Universal scaling behaviour of the transverse polarization for inclusively produced hyperons in hadron-hadron collisions

Abstract

Experimental data on the polarization of hyperons, inclusively produced in hadron-hadron collisions, have been analyzed. It is shown that the existing data can be described by a function of transverse momentum (Pt) and two scaling variables Xa+-=(Xr +- Xf)/2: P_H=A^alpha*F(Pt)[G(Xa+ -x2) -sigma*G(Xa- +x2)]. The function G(x) is proportional to sin[omega*(x -x1)]/omega, which results for some reactions in an oscillation of P_H as a function of Xf. The "omega", as well as the magnitude and the sign of the hyperon polarization depend on quark composition of hadrons participating in a reaction. The atomic weight dependence of the Lambda hyperon polarization is characterized by the parameter alpha = -0.16|Xf|. There is an analogy between the scaling properties of the hyperon polarization and the analyzing power (An) in hadron production reactions. This new scaling law allows one to predict hyperon polarization for reactions and kinematic regions, yet unexplored in experiments and to confront these predictions with future experiments and various models.