Nuclear Reactions at High Energy

Abstract

In the quark model, nuclei ($B\le 2$) have exotic quantum numbers. Given a nuclear reaction in which certain quantum numbers are exchanged, what is the scattering amplitude at high energies, in the GeV region? Does it have Regge behavior? Is it dual? Are there multibaryon resonances? In this context we present a general survey of all high-energy nuclear reactions - mainly those involving light nuclei. For $B=0\mathrm{}$ exchange reactions, like $\pi d\to \pi d$ and ${\pi }^{-}h\to {\pi }^{0}t$ ($h\equiv {}_{}{}^3{}_{}{}^{}\mathrm{He}, t={}_{}{}^3{}_{}{}^{}\mathrm{H}$), there is the impulse and rescattering (Glauber) model. For $B=1\mathrm{}$ exchange we discuss the one-pion-exchange (OPE) model for $\mathrm{pp}\to d{\pi }^{+}$, $\mathrm{pd}\to \mathrm{dp}$, and $\gamma d\to \mathrm{pn}$, and the "knock-on" model for $\mathrm{pd}\to {\pi }^{+}t$, $\mathrm{dd}\to \mathrm{tp}$, $\mathrm{dh}\to \mathrm{hd}$, $\gamma h\to \mathrm{pd}$, and $\gamma \alpha \to \mathrm{pt}$. In the case of $B=2\mathrm{}$ exchange we examine the impulse and rescattering diagrams for $\pi d\to d\pi$, $\gamma d\to d{\pi }^0$, and $\gamma d\to d\gamma$, and use the OPE model to calculate cross sections for $\mathrm{pd}\to t\pi$, $\mathrm{pt}\to \mathrm{tp}$, and $\mathrm{ph}\to \mathrm{hp}$. Briefly considered are: (1) backward elastic scattering from heavy nuclei ($\mathrm{pA}\to \mathrm{Ap}$) and (2) inclusive nuclear reactions such as ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}+A\to {}_{}{}^6{}_{}{}^{}\mathrm{Li}+\mathrm{anything}$ and $\mathrm{pA}\to \overline{d}+\mathrm{anything}$. We postulate that in general nuclear reactions have Regge behavior, but are not dual, because so far there are no exotic multibaryon resonances. Nuclear reactions appear to be completely dominated by anomalous singularities, whereas ordinary nonexotic hadron reactions appear to be dominated by normal singularities and poles.