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The quantum mechanical theory of collisions
textLecture notes by Roy Glauber, Department of Physics, Harvard University. Cours professe a l'Ecole d'ete de physique theorique. Les Houches, Haute-Savoie, FranceEcole d'ete de physique theorique. Les Houches, Haute-Savoie, FrancePhysic
Coulomb-nuclear interference in pion-nucleus bremsstrahlung
Pion-nucleus bremsstrahlung offers a possibility of measuring the structure
functions of pion-Compton scattering from a study of the
small-momentum-transfer region where the bremsstrahlung reaction is dominated
by the single-photon-exchange mechanism. The corresponding cross-section
distribution is characterized by a sharp peak at small momentum transfers. But
there is also a hadronic contribution which is smooth and constitutes an
undesired background. In this communication the modification of the
single-photon exchange amplitude by multiple-Coulomb scattering is investigated
as well as the Coulomb-nuclear interference term.Comment: 21 pages, 5 figures. Eqs.(51,52) corrected; some new figure
A remark on the Primakoff effect
The coherent-nuclear reaction a + A -> a* + A is in the small-angle region
dominated by the one-photon-exchange mechanism, often referred to as the
Primakoff effect. In this region information about the electromagnetic decay a*
-> a + gamma can be obtained. Well-known examples are the two-photon decays of
the pi- and eta-mesons. Also decays of charged hadrons can be studied. For
charged hadrons the one-photon-exchange amplitude comes with a Coulomb-phase
factor and a Coulomb-form factor, which depend on the ratio between transverse-
and logitudinal-momentum transfers, the latter being fixed. At the peak of the
cross-section distribution, where the two momentum transfers are equal, the
form factor could cut down the cross-section value by as much as 40 %.
Consequently, a determination of a radiative-decay rate that relies on the peak
value becomes sensitive to a proper treatment of the Coulomb-form factor.Comment: 5 pages, 2 figure
Slow Proton Production in Semi-Inclusive Deep Inelastic Scattering off Deuteron and Complex Nuclei: Hadronization and Final State Interaction Effects
The effects of the final state interaction in slow proton production in semi
inclusive deep inelastic scattering processes off nuclei, A(e,e'p)X, are
investigated in details within the spectator and target fragmentation
mechanisms; in the former mechanism, the hard interaction on a nucleon of a
correlated pair leads, by recoil, to the emission of the partner nucleon,
whereas in the latter mechanism proton is produced when the diquark, which is
formed right after the visrtual photon-quark interaction, captures a quark from
the vacuum. Unlike previous papers on the subject, particular attention is paid
on the effects of the final state interaction of the hadronizing quark with the
nuclear medium within an approach based upon an effective time-dependent cross
section which combines the soft and hard parts of hadronization dynamics in
terms of the string model and perturbative QCD, respectively. It is shown that
the final state interaction of the hadronizing quark with the medium plays a
relevant role both in deuteron and complex nuclei; nonetheless, kinematical
regions where final state interaction effects are minimized can experimentally
be selected, which would allow one to investigate the structure functions of
nucleons embedded in the nuclear medium; likewise, regions where the
interaction of the struck hadronizing quark with the nuclear medium is
maximized can be found, which would make it possible to study non perturbative
hadronization mechanisms.Comment: 35 pages, 12 figures, accepted for pubblication in Phys. Rev.
Title Quantum Optics and Heavy Ion Physics
I shall try to say a few words about two particular ways in which my own work
has a certain relation to your work with heavy ions. My title is therefore
"Quantum Optics and Heavy Ion Physics".Comment: Invited paper delivered at Quark Matter 2005 Conference, Budapest,
Hungary, August 4, 2005, 11 pages, 5 figure
Yoctosecond metrology through HBT correlations from a quark-gluon plasma
Expansion dynamics at the yoctosecond timescale affect the evolution of the
quark gluon plasma (QGP) created in heavy ion collisions. We show how these
dynamics are accessible through Hanbury Brown and Twiss (HBT) intensity
interferometry of direct photons emitted from the interior of the QGP. A
detector placed close to the beam axis is particularly sensitive to early polar
momentum anisotropies of the QGP. Observing a modification of the HBT signal at
the proposed FoCal detector of the LHC ALICE experiment would allow to measure
the isotropization time of the plasma and could provide first experimental
evidence for photon double pulses at the yoctosecond timescale.Comment: 5 pages, 3 figure
Dynamic radiation force of acoustic waves on solid elastic spheres
The present study concerns the dynamic radiation force on solid elastic
spheres exerted by a plane wave with two frequencies (bichromatic wave)
considering the nonlinearity of the fluid. Our approach is based on solving the
wave scattering for the sphere in the quasilinear approximation within the
preshock wave range. The dynamic radiation force is then obtained by
integrating the component of the momentum flux tensor at the difference of the
primary frequencies over the boundary of the sphere. Results reveal that
effects of the nonlinearity of the fluid plays a major role in dynamic
radiation force leading it to a parametric amplification regime. The developed
theory is used to calculate the dynamic radiation force on three different
solid spheres (aluminium, silver, and tungsten). Resonances are observed in the
spectrum of the force on the spheres. They have larger amplitude and better
shape than resonances present in static radiation force.Comment: 9 pages, 4 figures, to appear in Physical Review
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