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A study of the P 11 (1440) The transition helicity amplitudes from the proton ground state to the P11(1440) and D13(1520) excited states (γvpN * electrocouplings) were determined from the analysis of nine independent onefold differential π + π − p electroproduction cross sections off a proton target, taken with CLAS at photon virtualities 0.25 GeV 2 < Q 2 < 0.60 GeV 2 . The phenomenological reaction model was employed for separation of the resonant and non-resonant contributions to the final state. The P11(1440) and D13(1520) electrocouplings were obtained from the resonant amplitudes parametrized within the framework of a unitarized Breit-Wigner ansatz. They are consistent with results obtained in the previous CLAS analyses of the π + n and π 0 p channels. The successful description of a large body of data in dominant meson-electroproduction channels off protons with the same γvpN * electrocouplings offers clear evidence for the reliable extraction of these fundamental quantities from meson-electroproduction data. This analysis also led to the determination of the long-awaited hadronic branching ratios for the D13(1520) decay into ∆π (24%-32%) and N ρ (8%-17%).

The proton and deuteron structure functions F p 2 and F d 2 are measured in inelastic muon scattering with an average beam energy of 470 GeV. The data were taken at Fermilab experiment E665 during 1991-92 using liquid hydrogen and deuterium targets. The F2 measurements are reported in the range 0:0008 < x < 0 : 6 and 0:2 < Q 2 < 75 GeV 2. These are the rst precise measurements of F2 in the low x and Q 2 range of the data. In the high x range of the data where they overlap in x and Q 2 with the measurements from NMC, the two measurements are in agreement. The E665 data also overlap in x with the HERA data, and there is a smooth connection in Q 2 between the two data sets. At high Q 2 the E665 measurements are consistent with QCDevolved leading twist structure function models. The data are qualitatively described 2 by structure function models incorporating the hadronic nature of the photon at low Q 2. The Q 2 and the W dependence of the data measure the transition in the nature of the photon between a point-like probe at high Q 2 and a hadronic object at low Q 2 .

We report the first results of the beam-spin asymmetry measured in the reaction e⃗p→epγ at a beam energy of 4.25 GeV. A large asymmetry with a sinφ modulation is observed, as predicted for the interference term of deeply virtual compton scattering (DVCS) and the Bethe-Heitler process. The amplitude of this modulation is α = 0.202±0.028. In leading-order and leading-twist perturbative QCD, the α is directly proportional to the imaginary part of the DVCS amplitude

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