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Category :
Languages : en
Pages : 52
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The authors propose to measure the inclusive deep inelastic electron-nucleon scattering cross sections on hydrogen and deuterium. Cross sections will be measured in the range of momentum transfers Q{sub min}2 = 0.160 (GeV/c)2 and Q{sub max}2 = 160.0 (GeV/c)2, in the range of recoil hadronic mass squared of W{sub min}2 = 2 GeV2 and W{sub max}2 = 450 GeV2. The electromagnetic structure functions, [nu]W2(Q2, [nu]) and W1(Q2, [nu]), of both protons and neutrons will be measured and separated by well-known methods, in the highest possible unexplored FERMILAB kinematical regions. The high intensity Proton-West superconducting beam will be used to yield an electron beam of high purity, based on a synchrotron radiation compensated tuning technique. The electron beam will be used at 150 GeV (5 x 108 e{sup {+-}}/pulse), at 175 GeV (3.6 x 108 e{sup {+-}}/pulse) and at 250 GeV (1 x 108 e{sup {+-}}/pulse). The scattered electron will be detected with good acceptance, good resolution and excellent identification. The detector will be the E-192 apparatus with small additions. A simple self-calibration procedure is available, both in experiment and apparatus, removing beam-associated and target-associated background in the entire (Q2, W2) kinematical regions. Usually, interesting physics occurs where counting rates are small. This experiment will be completely trust-worthy in such regions because their apparatus provides excellent information on the tracking and identification of scattered electrons.
Author:
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Category :
Languages : en
Pages : 203
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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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Category :
Languages : en
Pages : 184
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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).
Author:
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Category :
Languages : en
Pages :
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A tagged deep inelastic scattering (TDIS) experiment is planned for Hall A of Jefferson Lab, which will probe the mesonic content of the nucleon directly. Low momentum recoiling (and spectator) protons will be measured in coincidence with electrons scattered in a deep inelastic regime from hydrogen (and deuterium) targets, covering kinematics of 8
Author: Jay Van Orden
Publisher:
ISBN:
Category : Electrons
Languages : en
Pages : 250
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Author: Vladas Tvaskis
Publisher:
ISBN:
Category :
Languages : en
Pages : 176
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Author: John Gerard McNicholas
Publisher:
ISBN:
Category : Deep inelastic collisions
Languages : en
Pages : 166
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Author:
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Category :
Languages : en
Pages : 15
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Author: Edwin Francis Erickson
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ISBN:
Category : Deuterons
Languages : en
Pages : 530
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The purposes of the present work are: (1) To investigate the method of elastic electron-deuteron scattering by detection of the recoil target nucleus. (2) To evaluate existing theory for the scattering process in light of the recent advances in understanding nucleon structure and the nuclear force. (3) To provide experimental data at values of the momentum transfer where none had previously existed. Some fundamental preliminary considerations are discussed in Chapter II. Chapter III contains a summary of theoretical aspects of the problem and results of calculation. Some basic experimental questions are answered in Chapter IV. In Chapter V the experimental apparatus is described. The data, method of analysis, and corrections are discussed in Chapter VI. In the last chapter a comparison of the experimental results with theoretical predictions is made, and conclusions and suggestions for further work are given.
Author: Alexei V. Klimenko
Publisher:
ISBN:
Category : Electrons
Languages : en
Pages : 426
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The deuterium nucleus is a system of two nucleons (proton and neutron) bound together. The configuration of the system is described by a quantum-mechanical wave function and the state of the nucleons at a given time is not known a priori. However, by detecting a backward going proton of moderate momentum in coincidence with a reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred if we assume that the proton was a spectator to the reaction. This method, known as spectator tagging, was used to study the electron scattering from high-momentum neutrons in deuterium. The data were taken with a 5.765 GeV polarized electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CLAS detector. The accumulated data cover a wide kinematic range, reaching values of the invariant mass of the unobserved final state W* up to 3 GeV. A data sample of approximately 5 · 10 5 events, with protons detected at large scattering angles (as high as 136)̕ in coincidence with the forward electrons, was selected. The product of the neutron structure function with the initial nucleon momentum distribution F 2n · S was extracted for different values of W *, backward proton momenta p s and momentum transfer Q 2 . The data were compared to a calculation based on the spectator approximation and using the free nucleon form factors and structure functions. A strong enhancement in the data, not reproduced by the model, was observed at cos([straight theta] pq)> -0.3 (where [straight theta] pq is the proton scattering angle relative to the direction of the momentum transfer) and can be associated with the contribution of final state interactions (FSI) that were not incorporated into the model. The bound nucleon structure function F 2n was studied in the region cos([straight theta] pq) -0.3 as a function of W * and scaling variable x *. At high spectator proton momenta the struck neutron is far off its mass shell. At p s 400 MeV/c the model overestimates the value of F 2n in the region of x * between 0.25 and 0.6. A modification of the bound neutron structure is one of possible effects that can cause the observed deviation.
