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Baryon spectroscopy: Symmetries, symmetry breaking, and hadronic loops
ANNALS
OF PHYSICS
Abstracts Buryon
168,
527-528
(1986)
of Papers
to Appear
in Future
Spectroscopy: Symmetries, Symmetry Breaking, and Hadronic Department of Theoretical Physics, Institute of Nuclear Physics, Krakow, Poland.
Issues
Loops. PI~TR Radzikowskiego
~ENCZYKOWSKI.
152. PL-3 I-342
The problem of hadronic loop effects in baryon spectroscopy is thoroughly discussed. It is argued that such effects very likely constitute the dominant contribution to the observed splitting and mixing pattern of the (56,O + ) and (70.1 ) baryon multiplets. In particular. this dominance is demonstrated in the original IsgurrKarl-Koniuk model of baryons, in which hadronic loops are shown to provide an explanation for at least 2/3 of the observed size of splittings, both for the ground-state and excited baryons. The unitarity-induced mixing angles in the (70,l~ )-multiplet are also shown to be in good agreement with experiment. For the ground-state baryons the formula relating Z - n and d - N mass differences-as originally derived by de Rujula, Georgi, and Glashow from the single gluon exchange-is obtained from the hadronic loop effects as well. This (and other) results are derived after taking into account a complete set of symmetry-related hadronic loops. Consideration of such a complete set of symmetry-related processes is shown to be crucial in restoring proper symmetry properties of the calculated spectrum. Towards Transport Joint Institute
Theory of Hadron Gases. STANISLAW for Nuclear Research, Dubna, USSR.
MRC~WCZY~SKI.
Laboratory
of High
Energies.
An important role of hadron resonances for determining the characteristics of hadron gases is argued. A kinetic theory model of hadron gas is developed. A classical. nonquantum, distribution function of a resonance is defined with the help of the profile function being an analog of the mass shell delta function of stable particles. The Boltzmann equation is generalized to include the resonance decay and resonance formation processes. To determine the unknown profile function, the transition rates are assumed to satisfy the bilateral normalization or the detailed balance condition. The protile function is expressed through the resonance formation cross section and the decay width. The H-theorem is proved, and it is shown that the form of the equilibrium distribution function of a resonance coincides with the one of a stable particle. Macroscopic equilibrium characteristics are studied. Significance of the resonance mass smearing effect is demonstrated. Operator
Quanti:ation of‘ Non-ahelian Gauge Theories in a Completely AND H. 0. GIROTTI. Instituto de Fisica. Universidade Federal Porto Alegre, RS, Brasil.
SIM~ES
Fired Axial Gauge. T. J. M. do Rio Grande do Sul, 90000
A consistent quantization of chromodynamics in a completely fixed axial gauge is carried out by using the Dirac bracket quantization procedure. The main results are: The translation of Dirac brackets into equal-time commutators is possible, without ambiguities, because of the absence of ordering problems. All equal-time commutators are compatible with constraints and gauge conditions holding as strong operator relations. All equal-time commutators are compatible with chromoelectric, chromomagnetic. and fermionic fields vanishing at spatial infinity. The colored gauge potentials A’,“, A ‘,U and A’.” are seen to develop a physically signiticant, although pure gauge, behavior at .? = iu, as required by the presence of a non-trivial topological content. Poincare invariance is satisfied without introducing in the Hamiltonian “extra” quantum mechanical potentials. The determinant of the Faddeev-Popov matrix does not depend upon the field variables.
527 0003-4916/86
$7.50
CopyrIght I(’ 1986 by Academic Press. Inc All rlghts of reproducuon ,n any form reserved
OF PHYSICS
Abstracts Buryon
168,
527-528
(1986)
of Papers
to Appear
in Future
Spectroscopy: Symmetries, Symmetry Breaking, and Hadronic Department of Theoretical Physics, Institute of Nuclear Physics, Krakow, Poland.
Issues
Loops. PI~TR Radzikowskiego
~ENCZYKOWSKI.
152. PL-3 I-342
The problem of hadronic loop effects in baryon spectroscopy is thoroughly discussed. It is argued that such effects very likely constitute the dominant contribution to the observed splitting and mixing pattern of the (56,O + ) and (70.1 ) baryon multiplets. In particular. this dominance is demonstrated in the original IsgurrKarl-Koniuk model of baryons, in which hadronic loops are shown to provide an explanation for at least 2/3 of the observed size of splittings, both for the ground-state and excited baryons. The unitarity-induced mixing angles in the (70,l~ )-multiplet are also shown to be in good agreement with experiment. For the ground-state baryons the formula relating Z - n and d - N mass differences-as originally derived by de Rujula, Georgi, and Glashow from the single gluon exchange-is obtained from the hadronic loop effects as well. This (and other) results are derived after taking into account a complete set of symmetry-related hadronic loops. Consideration of such a complete set of symmetry-related processes is shown to be crucial in restoring proper symmetry properties of the calculated spectrum. Towards Transport Joint Institute
Theory of Hadron Gases. STANISLAW for Nuclear Research, Dubna, USSR.
MRC~WCZY~SKI.
Laboratory
of High
Energies.
An important role of hadron resonances for determining the characteristics of hadron gases is argued. A kinetic theory model of hadron gas is developed. A classical. nonquantum, distribution function of a resonance is defined with the help of the profile function being an analog of the mass shell delta function of stable particles. The Boltzmann equation is generalized to include the resonance decay and resonance formation processes. To determine the unknown profile function, the transition rates are assumed to satisfy the bilateral normalization or the detailed balance condition. The protile function is expressed through the resonance formation cross section and the decay width. The H-theorem is proved, and it is shown that the form of the equilibrium distribution function of a resonance coincides with the one of a stable particle. Macroscopic equilibrium characteristics are studied. Significance of the resonance mass smearing effect is demonstrated. Operator
Quanti:ation of‘ Non-ahelian Gauge Theories in a Completely AND H. 0. GIROTTI. Instituto de Fisica. Universidade Federal Porto Alegre, RS, Brasil.
SIM~ES
Fired Axial Gauge. T. J. M. do Rio Grande do Sul, 90000
A consistent quantization of chromodynamics in a completely fixed axial gauge is carried out by using the Dirac bracket quantization procedure. The main results are: The translation of Dirac brackets into equal-time commutators is possible, without ambiguities, because of the absence of ordering problems. All equal-time commutators are compatible with constraints and gauge conditions holding as strong operator relations. All equal-time commutators are compatible with chromoelectric, chromomagnetic. and fermionic fields vanishing at spatial infinity. The colored gauge potentials A’,“, A ‘,U and A’.” are seen to develop a physically signiticant, although pure gauge, behavior at .? = iu, as required by the presence of a non-trivial topological content. Poincare invariance is satisfied without introducing in the Hamiltonian “extra” quantum mechanical potentials. The determinant of the Faddeev-Popov matrix does not depend upon the field variables.
527 0003-4916/86
$7.50
CopyrIght I(’ 1986 by Academic Press. Inc All rlghts of reproducuon ,n any form reserved