2007/02/28 by Zhi-Guo He, Ying Fan, Kuang-Ta Chao · 4 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex #hep-ph
paper · pdf · doi:10.1103/physrevd.75.074011
published as Phys.Rev.D75:074011,2007 · Version to appear in PRD. In the summary an explicit statement added: "for the J/ψeta_c cross section the relativistic correction alone gives an enhancement factor of 1.7 while the combination of relativistic correction with QCD radiative correction results in a much larger enhancement factor of 9". One reference added. A few typos corrected
arxiv created 2007/04/07 · openalex publication_date 2007/04/16 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
In order to clarify the puzzling problems in double-charm production, relativistic corrections at order v2 to the processes e+e^\ensuremath-\ensuremath→J/\ensuremathψ+\ensuremathηc and e+e^\ensuremath-\ensuremath→J/\ensuremathψ+cc at B factories are studied in nonrelativistic quantum chromodynamics. The short-distance parts of production cross sections are calculated perturbatively, while the long-distance matrix elements are estimated from J/\ensuremathψ and \ensuremathηc decays up to errors of order v4. Our results show that the relativistic correction to the exclusive process e+e^\ensuremath-\ensuremath→J/\ensuremathψ+\ensuremathηc is significant, which, when combined together with the next-to-leading-order \ensuremathαs corrections, could resolve the large discrepancy between theory and experiment; whereas for the inclusive process e+e^\ensuremath-\ensuremath→J/\ensuremathψ+cc the relativistic correction is tiny and negligible. The physical reason for the above difference between exclusive and inclusive processes largely lies in the fact that in the exclusive process the relative momentum between quarks in charmonium substantially reduces the virtuality of the gluon that converts into a charm quark pair, but this is not the case for the inclusive process, in which the charm quark fragmentation c\ensuremath→J/\ensuremathψ+c is significant, and QCD radiative corrections can be more essential.