54 research outputs found

    Spin-Flavor Structure of Large N Baryons

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    The spin-flavor structure of large N baryons is described in the 1/N expansion of QCD using quark operators. The complete set of quark operator identities is obtained, and used to derive an operator reduction rule which simplifies the 1/N expansion. The operator reduction rule is applied to the axial currents, masses, magnetic moments and hyperon non-leptonic decay amplitudes in the SU(3)SU(3) limit, to first order in SU(3)SU(3) breaking, and without assuming SU(3)SU(3) symmetry. The connection between the Skyrme and quark representations is discussed. An explicit formula is given for the quark model operators in terms of the Skyrme model operators to all orders in 1/N1/\N for the two flavor case.Comment: 36 pages, 2 eps figures, uses revte

    Chiral doublers of heavy-light baryons

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    We discuss the consequences of the chiral doubling scenario for baryons built of heavy and light quarks. In particular, we use the soliton description for baryons, demonstrating why each heavy-light baryon should be accompanied by the opposite parity partner. Our argumentation holds both for ordinary baryons and for exotic heavy pentaquarks which are required by the symmetries of QCD to appear in parity doublets, seperated by the mass shift of the chiral origin. Interpreting the recently observed by BaBaR, CLEO and Belle charmed mesons with assignment (0+,1+)(0^+,1^+) as the chiral partners of known DD and D∗D^* mesons, allows us to estimate the parameters of the mesonic effective lagrangian, and in consequence, estimate the masses of ground states and excited states of both parities. In particular, we interpret the state recently reported by the H1 experiment at HERA as a chiral partner Θ~c0(3099)\tilde{\Theta}_c^0(3099) of yet undiscovered ground state pentaquark Θc0(2700)\Theta_c^0(2700).Comment: 10 pages, in v2 some typos corrected, references adde

    Experimental progress in positronium laser physics

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