[PDF] Measurements Of Electron Proton Elastic Cross Sections For 04 Q2 55 Gev eBook

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Release : 2004
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We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The measurements were made at 28 unique kinematic settings covering a range in momentum transfer of 0.4

Author : Longwu Ou
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Page : 192 pages
File Size : 44,43 MB
Release : 2019
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The electromagnetic form factors are fundamental quantities characterizing the internal structure of the nucleon. Their measurements have provided significant insight into the spatial distribution and interaction of quarks inside the proton. The knowledge of high Q2 form factors proves essential in understanding the properties of quantum chromodynamics in the transition region from non-perturbative to perturbative behavior. It also provides important links to generalized parton distributions, which describe the three-dimensional structure of hadrons at the parton level. In view of the significant theoretical research activities in this field, high quality experimental data are crucial for providing stringent tests and benchmarks to guide and test different models. The form factors can be accessed in experiments by measuring elastic scattering of electrons off a hydrogen target. Experiment E12-07-108, which took place at the Thomas Jefferson National Accelerator Facility, conducted precise measurements of the unpolarized e-p elastic scattering cross section over a Q2 range of 0.6-16.5 GeV2 . This thesis presents the results for 7 kinematic settings with total uncertainties that are 1.5 times smaller than those of the existing data at large Q2 . The proton magnetic form factors were extracted using a parameterization of the form factor ratio obtained from recent polarized e-p scattering experiments. Comparisons to existing global and phenomenological fits are presented.

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Page : 92 pages
File Size : 31,65 MB
Release : 2002
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Experiment E89-008 measured inclusive electron scattering cross sections from different nuclei in Hall C at Jefferson Laboratory. Cross sections on the low energy loss side of the quasi-elastic peak (xBj > 1) are extracted for carbon, aluminum, iron and gold. The data cover four-momentum transfers squared of 0.97 to 5.73 GeV 2 =c 2 . The measured cross sections are compared to cross sections calculated using a microscopic spectral function. The cross section results are also analyzed in terms of the two scaling functions F (y) and f(?'). For both the data is found to be independent of the momentum transfer (scaling of the first kind). For f(?') the data is in addition independent of the mass number A (scaling of the second kind) and thus exhibits superscaling properties.

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Page : 4 pages
File Size : 50,9 MB
Release : 2004
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We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The measurements were made at 28 distinct kinematic settings covering a range in momentum transfer of 0.4

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File Size : 10,22 MB
Release : 2010
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The electromagnetic form factors of the proton are fundamental quantities sensitive to the distribution of charge and magnetization inside the proton. Precise knowledge of the form factors, in particular of the charge and magnetization radii provide strong tests for theory in the non-perturbative regime of QCD. However, the existing data at Q^2 below 1 (GeV/c)^2 are not precise enough for a hard test of theoretical predictions.rnrnFor a more precise determination of the form factors, within this work more than 1400 cross sections of the reaction H(e, e2 p were measured at the Mainz Microtron MAMI using the 3-spectrometer-facility of the A1-collaboration. The data were taken in three periods in the years 2006 and 2007 using beam energies of 180, 315, 450, 585, 720 and 855 MeV. They cover the Q^2 region from 0.004 to 1 (GeV/c)^2 with counting rate uncertainties below 0.2% for most of the data points. The relative luminosity of the measurements was determined using one of the spectrometers as a luminosity monitor. The overlapping acceptances of the measurements maximize the internal redundancy of the data and allow, together with several additions to the standard experimental setup, for tight control of systematic uncertainties.rnTo account for the radiative processes, an event generator was developed and implemented in the simulation package of the analysis software which works without peaking approximation by explicitly calculating the Bethe-Heitler and Born Feynman diagrams for each event.rnTo separate the form factors and to determine the radii, the data were analyzed by fitting a wide selection of form factor models directly to the measured cross sections. These fits also determined the absolute normalization of the different data subsets. The validity of this method was tested with extensive simulations. The results were compared to an extraction via the standard Rosenbluth technique.rnrnThe dip structure in G_E that was seen in the analysis of the previous world.