Precision corrections to dispersive bounds on form factors

C. Glenn Boyd, Benjamín Grinstein, Richard Lebed

Research output: Contribution to journalArticle

127 Citations (Scopus)

Abstract

We present precision corrections to dispersion relation bounds on form factors in bottom hadron semileptonic decays and analyze their effects on parametrizations derived from these bounds. We incorporate QCD two-loop and nonperturbative corrections to the two-point correlator, consider form factors whose contribution to decay rates is suppressed by lepton mass, and implement more realistic estimates of truncation errors associated with the parametrizations. We include higher resonances in the hadronic sum that, together with heavy quark symmetry relations near zero recoil, further tighten the sum rule bounds. Utilizing all these improvements, we show that each of the six form factors in B̄→Dℓν̄ and can be described with 3% or smaller precision using only the overall normalization and one unknown parameter. A similar one-coefficient parametrization of one of the Λb→Λcℓν̄ from factors, together with heavy quark symmetry relations valid to order 1/m2, describes the differential baryon decay rate in terms of one unknown parameter and the phenomenologically interesting quantity Λ̄Λ≈MΛb-mb. We discuss the validity of slope-curvature relations derived by Caprini and Neubert, and present weaker, corrected relations. Finally, we present sample fits of current experimental B̄→D*ℓν̄ and B̄→Dℓν̄ data to the improved one-parameter expansion.

Original languageEnglish (US)
Pages (from-to)6895-6911
Number of pages17
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume56
Issue number11
StatePublished - Dec 1 1997
Externally publishedYes

Fingerprint

Form Factors
form factors
Parametrization
decay rates
Decay Rate
quarks
Unknown Parameters
Quarks
truncation errors
symmetry
correlators
Symmetry
sum rules
leptons
baryons
Truncation Error
Sum Rules
Correlator
Baryon
Dispersion Relation

ASJC Scopus subject areas

  • Mathematical Physics
  • Physics and Astronomy(all)
  • Nuclear and High Energy Physics

Cite this

Precision corrections to dispersive bounds on form factors. / Boyd, C. Glenn; Grinstein, Benjamín; Lebed, Richard.

In: Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol. 56, No. 11, 01.12.1997, p. 6895-6911.

Research output: Contribution to journalArticle

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