Hadroproduction of quarkonium in fixed-target experiments

Journal Article · Thu Aug 01 04:00:00 EDT 1996 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.54.2005· OSTI ID:286409

Beneke, M ^[1]; Rothstein, I Z ^[2]

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1. Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)
2. University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States)

We analyze charmonium and bottomonium production at fixed-target experiments. We find that the inclusion of color octet production channels removes large discrepancies between experiment and the predictions of the color singlet model for the total production cross section. Furthermore, including octet contributions accounts for the observed direct to total {ital J}/{psi} production ratio. As found earlier for photoproduction of quarkonia, a fit to fixed-target data requires smaller color octet matrix elements than those extracted from high-{ital p}{sub {ital t}} production at the Fermilab Tevatron. We argue that this difference can be explained by systematic differences in the velocity expansion for collider and fixed-target predictions. While the color octet mechanism thus appears to be an essential part of a satisfactory description of fixed-target data, important discrepancies remain for the {chi}{sub {ital c}1}/{chi}{sub {ital c}2} production ratio and {ital J}/{psi} ({psi}{sup {prime}}) polarization. These discrepancies, as well as the differences between pion- and proton-induced collisions, emphasize the need for including higher twist effects in addition to the color octet mechanism. {copyright} {ital 1996 The American Physical Society.}

• Research Organization: Stanford Linear Accelerator Center
• DOE Contract Number: AC03-76SF00515
• OSTI ID: 286409
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 3 Vol. 54; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BOTTOMONIUM
CHARMONIUM
CHI1-3510 MESONS
CHI2-3555 MESONS
COLOR
FERMILAB TEVATRON
J PSI-3097 MESONS
MATRIX ELEMENTS
OCTET MODEL
PARTICLE PRODUCTION
PHOTOPRODUCTION
POLARIZATION
QUARKONIUM
TOTAL CROSS SECTIONS
TRANSVERSE MOMENTUM