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
. 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
. 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
. 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
, and point to future measurements that can distinguish between these mechanisms.
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.
Improving health literacy is a national public health priority. Given the context of the COVID-19 pandemic, it is even more critical for health and medical information to be clear and understandable ...for patients and their families. Clinic-based programs to improve health literacy need to be pragmatic, feasible, and helpful for the implementing clinic and patients. This paper describes the development, implementation, and evaluation of a pragmatic, clinic-based health literacy intervention in a safety-net clinic that serves uninsured and indigent patients. Study methods are guided by a previous pilot study and components recommended for pragmatic interventions. An electronic readiness assessment was distributed to out-patient clinics affiliated with a statewide hospital association. The AskMe3 tool was used for the intervention as it is evidence informed and relatively easy to implement. Implementation included ongoing dialogue between the clinic and the academic research team. Within the implementing clinic, data collected from patients
verbally administered questionnaires was analyzed using descriptive statistics and chi-squares. Interview data collected from the clinic director was analyzed qualitatively for themes. The implementing clinic had some of the lowest average scores of the 34 clinics who participated in the initial readiness assessment. Despite this, they were able to successfully implement the health literacy intervention during a global pandemic. Eighty-eight participants completed patient questionnaires at this clinic. Most patients (96%) agreed the AskMe3 questions helped them talk with the doctor or nurse at their current appointment. Most (99%) also perceived the AskMe3 tool to be very helpful when used in a clinical setting. The clinic director offered that the staff initially thought the intervention would be difficult to implement. However, implementation by clinic volunteers with encouragement and prioritization of health literacy by the clinic director contributed to success. When considering interventions for clinical settings, a pragmatic approach can help with selection and implementation of a program that fits with the realities on the ground. Further, frequent technical assistance can help resolve implementation barriers. Interventions utilizing tools such as AskMe3, because of their simplicity, allow creative solutions to capacity issues for clinics who see a need for health literacy improvements.
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 SeaQuest spectrometer at Fermilab Aidala, C.A.; Arrington, J.R.; Ayuso, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2019, Letnik:
930, Številka:
C
Journal Article
Recenzirano
Odprti dostop
The SeaQuest spectrometer at Fermilab was designed to detect oppositely-charged pairs of muons (dimuons) produced by interactions between a 120 GeV proton beam and liquid hydrogen, liquid deuterium ...and solid nuclear targets. The primary physics program uses the Drell–Yan process to probe antiquark distributions in the target nucleon. The spectrometer consists of a target system, two dipole magnets and four detector stations. The upstream magnet is a closed-aperture solid iron magnet which also serves as the beam dump, while the second magnet is an open aperture magnet. Each of the detector stations consists of scintillator hodoscopes and a high-resolution tracking device. The FPGA-based trigger compares the hodoscope signals to a set of pre-programmed roads to determine if the event contains oppositely-signed, high-mass muon pairs.
The NIFFTE project Ruz, J; Asner, D M; Baker, R G ...
Journal of instrumentation,
12/2013, Letnik:
8, Številka:
12
Journal Article
Recenzirano
Odprti dostop
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.
We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a deuterium target. The muon angular distributions in the dilepton rest frame have ...been measured over the kinematic range 4.5<m{mu mu}<15 GeV/c{2}, 0<p{T}<4 GeV/c, and 0<x{F}<0.8. No significant cos2phi dependence is found in these proton-induced Drell-Yan data, in contrast with the situation for pion-induced Drell-Yan data. The data are compared with expectations from models which attribute the cos2phi distribution to a QCD vacuum effect or to the presence of the transverse-momentum-dependent Boer-Mulders structure function h{1}{perpendicular}. Constraints on the magnitude of the sea-quark h{1}{perpendicular} structure functions are obtained.
Evidence for a flavor asymmetry between the $\bar{u}$ and $\bar{d}$ quark distributions in the proton has been found in deep-inelastic scattering and DrellYan 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 $\bar{d}$(x)/$\bar{u}$(x) ratio in the x > 0.15 region. We report results from the SeaQuest Fermilab E906 experiment with improved statistical precision for $\bar{d}$(x)/$\bar{u}$(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, σpd/2σpp, from the SeaQuest data give consistent results. The $\bar{d}$(x)/$\bar{u}$(x) ratios and the $\bar{d}$(x)- $\bar{u}$(x) differences are deduced from these cross section ratios for 0.13 < x < 0.45. The SeaQuest and E866/NuSea $\bar{d}$(x)/$\bar{u}$(x) ratios are in good agreement for the x≲0.25 region. The new SeaQuest data, however, show that $\bar{d}$(x) continues to be greater than $\bar{u}$(x) up to the highest x value (x = 0.45). The new results on $\bar{d}$(x)/$\bar{u}$(x) and $\bar{d}$(x)-$\bar{u}$(x) are compared with various parton distribution functions and theoretical calculations.
We present measurements of the polarization of the J/psi produced in 800-GeV proton interactions with a copper target. Polarization of the J/psi is sensitive to the ccmacr; production and ...hadronization processes. A longitudinal polarization is observed at large x(F), while at small x(F) the state is produced essentially unpolarized or slightly transversely polarized. No significant variation of the polarization is observed versus p(T).
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