2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/48188Central pseudoscalar production in $pp$ scattering is suppressed at small values of $Q_\perp$. Such a behavior is expected if the production occurs through the fusion of two vectors. We argue that an extension of the experiment could probe the gluon contribution to the proton spin.6 pages. Talk given at the Quarks'98 conference in Suzdal, Russia, May 1998High Energy Physics - Phenomenologytext