2013/06/03 by William Detmold, C.-J. David Lin, C. -J. David Lin +2
Mathematics · Physics and Astronomy · #Algorithm #High-Energy Particle Collisions Research #Lambda #Lattice (music) #Lattice QCD #Mathematics #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Quark #hep-lat #hep-ph
paper · pdf · doi:10.1103/physrevd.88.014512
published as Phys. Rev. D 88, 014512 (2013) · 14 pages, 5 figures
arxiv created 2013/06/03 · openalex publication_date 2013/07/23 · arxiv updated 2013/07/24 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We present a lattice QCD calculation of form factors for the decay \ensuremathΛb\ensuremath→p\ensuremathμ^\ensuremath-\ensuremathν_\ensuremathμ, which is a promising channel for determining the Cabibbo-Kobayashi-Maskawa matrix element |Vub| at the Large Hadron Collider. In this initial study we work in the limit of static b quarks, where the number of independent form factors reduces to two. We use dynamical domain-wall fermions for the light quarks, and perform the calculation at two different lattice spacings and at multiple values of the light-quark masses in a single large volume. Using our form factor results, we calculate the \ensuremathΛb\ensuremath→p\ensuremathμ^\ensuremath-\ensuremathν_\ensuremathμ differential decay rate in the range 14 GeV2\ensuremath≤q2\ensuremath≤qmax2, and obtain the integral \ensuremath∫_14 GeV2^qmax2[d\ensuremathΓ/dq2]dq2/|Vub|2=15.3\ifmmode±\else\textpm\fi4.2 ps^\ensuremath-1. Combined with future experimental data, this will give a novel determination of |Vub| with about 15% theoretical uncertainty. The uncertainty is dominated by the use of the static approximation for the b quark, and can be reduced further by performing the lattice calculation with a more sophisticated heavy-quark action.