Spin alignment in the production of charm and/or bottom vector mesons via heavy quark fragmentation

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.50.3181· OSTI ID:7253172

Cheung, K ^[1]; Yuan, T C ^[2]

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1. Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208 (United States)
2. Davis Institute for High Energy Physics, Department of Physics, University of California, Davis, California 95616 (United States)

We calculate the process-independent fragmentation functions for a [ital [bar b]] antiquark to fragment into longitudinally and transversely polarized [ital B][sub [ital c]][sup *] ([sup 3][ital S][sub 1]) mesons to leading order in the QCD strong coupling constant. In the special case of equal quark mass, we recover previous results for the fragmentation of [ital c][r arrow][psi] and [ital b][r arrow][Upsilon]. Various spin asymmetry parameters are defined as measures of the relative population of the longitudinally and transversely polarized vector meson states. In the heavy quark mass limit [ital m][sub [ital b]][r arrow][infinity], our polarized fragmentation functions obey heavy quark spin symmetry, we therefore apply them as a model to describe the fragmentation of charm and bottom quarks into heavy-light mesons like [ital D][sup *] and [ital B][sup *]. The spin asymmetry parameter, [alpha]([ital z]), is consistent with the existing CLEO data for [ital D][sup *]. The scaling behavior of [l angle][ital z][r angle] is studied in detail. We find excellent agreement between the predictions of [l angle][ital z][r angle] from our fragmentation functions and the experimental data for [ital D][sup *] and [ital B][sup *] from the CERN LEP, CLEO, and ARGUS detectors. Finally, we also point out that the spin asymmetry depends significantly on the transverse momentum [ital p][sub [perpendicular]] of the vector mesons relative to the fragmentation axis.

• DOE Contract Number: FG02-91ER40684
• OSTI ID: 7253172
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 50:5; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

662240* -- Models for Strong Interactions-- (1992-)
662420 -- Properties of Mesons & Meson Resonances-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANGULAR MOMENTUM
ASYMMETRY
BEAUTY PARTICLES
BOSONS
CHARM PARTICLES
COUPLING CONSTANTS
ELEMENTARY PARTICLES
FIELD THEORIES
FRAGMENTATION
HADRONS
LINEAR MOMENTUM
MESONS
PARTICLE PRODUCTION
PARTICLE PROPERTIES
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
SPIN
TRANSVERSE MOMENTUM
VECTOR MESONS