$KN$ Sigma Terms, Strangeness in the Nucleon, and DA$Φ$NE

Abstract

Expanded and updated version of a talk originally presented at ``IVth Int. Symp. on Pion--Nucleon Physics and the Structure of the Nucleon'', Bad Honnef, 9--13 September 1991, originally published in $πN$ Newletter 6 (1992) 21--32. Table of contents: 1. Introduction. 2. $σ$--terms and ``measurements'' of the strange--quark scalar density of the nucleon. 3. Methods of extrapolation to $q^2 = t = ω^2 = 0$: a subjective review: 3.1. The ``improved'' Altarelli--Cabibbo--Maiani method. 3.2. The Fubini--Furlan analysis of meson-nucleus scattering lengths. 3.2. The ``unitarized'' version of the Cheng--Dashen theorem. 4. Capabilities for a $\bar{K}N$--scattering experiment at DA$Φ$NE. 5. ``Envoi''.