1,144 research outputs found
Many-body theory interpretation of deep inelastic scattering
We analyze data on deep inelastic scattering of electrons from the proton
using ideas from standard many-body theory involving {\em bound} constituents
subject to {\em interactions}. This leads us to expect, at large three-momentum
transfer , scaling in terms of the variable . The response at constant scales well in this variable.
Interaction effects are manifestly displayed in this approach. They are
illustrated in two examples.Comment: 10 pages, 4 figure
On the behaviour of the nuclear spectral function at high momentum and removal energy
The extrapolation of the nuclear spectral function at large nucleon
three-momentum and removal energy is suggested.Comment: 13 pages, 2 Postscript figure
Backward hadron production in neutrino-nucleus interactions
The production of backward pions in lepton-nucleus collisions is analyzed. We
show that a large yield of high momentum backward pions can be explained by the
Regge asymptotic of the distribution of nucleons carrying a large momentum
fraction in the nuclear target. The calculated spectra of pions emitted in the
neutrino + Ne --> muon + pion + X reaction are in satisfactory agreement with
the available experimental data.Comment: 11 pages, 3 figure
Final-state interactions in the response of nuclear matter
Final-state interactions in the response of a many-body system to an external
probe delivering large momentum are normally described using the eikonal
approximation, for the trajectory of the struck particle, and the frozen
approximation, for the positions of the spectators. We propose a generalization
of this scheme, in which the initial momentum of the struck particle is
explicitly taken into account. Numerical calculations of the nuclear matter
response at 1 2 GeV/c show that the inclusion of this momentum
dependence leads to a sizable effect in the low energy tail. Possible
implications for the analysis of existing electron-nucleus scattering data are
discussed.Comment: 21 pages, 4 figure
Interpretation of y-scaling of the nuclear response
The behavior of the nuclear matter response in the region of large momentum
transfer, in which plane wave impulse approximation predicts the onset of
y-scaling, is discussed. The theoretical analysis shows that scaling violations
produced by final state interactions are driven by the momentum dependence of
the nucleon-nucleon scattering cross section.
Their study may provide valuable information on possible modifications of
nucleon-nucleon scattering in the nuclear medium.Comment: 4 pages with 3 figures. To appear in Physical Review Letter
Q**2-dependence of semi-inclusive electron-nucleus scattering and nucleon-nucleon correlations
We analize semi-inclusive electron-nucleus processes e+A->e'+h+X at moderate
Q**2 and energy transfer nu. Our results show that nucleons bound in the
nuclear medium are distributed according to a function f_A that reduces to the
standard light-cone distribution in the Bjorken limit and exhibits a sizeable
Q**2-dependence at lower Q**2, particular Q**2 is order of nu**2.Comment: 8 pages of LaTeX-text and 2 figure ps-file
Nuclear Physics with Electroweak Probes
In recent years, the italian theoretical Nuclear Physics community has played
a leading role in the development of a unified approach, allowing for a
consistent and fully quantitative description of the nuclear response to
electromagnetic and weak probes. In this paper I review the main achievements
in both fields, point out some of the open problems, and outline the most
promising prospects.Comment: Invited Talk at the XII Workshop on Theoretical Nuclear Physics in
Italy, Cortona, October 8-10, 200
Deuteron distribution in nuclear matter
We analyze the properties of deuteron-like structures in infinite, correlated
nuclear matter, described by a realistic hamiltonian containing the Urbana
two-nucleon and the Urbana TNI many-body potentials. The distribution
of neutron-proton pairs, carrying the deuteron quantum numbers, is obtained as
a function of the total momentum by computing the overlap between the nuclear
matter in its ground state and the deuteron wave functions in correlated basis
functions theory. We study the differences between the S- and D-wave components
of the deuteron and those of the deuteron-like pair in the nuclear medium. The
total number of deuteron type pairs is computed and compared with the
predictions of Levinger's quasideuteron model. The resulting Levinger's factor
in nuclear matter at equilibrium densityis 11.63. We use the local density
approximation to estimate the Levinger's factor for heavy nuclei, obtaining
results which are consistent with the available experimental data from
photoreactions.Comment: 22 pages, 7 figures, typeset using REVTe
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