Single-spin asymmetry in pion production in polarized proton–proton collisions and odderon

Abstract

Single-spin asymmetry appears due to the interference of single and double gluon exchanges between protons. A heavy fermion model is used to describe the jet production in the interaction of the gluon with the proton implying further averaging over its mass. As usual in one-spin correlations, the imaginary part of the double gluon exchange amplitude plays the relevant role. The asymmetry in the inclusive set-up with the pion tagged in the fragmentation region of the polarized proton does not depend on the centre of mass energy in the limits of its large values. The lowest order radiative corrections to the polarized and unpolarized contributions to the differential cross sections are calculated in the leading logarithmic approximation. In general, a coefficient of logarithm of the ratio of cms energy to the pion mass depends on the transversal momentum of the pion. This ratio of the lowest order contribution to the asymmetry may be interpreted as the partial contribution to the odderon intercept. The ratio of the relevant contributions in the unpolarized case can be associated with the partial contribution to the pomeron intercept. The numerical results given for the model describe the jet as heavy fermion decay fragments.