Search results for "charged kaon"

showing 3 items of 3 documents

Precision measurement of the ratio of the charged kaon leptonic decay rates

2013

A precision measurement of the ratio RK of the rates of kaon leptonic decays K+- --> e nu and K+- --> mu nu with the full data sample collected by the NA62 experiment at CERN in 2007-2008 is reported. The result, obtained by analysing ~150000 reconstructed K+- --> e nu candidates with 11% background contamination, is RK = (2.488+-0.010)*10^{-5}, in agreement with the Standard Model expectation.

Nuclear and High Energy PhysicsParticle physicsstandard modelFOS: Physical sciencesNA62 experiment01 natural sciencesHigh Energy Physics - ExperimentStandard ModelNuclear physicsHigh Energy Physics - Experiment (hep-ex)lepton universalityRare kaon decays; chiral perturbation theoryLepton universality; Charged Kaon Decay0103 physical scienceskaon decays leptonic decays lepton universality010306 general physicschiral perturbation theoryPhysicsleptonic decaysLarge Hadron Colliderkaon decays010308 nuclear & particles physicscharged kaon3. Good healthCharged Kaon DecayRare kaon decaysKaon rare decaysFull dataKaon rare decays; branching ratio; charged kaon; leptonic decays; standard modelbranching ratioParticle Physics - ExperimentLepton universality
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Flavour Separation of Helicity Distributions from Deep Inelastic Muon-Deuteron Scattering

2009

We present a LO evaluation of helicity densities of valence, \Delta u_v+\Delta d_v, non-strange sea, \Delta\bar{u}+\Delta\bar{d}, and strange quarks, \Delta s (assumed to be equal to \Delta\bar{s}). They have been obtained from the inclusive asymmetry A_{3,d} and the semi-inclusive asymmetries A^{\pi+}_{1,d}, A^{\pi-}_{1,d}, A^{K+}_{1,d}, A^{K-}_{1,d} measured in polarised deep inelastic muon-deuteron scattering. The full deuteron statistics of COMPASS (years 2002-2004 and 2006) has been used. The data cover the range Q^2 > 1 (GeV/c)^2 and 0.004<x<0.3. Both non-strange densities are found to be in a good agreement with previous measurements. The distribution of \Delta s(x) is compatible wit…

Strange quarkPOLARIZED TARGETNuclear TheoryVALENCE QUARK DISTRIBUTION; PARTON DISTRIBUTIONS; POLARIZED TARGET; NUCLEON; PROTON; DISPolarised DIS and SIDISPROTON01 natural sciencesCOMPASSParton distribution functionHigh Energy Physics - ExperimentCOMPASS; double-spin asymmetry; helicity density; parton distribution function; flavour sep- aration analysis; polarised DIS and SIDIS reactions; charged kaon asymmetrypolarised DIS and SIDIS reactionHigh Energy Physics - Experiment (hep-ex)Helicity densityVALENCE QUARK DISTRIBUTIONNUCLEONNuclear Experimentmedia_commonQuantum chromodynamicsPhysicsFlavour separation analysisHelicityCharged kaon asymmetryNucleondouble-spin asymmetryParticle Physics - Experimentcharged kaon asymmetryParticle physicsNuclear and High Energy Physicsreactionsflavour sep- aration analysismedia_common.quotation_subjectFOS: Physical sciencesparton distribution functionAsymmetryNuclear physics0103 physical sciencesflavour sep- aration analysiPolarised DIS and SIDIS reactions010306 general physicsfunctionDISMuonValence (chemistry)010308 nuclear & particles physicsScatteringParton distributionPARTON DISTRIBUTIONSHigh Energy Physics::Experimenthelicity densityDouble-spin asymmetry
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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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