1,385 research outputs found
Lepton-nucleus scattering in the impulse approximation regime
We discuss theoretical calculations of electron- and neutrino-nucleus
scattering, carried out using realistic nuclear spectral functions and
including the effect of final state interactions. Comparison between electron
scattering data and the calculated inclusive cross sections off oxygen shows
that the Fermi gas model fails to provide a satisfactory description of the
measured cross sections, and inclusion of nuclear dynamics is needed. The role
of Pauli blocking in charged-current neutrino induced reactions at low is
also analyzed.Comment: To be published in the Proceedings of NUFACT05 (Nucl. Phys. B,
Proceedings Supplements
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
Final state interaction contribution to the response of confined relativistic particles
We report studies of the response of a massless particle confined by a
potential. At large momentum transfer q it exhibits \tilde{y} or equivalently
Nachtmann \xi scaling, and acquires a constant width independent of q. This
width has a contribution from the final state interactions of the struck
particle, which persists in the q->\infty limit. The width of the response
predicted using plane wave impulse approximation is smaller because of the
neglect of final state interactions in that approximation. However, the exact
response may be obtained by folding the approximate response with a function
representing final state interaction effects. We also study the response
obtained from the momentum distribution assuming that the particle is on the
energy shell both before and after being struck. Quantitative results are
presented for the special case of a linear confining potential. In this case
the response predicted with the on-shell approximation has correct values for
the total strength, mean energy and width, however its shape is wrong.Comment: 11 pages, 3 figures, submitted to Phys. Rev.
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
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
Proton Decay: Improving the sensitivity through nuclear dynamics?
The kinematics of the decay of a bound proton is governed by the proton
spectral function. We evaluate this quantity in 16O using the information from
nuclear physics experiments. It also includes a correlated part. The
reliability of this evaluation is sufficient to open the possibility of
correlated cuts in the missing mass and momentum variables in order to identify
the decay events from the bound protons with a possible increase of the signal
to noise ratio.Comment: 6 pages, 6 figures. CERN preprint: CERN-PH-TH/2010-036. To appear in
Phys Rev
Nuclear matter hole spectral function in the Bethe-Brueckner-Goldstone approach
The hole spectral function is calculated in nuclear matter to assess the
relevance of nucleon-nucleon short range correlations. The calculation is
carried out within the Brueckner scheme of many-body theory by using several
nucleon-nucleon realistic interactions. Results are compared with other
approaches based on variational methods and transport theory. Discrepancies
appear in the high energy region, which is sensitive to short range
correlations, and are due to the different many-body treatment more than to the
specific N-N interaction used. Another conclusion is that the momentum
dependence of the G-matrix should be taken into account in any self consistent
approach.Comment: 7 pages, 5 figure
The \gamma-ray production in neutral-current neutrino oxygen interaction in the energy range above 100 MeV
We calculate the cross section of the gamma-ray production from
neutral-current neutrino-oxygen quasi-elastic interaction, , or , in
which the residual nuclei (15N* or 15O*) lead to the gamma-ray emission with
gamma-ray energy >6 MeV at the branching ratio of 41%. Above 200 MeV, this
cross section dominates over that of gamma-ray production from the inelastic
reaction, . In the present calculation, spectral
function and the spectroscopic factors of
states are essential. The gamma-ray production is dominated by the deexcitation
of state of the residual nucleus
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