dorsal/arxiv
View SchemaPartons in Phase Space
| Authors | David A. Brown, Pawel Danielewicz |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9802015 |
| URL | https://arxiv.org/abs/nucl-th/9802015 |
| DOI | 10.1103/PhysRevD.58.094003 |
| Journal | Phys.Rev.D58:094003,1998 |
Abstract
Within QED, we examine several issues related to constructing a parton-model-based QCD transport theory. We rewrite the QED analog of the parton model, the Weizsaecker-Williams Approximation, entirely in terms of phase-space quantities and we study the phase-space photon and electron densities created by a classical point charge. We find that the densities take a distinctive ``source-propagator'' form. This form does not arise in a conventional derivation of the semiclassical transport equations because of the overuse of the gradient approximation. We do not apply the gradient approximation and so derive the phase-space analog of the Generalized Fluctuation-Dissipation Theorem. Together, this theorem and the expression for the phase-space particle self-energies give a set of coupled phase-space evolution equations. We illustrate how these evolution equations can be used perturbatively or to derive semiclassical transport equations. Our work relies on phase-space propagators and sources, so we describe them in detail when calculating the photon and electron phase-space densities. We use these tools to discuss the shape of a nucleon's parton cloud.
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"abstract": "Within QED, we examine several issues related to constructing a\nparton-model-based QCD transport theory. We rewrite the QED analog of the\nparton model, the Weizsaecker-Williams Approximation, entirely in terms of\nphase-space quantities and we study the phase-space photon and electron\ndensities created by a classical point charge. We find that the densities take\na distinctive ``source-propagator\u0027\u0027 form. This form does not arise in a\nconventional derivation of the semiclassical transport equations because of the\noveruse of the gradient approximation. We do not apply the gradient\napproximation and so derive the phase-space analog of the Generalized\nFluctuation-Dissipation Theorem. Together, this theorem and the expression for\nthe phase-space particle self-energies give a set of coupled phase-space\nevolution equations. We illustrate how these evolution equations can be used\nperturbatively or to derive semiclassical transport equations. Our work relies\non phase-space propagators and sources, so we describe them in detail when\ncalculating the photon and electron phase-space densities. We use these tools\nto discuss the shape of a nucleon\u0027s parton cloud.",
"arxiv_id": "nucl-th/9802015",
"authors": [
"David A. Brown",
"Pawel Danielewicz"
],
"categories": [
"nucl-th",
"hep-ph"
],
"doi": "10.1103/PhysRevD.58.094003",
"journal_ref": "Phys.Rev.D58:094003,1998",
"title": "Partons in Phase Space",
"url": "https://arxiv.org/abs/nucl-th/9802015"
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