polar (\\(\\)) and azimuthal (\\(\\)) angles in the Collins-Soper frame are measured within the kinematic range of \\(4.5 < m_ < 10\\ GeV/c^2\\), \\(0.19 < p_T < 2.24\\ GeV/c\\), and \\(0 < x_F < 0.95\\). Unlike the results of a previous proton-induced Drell-Yan experiment at a higher energy, the data reveal a pronounced \\( 2\\) modulation in the angular distributions. Comparison with perturbative QCD (pQCD) predictions shows statistically significant deviations, with p-values of 3.5\\% for the \\(p+p\\) and 1.5\\% for the \\(p+d\\) Drell-Yan processes. These results suggest the presence of nonperturbative QCD contributions.

The fundamental building blocks of the proton, quarks and gluons, have been known for decades. However, we still have an incomplete theoretical and experimental understanding of how these particles and their dynamics give rise to the quantum bound state of the proton and its physical properties, such as for example its spin. The two up and the single down quarks that comprise the proton in the simplest picture account only for a few percent of the proton mass, the bulk of which is in the form of quark kinetic and potential energy and gluon energy from the strong force. An essential feature of this force, as described by quantum chromodynamics, is its ability to create matter-antimatter quark pairs inside the proton that exist only for a very short time. Their fleeting existence makes the antimatter quarks within protons difficult to study, but their existence is discernible in reactions where a matter-antimatter quark pair annihilates. In this picture of quark-antiquark creation by the strong force, the probability distributions as a function of momentum for the presence of up and down antimatter quarks should be nearly identical, since their masses are quite similar and small compared to the mass of the proton. In the present manuscript, we show evidence from muon pair production measurements that these distributions are significantly different, with more abundant down antimatter quarks than up antimatter quarks over a wide range of momentum. These results revive interest in several proposed mechanisms as the origin of this antimatter asymmetry in the proton that had been disfavored by the previous results and point to the future measurements that can distinguish between these mechanisms.

We report the \\(p+p\\) and \\(p+d\\) differential cross sections measured in the SeaQuest experiment for \\(J/\\) and \\((2S)\\) production at 120 GeV beam energy covering the forward \\(x\\)-Feynman (\\(x_F\\)) range of \\(0.5 < x_F <0.9\\). The measured cross sections are in good agreement with theoretical calculations based on the nonrelativistic QCD (NRQCD) using the long-distance matrix elements deduced from a recent global analysis of proton- and pion-induced charmonium production data. The \\(_(2S) / _J/\\) cross section ratios are found to increase as \\(x_F\\) increases, indicating that the \\(q q\\) annihilation process has larger contributions in the \\((2S)\\) production than the \\(J/\\) production. The \\(_pd/2_pp\\) cross section ratios are observed to be significantly different for the Drell-Yan process and \\(J/\\) production, reflecting their different production mechanisms. We find that the \\(_pd/2_pp\\) ratios for \\(J/\\) production at the forward \\(x_F\\) region are sensitive to the \\(d/ u\\) flavor asymmetry of the proton sea, analogous to the Drell-Yan process. The transverse momentum (\\(p_T\\)) distributions for \\(J/\\) and \\((2S)\\) production are also presented and compared with data collected at higher center-of-mass energies.

Evidence for a flavor asymmetry between the \\( u\\) and \\( d\\) quark distributions in the proton has been found in deep-inelastic scattering and Drell-Yan experiments. The pronounced dependence of this flavor asymmetry on \\(x\\) (fraction of nucleon momentum carried by partons) observed in the Fermilab E866 Drell-Yan experiment suggested a drop of the \\( d(x) / u(x)\\) ratio in the \\(x > 0.15\\) region. We report results from the SeaQuest Fermilab E906 experiment with improved statistical precision for \\( d(x) / u(x)\\) in the large \\(x\\) region up to \\(x=0.45\\) using the 120 GeV proton beam. Two different methods for extracting the Drell-Yan cross section ratios, \\(^pd /2 ^pp\\), from the SeaQuest data give consistent results. The \\(d(x) / u(x)\\) ratios and the \\( d(x) - u(x)\\) differences are deduced from these cross section ratios for \\(0.13 < x < 0.45\\). The SeaQuest and E866/NuSea \\(d(x) / u(x)\\) ratios are in good agreement for the \\(x 0.25\\) region. The new SeaQuest data, however, show that \\( d(x)\\) continues to be greater than \\( u(x)\\) up to the highest \\(x\\) value (\\(x = 0.45\\)). The new results on \\(d(x) / u(x)\\) and \\(d(x) - u(x)\\) are compared with various parton distribution functions and theoretical calculations.