An empirical fit is described to measurements of inclusive inelastic electron-proton cross sections in the kinematic range of four-momentum transfer 0 ≤ Q 2 < 8 GeV 2 and final state invariant mass 1.1 < W < 3.1 GeV. The fit is constrained by the recent high precision longitudinal and transverse (L/T) separated cross section measurements from Jefferson Lab Hall C, un-separated Hall C measurements up to Q 2 ≈ 7.5 GeV 2 , and photoproduction data at Q 2 = 0. Compared to previous fits, the present fit covers a wider kinematic range, fits both transverse and longitudinal cross sections, and features smooth transitions to the photoproduction data at Q 2 = 0 and DIS data at high Q 2 and W .
We report the results of a new Rosenbluth measurement of the proton electromagnetic form factors at Q2 values of 2.64, 3.20, and 4.10 GeV2. Cross sections were determined by detecting the recoiling proton, in contrast to previous measurements which detected the scattered electron. Cross sections were determined to 3%, with relative uncertainties below 1%. The ratio mu(p)G(E)/G(M) was determined to 4%-8% and showed mu(p)G(E)/G(M) approximately 1. These results are consistent with, and much more precise than, previous Rosenbluth extractions. They are inconsistent with recent polarization transfer measurements of similar precision, implying a systematic difference between the techniques.
Future high-precision neutrino interaction experiments are needed to extend the current program of GeV-scale neutrino interactions and should include:1. A feasibility study of a high-statistics hydrogen or deuterium scattering experiment to supplement the currently poorly known (anti)neutrino-nucleon cross sections.2. The need for (anti)neutrino Ar scattering data in the energy range relevant for the DUNE experiment.3. The possibility of muon-based neutrino beams providing extremely accurate knowledge of the neutrino flux and an intense electron neutrino beam.• Current and future long-and short-baseline neutrino oscillation programs should evaluate and articulate what additional neutrino-nucleus interaction data is required to meet their ambitious goals and support experiments that provide this data.In addition to these general challenges facing the community, there are more specific concerns for particular topics and interaction channels. These are summarized below in the form of observations, problem description or recommendations. For a deeper insight, the reader is encouraged to consult the subsequent sections of this paper.
New Jefferson Lab data are presented on the nuclear dependence of the inclusive cross section from (2)H, (3)He, (4)He, (9)Be and (12)C for 0.3 < x < 0.9, Q(2) approximately 3-6 GeV(2). These data represent the first measurement of the EMC effect for (3)He at large x and a significant improvement for (4)He. The data do not support previous A-dependent or density-dependent fits to the EMC effect and suggest that the nuclear dependence of the quark distributions may depend on the local nuclear environment.
We present new measurements of electron scattering from high-momentum nucleons in nuclei. These data allow an improved determination of the strength of two-nucleon correlations for several nuclei, including light nuclei where clustering effects can, for the first time, be examined. The data also include the kinematic region where three-nucleon correlations are expected to dominate.
We critically examine uncertainties in parton distribution functions (PDFs) at large x arising from nuclear effects in deuterium F 2 structure function data. Within a global PDF analysis, we assess the impact on the PDFs from uncertainties in the deuteron wave function at short distances and nucleon off-shell effects, from the use of relativistic kinematics, and from the use of a less restrictive parametrization of the d/u ratio. We find in particular that the d-quark and gluon PDFs vary significantly with the choice of nuclear model. We highlight the impact of these uncertainties on the determination of the neutron structure functions, and on W boson production and parton luminosity at the Tevatron and the LHC. Finally, we discuss prospects for new measurements sensitive to the d-quark and gluon distributions but insensitive to nuclear corrections.
We report a study of ν(μ) charged-current quasielastic events in the segmented scintillator inner tracker of the MINERvA experiment running in the NuMI neutrino beam at Fermilab. The events were selected by requiring a μ- and low calorimetric recoil energy separated from the interaction vertex. We measure the flux-averaged differential cross section, dσ/dQ², and study the low energy particle content of the final state. Deviations are found between the measured dσ/dQ² and the expectations of a model of independent nucleons in a relativistic Fermi gas. We also observe an excess of energy near the vertex consistent with multiple protons in the final state.
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