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Recoil Polarization for Δ Excitation in Pion Electroproduction
(American Physical Society, 2005-09-02)
We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W=1.23 GeV at Q2=1.0 (GeV/c)2, obtaining 14 separated response functions plus 2 Rosenbluth combinations; ...
Recoil polarization measurements for neutral pion electroproduction at Q2=1(GeV/c)2 near the Δ resonance
We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q2=1.0 (GeV/c)2 in 10 bins of 1.17⩽W⩽1.35 GeV across the Δ resonance. A ...
Cross section measurements of charged pion photoproduction in hydrogen and deuterium from 1.1 to 5.5 GeV
The differential cross sections for the γn→π-p and the γp→π+n processes were measured at Jefferson Lab. The photon energies ranged from 1.1 to 5.5 GeV, corresponding to center-of-mass energies from 1.7 to 3.4 GeV. The pion ...
Quasielastic (e,e′p) reaction on 12C,56Fe, and 197Au
We report the results from a systematic study of the quasielastic (e,e′p) reaction on 12C, 56Fe, and 197Au performed at Jefferson Lab. We have measured nuclear transparency and extracted spectral functions (corrected for ...
Charged pion form factor between Q2=0.60 and 2.45 GeV2. II. Determination of, and results for, the pion form factor
The charged pion form factor, Fπ(Q2), is an important quantity that can be used to advance our knowledge of hadronic structure. However, the extraction of Fπ from data requires a model of the 1H(e,e'π+)n reaction and thus ...
Separated spectral functions for the quasifree 12C(e,e′p) reaction
A separation of the longitudinal and transverse 12C(e,e′p) cross sections in the quasifree region has been performed in parallel kinematics at Q2 of 0.64 and 1.8 GeV2 for initial proton momentum <80 MeV. The separated ...
Nuclear transparency with the γn⃗π-p process in 4He
We have measured the nuclear transparency of the fundamental process γn⃗π-p in 4He. These measurements were performed at Jefferson Lab in the photon energy range of 1.6–4.5 GeV and at θcmπ=70° and 90°. These measurements ...
Measurement of longitudinal and transverse cross sections in the 3He(e,e′π+)3H reaction at W=1.6 GeV
The coherent 3He(e,e′π+)3H reaction was measured at Q2=0.4 (GeV/c)2 and W=1.6 GeV for two values of the virtual photon polarization, ε, allowing the separation of longitudinal and transverse cross sections. The results ...
False Vacuum at the Heart of Black Holes
It is proposed that the evaporation of black holes via Hawking radiation may conclude at densities and temperatures no higher than those invoked during the inflationary stage of common cosmological models, thus avoiding ...
John A Wheeler and the recertification of GR as true physics
The physics life of John Archibald Wheeler is surveyed; the main emphasis is on the years 1953--1976 in Princeton where his activity primarily centered on Einstein's theory of gravitation, general relativity.