Neutral B meson mixing in unquenched lattice QCD

Journal Article · Wed Jul 01 04:00:00 EDT 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.80.014503· OSTI ID:21308534

Gamiz, Elvira ^[1]; Davies, Christine T. H. ^[2]; Lepage, G Peter ^[3]; Shigemitsu, Junko ^[4]; Wingate, Matthew ^[5]

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1. Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States)
2. Department of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)
3. Laboratory of Elementary Particle Physics, Cornell University, Ithaca, New York 14853 (United States)
4. Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)
5. 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, Journal Name: Physical Review. D, Particles Fields Journal Issue: 1 Vol. 80; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
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