Absorptive effects in exclusive diffraction dissociation

Abstract

We report a detailed investigation of absorptive corrections in Good-Walker and Deck-type models for production of three-body final states in diffraction dissociation processes. Beginning with an input elastic diffractive amplitude which is central in impact parameter, the model generates naturally a peripheral structure for inelastic diffraction. For $\mathrm{pp}\to \left(n{\pi }^{+}\right)p$ and $\mathrm{np}\to \left(p{\pi }^{-}\right)p$, at small excitation mass, absorptive effects create significant dip structure in the production momentum transfer distribution $\frac{d\sigma }{\mathrm{dt}\mathrm{dM}}$ near $t\simeq -0.3\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$, in agreement with data from Fermilab and the CERN ISR. Similar behavior is predicted for $\pi p\to A_{1}p$ and $\mathrm{Kp}\to \mathrm{Qp}$, but at larger $\mathrm{}\left|t\right|\mathrm{}$. Distributions in other kinematic variables are much less affected by absorption. We provide a decomposition of the total $\frac{d\sigma }{\mathrm{dt}\mathrm{dM}}$ into partial cross sections for the various angular momentum and helicity states which comprise the low-mass diffractive enhancement. The $s$-wave amplitude is dominant in both absorbed and unabsorbed models. A pronounced mass-slope correlation is present both in the total $\frac{d\sigma }{\mathrm{dt}\mathrm{dM}}$ and in the $s$-wave part alone.