出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We extract the P-wave pp phase shift for five values of pion relative momenta, which gives information on the r resonance. The Breit-Wigner formula describes the pp phase shift dependence nicely and we extract mr = 792(7)(8) MeV and the coupling grpp = 5.13(20) at our mp = 266 MeV. We extract the P-wave scattering length app l=1 = 0.082(10)(3) fm3 from the state with the lowest pion relative momenta. We also determine the S-wave rp 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 ma1 = 1.44(4) GeV and the coupling ga1rp = 1.1(3) GeV. From the lowest state we also extract the rp scattering length arp l=0 = 0.23(12) fm for our mp . The simulation is performed using one Nf = 2 ensemble of gauge configurations with cloverimproved 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 mesonmeson interpolators. The correlation functions are calculated using the distillation method with the Laplacian Heaviside (LapH) smearing of quarks.
