0000000000685667

AUTHOR

R. Winston

showing 4 related works from this author

Measurement of the branching ratio of the decay Ξ0→Σ+μ−ν¯μ

2013

Abstract From the 2002 data taking with a neutral kaon beam extracted from the CERN-SPS, the NA48/1 experiment observed 97 Ξ 0 → Σ + μ − ν ¯ μ candidates with a background contamination of 30.8 ± 4.2 events. From this sample, the BR ( Ξ 0 → Σ + μ − ν ¯ μ ) is measured to be ( 2.17 ± 0.32 stat ± 0.17 syst ) × 10 − 6 .

PhysicsNuclear and High Energy PhysicsMeson010308 nuclear & particles physicsBranching fractionHadronAnalytical chemistryElementary particle01 natural sciencesNuclear physics0103 physical sciences010306 general physicsBosonDimensionless quantityPhysics Letters B
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First observation and measurement of the decay K±→π±e+e−γ

2008

Abstract Using the full data set of the NA48/2 experiment, the decay K ± → π ± e + e − γ is observed for the first time, selecting 120 candidates with 7.3 ± 1.7 estimated background events. With K ± → π ± π D 0 as normalisation channel, the branching ratio is determined in a model-independent way to be Br ( K ± → π ± e + e − γ , m e e γ > 260  MeV / c 2 ) = ( 1.19 ± 0.12 stat ± 0.04 syst ) × 10 −8 . This measured value and the spectrum of the e + e − γ invariant mass allow a comparison with predictions of chiral perturbation theory.

PhysicsNuclear and High Energy PhysicsAntiparticleChiral perturbation theoryMeson010308 nuclear & particles physicsBranching fractionHadronAnalytical chemistry01 natural sciencesNuclear physicsParticle decayPion0103 physical sciences010306 general physicsDimensionless quantityPhysics Letters B
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Search for direct CP-violation in K±→π±π0π0 decays

2006

Abstract A search for direct CP-violation in K ± → π ± π 0 π 0 decay based on 47.14 million events has been performed by the NA48/2 experiment at the CERN SPS. The asymmetry in the Dalitz plot linear slopes A g = ( g + − g − ) / ( g + + g − ) is measured to be A g = ( 1.8 ± 2.6 ) × 10 −4 . The design of the experiment and the method of analysis provide good control of instrumental charge asymmetries in this measurement. The precision of the result is limited by statistics and is almost one order of magnitude better than that of previous measurements by other experiments.

PhysicsNuclear and High Energy PhysicsParticle physicsLarge Hadron Collidermedia_common.quotation_subjectPiCP violationDalitz plotCharge (physics)Good controlAsymmetryOrder of magnitudemedia_commonPhysics Letters B
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First observation and study of the K± → π±π0e+e− decay

2018

The NA48/2 experiment at CERN reports the first observation of the K-+/- -> pi(+/-)pi(0)e(+)e(-) decay from an exposure of 1.7 x 10(11) charged kaon decays recorded in 2003-2004. A sample of 4919 candidates with 4.9% background contamination allows the determination of the branching ratio in the full kinematic region, BR(K-+/- -> pi(+/-)pi(0)e(+)e(-)) = (4.24 +/- 0.14) x 10(-6). The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on chiral perturbation theory. Several P- and CP-violating asymmetries are also evaluated.

rare decayNuclear and High Energy PhysicsChiral perturbation theoryCP violation; Monte-Carlo; searchAstronomy & AstrophysicsSpace (mathematics)quark mixing01 natural sciencesPartícules (Física nuclear)Charged Kaon decaysPhysics Particles & FieldsCharged Kaon decays quark mixing radiative kaon decay chiral perturbation theoryEconomica0202 Atomic Molecular Nuclear Particle And Plasma PhysicsViolació CP (Física nuclear)MONTE-CARLOSEARCH0103 physical sciencesKaon decaysradiative kaon decay010306 general physicsPhysicsScience & Technology010308 nuclear & particles physicsBranching fractionPhysicsKaon decays Chiral Perturbation TheoryAmbientaleK mesonNuclear & Particles PhysicsChiral Perturbation Theorylcsh:QC1-999fixed target experimentPhysics NuclearPhysical SciencesK meson rare decay fixed target experimentCP violationHigh Energy Physics::ExperimentCP VIOLATIONAtomic physicslcsh:PhysicsPhysics Letters B
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