Composite particle production in high-energy reactions and size of production source

Abstract

Production cross sections of composite particles at ${\ensuremath{\bigominus}}_{\mathrm{lab}}=90\ifmmode^\circ\else\textdegree\fi{}$ (the target-rapidity region) from 12-GeV proton reaction on nuclear targets have been measured. The particle spectra were analyzed with the coalescence model, and the radius of the production source was deduced to be ${R}_{0}^{\mathrm{rms}}=1.7\ifmmode\pm\else\textpm\fi{}0.5$ fm. The radius is significantly smaller than the nuclear radii, and is independent on the target nuclear mass within uncertainties.NUCLEAR REACTIONS: Al, Cu, Ag, Ta $(p,x)p$, $d$, $^{3}\mathrm{He}$, $^{4}\mathrm{He}$, ${E}_{p}=12$ GeV; measured $\ensuremath{\sigma}(\frac{p}{A},\ensuremath{\bigominus}=90\ifmmode^\circ\else\textdegree\fi{})$; deduced size of emitting source.