Compton Scattering on Protons: Project of Experimental Determination of Electric and Magnetic Polarizabilities of the Proton
Author: D. V. Balin
Publisher:
Published: 1996
Total Pages: 49
ISBN-13:
DOWNLOAD EBOOKRead and Download eBook Full
Author: D. V. Balin
Publisher:
Published: 1996
Total Pages: 49
ISBN-13:
DOWNLOAD EBOOKAuthor: Bruce Everett MacGibbon
Publisher:
Published: 1995
Total Pages: 296
ISBN-13:
DOWNLOAD EBOOKThe Compton scattering cross section on the proton was measured at laboratory angles of 90$spcirc$ and 135$spcirc$, using 70-100 MeV tagged photons, and simultaneously using 100-150 MeV untagged photons, in order to determine the electric and magnetic polarizabilities. The 135$spcirc$ cross section is sensitive to the difference of the electric and magnetic polarizabilities, $bar alpha - barbeta$, while the 90$spcirc$ cross section is sensitive to the electric polarizability $bar alpha$. Using the model independent sum rule constraint for $bar alpha$ + $bar beta$ and a model dependent dispersion relation calculation, the values for the polarizabilities extracted from the cross sections are:$$bar alpha = (12.5 pm 0.6 pm 0.8 pm 0.6) times 10sp{-4} fmsp3cr bar beta = (1.8 mp 0.6 mp 0.8 mp 0.6) times 10sp{-4} fmsp3$$where the errors shown are statistical, systematic, and model, respectively.
Author: Frank Wissmann
Publisher: Springer Science & Business Media
Published: 2003-12-03
Total Pages: 170
ISBN-13: 9783540407423
DOWNLOAD EBOOKA comprehensive summary of experiments on Compton scattering from the proton and neutron performed at the electron accelerator MAMI. The experiments cover a photon energy range from 30 MeV to 500 MeV. The reader is introduced to the theoretical concepts of Compton scattering, followed by a description of the experiments on the proton, their analysis and results.
Author:
Publisher:
Published: 1993
Total Pages: 490
ISBN-13:
DOWNLOAD EBOOKAuthor:
Publisher:
Published: 2003
Total Pages:
ISBN-13:
DOWNLOAD EBOOKVirtual Compton Scattering is studied at the Thomas Jefferson National Accelerator Facility in the energy domain below pion threshold and in the Delta(1232) resonance region. The data analysis is based on the Dispersion Relation (DR) approach. The electric and magnetic Generalized Polarizabilities (GPs) of the proton and the structure functions Pll-Ptt/epsilon and Plt are determined at four-momentum transfer squared Q2=0.92 and 1.76 GeV2. The DR analysis is consistent with the low-energy expansion analysis. The world data set indicates that neither the electric nor magnetic GP follows a simple dipole form.
Author: Frank Wissmann
Publisher: Springer
Published: 2014-01-15
Total Pages: 168
ISBN-13: 9783662145708
DOWNLOAD EBOOKA comprehensive summary of experiments on Compton scattering from the proton and neutron performed at the electron accelerator MAMI. The experiments cover a photon energy range from 30 MeV to 500 MeV. The reader is introduced to the theoretical concepts of Compton scattering, followed by a description of the experiments on the proton, their analysis and results.
Author: Fred J. Federspiel
Publisher:
Published: 1991
Total Pages:
ISBN-13:
DOWNLOAD EBOOKThe Compton scattering cross section on hydrogen was measured at 60$spcirc$ and 135$spcirc$ in order to determine the largely unknown electric and magnetic polarizabilities of the proton. The cross sections were measured using tagged photons spanning 32 through 72 MeV in energy. In this energy range, the forward scattering cross section is well constrained by model-independent theory and was measured to check the systematics of our experimental and data reduction procedures. Within the statistical errors, the measured forward cross section agrees with theory. The following values for the polarizabilities are extracted from the measured cross sections: $baralpha = (10.1 pm 2.2 pm 1.4)cdot 10sp{-4}fmsp3$ and $barbeta = (4.1 mp 2.2 mp 1.4)cdot 10sp{-4}fmsp3$, where the errors shown are statistical and systematic, respectively.
Author: Ruonan Li
Publisher:
Published: 2022
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKUnderstanding how the visible matter in the universe arises from its elementary quark andgluon constituents is a central question for science. The visible world is founded on the proton, the only composite building block of matter that is stable in nature. Consequently, understanding the formation of matter relies on explaining the dynamics and the properties of the proton's bound state. A fundamental property of the proton involves the system's response to an external electromagnetic (EM) field. It is characterized by the EM polarizabilities that describe how easily the charge and magnetization distributions inside the system are distorted by the EM field. When the polarizabilities are generalized to finite momentum transfer, their Fourier transform can map out the spatial distribution of the polarization densities in a proton subject to an EM field. This thesis focuses on the measurement of the proton generalized polarizabilities (GPs) at low four-momentum transfer in experimental Hall C at the Thomas Jefferson National Accelerator Facility (TJNAF). Among the six independent GPs, we will focus on the electric (aE1) and the magnetic (bM1) scalar GPs. The GPs can be accessed through measurements of the Virtual Compton Scattering reaction, by replacing the incoming real photon of the Compton scattering process with a space-like virtual photon. The outgoing real photon provides the EM perturbation to the system. In addition, the Dispersion Relation Formalism is used for generalized polarizability extraction. In this work, the two scalar GPs measured with unprecedented precision, and the measurements help explore a momentum transfer region where an anomalous enhancement of the electric GP that contradicts the predictions of nuclear theory has been observed.
Author:
Publisher:
Published: 2016
Total Pages: 240
ISBN-13:
DOWNLOAD EBOOKThe Standard Model has been a theory with the greatest success in describing the fundamental interactions of particles. As of the writing of this dissertation, the Standard Model has not been shown to make a false prediction. However, the limitations of the Standard Model have long been suspected by its lack of a description of gravity, nor dark matter. Its largest challenge to date, has been the observation of neutrino oscillations, and the implication that they may not be massless, as required by the Standard Model. The growing consensus is that the Standard Model is simply a lower energy effective field theory, and that new physics lies at much higher energies. The Qweak Experiment is testing the Electroweak theory of the Standard Model by making a precise determination of the weak charge of the proton (Qpw). Any signs of "new physics" will appear as a deviation to the Standard Model prediction. The weak charge is determined via a precise measurement of the parity-violating asymmetry of the electron-proton interaction via elastic scattering of a longitudinally polarized electron beam of an un-polarized proton target. The experiment required that the electron beam polarization be measured to an absolute uncertainty of 1%. At this level the electron beam polarization was projected to contribute the single largest experimental uncertainty to the parity-violating asymmetry measurement. This dissertation will detail the use of Compton scattering to determine the electron beam polarization via the detection of the scattered photon. I will conclude the remainder of the dissertation with an independent analysis of the blinded Qweak.
Author:
Publisher:
Published: 2004
Total Pages: 1
ISBN-13:
DOWNLOAD EBOOKWe report a Virtual Compton Scattering study of the proton at low CM energies. We have determined the structure functions P{sub LL} - P{sub TT}/[epsilon] and P{sub LT}, and the electric and magnetic Generalized Polarizabilities (GPs) [alpha]{sub E}(Q2) and [beta]{sub M}(Q2) at momentum transfer Q2 = 0.92 and 1.76 GeV2. The electric GP shows a strong fall-off with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a fall-off; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q2, compensated at higher Q2 by a paramagnetic contribution from [pi]N intermediate states.