A method to extract fs/fd and similar ratios from exclusive semi-leptonic B decays yields a 7% uncertainty constraint using existing measurements.
Precision Corrections to Dispersive Bounds on Form Factors
7 Pith papers cite this work. Polarity classification is still indexing.
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abstract
We present precision corrections to dispersion relation bounds on form factors in bottom hadron semileptonic decays and analyze their effects on parameterizations 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 parameterizations. 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 B --> D l nu and B --> D^* l nu can be described with 3% or smaller precision using only the overall normalization and one unknown parameter. A similar one-coefficient parameterization of one of the Lambda_b --> Lambda_c l nu form factors, together with heavy quark symmetry relations valid to order 1/m^2, describes the differential baryon decay rate in terms of one unknown parameter and the phenomenologically interesting quantity (\bar Lambda)_Lambda \approx M_{Lambda_b} - m_b. 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 B --> D^*l nu and B --> D l nu data to the improved one-parameter expansion.
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Computes pQCD form factors for B_c to D(*) transitions via lattice inputs and heavy quark symmetry, then predicts branching fractions and angular observables for semileptonic and rare dilepton decays.
Introduces a reconstructible angular distribution for B to D* tau nu decays via tau to lepton chain to extract new physics parameters, projecting 5-6% sensitivities from simulation and lattice form factors.
Angular observables in B→D(*)ℓν decays can distinguish Lorentz structures of new physics contributions fitted to measured R(D(*)) ratios, even when those ratios agree with the Standard Model.
A combined fit to B to D(*) l nu data yields R^{±0}=1.062(19) as evidence for isospin violation in Υ(4S) decays and branching fractions up to 1.6σ larger than prior averages, addressing inconsistencies in V_cb extractions.
The Heavy Flavour Averaging Group reports updated world averages for b-hadron, c-hadron, and tau-lepton properties including branching fractions, lifetimes, mixing, CP violation, and CKM elements.
citing papers explorer
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Extracting production fractions of $b$ hadrons from exclusive semi-leptonic decays
A method to extract fs/fd and similar ratios from exclusive semi-leptonic B decays yields a 7% uncertainty constraint using existing measurements.
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Study of Form Factors and Observables in $B_c^- \rightarrow \bar{D}^{(*)0}\ell^-\bar{\nu}_{\ell}$ and $B_c^- \rightarrow D^{(*)-}\ell^+\ell^-$ decays
Computes pQCD form factors for B_c to D(*) transitions via lattice inputs and heavy quark symmetry, then predicts branching fractions and angular observables for semileptonic and rare dilepton decays.
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New physics searches via angular distributions of $ \bar{B} \to D^* (\to D \pi) \tau (\to \ell \nu_\tau \bar{\nu}_\ell) \bar{\nu}_\tau$ decays
Introduces a reconstructible angular distribution for B to D* tau nu decays via tau to lepton chain to extract new physics parameters, projecting 5-6% sensitivities from simulation and lattice form factors.
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Lepton Flavor Universality tests through angular observables of $\overline{B}\to D^{(\ast)}\ell\overline{\nu}$ decay modes
Angular observables in B→D(*)ℓν decays can distinguish Lorentz structures of new physics contributions fitted to measured R(D(*)) ratios, even when those ratios agree with the Standard Model.
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$\bar B\to D^{(*)}\ell\bar \nu$ Branching Ratios and Evidence for Isospin Breaking in $\Upsilon(4S)$ Decays
A combined fit to B to D(*) l nu data yields R^{±0}=1.062(19) as evidence for isospin violation in Υ(4S) decays and branching fractions up to 1.6σ larger than prior averages, addressing inconsistencies in V_cb extractions.
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Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2023
The Heavy Flavour Averaging Group reports updated world averages for b-hadron, c-hadron, and tau-lepton properties including branching fractions, lifetimes, mixing, CP violation, and CKM elements.
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