[Triumf-seminars] TRIUMF Theory Seminar today at 13:00

[TRIUMF Seminars]

Date/Time: Tue 2012-02-14 at 13:00

Location:  Theory Room         

Speaker:   Derek Leinweber (U Adelaide)

Title:     Discovering the Mass Spectrum of the Nucleon and Lambda in Lattice QCD

Abstract: I will present recent developments in revealing the mass spectrum of
the nucleon and Lambda in simulations of QCD on a space-time lattice.
Focusing on the first 8 to 12 states, new methods for tracking the
quark-mass dependence of these states will be examined.  Of particular
interest, due to their possible exotic structure, is the first
positive-parity excitation of the nucleon, the Roper resonance, and
the first negative-parity excitation of the Lambda, the Lambda(1405).
Using the PACS-CS collaboration 2+1 flavour gauge fields made
available via the International Lattice DataGrid (ILDG), we are able
to present results for these states at quark masses similar to those
of Nature.  Through comparisons with earlier results from quenched QCD
simulations, the importance of sea-quark loop contributions to these
states is revealed.  On a final note, visualizations of the wave
function of the Roper will be presented and compared with early
constituent quark model predictions.





______________________________

Subscription information available at http://admin.triumf.ca/netdata/seminars/list