# Diffractive incoherent vector meson production off protons: a quark model approach to gluon fluctuation effects

The European Physical Journal C, Apr 2019

Fluctuations play an important role in diffractive production of vector mesons. It was in particular recently suggested, based on the Impact-Parameter dependent Saturation model (IPSat), that geometrical fluctuations triggered by the motion of the constituent quarks within the protons could explain incoherent diffractive processes observed at HERA. We propose a variant of the IPSat model which includes spatial and symmetry correlations between constituent quarks, thereby reducing the number of parameters needed to describe diffractive vector meson production to a single one, the size of the gluon cloud around each valence quark. The application to $$J/\varPsi$$, $$\rho$$ and $$\phi$$ diffractive electron and photon production cross sections reveal the important role of geometrical fluctuations in incoherent channels, while other sources of fluctuations are needed to fully account for electroproduction of light mesons, as well as photo production of $$J/\varPsi$$ mesons at small momentum transfer.

This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1140%2Fepjc%2Fs10052-019-6826-0.pdf

Marco Claudio Traini, Jean-Paul Blaizot. Diffractive incoherent vector meson production off protons: a quark model approach to gluon fluctuation effects, The European Physical Journal C, 2019, 327, DOI: 10.1140/epjc/s10052-019-6826-0