2011/11/02 by S. Prelovsek, Prelovsek, S., C. B. Lang +5
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #hep-lat
paper · pdf · doi:10.48550/arxiv.1111.0409
7 pages, presented at The XXIX International Symposium on Lattice Field Theory - Lattice 2011, July 10-16, 2011, Squaw Valley, Lake Tahoe, California
arxiv created 2011/11/02 · arxiv updated 2011/11/03
We extract the P-wave pi-pi phase shift for five values of pion relative momenta, which gives information on the rho resonance. The Breit-Wigner formula describes the pi-pi phase shift dependence nicely and we extract m(rho)=792(7)(8) MeV and the coupling gρππ=5.13(20) at our mpi=266 MeV. We extract the P-wave scattering length al=1ππ=0.082(10)(3) fm3 from the state with the lowest pion relative momenta. We also determine the S-wave rho-pi phase shift for two values of relative momenta, which provides parameters of the lowest axial resonance a1(1260). Using the Breit-Wigner fit we extract m(a1)=1.44(4) GeV and the coupling ga1ρπ=1.1(3) GeV. From the lowest state we also extract the rho-pi scattering length al=0ρπ=0.23(12) fm for our mpi. The simulation is performed using one Nf=2 ensemble of gauge configurations with clover-improved Wilson quarks. The phase shifts are determined from the lowest two energy-levels, which are obtained by the variational analysis with a number of quark-antiquark and meson-meson interpolators. The correlation functions are calculated using the distillation method with the Laplacian Heaviside (LapH) smearing of quarks.