Precision pion-proton elastic differential cross sections at energies spanning the Δ resonance

Abstract

A precision measurement of absolute π±p elastic differential cross sections at incident pion laboratory kinetic energies from Tπ= 141.15 to 267.3 MeV is described. Data were obtained detecting the scattered pion and recoil proton in coincidence at 12 laboratory pion angles from 55° to 155° for π+p and six angles from 60° to 155° for π-p. Single arm measurements were also obtained for π+p energies up to 218.1 MeV, with the scattered π+ detected at six angles from 20° to 70°. A flat-walled, supercooled liquid hydrogen target and solid CH2 targets were used. The data are characterized by small uncertainties, ∼ 1-2 % statistical and ∼ 1-1.5 % normalization. The reliability of the cross section r..