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Phys. Rev. D 57, 1449–1486 (1998)

1/Nc expansion for excited baryons

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Dan Pirjol
Department of Physics, Technion-Israel Institute of Technology, 32000 Haifa, Israel

Tung-Mow Yan
Floyd R. Newman Laboratory of Nuclear Studies, Cornell University, Ithaca, New York 14853

Received 5 August 1997; published in the issue dated 1 February 1998

We derive consistency conditions which constrain the possible form of the strong couplings of the excited baryons to the pions. The consistency conditions follow from requiring the pion-excited baryon scattering amplitudes to satisfy the large-Nc Witten counting rules and are analogous to consistency conditions used by Dashen, Jenkins, and Manohar and others for s-wave baryons. The consistency conditions are explicitly solved, giving the most general allowed form of the strong vertices for excited baryons in the large-Nc limit. We show that the solutions to the large-Nc consistency conditions coincide with the predictions of the nonrelativistic quark model for these states, extending the results previously obtained for the s-wave baryons. The 1/Nc corrections to these predictions are studied in the quark model with arbitrary number of colors Nc.

© 1997 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevD.57.1449
DOI:
10.1103/PhysRevD.57.1449
PACS:
11.15.Pg, 13.75.Gx, 14.20.-c