Finite formation time effects in inclusive and semi-inclusive electro-disintegration of few-body nuclei

Finite Formation Time (FFT) effects in the exclusive reaction ^4He(e,e'p)^3H at high values of Q^2 are introduced and discussed. It is shown that the minimum in the momentum distributions predicted by the Plane Wave Impulse Approximation (PWIA), which is filled by the Glauber-type Final State Interaction (FSI), is completely recovered when FFT effects are taken into account. The semi-inclusive process ^4 He(e,e'p)X is also investigated.Comment: 4 pages, 2 eps figure

Electromagnetic Transition Form Factors of Nucleon Resonances

Recent measurements of nucleon resonance transition form factors with CLAS at Jefferson Lab are discussed. The new data resolve a long-standing puzzle of the nature of the Roper resonance, and confirm the assertion of the symmetric constituent quark model of the Roper as the first radial excitation of the nucleon. The data on $n\pi^+$ production at high $Q^2$ confirm the slow fall off of the $S_{11}(1535)$ transition form factor with $Q^2$, and better constrain the branching ratios $\beta_{N\pi}=0.50$ and $\beta_{N\eta}=0.45$. Also, new results on the transition amplitudes for the $D_{13}(1520)$ resonance are presented showing a rapid change from helicity 3/2 dominance seen at the real photon point to helicty 1/2 dominance at higher $Q^2$.Comment: 5 pages, 7 figure

On the effects of the final state interaction in the electro-disintegration of the deuteron at intermediate and high energies

The role of the final state interactions (FSI) in the inclusive quasi-elastic disintegration of the deuteron is investigated treating the two-nucleon final state within the exact continuum solutions of the non-relativistic Schroedinger equation, as well as within the Glauber multiple scattering approach. It is shown that for values of the Bjorken scaling variable $x_{Bj}\simeq 1$ both approaches provide similar results, unless the case $x_{Bj}\gtrsim 1$, where they appreciably disagree. It is demonstrated that present experimental data, which are mostly limited to a region of four-momentum transfer ($Q^2 \lesssim 4 (GeV/c)^2$) where the Center-of-Mass energy of the final state is below the pion threshold production, can be satisfactorily reproduced by the approach based on the exact solution of the Schroedinger equation and not by the Glauber approach. It is also pointed out that the latter, unlike the former, does not satisfy the inelastic Coulomb sum rule, the violation being of the order of about 20%.Comment: 16 LaTeX pages, 10 eps-figures, 1 tabl

Final state interaction in inclusive and exclusive quasi-elastic processes

We discuss a new approach to final state interactions, that keeps explicitly into account the virtuality of the ejected nucleon in quasi-elastic $A(e,e'p)X$ scattering at very large $Q^2$, and we present some recent results, at moderately large $Q^2$ values, for the nuclear transparency in $^4He$, $^{16}O$ and $^{40}Ca$ and for the momentum distributions of $^4He$.Comment: 10 pages, 5 figures, Prepared for the workshop "Cortona 2000, VIII Convegno su Problemi di Fisica Nucleare Teorica

Many-Body Theory of the Electroweak Nuclear Response

After a brief review of the theoretical description of nuclei based on nonrelativistic many-body theory and realistic hamiltonians, these lectures focus on its application to the analysis of the electroweak response. Special emphasis is given to electron-nucleus scattering, whose experimental study has provided a wealth of information on nuclear structure and dynamics, exposing the limitations of the shell model. The extension of the formalism to the case of neutrino-nucleus interactions, whose quantitative understanding is required to reduce the systematic uncertainty of neutrino oscillation experiments, is also discussed.Comment: Lectures delivered at the DAE-BRNS Workshop on Hadron Physics. Aligarh Muslim University, Aligarh (India), February 18-23, 200

Ground-state correlations and final state interactions in the process 3He(e,e'pp)n

The two-proton emission process $^3He(e,e'pp)n$ is theoretically investigated using realistic three-nucleon wave functions and taking the final state interaction into account by an approach which can be used when the value of the three-nucleon invariant mass is either below or above the pion emission threshold. Various kinematical conditions which enhance or minimize the effects of the final state interaction are thoroughly analyzed.Comment: 26 pages, 12 eps-figures. Introduction and abstract updated, few references added and Apendix A remove