Abstract
We calculate the cross section of a pion diffraction dissociation in two jets with large transverse momenta originating from a hard gluon exchange between the pion constituents. To the leading logarithmic accuracy tin energy), the contribution coming From small transverse separations between the quark and the antiquark in the pion acquires the expected factorized form, the longitudinal momentum ...
Abstract
We calculate the cross section of a pion diffraction dissociation in two jets with large transverse momenta originating from a hard gluon exchange between the pion constituents. To the leading logarithmic accuracy tin energy), the contribution coming From small transverse separations between the quark and the antiquark in the pion acquires the expected factorized form, the longitudinal momentum distribution of the jets being proportional to the pion distribution amplitude. The hard gluon exchange can in this case be considered as a part of the unintegrated gluon distribution. Beyond the leading logarithms tin energy) this proportionality does not hold. Moreover, the collinear factorization appears to be broken by the end-point singularities. Remarkably enough, the longitudinal momentum distribution of the jets for the non-factorizable contribution is calculable, and turns out to be the same as for the factorizable contribution with the asymptotic pion distribution amplitude. (C) 2001 Elsevier Science B.V. All rights reserved.
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