2014/07/03 by Damir Becirevic, Damir Bečirević, Becirevic, Damir +11
Engineering · Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #Superconducting Materials and Applications #hep-ex #hep-lat #hep-ph
paper · pdf · doi:10.48550/arxiv.1407.1019
33 pages, 5 figs [all available experimental data included!]
openalex publication_date 2014/07/03 · arxiv created 2014/10/17 · arxiv updated 2014/10/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
After improving the knowledge about residua of the semileptonic form factor at its first two poles we show that f+Dπ(q2) is not saturated when compared with the experimental data. To fill the difference we approximate the rest of discontinuity by an effective pole and show that the data can be described very well with the position of the effective pole larger than the next excitation in the spectrum of D^∗ state. The results of fits with experimental data also suggest the validity of superconvergence which in the pole models translates to a vanishing of the sum of residua of the form factor at all poles. A similar discussion in the case of B→ πℓν_ℓ leads to the possibility of extracting \vert Vub\vert, the error of which appears to be dominated by gB^∗ Bπ, which can be nowadays computed on the lattice. In evaluating the residua of the form factors at their nearest pole we needed the vector meson decay constants fD^∗ and fB^∗, which we computed by using the numerical simulations of QCD on the lattice with N\rm f=2 dynamical quarks. We obtain, fD^∗/fD=1.208(27) and fB^∗/fB=1.051(17).