Exclusive and semi-inclusive strangeness and charm production in π N and NN reactions.

Using the Quark-Gluon Strings Model (QGSM) combined with Regge phenomenology we consider the reactions π-→ K0Λ and π-p→ D Λ+c which are dominated by the contributions of the K* and D* Regge trajectories, respectively. The spin structure of the amplitudes is described by introducing Reggeized Born terms. It is found that the existing data for the reaction π-p →K 0;Λ are in reasonable agreement with the model predictions. To describe the absolute values of the cross-sections it is necessary to introduce also suppression factors which can be related to absorption corrections. Furthermore, assuming the SU(4) symmetry to hold for Regge residues and the universality of absorption corrections we calculate the cross-section of the reaction π-p→D-Λ+C. Employing the latter results from π-p reactions we then estimate the contributions of the pion exchange mechanism to the cross-sections of the reactions NN → NKA and NN → NDACand compare them with the contributions of the K and D exchanges. We find that the NN reactions are dominated not by pion exchange but by K and D exchanges, respectively. Moreover, assuming the SU(4) symmetry to hold approximately for the coupling constants gND&lambdac= gNKA we analyze also the production of leading Λc-hyperons in the reaction NN ↠ΛcX. It is shown that the non-perturbative mechanism should give an essential contribution to theΛc yield for x &Ge;0.5. [ABSTRACT FROM AUTHOR]