Measurement of the structure function of the nearly free neutron using spectator tagging in inelastic ${}^2$H(e, e'p)X scattering with CLAS

Abstract

Much less is known about neutron structure than that of the proton due to the absence of free neutron targets. Neutron information is usually extracted from data on nuclear targets such as deuterium, requiring corrections for nuclear binding and nucleon off-shell effects. These corrections are model dependent and have significant uncertainties, especially for large values of the Bjorken scaling variable x. The Barely Off-shell Nucleon Structure (BONuS) experiment at Jefferson Lab measured the inelastic electron deuteron scattering cross section, tagging spectator protons in coincidence with the scattered electrons. This method reduces nuclear binding uncertainties significantly and has allowed for the first time a (nearly) model independent extraction of the neutron structure function. A novel compact radial time projection chamber was built to detect protons with momentum between 70 and 150 MeV/c. For the extraction of the free neutron structure function $F_{2n}$, spectator protons at backward angle and with momenta below 100 MeV/c were selected, ensuring that the scattering took place on a nearly free neutron. The scattered electrons were detected with Jefferson Lab's CLAS spectrometer. The extracted neutron structure function $F_{2n}$ and its ratio to the deuteron structure function $F_{2d}$ are presented in both the resonance and deep inelastic regions. The dependence of the cross section on the spectator proton momentum and angle is investigated, and tests of the spectator mechanism for different kinematics are performed. Our data set can be used to study neutron resonance excitations, test quark hadron duality in the neutron, develop more precise parametrizations of structure functions, as well as investigate binding effects (including possible mechanisms for the nuclear EMC effect) and provide a first glimpse of the asymptotic behavior of d/u as x goes to 1.

28 pages, 22 figures; published in Phys. Rev. C. Revised to include three authors inadvertently left off the original version: D. Dutta, R. Ent, and M. Ispiryan

References in corpus (4)

• Distribution Functions of the Nucleon and Pion in the Valence Region
• Empirical Fit to Inelastic Electron-Deuteron and Electron-Neutron Resonance Region Transverse Cross Sections
• Neutron Structure Functions
• Final-state interactions in semi-inclusive deep inelastic scattering off the Deuteron

Cited by in corpus (51)

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• Pion and kaon valence-quark quasiparton distributions
• Progress in understanding short-range structure in nuclei: an experimental perspective
• Parton distributions with threshold resummation
• Nuclear Effects in the Deuteron and Constraints on the d/u Ratio
• Pion structure function from leading neutron electroproduction and SU(2) flavor asymmetry
• Precise Determination of the Deuteron Spin Structure at Low to Moderate $Q^2$ with CLAS and Extraction of the Neutron Contribution
• Constraints on spin-dependent parton distributions at large x from global QCD analysis
• Measurement of the EMC Effect in the Deuteron
• Proton and pion distribution functions in counterpoint
• Isovector EMC effect from global QCD analysis with MARATHON data
• Global study of nuclear modifications on parton distribution functions
• nCTEQ15HIX -- Extending nPDF Analyses into the High-$x$, Low $Q^2$ Region
• Parton distributions of light quarks and antiquarks in the proton
• Polarized electron-deuteron deep-inelastic scattering with spectator nucleon tagging
• Electron-deuteron deep-inelastic scattering with spectator nucleon tagging and final-state interactions at intermediate x
• Neutron spin structure with polarized deuterons and spectator proton tagging at EIC
• Deep-inelastic electron-deuteron scattering with spectator nucleon tagging at the electron-ion collider. Extracting free nucleon structure
• Nuclear effects in the deuteron and global QCD analyses
• Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab
• Do short-range correlations cause the nuclear EMC effect in the deuteron?
• Deep-inelastic and quasielastic electron scattering from $A=3$ nuclei
• Direct observation of quark-hadron duality in the free neutron F_2 structure function
• Light quark and antiquark constraints from new electroweak data
• Electron-deuteron DIS with spectator tagging at EIC: Development of theoretical framework
• Neutron spin structure from polarized deuteron DIS with proton tagging
• Short-range correlations and their implications for isospin-dependent modification of nuclear quark distributions
• Nuclear force and the EMC effect
• Extraction of $\omega$n, $\omega$p and $\varphi$N scattering lengths from $\omega$ and $\varphi$ differential photoproduction cross sections on the deuterium target
• Probing Free Nucleons with (Anti)neutrinos
• Flavor-dependent EMC effect from a nucleon swelling model
• Extraction of the neutron F2 structure function from inclusive proton and deuteron deep-inelastic scattering data
• Systematic uncertainties from higher-twist corrections in DIS at large x
• Improved determination of $\bar{d}(x)-\bar{u}(x)$ flavor asymmetry in the proton by BONuS experiment at JLAB and using an approach by Brodsky, Hoyer, Peterson, and Sakai
• High x Structure Function of the Virtually Free Neutron
• Beam-target double spin asymmetry in quasi-elastic electron scattering off the deuteron with CLAS
• The neutron and proton mass radii from the vector meson photoproduction data on the deuterium target
• Deuteron structure in the deep inelastic regime
• Nuclear effects in the deuteron in the resonance and deep-inelastic scattering region
• Design, Construction, and Performance of the GEM based Radial Time Projection Chamber for the BONuS12 Experiment with CLAS12
• Exploring Nucleon Structure with the Self-Organizing Maps Algorithm
• Studying the Impact of Virtuality-Dependent Nucleon Structure Modification on Spectator-Tagged Deep Inelastic Scattering
• Re-examining valence quark spin distributions
• Tagged spectator DIS on a polarized spin-1 target
• Tagged spectator deep-inelastic scattering off the deuteron as a tool to study neutron structure
• Neutron Spin Structure from e-3He Scattering with Double Spectator Tagging at the Electron-Ion Collider
• Probing Pion Valence Quark Distribution with Beam-charge Asymmetry of Pion-induced $J/\psi$ Production
• Neutron structure function via a maximum entropy analysis
• Bayesian Monte Carlo extraction of sea asymmetry with SeaQuest and STAR data