[PDF] Deep Inelastic Structure Functions From Electron Scattering On Hydrogen Deuterium And Iron At 0 6 Gev Sup 2 Le Q Sup 2 Le 30 0 Gev Sup 2 eBook

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Page : 203 pages
File Size : 45,52 MB
Release : 1990
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We report the final results from experiment E140, a recent deep inelastic electron-deuterium and electron-iron scattering experiment at SLAC. In addition, we present the results of a combined global analysis of all SLAC deep inelastic electron-hydrogen and electron-deuterium cross section measurements between 1970 and 1983. Data from seven earlier experiments are re-radiatively corrected and normalized to experiment E140. We report extractions of R(x, Q2) and F2(x, Q2) for hydrogen and deuterium over the entire SLAC kinematic range: .06(less-than or equal to) x (less-than or equal to).90 and 0.6(less-than or equal to) Q2 (less-than or equal to)30.0 (GeV2). We fine that R{sup p} = R{sup d}, as expected by QCD. Extracted values of R(x, Q2) are significantly larger than predictions based on QCD and on QCD with the inclusion of kinematic target mass terms. This difference indicates that dynamical higher twist effects may be important in the SLAC kinematic range. A best fit empirical model of R(x, Q2) is used to extract F2 from each cross section measurement. These F2 extractions are compared with F2 data from EMC and BCDMS. Agreement is observed with EMC when the EMC data are multiplied by 1.07. Agreement is observed with BCDMS over a limited range in x. The ratios of F2{sup d}/F2{sup p} are examined for Q2 dependence. We observe a significant negative slope for x (less-than or equal to) .6, and a significant positive slope above x> .7, in excellent agreement with predictions based on QCD with the inclusion of kinematic target mass terms. 111 refs., 40 figs., 34 tabs.

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Page : 4 pages
File Size : 36,52 MB
Release : 1999
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Measurements of the deuteron elastic structure function A(Q2) for 0.7 ≤ Q2 ≤ 6.0 (GeV/c)2 are reported. The experiment performed elastic electron-deuteron scattering in coincidence, using the Hall A Facility of Jefferson Laboratory. The data are compared to theoretical models based on the impulse approximation with the inclusion of meson-exchange currents, and to predictions of quark dimensional scaling and perturbative quantum chromodynamics.

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Release : 2005
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Experiments on parity violation in electron scattering measure the asymmetry A = [sigma][sub R] - [sigma][sub L]/[sigma][sub R] + [sigma][sub L] where [sigma][sub R(L)] is the cross section for Right(Left) handed longitudinally polarized electrons. This asymmetry arises, in first order, from the interference between photon and Z-boson exchange amplitudes. Experiments make two basic uses of the Z-boson as a probe in electron-quark or electron-nucleon scattering. Historically the first usage was to test the electroweak theory in regions of kinematics where the hadronic structure is sufficiently understood. They discuss the application of higher energies at Jefferson Lab to repeat the SLAC e-D deep inelastic parity violation experiment [1] at a level of precision [approx] 0.5% in sin[sup 2][theta][sub W] which would be a useful constrain on extensions of the Standard Model [2]. The second, more recent usage of the Z-boson probe is to assume the Standard Model is correct at about the 1% level and use this as a unique method to address fundamental issues of nucleon structure, such as: (1) are the strange quarks an important component of the nucleon [3]; (2) In deep inelastic scattering, are the high momentum quarks u or d quarks? To address the first question, they discuss the feasibility of extending the HAPPEX experiment to higher Q[sup 2]. For the second question, they discuss a possible measurement of the ratio of valence quarks d/u in the proton using deep inelastic parity violation.

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Page : 5 pages
File Size : 29,83 MB
Release : 1994
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Preliminary measurements of the structure functions F2{sup p} and F2{sup d}, and the structure function ratio F2??20--??/F2{sup p}, in inelastic?N scattering are presented. The data were obtained by the Fermilab E665 experiment using a 465 GeV muon beam and liquid hydrogen and deuterium targets. The structure functions are presented in the range?{sub Bj}> 8 × 10−4 and Q 2> 0.2 GeV2/c2. This structure function ration is presented as a function of? {sub Bj} for?{sub Bj}> 10−6.

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Page : 184 pages
File Size : 43,40 MB
Release : 2004
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Since the early experiments at SLAC, which discovered the nucleon substructure and led to the development of the quark parton model, deep inelastic scattering (DIS) has been the most powerful tool to investigate the partonic substructure of the nucleon. After about 30 years of experiments with electron and muon beams the nucleon structure function F2(x,Q2) is known with high precision over about four orders of magnitude in x and Q2. In the region of Q2 > 1 (GeV/c)2 the results of the DIS measurements are interpreted in terms of partons (quarks and gluons). The theoretical framework is provided in this case by perturbative Quantum Chromo Dynamics (pQCD), which includes scaling violations, as described by the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) equations. The description starts to fail when Q2 becomes of the order of 1 (GeV/c)2, where non-perturbative effects (higher-twist effects), which are still not fully understood, become important (non-pQCD). The sensitivity for order-n twist effects increases with decreasing Q2, since they include a factor 1/(Q2n) (n ≥ 1).