Ground-state energies, densities and momentum distributions in closed-shell nuclei calculated within a cluster expansion approach and realistic interactions

A linked cluster expansion suitable for the treatment of ground-state properties of complex nuclei, as well as of various particle-nucleus scattering processes, has been used to calculate the ground-state energy, density and momentum distribution of 16-O and 40-Ca using realistic interactions. First of all, a benchmark calculation for the ground-state energy has been performed using the truncated V8' potential, and consisting in the comparison of our results with the ones obtained by the Fermi Hypernetted Chain approach, adopting in both cases the same mean field wave functions and the same correlation functions. The results exhibited a nice agreement between the two methods. Therefore, the approach has been applied to the calculation of the ground-state energy, density and momentum distributions of 16-O and 40-Ca using the full V8' potential, finding again a satisfactory agreement with the results based on more advanced approaches where higher order cluster contributions are taken into account. It appears therefore that the cluster expansion approach can provide accurate approximations for various diagonal and non diagonal density matrices, so that it could be used for a reliable evaluation of nuclear effects in various medium and high energy scattering processes off nuclear targets. The developed approach can be readily generalized to the treatment of Glauber type final state interaction effects in inclusive, semi-inclusive and exclusive processes off nuclei at medium and high energies.Comment: 42 pages, 18 figure

Use of Spineless Cactus (Opuntia ficus indica f. inermis) for Dairy Goats and Growing Kids: Impacts on Milk Production, Kid's Growth, and Meat Quality

The objective of this study was to determine the effect of spineless cactus incorporation in food of dairy goats and growing kids on milk production and composition and on kid's growth and meat characteristics. Two experiments were conducted on Tunisian local goats. In the first, 30 females were divided into two groups; goats of Control group were reared on grazing pasture receiving indoor 0.5 kg of hay and 0.4 kg of concentrate. Goats for the second group (Cac-FL) were kept in feedlot and fed cactus ad libitum more 0.5 kg of hay and 0.4 kg of concentrate. In the second experiment, 14 kids were divided into 2 groups receiving 600 g of hay. The Control group received ad libitum a concentrate containing 130 g crude protein (CP) per kg of dry matter. The second group received cactus ad-libitum plus the half concentrate quantity of control one with 260 g CP/kg DM (Cactus). The daily milk production averaged 485 ml for Control group and 407 ml for Cac-FL one. The milk fat content was significantly higher for Control than Cac-FL group. In the second experiment, animals in Control and Cactus groups had similar growth rate. Carcass fat was significantly lower in Cactus than in the Control group. Cactus in the diet was associated with more C18:2 and conjugated linoleic acid as well as a higher proportion of PUFA than Control ones

A non factorized calculation of the process ^3He(e,e'p)^2H at medium energies

The exclusive process ^3He(e,e^\prime p)^2H has been analyzed using realistic few-body wave functions corresponding to the AV18 interaction and treating the final state interaction (FSI) within the Eikonal Approximation to describe the multiple rescattering of the struck nucleon with the nucleons of the spectator two-nucleon system. Calculations have been performed in momentum space so that the nucleon electromagnetic current could be left in the fully covariant form avoiding by this way non relativistic reductions and the factorization approximation. The results of calculations, which are compared with recent JLab experimental data, show that the left-right asymmetry exhibit a clear dependence upon the multiple scattering in the final state and demonstrate the breaking down of the factorization approximation at \phi=0 i.e. for "negative" and large \geq 300MeV/c values of the missing momentum.Comment: 14 pages, 6 figure

Calculations of the Exclusive Processes 2H(e,e'p)n, 3He(e,e'p)2H and 3He(e,e'p)(pn) within a Generalized Glauber Approach

The exclusive processes 2H(e,e'p)n, 3He(e,e'p)2H and 3He(e,e'p)(pn), have been analyzed using realistic few-body wave functions and treating the final state interaction (FSI) within a Generalized Eikonal Approximation (GEA), based upon the direct calculation of the Feynman diagrams describing the rescattering of the struck nucleon with the nucleons of the A-1 system. The approach represents an improvement of the conventional Glauber approach (GA), in that it allows one to take into account the effects of the nuclear excitation of the $A-1$ system on the rescattering of the struck nucleon. Using realistic three-body wave functions corresponding to the AV18 interaction, the results of our parameter free calculations are compared with available experimental data. It is found that in some kinematical conditions FSI effects represent small corrections, whereas in other kinematics conditions they are very large and absolutely necessary to provide a satisfactory agreement between theoretical calculations and experimental data. It is shown that in the kinematics of the experimental data which have been considered, covering the region of missing momentum and energy with p_m < 0.6 GeV/c and E_m < 100 MeV in the perpendicular kinematics, the GA and GEA predictions differ only by less than 3-4 %.Comment: Typos detected and removed while Proof reading. Physical Review C. in Pres

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

Effects of Ground-State Correlations on High Energy Scattering off Nuclei: the Case of the Total Neutron-Nucleus Cross Section

With the aim at quantitatively investigating the longstanding problem concerning the effect of short range nucleon-nucleon correlations on scattering processes at high energies, the total neutron-nucleus cross section is calculated within a parameter-free approach which, for the first time, takes into account, simultaneously, central, spin, isospin and tensor nucleon-nucleon (NN) correlations, and Glauber elastic and Gribov inelastic shadowing corrections. Nuclei ranging from 4He to 208Pb and incident neutron momenta in the range 3 GeV/c - 300 GeV/c are considered; the commonly used approach which approximates the square of the nuclear wave function by a product of one-body densities is carefully analyzed, showing that NN correlations can play a non-negligible role in high energy scattering off nuclei.Comment: 5 pages, 3 figure

Finite formation time effects in quasi-elastic (e,e′)(e,e') scattering on nuclear targets

The problem of the final state interaction in quasi-elastic $(e,e')$ scattering at large $Q^2$, is investigated by exploiting the idea that the ejected nucleon needs a finite amount of time to assume its asymptotic form. It is shown that when the dependence of the scattering amplitude of the ejected nucleon on its virtuality is taken into account, the final state interaction is decreased. The developed approach is simpler to implement than the one based on the color transparency description of the damping of the final state interaction, and is essentially equivalent to the latter in the case of the single rescattering term. The $(e,e')$ process on the deuteron is numerically investigated and it is shown that, at $x=1$, appreciable finite formation time effects at $Q^2$ of the order of 10 (GeV/c)$^2$ are expected.Comment: 23 pages, 3 figure

Q**2-dependence of deep inelastic lepton scattering off nuclear targets

Deep inelastic scattering of leptons off nuclear targets is analized within the convolution model taking into account nucleon-nucleon correlations. We show that in the nuclear medium nucleons are distributed according to a function that exhibits a sizeable Q**2-dependence and reduces to the ordinary light-cone distribution in the Bjorken limit. At Q**2 1 this Q**2-dependence turns out to be stronger than the one associated with the nucleon structure function, predicted by pertubative quantum chromodynamics.Comment: 11 pages including figs. Figs. can be sent by PS-fil

Efecto de la incorporación de aceites esenciales de romero sobre la producción de leche de cabra y el crecimiento de los cabritos

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GRS computation of deep inelastic electron scattering on 4He

We compute cross sections for inclusive scattering of high energy electrons on 4He, based on the two lowest orders of the Gersch-Rodriguez-Smith (GRS) series. The required one- and two-particle density matrices are obtained from non-relativistic 4He wave functions using realistic models for the nucleon-nucleon and three-nucleon interaction. Predictions for E=3.6 GeV agree well with the NE3 SLAC-Virginia data.Comment: 18 pages, 7 figures, submitted to PR