2011/09/07 by Heechang Na, Christine T. H. Davies, C. T. H. Davies +7 · 2 citations
Physics and Astronomy · #Fermilab #High-Energy Particle Collisions Research #Lepton #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Quark #Semileptonic decay #Valence (chemistry) #hep-lat #hep-ph
paper · pdf · doi:10.1103/physrevd.84.114505
published as PhysRevD.84.114505,2011 · 7 pages, 7 figures, and 4 tables
arxiv created 2011/09/07 · openalex publication_date 2011/12/27 · arxiv updated 2012/01/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a new calculation of the D\ensuremath→\ensuremathπ, l\ensuremathν semileptonic form factor f+^D\ensuremath→\ensuremathπ(q2) at q2=0 based on ``highly improved staggered quark'' charm and light valence quarks on MILC Nf=2+1 lattices. Using methods developed recently for HPQCD's study of D\ensuremath→K, l\ensuremathν decays, we find f+^D\ensuremath→\ensuremathπ(0)=0.666(29). This signifies a better than factor 2 improvement in errors for this quantity compared to previous calculations. Combining the new result with CLEO-c branching fraction data, we extract the Cabibbo-Kobayashi-Maskawa matrix element |Vcd|=0.225(6)exp(10)lat, where the first error comes from experiment and the second from theory. With a total error of \ensuremath∼5.3% the accuracy of the direct determination of |Vcd| from D semileptonic decays has become comparable to (and in good agreement with) that from neutrino scattering. We also check for second row unitarity using this new |Vcd|, HPQCD's earlier |Vcs|, and |Vcb| from the Fermilab Lattice and MILC collaborations. We find |Vcd|2+|Vcs|2+|Vcb|2=0.976(50), improving on the current PDG2010 value.