16 research outputs found

    A first estimate of triply heavy baryon masses from the pNRQCD perturbative static potential

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    Within pNRQCD we compute the masses of spin-averaged triply heavy baryons using the now-available NNLO pNRQCD potentials and three-body variational approach. We focus in particular on the role of the purely three-body interaction in perturbation theory. This we find to be reasonably small and of the order 25 MeV Our prediction for the Omega_ccc baryon mass is 4900(250) in keeping with other approaches. We propose to search for this hitherto unobserved state at B factories by examining the end point of the recoil spectrum against triple charm.Comment: 18 figures, 21 page

    Nucleon resonances in the fourth resonance region

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    Nucleon and Δ\Delta resonances in the fourth resonance region are studied in a multichannel partial-wave analysis which includes nearly all available data on pion- and photo-induced reactions off protons. In the high-mass range, above 1850\,MeV, several alternative solutions yield a good description of the data. For these solutions, masses, widths, pole residues and photo-couplings are given. In particular, we find evidence for nucleon resonances with spin-parities JP=1/2+...7/2+J^P=1/2^+...7/2^+. For one set of solutions, there are four resonances forming naturally a spin-quartet of resonances with orbital angular momentum L=2 and spin S=3/2 coupling to J=1/2,...,7/2J=1/2,...,7/2. Just below 1.9\,GeV we find a spin doublet of resonances with JP=1/2J^P=1/2^- and 3/23/2^-. Since a spin partner with JP=5/2J^P=5/2^- is missing at this mass, the two resonances form a spin doublet which must have a symmetric orbital-angular-momentum wave function with L=1. For another set of solutions, the four positive-parity resonances are accompanied by mass-degenerate negative-parity partners -- as suggested by the conjecture of chiral symmetry restoration. The possibility of a JP=1/2+,3/2+J^P=1/2^+, 3/2^+ spin doublet at 1900\,MeV belonging to a 20-plet is discussed.Comment: 16 page

    Relativistic quark-diquark model of baryons with a spin-isospin transition interaction: Non-strange baryon spectrum and nucleon magnetic moments

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    The relativistic interacting quark-diquark model of baryons, recently developed, is here extended introducing in the mass operator a spin-isospin transition interaction. This refined version of the model is used to calculate the non-strange baryon spectrum. The results are compared to the present experimental data. A preliminary calculation of the magnetic moments of the proton and neutron is also presented
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