274 research outputs found
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
On the dependence of the wave function of a bound nucleon on its momentum and the EMC effect
It is widely discussed in the literature that the wave function of the
nucleon bound in a nucleus is modified due to the interaction with the
surrounding medium. We argue that the modification should strongly depend on
the momentum of the nucleon. We study such an effect in the case of the
point-like configuration component of the wave function of a nucleon bound in a
nucleus A, considering the case of arbitrary final state of the spectator A-1
system. We show that for non relativistic values of the nucleon momentum, the
momentum dependence of the nucleon deformation appears to follow from rather
general considerations and discuss the implications of our theoretical
observation for two different phenomena: i) the search for medium induced
modifications of the nucleon radius of a bound nucleon through the measurement
of the electromagnetic nucleon form factors via the A(e,e'p)X process, and ii)
the A-dependence of the EMC effect; in this latter case we also present a new
method of estimating the fraction of the nucleus light-cone momentum carried by
the photons and find that in a heavy nuclei protons loose about 2% of their
momentum.Comment: 38 pages, 1 figure; changed references and text in Section I
(Introduction
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
Ground-state correlations and final state interactions in the process 3He(e,e'pp)n
The two-proton emission process 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
Realistic Model of the Nucleon Spectral Function in Few- and Many- Nucleon Systems
By analysing the high momentum features of the nucleon momentum distribution
in light and complex nuclei, it is argued that the basic two-nucleon
configurations generating the structure of the nucleon Spectral Function at
high values of the nucleon momentum and removal energy, can be properly
described by a factorised ansatz for the nuclear wave function, which leads to
a nucleon Spectral Function in the form of a convolution integral involving the
momentum distributions describing the relative and center-of-mass motion of a
correlated nucleon-nucleon pair embedded in the medium. The Spectral Functions
of and infinite nuclear matter resulting from the convolution formula
and from many-body calculations are compared, and a very good agreement in a
wide range of values of nucleon momentum and removal energy is found.
Applications of the model to the analysis of inclusive and exclusive processes
are presented, illustrating those features of the cross section which are
sensitive to that part of the Spectral Function which is governed by
short-range and tensor nucleon-nucleon correlations.Comment: 40 pages Latex , 16 ps figures available from the above e-mail
address or from [email protected]
Chemical genetics approach to identify new small molecule modulators of cell growth by phenotypic screening of Saccharomyces cerevisiae strains with a library of morpholine-derived compounds
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
Number of Collisions in the Glauber Model and Beyond
The so called number of hadron-nucleus collisions n_coll(b) at impact
parameter b, and its integral value N_coll, which are used to normalize the
measured fractional cross section of a hard process, are calculated within the
Glauber-Gribov theory including the effects of nucleon short-range
correlations. The Gribov inelastic shadowing corrections are summed to all
orders by employing the dipole representation. Numerical calculations are
performed at the energies of the BNL Relativistic Heavy Ion Collider (RHIC) and
CERN Large Hadron Collider (LHC). We found that whereas the Gribov corrections
generally increase the value of N_coll, the inclusion of nucleon correlations,
acting in the opposite directions, decreases it by a comparable amount. The
interplay of the two effects varies with the value of the impact parameter.Comment: Text expanded; typos corrected; results and conclusions unchanged. To
appear in Phys. Rev.
First record of VKORC1 sequence mutation associated with resistance to anticoagulant rodenticides in italian individuals of Mus musculus domesticus
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