Zusammenfassung
We determine the ground state and first excited state masses of singly and doubly charmed spin 1/2 and 3/2 baryons with positive and negative parity. Configurations with N-f = 2 + 1 nonperturbatively improved Wilson-clover fermions were employed, with the same quark action also being used for the valence quarks, including the charm. The spectrum is calculated for pion masses in the range M-pi ...
Zusammenfassung
We determine the ground state and first excited state masses of singly and doubly charmed spin 1/2 and 3/2 baryons with positive and negative parity. Configurations with N-f = 2 + 1 nonperturbatively improved Wilson-clover fermions were employed, with the same quark action also being used for the valence quarks, including the charm. The spectrum is calculated for pion masses in the range M-pi similar to 259-460 MeV at a lattice spacing a similar to 0.075 fm. Finite volume effects are studied comparing lattices with two different linear spatial extents (1.8 fm and 2.4 fm). The physical point is approached from the SU(3) limit keeping the flavor averaged light quark mass fixed. The baryon masses are extrapolated using expansions in the strange-light quark mass difference. Most particles fall into the expected SU(3) multiplets with well-constrained extrapolations, the exceptions having a possibly more complex internal structure. Overall agreement is found with experiment for the masses and splittings of the singly charmed baryons. As part of the calculation an analysis of the lower lying charmonium, D and D-s spectra was performed in order to assess discretization errors. The gross spectra are reproduced, including the D-s0*, D-s1 and D-1 mesons, while at this single lattice spacing hyperfine splittings come out 10-20 MeV too low.
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