Negative Parity Baryon Decays in the 1/Nc Expansion
Negative Parity Baryon Decays in the 1/Nc Expansion

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Published: 2010

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The $1/N_c$ expansion of QCD provides a useful framework for phenomenological studies of both ground state and excited baryons. Here, we focus on its application to the excited baryon strong decays via emission of single pseudoscalar meson. The S- and D-wave decay amplitudes of the negative parity baryons in the $[70,1^-]$ of $SU(6)$ are analyzed to subleading order in $1/N_c$ and to first order in SU(3) symmetry breaking. In particular, the SU(3) symmetry breaking is studied in detail through SU(3) breaking decay operators and state mixing.

Decays of Negative Parity Non-strange Baryons in the 1/Nc Expansion
Decays of Negative Parity Non-strange Baryons in the 1/Nc Expansion

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Published: 2004

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The decays of non-strange negative parity baryons via the emission of single [pi] and [eta] mesons are analyzed in the framework of the 1/N{sub c} expansion. A basis of spin-flavor operators is established to that order, and with this basis the different partial wave decay amplitudes are obtained. The unknown effective coefficients are determined by fitting to the S- and D-wave partial widths as provided by the PDG. A full set of relations between widths that result at the leading order, i.e. order N{sub c0}, is given and tested with the data. The rather large errors of the input partial widths, that result from the often discrepant results for the resonance parameters from different analyses of the data, lead to a rather good fit at the leading order N{sub c0}. The next to leading order fit fails for that reason to pin down with satisfactory accuracy the effective sub leading effective constants.

Excited Baryon Decays in 1
Excited Baryon Decays in 1

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Published: 2007

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The decays of excited baryons are analyzed using the 1/Nc expansion of QCD. These studies are performed up to order 1/Nc, and include positive and negative parity states.

Analysis of 56-plet Positive Parity Baryon Decays in the 1/Nc Expansion
Analysis of 56-plet Positive Parity Baryon Decays in the 1/Nc Expansion

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Published: 2009

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The partial decay widths of positive parity baryons belonging to 56-plets of SU(6) are analyzed in the framework of the 1/Nc expansion. The channels considered are those with emission of a single pion, K or K-bar mesons, and the analysis is carried out to subleading order in 1/Nc and to first order in SU(3) symmetry breaking. The results for the multiplet [56,0+], to which the Roper resonance belongs, indicate a poor description at leading order, requiring large next to leading order corrections. For the multiplet [56,2+], the P-wave decays in the non-strange sector are well described at leading order and important SU(3) breaking corrections are necessary to describe transitions involving strangeness, on the other hand, the F-wave decays require the next to leading order corrections, which turn out to be however of natural magnitude.

Decays of Non-strange Positive Parity Excited Baryons in the 1
Decays of Non-strange Positive Parity Excited Baryons in the 1

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Published: 2005

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The decays of non-strange positive parity baryons via emission of a pseudo-scalar meson are studied in the framework of the 1/Nc expansion to order 1/Nc. In particular, the pionic decays of the l=0 Roper baryons and of the l=2 baryons in the mass interval 1680-1950 MeV are analyzed using the available partial decay widths. Decay widths by emission of an eta meson are shown to be suppressed by a factor 1/Nc2 with respect to the pionic ones.

The IVth International Conference on Quarks and Nuclear Physics
The IVth International Conference on Quarks and Nuclear Physics

Author: Antonio Dobado

Publisher: Springer Science & Business Media

Published: 2008-11-07

Total Pages: 615

ISBN-13: 3540725164

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The QNP series of international conferences on Quarks and Nuclear Physics is by now a well established and highly respected forum where the most recent developments in the field are discussed and communicated. QNP 2006 is the forth edition of this biennial meeting. Selected and refereed original contributions of QNP 2006 have been published in The European Physical Journal A - Hadrons and Nuclei (EPJ A), while the present proceedings book, in addition to reprinting the articles published in EPJ A, further includes all other contributions selected and accepted by the organizing committee for publication and archiving.

Large Nc Qcd 2004 - Proceedings Of The Workshop
Large Nc Qcd 2004 - Proceedings Of The Workshop

Author: Jose Luis Goity

Publisher: World Scientific

Published: 2005-08-04

Total Pages: 319

ISBN-13: 9814479896

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The large Nc limit plays a fundamental role in the study of non-abelian gauge theories such as quantum chromodynamics (QCD). Since its discovery in 1974 by 't Hooft, the 1/Nc expansion has provided crucial insights into the non-perturbative aspects of gauge theories. The expansion implemented at the effective theory level is one of the fundamental tools currently in use in hadronic physics; there are important effects and relations that follow from the 1/Nc expansion, which held remarkably well in the real world with Nc= 3. The 1/Ncexpansion also plays a central role in the recently discovered connections between non-Abelian gauge and string theories, promising new ways to analyze the non-perturbative domain of gauge theories.This volume contains contributions from leading theorists and covers the recent developments in the 1/Nc expansion in QCD. The topics addressed include confinement, AdS/CFT correspondence and the string-QCD connection, topology in large Nc, lattice QCD, and a variety of applications to mesons and baryons.

Global Analysis Of The Negative Parity Non-Strange Baryons In The 1/N{sub C} Expansion
Global Analysis Of The Negative Parity Non-Strange Baryons In The 1/N{sub C} Expansion

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Published: 2014

Total Pages: 28

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A global study of the negative parity non-strange baryon observables is performed in the framework of the 1/N{sub c} expansion. Masses, partial decay widths and photo-couplings are simultaneously analyzed. A main objective is to determine the composition of the spin 1/2 and 3/2 nucleon states, which come in pairs and involve two mixing angles which can be determined and tested for consistency by the mentioned observables. The issue of the assignment of those nucleon states to the broken SU(4) X O(3) mixed-symmetry multiplet is studied in detail, with the conclusion that the assignment made in the old studies based on the non-relativistic quark model is the preferred one. In addition, the analysis involves an update of the input data with respect to previous works.

The 1/Nc Expansion in Baryons
The 1/Nc Expansion in Baryons

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Published: 2010

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The 1/N_c expansion in baryons is discussed with two applications, namely baryon masses and partial decay widths. These applications provide the basic insights on the utility of the expansion.

Analysis of Negative Parity Baryon Photoproduction Helicity Amplitudes in the 1
Analysis of Negative Parity Baryon Photoproduction Helicity Amplitudes in the 1

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Published: 2007

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We study the photoproduction helicity amplitudes of negative parity baryons in the context of the 1/Nc expansion of QCD. A complete analysis to next-to-leading order is carried out. The results show sub-leading effects to be within the magnitude expected from the $1/N_c$ power counting. They also show significant deviations from the quark model, in particular the need for 2-body effects.