2007/10/31 by S. P. Baranov, Antoni Szczurek, A. Szczurek
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.77.054016
published as Phys.Rev.D77:054016,2008 · 26 pages, 20 figures, the text was slightly modified, the title was modified, more discussion was added, one figure was removed, one was added
arxiv created 2008/01/18 · openalex publication_date 2008/03/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Inclusive cross sections for J/\ensuremathψ production in proton-proton collisions were calculated in the kt-factorization approach for the Relativistic Heavy Ion Collider (RHIC) energy. Several mechanisms were considered, including direct color-singlet mechanism, radiative decays of \ensuremathχc mesons, decays of \ensuremathψ^\ensuremath', open-charm-associated production of J/\ensuremathψ as well as weak decays of B mesons. Different unintegrated gluon distributions from the literature were used. We find that radiative \ensuremathχc decays and direct color-singlet contributions constitute the dominant mechanism of J/\ensuremathψ production. These processes cannot be consistently treated within a collinear-factorization approach. The results are compared with recent RHIC data. The new precise data at small transverse momenta impose stringent constraints on unintegrated gluon distribution functions (UGDFs). Some UGDFs are inconsistent with the new data. The Kwieci\ifmmode \acuten\else 'n\fiski UGDFs give the best description of the data. In order to verify the mechanism suggested here we propose J/\ensuremathψ--jet correlation measurement and an independent measurement of \ensuremathχc meson production in \ensuremathπ+\ensuremathπ^\ensuremath- and/or K+K^\ensuremath- decay channels. Finally, we address the issue of J/\ensuremathψ spin alignment.