QCD space-time analysis of quarkonium formation and evolution in hadronic collisions

Journal Article · Sun Feb 01 04:00:00 EST 1998 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.57.1895· OSTI ID:567137

Geiger, K ^[1]

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1. Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States)

The production of heavy quarkonium as Q{bar Q} bound states in hadron-hadron collisions is considered within the framework of a space-time description, combining parton-cascade evolution with a coalescence model for bound-state formation. The {open_quotes}hard{close_quotes} production of the initial Q{bar Q}, directly or via gluon fragmentation and including both color-singlet and color-octet contributions, is calculated from the perturbative QCD cross sections. The subsequent development of the Q{bar Q} system is described within a space-time generalization of the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi parton-evolution formalism in position and momentum space. The actual formation of the bound states is accomplished through overlap of the Q{bar Q} pair and a spectrum of quarkonium wave functions. This coalescence can only occur after sufficient gluon radiation reduces the Q{bar Q} relative velocity to a value commensurate with the nonrelativistic kinematics of these bound systems. The presence of gluon participants in the cascade then is both necessary and leads to the natural inclusion of both color-singlet and color-octet mechanisms. The application of this approach to pp (p{bar p}) collisions from {radical} (s) = 30 GeV{endash}14 TeV reveals very decent agreement with available data from the CERN Intersecting Storage Rings and Fermilab Tevatron{emdash}without the necessity of introducing fit parameters. Moreover, production probabilities are calculated for a complete spectrum of charmonium and bottomonium states, with the relative significance compared to open charm (bottom) production. An analysis of the space-time development is carried through which sheds light on the relevance of gluon radiation and color structure, suggesting a corresponding experimental investigation. {copyright} {ital 1998} {ital The American Physical Society}

• OSTI ID: 567137
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 3 Vol. 57; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BOTTOMONIUM
BOUND STATE
CHARMONIUM
FERMILAB TEVATRON
FRAGMENTATION
GLUONS
HADRON-HADRON INTERACTIONS
OCTET MODEL
PARTICLE PRODUCTION
PARTON MODEL
PARTONS
PERTURBATION THEORY
QUANTUM CHROMODYNAMICS
QUARKONIUM
SPACE-TIME
WAVE FUNCTIONS