P-wave resonances in positron-hydrogen scattering

P-wave resonances in positron-hydrogen scattering are investigated by using the method of complex-coordinate rotation. Elaborate Hylleraas-type wavefunctions with up to N=1120 terms are used in the present investigation. A resonance below the hydrogen N=2 threshold is found at E=-0.254 112 Ryd with a half width of 1/2 Gamma =8.1*10^-6 Ryd. Three resonances below the positronium N=2 threshold are also located. The lowest member is determined to lie at E=-0.148 181 Ryd, with a half width of 1/2 Gamma =0.000 297 Ryd. Error estimates for the resonance parameters are also given.