Leading-particle effects in the spectra of Λc and $$\bar \Lambda _c$$ produced in Σ− p, pp, and π − p interactions

The spectra of leading and nonleading charmed baryons (Λc and $$\bar \Lambda _c$$ ) and the asymmetries between these spectra measured in Σ− A, π − A, and pA collisions at p L =600 GeV/c in the E781 experiment are simultaneously described within the framework of the Quark-Gluon String Model (QGSM). It is shown that the charmed baryon spectra can be fitted by QGSM curves calculated with the parameter of diquark fragmentation, $$a_f^{\Lambda _c } = 0.006$$ . It was found in this experiment that the asymmetry between the spectra of Λc and $$\bar \Lambda _c$$ in π − A collisions is of nonzero value. It might be described in our model only assuming that the string junction is transferred from target proton into the kinematical region of pion projectile fragmentation.