#### Abstract

The present paper is based on 378 $\Lambda -p$ elastic scattering events in the incident-momentum region 120-320 $\frac{\mathrm{MeV}}{c}$. Differential and total cross sections have been measured in several momentum intervals and found to be consistent with predominantly $S$-wave scattering. No significant indication for the existence of a low-energy $\Lambda -p$ resonance has been found. Using the effective-range approximation, the four scattering parameters ${a}_{s}$, ${a}_{t}$, ${r}_{s}$, and ${r}_{t}$ were evaluated with and without further assumptions on the $\Lambda -p$ interaction properties. Best values obtained from the four-parameter fit were ${a}_{s}=-1.8\mathrm{}$, ${a}_{t}=-1.6\mathrm{}$, ${r}_{s}=2.8\mathrm{}$, and ${r}_{t}=3.3\mathrm{}$ F. A likelihood-function mapping procedure is used to describe the large and strongly correlated errors of these values.

- Received 6 May 1968

DOI:https://doi.org/10.1103/PhysRev.173.1452

©1968 American Physical Society