214 research outputs found
Hyperfine effects in charmed baryons
Hadron masses are calculated in quenched lattice QCD with a fermion action of
the D234 type on an anisotropic lattice. Hyperfine splittings for singly
charmed baryons are found to be in agreement with expectations from the quark
model and with a magnitude slightly larger than experimental values. Masses of
doubly charmed baryons are also calculated and compared to a variety of model
calculations. Hyperfine splittings in doubly charmed baryons are found to be
slightly smaller than in singly charmed states.Comment: 12 pages, Latex, one postscript figur
More about excited bottomonium radiative decays
Radiative decays of bottomonium are revisited, focusing on contributions from
higher-order relativistic effects. The leading relativistic correction to the
magnetic spin-flip operator at the photon vertex is found to be particularly
important. The combination of O(v^6) effects in the nonrelativistic QCD action
and in the transition operator moves previous lattice results for excited
Upsilon decays into agreement with experiment.Comment: 4 pages, 3 figures, published versio
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