0000000000718176

AUTHOR

John F. Donoghue

showing 4 related works from this author

and the electroweak penguin contribution

2003

Abstract Our dispersive sum rule calculation of the electroweak penguin contribution to ϵ′ ϵ is reviewed. A more recent analysis based on the finite-energy sum rule approach is described. Finally, a new determination of the electroweak penguin contribution to ϵ′ ϵ is presented.

Quantum chromodynamicsNuclear and High Energy PhysicsParticle physicsHigh Energy Physics::PhenomenologyElectroweak interactionAtomic and Molecular Physics and OpticsStandard ModelCombinatoricsGrand Unified TheoryHigh Energy Physics::ExperimentPerturbation theory (quantum mechanics)Sum rule in quantum mechanicsGauge theoryOperator product expansionMathematicsNuclear Physics B - Proceedings Supplements
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K -> pi pi Electroweak Penguins in the Chiral Limit

2002

We report on dispersive and finite energy sum rule analyses of the electroweak penguin matrix elements in the chiral limit. We accomplish the correct perturbative matching (scale and scheme dependence) at NLO in alpha_s, and we describe two different strategies for numerical evaluation.

PhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsElectroweak interactionHigh Energy Physics::PhenomenologyScale (descriptive set theory)01 natural sciencesAtomic and Molecular Physics and OpticsMatrix (mathematics)High Energy Physics - Phenomenology0103 physical sciencesHigh Energy Physics::ExperimentLimit (mathematics)Sum rule in quantum mechanics010306 general physics
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Long distance chiral corrections in B meson amplitudes

2003

We discuss the chiral corrections to f_B and B_B with particular emphasis on determining the portion of the correction that arises from long distance physics. For very small pion and kaon masses all of the usual corrections are truly long distance, while for larger masses the long distance portion decreases. These chiral corrections have been used to extrapolate lattice calculations towards the physical region of lighter masses. We show in particular that the chiral extrapolation is better behaved if only the long distance portion of the correction is used.

PhysicsNuclear and High Energy PhysicsParticle physicsHigh Energy Physics::LatticeHigh Energy Physics - Lattice (hep-lat)High Energy Physics::PhenomenologyExtrapolationFOS: Physical sciencesHigh Energy Physics - PhenomenologyHigh Energy Physics - Phenomenology (hep-ph)High Energy Physics - LatticePionAmplitudeQuantum electrodynamicsLattice (order)B mesonPhysics Letters B
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Improved determination of the electroweak penguin contribution to ϵ′/ϵ in the chiral limit

2003

We perform a finite energy sum rule analysis of the flavor ud two-point V-A current correlator, Delta Pi (Q^2). The analysis, which is performed using both the ALEPH and OPAL databases for the V-A spectral function, Delta rho, allows us to extract the dimension six V-A OPE coefficient, a_6, which is related to the matrix element of the electroweak penguin operator, Q_8, by chiral symmetry. The result for a_6 leads directly to the improved (chiral limit) determination epsilon'/epsilon = (- 15.0 +- 2.7) 10^{-4}. Determination of higher dimension OPE contributions also allows us to perform an independent test using a low-scale constrained dispersive analysis, which provides a highly nontrivial…

PhysicsNuclear and High Energy PhysicsParticle physicsCurrent (mathematics)010308 nuclear & particles physicsOperator (physics)High Energy Physics::PhenomenologyElectroweak interaction01 natural sciencesDimension (vector space)Consistency (statistics)0103 physical sciencesHigh Energy Physics::ExperimentLimit (mathematics)Sum rule in quantum mechanics010306 general physicsEnergy (signal processing)Physics Letters B
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