Effects of short-range correlations in(e,e′p)reactions and nuclear overlap functions

Abstract

A study of the effects of short-range correlations over the (e, e ′ p) reaction for low missing energy in closed shell nuclei is presented. We use correlated, quasi-hole overlap functions extracted from the asymptotic behavior of the one-body density matrix, containing central correlations of Jastrow type, up to first-order in a cluster expansion, and computed in the very high asymptotic region, up to 100 fm. The method to extract the overlap functions is checked in a simple shell model, where the exact results are known. We find that the single-particle wave functions of the valence shells are shifted to the right due to the short-range repulsion by the nuclear core. The corresponding spectroscopic factors are reduced only a few percent with respect to the shell model. However, the (e, e ′ p) response functions and cross sections are enhanced in the region of the maximum of the missing momentum distribution due to short-range correlations.

Semirelativistic description of quasielastic neutrino reactions and superscaling in a continuum shell model

“…Moreover, the resulting semirelativistic (SR) current is simple enough to be easily implemented in already existing nonrelativistic models of (ν l , l − ) and (ν l , l + ) reactions, where l = e or µ. It is presented here as an extension of the electromagnetic and weak-neutral current expansion originally derived in [26] and that in recent years has been widely tested and applied in several Collaborations to describe a wide variety of inclusive and exclusive electron scattering observables for intermediate energies and excitations in the vicinity of the QE peak [27][28][29][30][31][32][33][34][35][36][37]. Extensions of the SR expansion to meson-exchange currents have also been developed [38,39], and a detailed description of their application to two-body currents can be found in a recent review article [40].…”

Equivalence between local Fermi gas and shell models in inclusive muon capture from nuclei

“…In this approximation there is no final-state interaction and hence the final neutron states are plane waves. The transition matrix elements appearing in the hadronic tensor (13) are computed trivially in terms of the product of a single nucleon current matrix element times the Fourier transform of a nuclear overlap function of the missing momentum, in a way which is similar to the analysis of exclusive (e, e ′ p) reactions [37] (but this time the nuclear overlap function includes the bound muon wave function). As a consequence, the exclusive hadronic tensor factorizes as the product of a single nucleon hadronic tensor times a partial momentum distribution, and the calculation is straightforward in the shell model.…”

Final-state interaction and recoil polarization in reactions: comparison with the polarized target case

“…Second we use the so-called semi-relativistic form of the nuclear (one-body) electromagnetic current operator, J µ (q), obtained as an expansion in powers of p/m N , the missing momentum over the nucleon mass, maintaining the exact dependence on the energy-momentum transfer. The resulting semi-relativistic DWIA model (SR-DWIA) was applied to (e, e ′ p) reactions from polarized nuclei in [25,26,36], to recoil polarization observables in [11,12], and to the unpolarized reaction in [35,39,41]. Effects beyond the impulse approximation due to meson-exchange currents (MEC) were discussed in [11,12,35] -it can be shown that they do not affect the results of the present work significantly.…”

“…We closely follow the pioneering work on polarization observables developed in [20,37,38]. For brevity here we just give the basic required expressions; more details about our model can be found in our previous work [11,39] and references therein.…”

“…(12), are purely spin-vector; hence they are zero in absence of polarization and they have no normal component, i.e., only the components of the spin in the reaction plane contribute. Expressions for the reduced response functions, W K i , using the present DWIA model were presented in [11] as a general multipole expansion, and in [39] for the case of the unpolarized ones, W K unpol . Using the above-defined sets of response functions, the cross section in Eq.…”