711 research outputs found
Quantum Treatment of the Multiple Scattering and Collective Flow in Intensity Interferometry
We apply the path-integral method to study the multiple scattering and
collective flow in intensity interferometry in high-energy heavy-ion
collisions. We show that the Glauber model and eikonal approximation in an
earlier quantum treatment are special examples of the more general
path-integral method. The multiple scattering and collective flow lead
essentially to an initial source at a shifted momentum, with a multiple
collision absorption factor that depends on the pion absorption cross section
and a phase factor that depends on the deviations of the in-medium particle
momenta from their asymptotic values.Comment: 6 pages, in LaTex, to be published in the Proceedings of the Workshop
on Particle Correlations and Femtoscopy, Kromeriz, Czech Republic, August
15-17, 200
An Overview of the Anomalous Soft Photons in Hadron Production
Productions of soft photon with low transverse momenta in high-energy
hadron-hadron collisions and - annihilations indicate that they are
consistently produced in excess of what are predicted by electromagnetic
bremsstrahlung when hadrons (mostly mesons) are produced, but they agree with
electromagnetic bremsstrahlung predictions in the absence of hadron production.
These excess soft photons are called anomalous soft photons. The occurrence of
anomalous soft photons in association with hadron production reveals the
presence of additional QED soft photon sources in QCD hadron production. Many
different models have been proposed to explain the anomalous soft production.
We shall examine specifically a quantum field theory of simultaneous meson and
soft photon production in QCDxQED in which the meson production arises from the
oscillation of color charge densities of the quarks of the underlying vacuum in
a flux tube. As a quark carries both a color charge and an electric charge, the
oscillation of the color charge densities will be accompanied by the
oscillation of electric charge densities, which will in turn lead to the
simultaneous production of anomalous soft photons during the meson production
process.Comment: 16 pages, 2 figures, invited talk presented at International
Conference on the Structure and the Interactions of the Photon including the
20th International Workshop on Photon-Photon Collisions and the International
Workshop on High Energy Photon Linear Colliders 20-24 May 2013, Paris,
France, to be published in Proceedings of Scienc
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