The deep-inelastic electromagnetic structure functions of steel, deuterium, and hydrogen nuclei have been measured with use of the high-energy electron beam at the Stanford Linear Accelerator Center. The ratio of the structure functions of steel and deuterium cannot be understood simply by corrections due to Fermi-motion effects. The data indicate that the quark momentum distributions in the nucleon become distorted in the nucleus. The present results are consistent with recent measurements with high-energy muon beams.
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The deep-inelastic electromagnetic structure functions of deuterium and aluminum nuclei have been measured. The kinematic dependence of the ratio of aluminum and deuterium structure functions is similar to the dependence of the ratio of steel and deuterium structure functions, and provides further evidence for the distortion of the quark momentum distributions of nucleons bound in a nucleus.
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We report new results on a precision measurement of the ratio R=σLσT and the structure function F2 for deep-inelastic electron-nucleon scattering in the kinematic range 0.2≤x≤0.5 and 1≤Q2≤10 (GeV/c)2. Our results show, for the first time, a clear falloff of R with increasing Q2. Our R and F2 results are in good agreement with QCD predictions only when corrections for target-mass effects are included.
2.6 pct rad length target.
2.6 pct rad length target.
2.6 pct rad length target.
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We report the extraction of R = σ L / σ T from a global analysis of eight SLAC deep inelastic experiments on e-p and e-d scattering performed between 1970 and 1985. Values of R p , R d , and R d − R p are determined over the entire SLAC kinematic range: 0.1⩽ x ⩽0.9 and 0.6⩽ Q 2 ⩽20.0 (GeV/ c ) 2 . We find that R p = R d . Measured values of R ( x , Q 2 ) are larger than predictions based on perturbative QCD and on QCD with the inclusion of kinematic target mass terms, indicating that dynamical higher twist effects may be important in the SLAC kinematic range.
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Data from experiment E-140.
Global extracting of R from all the experiments.
The photon structure function F 2 has been measured at average Q 2 values of 73,160 and 390 ( GeV c ) 2 . We compare the x dependence of the Q 2 = 73 ( GeV c ) 2 data with theoretical expectations based on QCD. In addition we present results on the Q 2 evolution of the structure function for the intermediate x range (0.3⩽ x ⩽0.8). The results are consistent with QCD.
X dependence at Q**2 = 73 GeV**2 for light quark data.
X dependence at Q**2 = 73 GeV**2 for total data.
Photon structure function F2 for total data.
Cross sections for deep-inelastic electron scattering from liquid deuterium, gaseous He4, and solid Be, C, Al, Ca, Fe, Ag, and Au targets were measured at the Stanford Linear Accelerator Center using electrons with energies ranging from 8 to 24.5 GeV. These data cover a range in the Bjorken variable x from 0.089 to 0.8, and in momentum transfer Q2 from 2 to 15 (GeV/c)2. The ratios of cross sections per nucleon (σAσd)is for isoscalar nuclei have been extracted from the data. These ratios are greater than unity in the range 0.1<x<0.3, while for 0.3<x<0.8 they are less than unity and decrease logarithmically with atomic weight A, or linearly with average nuclear density. No Q2 dependence in the ratios was observed over the kinematic range of the data. These results are compared to various theoretical predictions.
Additional overall systematic error of 2.1 pct plus a target to target systematic error of 1 pct.
Additional overall systematic error of 2.1 pct plus a target to target systematic error of 2.1 pct.
Additional overall systematic error of 2.1 pct plus a target to target systematic error of 0.6 pct.
A measurement of the proton structure function F 2 ( x , Q 2 ) is presented with about 1000 neutral current deep inelastic scattering events for Bjorken x in the range x ⋍ 10 −2 – 10 −4 and Q 2 > 5 GeV 2 . The measurement is based on an integrated luminosity of 22.5 nb −1 recorded by the H1 detector in the first year of HERA operation. The structure function F 2 ( x , Q 2 ) shows a significant rise with decreasing x .
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This paper presents our first measurement of the F 2 structure function in neutral-current, deep inelastic scattering using the ZEUS detector at HERA, the ep colliding beam facility at DESY. The data correspond to an integrated luminosity of 24.7 nb −1 . Results are presented for data in range of Q 2 from 10 GeV 2 to 4700 GeV 2 and Bjorken x down to 3.0 × 10 −4 . The F 2 structure function increases rapidly as x decreases.
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We report results on a precision measurement of the ratio R=σLσT in deep inelastic electron-nucleon scattering in the kinematic range 0.2≤x≤0.5 and 1≤Q2≤10 (GeV/c)2. Our results show, for the first time, a clear falloff of R with increasing Q2. Our R results are in agreement with QCD predictions only when corrections for target mass effects and some additional higher twist effects are included. At small x, the data on R favor structure functions with a large gluon contribution. We also report results on the differences RA−RD and the cross section ratio σAσD between Fe and Au nuclei and the deuteron. Our results for RA−RD are consistent with zero for all x, Q2 indicating that possible contributions to R from nuclear higher twist effects and spin-0 constituents in nuclei are not different from those in nucleons. The ratios σAσD from all recent experiments, at all x, Q2 values, are now in agreement.
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