Probing of compact baryonic configurations in nuclei in $A(p,{\bar p})X$   reactions and antiproton formation length in nuclear matter
  Inclusive cross sections $\sigma^A=Ed^3{\sigma(X,P_t^2)/d^3p}$ of antiproton and negative pion production on Be, Al, Cu and Ta targets hit by 10 GeV protons were measured at the laboratory angles of 10.5$^{\circ}$ and 59$^{\circ}$. Antiproton cross sections were obtained in both kinematically allowed and kinematically forbidden regions for antiproton production on a free nucleon. The antiproton cross section ratio as a function of the longitudinal variable $X$ exhibits three separate plateaus which gives evidence for the existence of compact baryon configurations in nuclei-small-distance scaled objects of nuclear structure. Comparability of the measured cross section ratios with those obtained in the inclusive electron scattering off nuclei suggests a weak antiproton absorption in nuclei. Observed behavior of the cross section ratios is interpreted in the framework of a model considering the hadron production as a fragmentation of quarks (antiquarks) into hadrons. It has been established that the antiproton formation length in nuclear matter can reach the magnitude of 4.5 fm. 
Yu. T. Kiselev, V. A. Sheinkman, A. V. Akindinov, M. M. Chumakov, A.   N. Martemyanov, V. A. Smirnitsky, Yu. V. Terekhov and...
nucl-ex hep-ex