0000000000190441

AUTHOR

E. Swallow

showing 2 related works from this author

Searches for lepton number violation and resonances in K± → πμμ decays

2017

The NA48/2 experiment at CERN collected a large sample of charged kaon decays to final states with multiple charged particles in 2003–2004. A new upper limit on the rate of the lepton number violating decay K±→π∓μ±μ± is reported: B(K±→π∓μ±μ±)<8.6×10−11 at 90% CL. Searches for two-body resonances X in K±→πμμ decays (such as heavy neutral leptons N4 and inflatons χ ) are also presented. In the absence of signals, upper limits are set on the products of branching fractions B(K±→μ±N4)B(N4→πμ) and B(K±→π±X)B(X→μ+μ−) for ranges of assumed resonance masses and lifetimes. The limits are in the (10−11,10−9) range for resonance lifetimes below 100 ps.

leptonBEAM01 natural sciences7. Clean energyPhysics Particles & FieldsHigh Energy Physics - ExperimentLIMITSkaon physicsCERNIntermediate statelepton number violation neutrinos dark matter kaon physicsPhysicsVMSMLarge Hadron ColliderPhysicsCharge KaonsneutrinosNuclear and High Energy Physics; CERN; leptonsHigh Energy Physics - Experiment; Charge Kaons; Lepton number violationNuclear & Particles PhysicsCharged particlelcsh:QC1-999NEUTRAL HEAVY-LEPTONSPhysics Nuclearlepton number violationPhysical SciencesParticle physicsNuclear and High Energy Physicsleptonskaon decays lepton number violationNuclear and High Energy Physics lepton kaon meson lepton number violation NA48Socio-culturaleAstronomy & AstrophysicsUPPER-BOUNDSdark matterNuclear physics0202 Atomic Molecular Nuclear Particle And Plasma Physics0103 physical sciencesDARK-MATTERPARTICLES010306 general physicsScience & Technologykaon decays010308 nuclear & particles physicsBranching fractionResonanceInflatonLepton numberkaon mesonNA48High Energy Physics::Experimentlcsh:PhysicsLepton
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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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