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

[TRIUMF Seminars]

Date/Time: Tue 2018-09-11 at 13:00

Location:  Theory Room         

Speaker:   Matthias Lutz (GSI Darmstadt)

Title:     From hadrons at unphysical quark masses to coupled-channel reaction dynamics in the laboratory

Abstract: In this talk I discuss recent progress on how to study QCD in its regime where non-perturbative structures emerge. Such a program is illustrated at the hand of two systems. First we consider the quark-mass dependence of the baryon masses in their flavor octet and decuplet ground states. Here, any significant progress requires an improved understanding of the role played by the strange quarks. A quantitative description of the baryon masses on all available QCD lattice ensembles is possible. In turn an accurate set of low-energy constants is established, which, moreover, is found compatible with the hierarchy of sum rules as predicted by QCD with a large number of colors (N_c). The implications of this set on the baryon sigma terms is eluded on.

The second case we discuss are meson systems that involve a charm quark. A quantitative reproduction of the masses of the D mesons in the J^P = 0^- and J^P = 1^- flavor triplet ground states on all available QCD lattice ensembles is achieved. The low-energy constants are used in a coupled-channel approach and predictions for the s-wave scattering phase-shifts and in-elasticity parameters are made. Such results are scrutinized against first QCD lattice computations of the \pi D scattering phase shifts by HSC at unphysical quark masses. A striking dependence on the choice of quark masses is predicted. At physical quark masses a clear signal of a member of an exotic flavor sextet multiplet in the \eta D invariant mass distribution is foreseen.



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