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Multiple electromagnetic pair production in ultrarelativistic heavy ion collisions; Multiple elektromagnetische Paarerzeugung in ultrarelativistischen Schwerionenstoessen

Thesis/Dissertation:

Abstract

The problem of the unitary violation in the pair production in ultrarelativistic heavy ion collisions was studied by a consideration of the field-theoretical foundations. The quantum electrodynamics in an external field were thereby reduced to a Dirac-sea model, the equivalence of which to the non-radiative QED resulted from the equality of the generating functionals. The latter can both be expressed explicitely by means of the complet set of the solutions of the Dirac equation in an external field. This method is based solely on the path-integral approach, which makes it possible to discriminate clearly between the physically given correlation functions and their generating functional at the one hand and at the other hand between the models constructed to their interpretation. From the model expression for the pair production amplitudes and multiplicities could be calculated, for which only the knowledge of the one-particle S matrix is necessary. For the calculation of the multiplicities different forms of the perturbation theory were discussed. Finally an impact-parameter dependent Weizsaecker-Williams approximation for the calculation of arbitrary two-photon graphs was constructed and applied to the given problem. The results indicate that at small distances very high pair multiplicities are to be expected. Finally a new approach  More>>
Authors:
Publication Date:
Apr 01, 1992
Product Type:
Thesis/Dissertation
Report Number:
GSI-92-09
Reference Number:
SCA: 664300; PA: DEN-92:015609; SN: 93000903911
Resource Relation:
Other Information: TH: Diploma Thesis; PBD: Apr 1992
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; QUANTUM ELECTRODYNAMICS; ION COLLISIONS; MULTIPLE PRODUCTION; PAIR PRODUCTION; POSITRONS; ELECTRONS; UNITARITY; FUNCTIONALS; DIRAC EQUATION; SYMMETRY BREAKING; ELECTRONIC STRUCTURE; FEYNMAN PATH INTEGRAL; CORRELATION FUNCTIONS; SCATTERING AMPLITUDES; S MATRIX; MULTIPLICITY; RELATIVISTIC RANGE; PERTURBATION THEORY; FEYNMAN DIAGRAM; IMPACT PARAMETER; EQUIVALENT-PHOTON APPROXIMATION; PHOTONS; VIRTUAL PARTICLES; DISTRIBUTION FUNCTIONS; PHASE SPACE; WIGNER DISTRIBUTION; ELECTRIC FIELDS; SECOND QUANTIZATION; LAGRANGIAN FIELD THEORY; 664300; COLLISION PHENOMENA
OSTI ID:
10104311
Research Organizations:
Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik
Country of Origin:
Germany
Language:
German
Other Identifying Numbers:
Other: ON: DE93742920; TRN: DE9215609
Availability:
OSTI; NTIS (US Sales Only); INIS
Submitting Site:
DEN
Size:
145 p.
Announcement Date:
Jun 30, 2005

Thesis/Dissertation:

Citation Formats

Best, C. Multiple electromagnetic pair production in ultrarelativistic heavy ion collisions; Multiple elektromagnetische Paarerzeugung in ultrarelativistischen Schwerionenstoessen. Germany: N. p., 1992. Web.
Best, C. Multiple electromagnetic pair production in ultrarelativistic heavy ion collisions; Multiple elektromagnetische Paarerzeugung in ultrarelativistischen Schwerionenstoessen. Germany.
Best, C. 1992. "Multiple electromagnetic pair production in ultrarelativistic heavy ion collisions; Multiple elektromagnetische Paarerzeugung in ultrarelativistischen Schwerionenstoessen." Germany.
@misc{etde_10104311,
title = {Multiple electromagnetic pair production in ultrarelativistic heavy ion collisions; Multiple elektromagnetische Paarerzeugung in ultrarelativistischen Schwerionenstoessen}
author = {Best, C}
abstractNote = {The problem of the unitary violation in the pair production in ultrarelativistic heavy ion collisions was studied by a consideration of the field-theoretical foundations. The quantum electrodynamics in an external field were thereby reduced to a Dirac-sea model, the equivalence of which to the non-radiative QED resulted from the equality of the generating functionals. The latter can both be expressed explicitely by means of the complet set of the solutions of the Dirac equation in an external field. This method is based solely on the path-integral approach, which makes it possible to discriminate clearly between the physically given correlation functions and their generating functional at the one hand and at the other hand between the models constructed to their interpretation. From the model expression for the pair production amplitudes and multiplicities could be calculated, for which only the knowledge of the one-particle S matrix is necessary. For the calculation of the multiplicities different forms of the perturbation theory were discussed. Finally an impact-parameter dependent Weizsaecker-Williams approximation for the calculation of arbitrary two-photon graphs was constructed and applied to the given problem. The results indicate that at small distances very high pair multiplicities are to be expected. Finally a new approach to the pair production in an external field was discussed, which is not based on the canonical field theory, but on the formalism of the Wigner functions. (orig./HSI). [Deutsch] Das Problem der Unitaritaetsverletzung bei der Paarerzeugung in ultrarelativistischen Schwerionenstoessen wurde durch eine Betrachtung der feldtheoretischen Grundlagen untersucht. Die Quantenelektrodynamik in einem aeusseren Feld wurde dabei auf ein Dirac-See-Modell zurueckgefuehrt, dessen Aequivalenz zur nicht-radiativen QED sich aus der Gleichheit der generierenden Funktionale ergab. Letztere lassen sich beide explizit mittels des vollstaendigen Satzes der Loesungen der Dirac-Gleichung im aeusseren Feld ausdruecken. Diese Methode basiert allein auf dem Pfadintegral-Ansatz, was es ermoeglicht, klar zwischen den physikalisch vorgegebenen Korrelationsfunktionen und ihrem generierenden Funktional einerseits und andererseits zwischen den zu ihrer Interpretation konstruierten Modellen zu unterscheiden. Aus dem Modell liessen sich Ausdruecke fuer die Paarerzeugungsamplituden und -multiplizitaeten errechnen, fuer die nur die Kenntnis der Ein-Teilchen-S-Matrix erforderlich ist. Zur Berechnung der Multiplizitaeten wurden verschiedene Formen der Stoerungstheorie diskutiert. Schliesslich wurde eine stossparameterabhaengige Weizsaecker-Williams-Naeherung fuer die Berechnung beliebiger Zwei-Photonen-Graphen konstruiert und auf das gestellte Problem angewandt. Die Ergebnisse deuten darauf hin, dass bei kleinen Abstaenden sehr hohe Paarmultiplizitaeten zu erwarten sind. Schliesslich wurde ein neuer Zugang zur Paarerzeugung in einem aeusseren Feld diskutiert, der nicht auf der kanonisch quantisierten Feldtheorie basiert, sondern auf dem Formalismus der Wigner-Funktionen. (orig./HSI).}
place = {Germany}
year = {1992}
month = {Apr}
}