Lattice QCD inputs to the CKM unitarity triangle analysis

Journal Article · Mon Feb 01 00:00:00 EST 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.81.034503· OSTI ID:21409189

Laiho, Jack ^[1]; Lunghi, E ^[2]; Van de Water, Ruth S ^[3]

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1. Physics Department, Washington University, St. Louis, Missouri 63130 (United States)
2. Physics Department, Indiana University, Bloomington, Indiana 47405 (United States)
3. Physics Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

We perform a global fit to the Cabibbo-Kobayashi-Maskawa unitarity triangle using the latest experimental and theoretical constraints. Our emphasis is on the hadronic weak matrix elements that enter the analysis, which must be computed using lattice QCD or other nonperturbative methods. Realistic lattice QCD calculations which include the effects of the dynamical up, down, and strange quarks are now available for all of the standard inputs to the global fit. We therefore present lattice averages for all of the necessary hadronic weak matrix elements. We attempt to account for correlations between lattice QCD results in a reasonable but conservative manner: whenever there are reasons to believe that an error is correlated between two lattice calculations, we take the degree of correlation to be 100%. These averages are suitable for use as inputs both in the global Cabibbo-Kobayashi-Maskawa unitarity triangle fit and other phenomenological analyses. In order to illustrate the impact of the lattice averages, we make standard model predictions for the parameters B-circumflex{sub K}, |V{sub cb}|, and |V{sub ub}|/|V{sub cb}|. We find a (2-3){sigma} tension in the unitarity triangle, depending upon whether we use the inclusive or exclusive determination of |V{sub cb}|. If we interpret the tension as a sign of new physics in either neutral kaon or B mixing, we find that the scenario with new physics in kaon mixing is preferred by present data.

• OSTI ID: 21409189
• Journal Information: Physical Review. D, Particles Fields, Vol. 81, Issue 3; Other Information: DOI: 10.1103/PhysRevD.81.034503; (c) 2010 The American Physical Society; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CORRELATIONS
FORECASTING
KAONS NEUTRAL
KOBAYASHI-MASKAWA MATRIX
MATRIX ELEMENTS
MIXING
QUANTUM CHROMODYNAMICS
S QUARKS
STANDARD MODEL
UNITARITY
BOSONS
ELEMENTARY PARTICLES
FERMIONS
FIELD THEORIES
GRAND UNIFIED THEORY
HADRONS
KAONS
MATHEMATICAL MODELS
MATRICES
MESONS
PARTICLE MODELS
PSEUDOSCALAR MESONS
QUANTUM FIELD THEORY
QUARKS
STRANGE MESONS
STRANGE PARTICLES
UNIFIED GAUGE MODELS