33 research outputs found

    Properties of "35" Spin-(5/2) Baryon Resonances in a Model with Broken SU(3)

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    We investigate the properties of a set of J =(5/2)^+ resonances appearing in a 35-dimensional representation of SU(3), as proposed by Abers, Balázs, and Hara. A simple dynamical calculation gives an estimate for the mass differences within the supermultiplet. The matrix elements for the SU(3) allowed decays into meson plus resonance are given in terms of one parameter and the SU(3)-violating matrix elements for decay into meson plus baryon are given by two parameters

    General S-Matrix Methods for Calculation of Perturbations on the Strong Interactions

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    Recently, the authors proposed an on-the-mass-shell, S-matrix method for computing the effects of small perturbations on the masses and coupling constants of strongly interacting particles. In the present paper, the method is generalized to the multichannel case. The use of group-theoretical techniques in reducing the complexity of the method is described in detail

    Some general features of the bootstrap theory of octet enhancement

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    Some general features of the boostrap theory of octet enhancement, which can be understood without detailed calculations, are discussed. These features include: (i) the connection of this theory to the vector-mixing theory of symmetry breaking advocated by Sakurai, and to the tadpole theory of Coleman and Glashow; (ii) an understanding of why it is representations of low multiplicity that are dynamically emphasized in symmetry breaking; (iii) a demonstration that the theory remains valid when a number of assumptions made in previous applications are dropped

    Chew-Low model for Regge-pole couplings

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    The couplings of a meson trajectory α(t) to the baryon octet B and the decimet Δ are studied in the Chew-Low model. The model predicts ratios, though not absolute magnitudes, for SU(3)-symmetric couplings of the 0- octet Π, 1- octet V, and 2+ octet T trajectories at the small t of either sign for which static kinematics is applicable. For non-spin-flip, the V and T trajectories are predicted to couple to B̅ B like F+1 / 4D, independent of t. For magnetic dipole terms, the Π, V, and T trajectories are all predicted to couple to B̅ B like D+2 / 3F, and to Δ̅ B with the same relative strength as the 0- octet, independent of t. The electric quadrupole couplings of the Π, V, and T trajectories are predicted to be small, independent of t. These results generally agree with existing data, improve Sawyer's explanation of the Johnson-Treiman relations, provide a partial justification of the recent suggestion that V and T couplings are similar, predict that T exchange produces large spin flips, and predict certain ratios such as dσ / dt(π-p→π0n) / (dσ / dt)(π+p→π0N*++)

    Baryon-Pion Couplings from Large-N QCD

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    We derive a set of consistency conditions for the pion-baryon coupling constants in the large-N limit of QCD. The consistency conditions have a unique solution which are precisely the values for the pion-baryon coupling constants in the Skyrme model. We also prove that non-relativistic SU(2Nf)SU(2N_f) spin-flavor symmetry (where NfN_f is the number of light flavors) is a symmetry of the baryon-pion couplings in the large-N limit of QCD. The symmetry breaking corrections to the pion-baryon couplings vanish to first order in 1/N1/N. Consistency conditions for other couplings, such as the magnetic moments are also derived.Comment: (12 pages, 2 figs, uses harvmac and uufiles), UCSD/PTH 93-1

    Representation of local current algebra at infinite momentum

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    It has been proposed (1,2) that the charge operators Fi and Fi5 of the vector and axial-vector current octets may obey the algebra of SU(3)×SU(3) exactly, to all orders in the strong interactions, under equal-time commutation
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