Determination of the π±p→π±π+n Cross Section Near Threshold

Publisher Website

23 February 1998

journal article
research article
Published by American Physical Society (APS) in Physical Review Letters

Vol. 80 (8) , 1597-1600
https://doi.org/10.1103/physrevlett.80.1597

Abstract

The total cross section for the

π^{-} p \to π^{-} π^{+} n

reaction has been measured at incident pion kinetic energies of 200, 190, 184, and 180 MeV. In addition, the

π^{+} p \to π^{+} π^{+} 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 \pm 0.6 (m_{π}^{- 3})

and

2.5 \pm 0.1 (m_{π}^{- 3})

for the reaction matrix elements

A_{10}

and

A_{32}

, which correspond to values for the

s

-wave isospin-0 and isospin-2

π - π

scattering lengths of

a_{0} = 0.23 \pm 0.08 (m_{π}^{- 1})

and

a_{2} = - 0.031 \pm 0.008 (m_{π}^{- 1})

, respectively.

Keywords

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