Recent Developments in Heavy Quark and Quarkonium.

Mehen, T.

Technical Information Center Oak Ridge Tennessee

关键词: Quarkonium;    Quarks;    Cross sections;    Baryons;    Distribution;   

RP-ID  :  DE2005836843

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Recent measurements of J/(psi) production in e(sup +)e(sup -) colliders pose a challenge to the NRQCD factorization theorem for quarkonium production. Discrepancies between leading order calculations of color-octet contributions and the momentum distribution of J/(psi) observed by Belle and BaBar are resolved by resumming large perturbative and nonperturbative corrections that are enhanced near the kinematic endpoint. The large cross sections for J/(psi) + c + (bar c) and double quarkonium production remain poorly understood. Nonperturbative effects in fixed-target hadroproduction of open charm are also discussed. Large asymmetries in the production of charm mesons and baryons probe nonperturbative corrections to the QCD factorization theorem. A power correction called heavy-quark recombination can economically explain these asymmetries with a few universal parameters.