The x and Q 2 dependence of the single photon exchange cross section d 2 σ /d Q 2 d x and the proton structure functions F 2 ( x , Q 2 ) and R ( x , Q 2 ) have been measured in deep inelastic muon proton scattering in the region 0.02 < x < 0.8 and 3 < Q 2 < 190 GeV 2 . By comparing data at different incident muon energies R was found to have little kinematic dependence and an average value of −0.010 ± 0.037 (stat.) ± 0.102 (stat.). The observed deviations from scaling gave the value of Λ MS , the QCD mass scale parameter, to be 105 −45 +55 (stat.) −45 +85 (syst.) MeV. The fraction of the momentum of the nucleon carried by gluons was found to be ∼56% at Q 2 ∼22.5 GeV 2 . It is shown that to obtain a description of the data for F 2 ( x , Q 2 ) together with that measured in deep inelastic electron-proton scattering at lower Q 2 it is necessary to include additional higher twist contributions. The value of Λ MS remains unchanged with the inclusion of these contributions which were found to have an x -dependence of the form x 3 /(1 − x ).
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This paper presents the results of the analysis of a single-arm inelastic-electron-scattering experiment at an angle of 4°. We present data on the turnon of scaling in the low-q2 region 0.1<q2<1.8, the neutron-proton comparison at large values of the scaling variable ω, resonance excitation, and the shadowing in scattering from heavy nuclei.
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The electroproduction of π0 on the proton was measured from 0 to 2.5 MeV above threshold for virtual-photon 4-momenta of -0.05 and -0.1 (GeV/c)2. The sum of the lowest-order contributing multipoles, a0=‖E0+‖2-εL‖L0+‖2, was determined with a precision an order of magnitude better than previously possible. Our results for a0 are consistent with present calculations. Our extracted value for ‖L0+‖2 at the ‘‘photon point’’ is in agreement with recent predictions.
Joined statistics for two incident electron energy of 300 and 500 MeV.
Cross sections for inelastic scattering of electrons from hydrogen were measured for incident energies from 7 to 17 GeV at scattering angles of 6° to 10° covering a range of squared four-momentum transfers up to 7.4 (GeV/c)2. For low center-of-mass energies of the final hadronic system the cross section shows prominent resonances at low momentum transfer and diminishes markedly at higher momentum transfer. For high excitations the cross section shows only a weak momentum-transfer dependence.
Axis error includes +- 0.0/0.0 contribution (?////FROM UNCERTAINTY IN ELECTRON-DETECTION EFFICIENCY).
Axis error includes +- 0.0/0.0 contribution (?////FROM UNCERTAINTY IN ELECTRON-DETECTION EFFICIENCY).
Axis error includes +- 0.0/0.0 contribution (?////FROM UNCERTAINTY IN ELECTRON-DETECTION EFFICIENCY).
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Inelastic electron scattering cross sections have been measured for four-momentum transfers between 4.1 GeV 2 and 30.5 GeV 2 . At the large scattering angles of this experiment, the dominant contribution to the cross section comes from the W 1 structure function. In the conventional scaling variables, x and x ′, this structure function does not exhibit scaling behavior, and at fixed x or x ′ it is found to decrease with increasing four-momentum transfer.
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Inelastic electron proton scattering has been measured by detecting the scattered electron, thus obtaining the total absorption cross section for virtual photons. Two complete spectra from threshold to a pion nucleon mass of W = 2 GeV were taken at θ e = 48.3° and fixed primary energies of 3.963 GeV and 5.159 GeV, respectively, corresponding to a momentum transfer at the first resonance of q 2 = 3.98 (GeV/ c ) 2 and q 2 = 5.84 (GeV/ c ) 2 . In addition, a measurement at θ e = 47.9° and at a primary energy of 3.306 GeV in the region of the first resonance is reported.
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The twofold differential cross section for the inelastic scattering of electrons on protons wa was measured as a function of the scattered electron energy for an electron scattering angle of 12°. The kinematic region covered in this experiment was 0.3 (GeV/ c ) 2 < q 2 < 1.0 (GeV/ c ) 2 and W < 2.9 GeV. The Bloom-Gilman as well as the constant scattering angle sum rule of Rittenberg and Rubinstein were tested.
Axis error includes +- 0.0/0.0 contribution (3.7 TO 5////UNCERTAINTIES IN TARGET DENSITY, TARGET DIAMETER, SOLID ANGLE, E- SCATTERING ANGLE, INCIDENT E- ENERGY, DEAD TIME CORRECTIONS, CONSTANT OF FARADAY-CUP INTEGRATOR EFFICIENCY OF SPARK CHAMBERS, RADIATIVE CORRECTIONS).
Axis error includes +- 0.0/0.0 contribution (3.7 TO 5////UNCERTAINTIES IN TARGET DENSITY, TARGET DIAMETER, SOLID ANGLE, E- SCATTERING ANGLE, INCIDENT E- ENERGY, DEAD TIME CORRECTIONS, CONSTANT OF FARADAY-CUP INTEGRATOR EFFICIENCY OF SPARK CHAMBERS, RADIATIVE CORRECTIONS).
Axis error includes +- 0.0/0.0 contribution (3.7 TO 5////UNCERTAINTIES IN TARGET DENSITY, TARGET DIAMETER, SOLID ANGLE, E- SCATTERING ANGLE, INCIDENT E- ENERGY, DEAD TIME CORRECTIONS, CONSTANT OF FARADAY-CUP INTEGRATOR EFFICIENCY OF SPARK CHAMBERS, RADIATIVE CORRECTIONS).
Differential cross sections for electrons scattered inelastically from hydrogen have been measured at 18°, 26°, and 34°. The range of incident energy was 4.5 to 18 GeV, and the range of four-momentum transfer squared was 1.5 to 21 (GeVc)2. With the use of these data in conjunction with previously measured data at 6° and 10°, the contributions from the longitudinal and transverse components of the exchanged photon have been separately determined. The values of the ratio of the photoabsorption cross sections σSσT are found to lie in the range 0 to 0.5. The question of scaling of 2MpW1 and νW2 as a function of ω is discussed, and scaling is verified for a large kinematic range. Also, a new scaling variable which reduces to ω in the Bjorken limit is introduced which extends the scaling region. The behavior of σT and σS is also discussed as a function of ν and q2. Various weighted sum rules of νW2 are evaluated.
Axis error includes +- 0.0/0.0 contribution (0. TO 2.////DUE TO PION CONTAMINATION).
Axis error includes +- 0.0/0.0 contribution (0. TO 2.////DUE TO PION CONTAMINATION).
Axis error includes +- 0.0/0.0 contribution (0. TO 2.////DUE TO PION CONTAMINATION).
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