The B → π l ν semileptonic form factor from three - flavor lattice QCD : A model - independent determination
نویسنده
چکیده
We calculate the form factor f+(q 2) for B-meson semileptonic decay in unquenched lattice QCD with 2+1 flavors of light sea quarks. We use Asqtad-improved staggered light quarks and a Fermilab bottom quark on gauge configurations generated by the MILC Collaboration. We simulate with several light quark masses and at two lattice spacings, and extrapolate to the physical quark mass and continuum limit using heavy-light meson staggered chiral perturbation theory. We then fit the lattice result for f+(q 2) simultaneously with that measured by the BABAR experiment using a parameterization of the form factor shape in q2 which relies only on analyticity and unitarity in order to determine the CKM matrix element |Vub|. This approach reduces the total uncertainty in |Vub| by combining the lattice and experimental information in an optimal, model-independent manner. We find a value of |Vub| × 103 = 3.38 ± 0.35. PACS numbers: 12.15.Hh, 12.38.Gc, 13.20.He
منابع مشابه
ν semileptonic form factor from three - flavor lattice QCD : A
We calculate the form factor f+(q 2) for B-meson semileptonic decay in unquenched lattice QCD with 2+1 flavors of light sea quarks. We use Asqtad-improved staggered light quarks and a Fermilab bottom quark on gauge configurations generated by the MILC Collaboration. We simulate with several light quark masses and at two lattice spacings, and extrapolate to the physical quark mass and continuum ...
متن کاملLattice Determination of Semileptonic Form Factors
Computation of the semileptonic form factors for B → π(ρ)lν, B → D(∗)lν and B → K(∗)l+l− decays is a key to the determination of the CKM matrix elements |Vub|, |Vcb| and |Vts| . In this report, I review the recent results by lattice QCD methods. I will mainly focus on the semileptonic decay B → πlν, because lattice calculations in various approaches are already at hand [ 1, 2, 3, 4, 5] and beca...
متن کاملThe Rare Decay K + → π + νν̄ at the Next - to - Next - to - Leading Order in QCD
We calculate the complete next-to-next-to-leading order QCD correction of the charm quark contribution to the branching ratio for the rare decay K + → π + ν ¯ ν in the standard model. The inclusion of these O(αs) contributions leads to a significant reduction of the theoretical uncertainty from ±10.1% down to ±2.4% in the relevant parameter Pc, implying the left over scale uncertainties in B(K ...
متن کاملPredictions on B → πl̄ν l , D → πl̄ν l and D → Kl̄ν l from QCD Light - Cone Sum Rules
The f+ form factors of the B → π, D → π and D → K transitions are calculated from QCD light-cone sum rules (LCSR) and used to predict the widths and differential distributions of the exclusive semileptonic decays B → πl̄νl, D → πl̄νl and D → Kl̄νl, where l = e, μ. The current theoretical uncertainties are estimated. The LCSR results are found to agree with the results of lattice QCD calculations a...
متن کاملThe Semileptonic Decays B → πlν and D → πlν from Lattice QCD Aida
We present a lattice QCD calculation of the form factors and differential decay rates for semileptonic decays of the heavy-light mesons B and D to the final state πlν. The results are obtained with three methodological improvements over previous lattice calculations: a matching procedure that reduces heavyquark lattice artifacts, the first study of lattice-spacing dependence, and the introducti...
متن کامل