Two-pronged events in ${}_{}{}^4{}_{}{}^{}\mathrm{He}$-$p$ collisions at 8.56 GeV/c ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ incident momentum

We have studied ${}_{}{}^4{}_{}{}^{}\mathrm{He}$-$p$ collisions at a ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ incident momentum of 8.56 GeV/c using the 1 m Dubna bubble chamber. The $p$— ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ elastic scattering, the coherent $p+{}_{}{}^4{}_{}{}^{}\mathrm{He}\to N+{}_{}{}^4{}_{}{}^{}\mathrm{He}+\pi$ production and the breakup reaction $p+{}_{}{}^4{}_{}{}^{}\mathrm{He}\to p+{}_{}{}^3{}_{}{}^{}\mathrm{He}+n$ have been investigated. Cross sections and production features are presented. From the breakup reaction, subsamples of events in which a ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ or a $n$ appear as spectators were selected. These events were used to study the virtual $\mathrm{pn}\to \mathrm{pn}$ and $p+{}_{}{}^3{}_{}{}^{}\mathrm{He}\to p+{}_{}{}^3{}_{}{}^{}\mathrm{He}$ scattering.

NUCLEAR REACTIONS ${}_{}{}^4{}_{}{}^{}\mathrm{He}(p, p)$, ($p, p{\pi }^0$), ($p, n{\pi }^{+}$), ($p, \mathrm{pn}$), $E=1.41\mathrm{}$ GeV; bubble chamber; measured $\sigma$; deduced $n(p, p)$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}(p, p)$.