Speaker
Derek Leinweber
(University of Adelaide)
Description
Recent developments on the determination of the spin-1/2 spectrum of
the nucleon in full QCD are presented. Our focus is on the PACS-CS
2+1 flavour configurations made available through the ILDG. Using
correlation matrix techniques, in which a wide variety of
gauge-invariant Gaussian-smeared fermion-propagator sources and sinks
are considered, excited states are determined. We consider several
correlation matrices of various sizes, each constructed with a
different set of basis interpolators, in order to demonstrate the
invariance of the eigenstates on the basis choice. Of particular
interest is the approach to the elusive Roper resonance and the nature
of the level crossing between the lowest-lying even- and odd-parity
eigenstates as the quark masses approach their physical values. We
report new results in full QCD which differ significantly from that
observed in the quenched approximation, providing further insight into
QCD dynamics.
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Primary author
Derek Leinweber
(University of Adelaide)
Co-authors
Prof.
Anthony Williams
(University of Adelaide)
Mr
Md. Selim Mahbub
(University of Adelaide)
Mr
Peter Moran
(University of Adelaide)
Dr
Waseem Kamleh
(University of Adelaide)
