We report a virtual Compton scattering study of the proton at low c.m. energies. We have determined the structure functions PLL–PTT/and PLT, and the electric and magnetic generalized polarizabilities ...(GPs) E(Q2) and M(Q2) at momentum transfer Q2=0.92 and 1.76 GeV2. The electric GP shows a strong falloff with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a falloff; 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 N intermediate states.
We have measured the spin structure functions g(1) and g(2) of 3He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.058 GeV off a ...polarized 3He target at a 15.5 degrees scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q2 evolution of Gamma(1)(Q2)= integral (1)(0)g(1)(x,Q2)dx, Gamma(2)(Q2)= integral (1)(0)g(2)(x,Q2)dx, and d(2)(Q2)= integral (1)(0)x(2)2g(1)(x,Q2)+3g(2)(x,Q2)dx for the neutron in the range 0.1< or =Q2< or =0.9 GeV2 with good precision. Gamma(1)(Q2) displays a smooth variation from high to low Q2. The Burkhardt-Cottingham sum rule holds within uncertainties and d(2) is nonzero over the measured range.
We have measured the spin structure functions g{sub 1} and g{sub 2} of {sup 3}He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.07 GeV ...off a polarized {sup 3}He target at a 15.5{sup o} scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q{sup 2} evolution of {Gamma}{sub 1}(Q{sup 2})=/int{sub 0}{sup 1} g{sub 1}(x,Q{sup 2}) dx, {Gamma}{sub 2}(Q{sup 2})=/int{sub 0}{sup 1} g{sub 2}(x,Q{sup 2}) dx and d{sub 2} (Q{sup 2}) = /int{sub 0}{sup 1} x {sup 2}2g{sub 1}(x,Q{sup 2}) + 3g{sub 2}(x,Q{sup 2}) dx for the neutron in the range 0.1 GeV{sup 2} /leq Q{sup 2} /leq 0.9 GeV{sup 2} with good precision. {Gamma}{sub 1}(Q{sup 2}) displays a smooth variation from high to low Q{sup 2}. The Burkhardt-Cottingham sum rule holds within uncertainties and d{sub 2} is non-zero over the measured range.
We report a Virtual Compton Scattering study of the proton in Hall A at the Thomas Jefferson National Accelerator Facility at low CM energies. We have determined the structure functions ...$P_{LL}-P_{TT}/\epsilon$ and $P_{LT}$, and the electric and magnetic Generalized Polarizabilities (GP) $\alpha_E(Q2)$ and $\beta_M(Q2)$ at momentum transfer Q2= 0.92 and 1.76 GeV2. All these observables show a strong fall-off with Q2, and neither the electric nor magnetic GP follows a simple dipole form.
The cross section of atomic electron Compton scattering \(\gamma + e \rightarrow \gamma^\prime + e^\prime \) was measured in the 4.40--5.475 GeV photon beam energy region by the {\em PrimEx} ...collaboration at Jefferson Lab with an accuracy of 2\% and less. The results are consistent with theoretical predictions that include next-to-leading order radiative corrections. The measurements provide the first high precision test of this elementary QED process at beam energies greater than 0.1 GeV.
We present data on the inclusive scattering of polarized electrons from a polarized 3He target at energies from 0.862 to 5.06 GeV, obtained at a scattering angle of 15.5 degrees. Our data include ...measurements from the quasielastic peak, through the nucleon resonance region, and beyond, and were used to determine the virtual photon cross-section difference sigma(1/2)-sigma(3/2). We extract the extended Gerasimov-Drell-Hearn integral for the neutron in the range of four-momentum transfer squared Q2 of 0.1-0.9 GeV2.
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