Color evaporation and elastic [ípsilon] photoproduction at DESY HERA

• Autor(a) principal: Gay Ducati, Maria Beatriz
• Data de Publicação: 2002
• Outros Autores: Goncalves, Victor Paulo Barros, Mariotto, Cristiano Brenner
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/104011
• topic: Modelo de cor; Interações elétron-próton; Fotoproducao de mesons; Interações foton-próton; Pomerons

The diffractive photoproduction of vector mesons is usually described by considering the two-gluon (Pomeron) exchange, the nondiagonal parton distributions, and the contribution of the real part to the cross section. In this Brief Report we analyze the diffractive photoproduction of the Y at DESY HERA using an alternative model, the color evaporation model (CEM), where the cross section is simply determined by the boson-gluon cross section and an assumption for the production of the colorless state. We verify that, as in the J/Ψ case, the HERA data for this process can be well described by the CEM. Moreover, we propose the analysis of the ratio R=σY /σJ/Ψ to discriminate between the different approaches.