786 research outputs found
Finite formation time effects in quasi-elastic scattering on nuclear targets
The problem of the final state interaction in quasi-elastic
scattering at large , 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 process on the deuteron is numerically
investigated and it is shown that, at , appreciable finite formation time
effects at of the order of 10 (GeV/c) are expected.Comment: 23 pages, 3 figure
Scattering from Singular Potentials in Quantum Mechanics
In non-relativistic quantum mechanics, singular potentials in problems with
spherical symmetry lead to a Schrodinger equation for stationary states with
non-Fuchsian singularities both as r tends to zero and as r tends to infinity.
In the sixties, an analytic approach was developed for the investigation of
scattering from such potentials, with emphasis on the polydromy of the wave
function in the r variable. The present paper extends those early results to an
arbitrary number of spatial dimensions. The Hill-type equation which leads, in
principle, to the evaluation of the polydromy parameter, is obtained from the
Hill equation for a two-dimensional problem by means of a simple change of
variables. The asymptotic forms of the wave function as r tends to zero and as
r tends to infinity are also derived. The Darboux technique of intertwining
operators is then applied to obtain an algorithm that makes it possible to
solve the Schrodinger equation with a singular potential containing many
negative powers of r, if the exact solution with even just one term is already
known.Comment: 19 pages, plain Tex. In this revised version, the analysis of Eq.
(5.29) has been amended, and an appendix has been added for completenes
Coherent Vector Meson Photo-Production from Deuterium at Intermediate Energies
We analyze the cross section for vector meson photo-production off a deuteron
for the intermediate range of photon energies starting at a few GeVs above the
threshold and higher. We reproduce the steps in the derivation of the
conventional non-relativistic Glauber expression based on an effective
diagrammatic method while making corrections for Fermi motion and intermediate
energy kinematic effects. We show that, for intermediate energy vector meson
production, the usual Glauber factorization breaks down and we derive
corrections to the usual Glauber method to linear order in longitudinal nucleon
momentum. The purpose of our analysis is to establish methods for probing
interesting physics in the production mechanism for phi-mesons and heavier
vector mesons. We demonstrate how neglecting the breakdown of Glauber
factorization can lead to errors in measurements of basic cross sections
extracted from nuclear data.Comment: 41 pages, 13 figures, figure 9 is compressed from previous version,
typos fixe
Glutamine deprivation enhances antitumor activity of 3-bromopyruvate through the stabilization of monocarboxylate transporter-1
Anticancer drug efficacy might be leveraged by strategies to target certain biochemical adaptations of tumors. Here we show how depriving cancer cells of glutamine can enhance the anticancer properties of 3-bromopyruvate, a halogenated analog of pyruvic acid. Glutamine deprival potentiated 3-bromopyruvate chemotherapy by increasing the stability of the monocarboxylate transporter-1, an effect that sensitized cells to metabolic oxidative stress and autophagic cell death. We further elucidated mechanisms through which resistance to chemopotentiation by glutamine deprival could be circumvented. Overall, our findings offer a preclinical proof-of-concept for how to employ 3-bromopyruvate or other monocarboxylic-based drugs to sensitize tumors to chemotherap
Diffractive Phenomena and Shadowing in Deep-Inelastic Scattering
Shadowing effects in deep-inelastic lepton-nucleus scattering probe the mass
spectrum of diffractive leptoproduction from individual nucleons. We explore
this relationship using current experimental information on both processes. In
recent data from the NMC and E665 collaboration, taken at small x << 0.1 and
Q^2 < 1 GeV^2, shadowing is dominated by the diffractive excitation and
coherent interaction of low mass vector mesons. If shadowing is explored at
small x > 1 GeV^2 as discussed at HERA, the situation is
different. Here dominant contributions come from the coherent interaction of
diffractively produced heavy mass states. Furthermore we observe that the
energy dependence of shadowing is directly related to the mass dependence of
the diffractive production cross section for free nucleon targets.Comment: 12 pages Latex, 8 figure
Nuclear shadowing at low photon energies
We calculate the shadowing effect in nuclear photoabsorption at low photon
energies (1-3 GeV) within a multiple scattering approach. We avoid some of the
high energy approximations that are usually made in simple Glauber theory like
the narrow width and the eikonal approximation. We find that the main
contribution to nuclear shadowing at low energies stems from mesons
with masses well below their pole mass. We also show that the possibility of
scattering in non forward directions allows for a new contribution to shadowing
at low energies: the production of neutral pions as intermediate hadronic
states enhances the shadowing effect in the onset region. For light nuclei and
small photon energies they give rise to about 30% of the total shadowing
effect.Comment: RevTeX, 16 pages including 6 eps figures; new calculation of
effective pion propagator, negligible effect on results; version to be
published in Phys. Rev.
The p(d,p)d and p(d,p)pn reactions as a tool for the study of the short range internal structure of the deuteron
In recent time the deuteron structure at short distances is often treated
from the point of view nonnucleonic degrees of freedom. In this paper the
measurements of T-odd polarization observables using tensor polarized deuteron
beam and polarized proton target or proton polarimeter are proposed to search
the quark configurations inside the deuteron.Comment: 12 pages, 8 Postscript figures, submitted in Phys.Atom.Nuc
Multiparton interactions and production of minijets in high energy hadronic collisions
We discuss the inclusive cross section to produce two minijets with a large
separation in rapidity in high energy hadronic collisions. The contribution to
the inclusive cross section from the exchange of a BFKL Pomeron is compared
with the contribution from the exchange of two BFKL Pomerons, which is induced
by the unitarization of the semi-hard interaction. The effect of the multiple
exchange is studied both as a function of the azimuthal correlation and as a
function of the transverse momentum of the observed minijets.Comment: TeX file, 20 pages, 4 figures available on reques
Measurements of Direct CP Violation, CPT Symmetry, and Other Parameters in the Neutral Kaon System
We present a series of measurements based on K -> pi+pi- and K -> pi0pi0
decays collected in 1996-1997 by the KTeV experiment (E832) at Fermilab. We
compare these four K -> pipi decay rates to measure the direct CP violation
parameter Re(e'/e) = (20.7 +- 2.8) x 10^-4. We also test CPT symmetry by
measuring the relative phase between the CP violating and CP conserving decay
amplitudes for K->pi+pi- (phi+-) and for K -> pi0pi0 (phi00). We find the
difference between the relative phases to be Delta-phi = phi00 - phi+- = (+0.39
+- 0.50) degrees and the deviation of phi+- from the superweak phase to be
phi+- - phi_SW =(+0.61 +- 1.19) degrees; both results are consistent with CPT
symmetry. In addition, we present new measurements of the KL-KS mass difference
and KS lifetime: Delta-m = (5261 +- 15) x 10^6 hbar/s and tauS = (89.65 +-
0.07) x 10^-12 s.Comment: Submitted to Phys. Rev. D, August 6, 2002; 37 pages, 32 figure
Evidence for Color Fluctuations in Hadrons from Coherent Nuclear Diffraction}
A QCD-based treatment of projectile size fluctuations is used to compute
inelastic diffractive cross sections for coherent
hadron-nuclear processes. We find that fluctuations near the average size give
the major contribution to the cross section with contribution
from small size configurations.
The computed values of are consistent with the limited
available data. The importance of coherent diffraction studies for a wide range
of projectiles for high energy Fermilab fixed target experiments is emphasized.
The implications of these significant color fluctuations for relativistic heavy
ion collisions are discussed.Comment: Report number DOE/ER 40427-13-N93 11 pages, 3 figures available from
author Mille
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