NeutralB-meson mixing from unquenched lattice QCD with domain-wall light quarks and staticbquarks

2010/01/12 by Conrado Albertus, C. Albertus, Yasumichi Aoki +17
Physics and Astronomy · #Chiral perturbation theory #High-Energy Particle Collisions Research #Lattice (music) #Lattice QCD #Lattice constant #Meson #Particle physics #Particle physics theoretical and experimental studies #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Quark #hep-lat

paper · pdf · doi:10.1103/physrevd.82.014505

published as Phys.Rev.D82:014505,2010 · 60 pages, 9 figures

arxiv created 2010/01/12 · openalex publication_date 2010/07/20 · arxiv updated 2014/11/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We demonstrate a method for calculating the neutral B-meson decay constants and mixing matrix elements in unquenched lattice QCD with domain-wall light quarks and static b-quarks. Our computation is performed on the ``2+1'' flavor gauge configurations generated by the RBC and UKQCD Collaborations with a lattice spacing of a\ensuremath≈0.11 fm (a^\ensuremath-1=1.729 GeV) and a lattice spatial volume of approximately (1.8 fm)³. We simulate at three different light sea quark masses with pion masses down to approximately 430 MeV, and extrapolate to the physical quark masses using a phenomenologically-motivated fit function based on next-to-leading order heavy-light meson SU(2) chiral perturbation theory. For the b-quarks, we use an improved formulation of the Eichten-Hill action with static link-smearing to increase the signal-to-noise ratio. We also improve the heavy-light axial current used to compute the B-meson decay constant to O(\ensuremathα_spa) using one-loop lattice perturbation theory. We present initial results for the SU(3)-breaking ratios f_B_s/f_B_d and \ensuremathξ=f_B_s√B_B_s/f_B_d√B_B_d, thereby demonstrating the viability of the method. For the ratio of decay constants, we find f_B_s/f_B_d=1.15(12) and for the ratio of mixing matrix elements, we find \ensuremathξ=1.13(12), where in both cases the errors reflect the combined statistical and systematic uncertainties, including an estimate of the size of neglected O(1/m_b) effects.

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