Spin Alignment in the Production of Vector Mesons with Charm and/or Beauty via Heavy Quark Fragmentation

Abstract

We calculate the process-independent fragmentation functions for a $\bar{b}$ antiquark to fragment into longitudinally and transversely polarized $B_c^{\ast }$ (${}^3{S}_1$) 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 $c\to \psi$ and $b\to {\rm Y}$. 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 $m_b\to \infty$ our polarized fragmentation functions obey heavy quark spin symmetry, we therefore apply them as a model to describe the fragmentation of charm and bottom into heavy-light mesons like $D^{\ast }$ and $B^{\ast }$. The spin asymmetry parameter, $\alpha (z)$, is consistent with the existing CLEO data for $D^{\ast }$. The scaling behavior of $⟨z⟩$ is studied in detail. We find excellent agreement between the predictions of $⟨z⟩$ from our fragmentation functions and the experimental data for $D^{\ast }$ and $B^{\ast }$ from the LEP, CLEO, and ARGUS detectors. Finally, we also point out that the spin asymmetry depends significantly on the transverse momentum $p_{\perp }$ of the vector mesons relative to the fragmentation axis.

32 pages, 8 figures (not included but will send upon request), standard LaTeX file, Report # NUHEP-TH-94-7 and UCD-94-4

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• Mesons with Beauty and Charm: Spectroscopy
• Z^0 Decay into Charmonium via Charm Quark Fragmentation
• Perturbative QCD Fragmentation Functions for $B_c$ and $B_c^{\ast }$ Production
• Production, Decay, and Polarization of Excited Heavy Hadrons
• Heavy Quark Fragmentation into Heavy Mesons
• $B_c$ Mesons Production at Hadron Colliders by Heavy Quark Fragmentation
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Cited by in corpus (10)

• Perturbative QCD Fragmentation Functions as a Model for Heavy-Quark Fragmentation
• Production of Heavy Quarkonium in High Energy Colliders
• Gluon fragmentation into polarized charmonium
• Inclusive B-Meson Production in e^+ e^- and p p-bar Collisions
• Perturbative QCD Fragmentation Functions for Production of P-wave Mesons with Charm and Beauty
• Hadronic Production of S-wave and P-wave Charmed Beauty Mesons via Heavy Quark Fragmentation
• Transverse Momentum Distributions of Heavy Hadrons and Polarized Heavy Quarks
• Continuum Charged $D^{\ast }$ Spin Alignment at $sqrts$ = 10.5 GeV
• Helicity Probabilities For Heavy Quark Fragmentation Into Excited Mesons
• Understanding the $e^{+}{e}^{-}\to D^{(\ast )+}{D}^{(\ast )-}$ processes observed by Belle