Determination of the π±p→π±π+n cross section near threshold

The total cross section for the pi(-) p --> pi(-)pi(+) n reaction has been measured at incident pion kinetic energies of 200, 190, 184, and 180 MeV. In addition, the pi(+) p --> pi(+) pi(+) n reaction was measured at 200 and 184 MeV. A fit of the cross sections by heavy baryon chiral perturbation theory yields values of 8.5 +/- 0.6(m(pi)(-3)) and 2.5 +/- 0.1(m(pi)(-3)) for the reaction matrix elements A(10) and A(32), which correspond to values for the s-wave isospin-0 and isospin-2 pi-pi scattering lengths of a(0) = 0.23 +/- 0.08(m(pi)(-1)) and a(2) = -0.031 +/- 0.008(m(pi)(-1)), respectively.