Bottomonium Decay Matrix Elements from Lattice QCD with Two Light Quarks

Abstract

We calculate the long-distance matrix elements for the decays of the Upsilon (eta_b) and chi_b (h_b) states in lattice QCD with two flavors of light dynamical quarks. We relate the lattice matrix elements to their continuum counterparts through one-loop order in perturbation theory. In the case of the leading S-wave matrix element, we compare our result with a phenomenological value that we extract from the experimental leptonic decay rate by using the theoretical expression for the decay rate, accurate through relative order alpha_s. Whereas estimates of the leading S-wave matrix element from quenched QCD are 40--45% lower than the phenomenological value, the two-flavor estimate of the same matrix element is close to the phenomenological value. Extrapolating to the real world of 2+1 light flavors, we find that this matrix element is approximately 6% higher than the phenomenological value, but that the phenomenological value lies within our error bars. We also compute the color-singlet and color-octet matrix elements for P-wave decays. We find the value of the color-singlet matrix element for 2+1 flavors to be approximately 70% larger than the quenched value and the value of the color-octet matrix element for 2+1 flavors to be approximately 40% larger than the quenched value.

29 pages, REVTEX, 4 Postscript figures, more extensive discussion of fitting procedures and uncertainties, minor additional revisions and corrections

Cited by in corpus (31)

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• Observation potential for eta_b at the Tevatron
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• Electromagnetic quarkonium decays at order v^7
• Relativistic Correction to J/psi and Upsilon Pair Production
• The Photon Spectrum in Upsilon Decays
• Relativistic Correction to Color Octet J/psi Production at Hadron Colliders
• Inclusive production of $J/\psi$, $\psi (2S)$, and ${\rm Y}$ states in pNRQCD
• Spin correlations and velocity-scaling in color-octet NRQCD matrix elements
• Inclusive Charm Production in chi_b Decays
• $\overline{\mathrm{MS}}$ renormalization of $S$-wave quarkonium wavefunctions at the origin
• Inclusive Charm Production in Upsilon(nS) Decay
• Leptonic widths of heavy quarkonia: S-Wave QCD/NRQCD matching coefficients for the electromagnetic vector annihilation current at O(alpha_s v^2)
• Heavy Quarks on the Lattice
• Overview of Non-Relativistic QCD
• Average speed and its powers $v^n$ of a heavy quark in quarkonia
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• NRQCD: Fundamentals and Applications to Quarkonium Decay and Production
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• Heavy Quarkonium Physics from Effective Field Theories
• Overview of charmonium decays and production from Non-Relativistic QCD
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