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Excited hadrons in n_f=2 QCD

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 Added by Christian B. Lang
 Publication date 2009
  fields
and research's language is English




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The chirally improved (CI) fermion action allows us to obtain results for pion masses down to 320 MeV on (in lattice units) comparatively small lattices with physical extent of 2.4 fm. We use differently smeared quarks sources to build sets of several interpolators. The variational method then leads to excellent ground state masses for most mesons and baryons. The excited state signals weaken in quality towards smaller quark masses. In particular the excited baryons come out too high.



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Results of hadron spectroscopy with two dynamical mass-degenerate chirally improved quarks are presented. Three ensembles with pion masses of 322(5), 470(4) and 525(7) MeV, lattices of size 16^3 times 32, and lattice spacings close to 0.15 fm are investigated. We discuss the possible appearance of scattering states, considering masses and eigenvectors. Partially quenched results in the scalar channel suggest the presence of a 2-particle state, however, in most channels we cannot identify them. Where available, we compare to results from quenched simulations using the same action.
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