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Recent results on Kaon decays from NA48/2

The first observation of the $K^\pm → π^\pm π^0 e^+ e^-$ rare decay by the NA48/2 experiment at CERN SPS is reported, based on $∼2\times 10^{11} K^\pm$ decays recorded in 2003-2004. From a sample of 4919 candidates with 4.9% background the branching ratio in the full kinematic region is measured to...

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Autor principal: Bizzeti, Andrea
Lenguaje:eng
Publicado: SISSA 2019
Materias:
Acceso en línea:https://dx.doi.org/10.22323/1.352.0116
http://cds.cern.ch/record/2693925
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author Bizzeti, Andrea
author_facet Bizzeti, Andrea
author_sort Bizzeti, Andrea
collection CERN
description The first observation of the $K^\pm → π^\pm π^0 e^+ e^-$ rare decay by the NA48/2 experiment at CERN SPS is reported, based on $∼2\times 10^{11} K^\pm$ decays recorded in 2003-2004. From a sample of 4919 candidates with 4.9% background the branching ratio in the full kinematic region is measured to be BR($K^± → π^± π^0 e^+ e^-) = (4.24\pm 0.14)\times 10^-6$.The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on Chiral Perturbation Theory. The CP-violating asymmetry between $K^\pm → π^+ π^0 e^+ e^-$ and $K^- → π^- π^0 e^+ e^-$ decay rates has been measured, providing an upper limit $|A_{CP}| < 4.82 \times 10^{-2}$ at 90% CL.The NA48/2 combined measurement of the charged kaon semileptonic form factors, based on 4.4 million $K^\pm → π^0 e^± ν_e$ and 2.3 million $K^\pm → π^0 μ^\pm ν_μ$ events collected in 2004, is presented. This result represents the most precise form factor measurement from a combined $K_{l3}^{\pm}$ analysis.
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institution Organización Europea para la Investigación Nuclear
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spelling oai-inspirehep.net-17564302022-08-10T12:23:22Zdoi:10.22323/1.352.0116http://cds.cern.ch/record/2693925engBizzeti, AndreaRecent results on Kaon decays from NA48/2Particle Physics - ExperimentThe first observation of the $K^\pm → π^\pm π^0 e^+ e^-$ rare decay by the NA48/2 experiment at CERN SPS is reported, based on $∼2\times 10^{11} K^\pm$ decays recorded in 2003-2004. From a sample of 4919 candidates with 4.9% background the branching ratio in the full kinematic region is measured to be BR($K^± → π^± π^0 e^+ e^-) = (4.24\pm 0.14)\times 10^-6$.The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on Chiral Perturbation Theory. The CP-violating asymmetry between $K^\pm → π^+ π^0 e^+ e^-$ and $K^- → π^- π^0 e^+ e^-$ decay rates has been measured, providing an upper limit $|A_{CP}| < 4.82 \times 10^{-2}$ at 90% CL.The NA48/2 combined measurement of the charged kaon semileptonic form factors, based on 4.4 million $K^\pm → π^0 e^± ν_e$ and 2.3 million $K^\pm → π^0 μ^\pm ν_μ$ events collected in 2004, is presented. This result represents the most precise form factor measurement from a combined $K_{l3}^{\pm}$ analysis.SISSAoai:inspirehep.net:17564302019
spellingShingle Particle Physics - Experiment
Bizzeti, Andrea
Recent results on Kaon decays from NA48/2
title Recent results on Kaon decays from NA48/2
title_full Recent results on Kaon decays from NA48/2
title_fullStr Recent results on Kaon decays from NA48/2
title_full_unstemmed Recent results on Kaon decays from NA48/2
title_short Recent results on Kaon decays from NA48/2
title_sort recent results on kaon decays from na48/2
topic Particle Physics - Experiment
url https://dx.doi.org/10.22323/1.352.0116
http://cds.cern.ch/record/2693925
work_keys_str_mv AT bizzetiandrea recentresultsonkaondecaysfromna482