Neutral B meson mixing in unquenched lattice QCD
- Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States)
- Department of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)
- Laboratory of Elementary Particle Physics, Cornell University, Ithaca, New York 14853 (United States)
- Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA (United Kingdom)
We study B{sub d} and B{sub s} mixing in unquenched lattice QCD employing the MILC Collaboration gauge configurations that include u, d, and s sea quarks based on the improved staggered quark (AsqTad) action and a highly improved gluon action. We implement the valence light quarks also with the AsqTad action and use the nonrelativistic NRQCD action for the valence b quark. We calculate hadronic matrix elements necessary for extracting Cabibbo-Kobayashi-Maskawa matrix elements from experimental measurements of mass differences {delta}M{sub d} and {delta}M{sub s}. We find {xi}{identical_to}f{sub B{sub s}}{radical}(B-circumflex{sub B{sub s}})/f{sub B{sub d}}{radical}(B-circumflex{sub B{sub d}})=1.258(33), f{sub B{sub d}}{radical}(B-circumflex{sub B{sub d}})=216(15) MeV, and f{sub B{sub s}}{radical}(B-circumflex{sub B{sub s}})=266(18) MeV. We also update previous results for decay constants and obtain f{sub B{sub d}}=190(13) MeV, f{sub B{sub s}}=231(15) MeV, and f{sub B{sub s}}/f{sub B{sub d}}=1.226(26). The new lattice results lead to updated values for the ratio of Cabibbo-Kobayashi-Maskawa matrix elements |V{sub td}|/|V{sub ts}| and for the standard model prediction for Br(B{sub s}{yields}{mu}{sup +}{mu}{sup -}) with reduced errors. We determine |V{sub td}|/|V{sub ts}|=0.214(1)(5) and Br(B{sub s}{yields}{mu}{sup +}{mu}{sup -})=3.19(19)x10{sup -9}.
- OSTI ID:
- 21308534
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 80, Issue 1; Other Information: DOI: 10.1103/PhysRevD.80.014503; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
B MESONS
B S MESONS
COMPUTERIZED SIMULATION
CONFIGURATION
D QUARKS
FORECASTING
GLUONS
KOBAYASHI-MASKAWA MATRIX
LATTICE FIELD THEORY
MASS DIFFERENCE
MATRIX ELEMENTS
MEV RANGE 100-1000
MIXING
MUONS MINUS
MUONS PLUS
PARTICLE DECAY
QUANTUM CHROMODYNAMICS
S QUARKS
STANDARD MODEL
U QUARKS