Searches for lepton number violating K+ → π−(π0)e+e+ decays

NA62 Collaboration, Thomas Bache, Maria Brigida Brunetti, Viacheslav Duk, Evgueni Goudzovski*, Valeria Fascianelli, John Fry, Francesco Gonnella, Jack Henshaw, Lorenza Iacobuzio, Cristina Lazzeroni, Nicolas Lurkin, Francis Newson, Chris Parkinson, Angela Romano, Antonino Sergi, Andy Sturgess, Joel Swallow, Adam Tomczak

*Corresponding author for this work

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Searches for lepton number violating K+ → π−e+e+ and K+ → π−π0e+e+ decays have been performed using the complete dataset collected by the NA62 experiment at CERN in 2016–2018. Upper limits of 5.3 × 10−11 and 8.5 × 10−10 are obtained on the decay branching fractions at 90% confidence level. The former result improves by a factor of four over the previous best limit, while the latter result represents the first limit on the K+ → π−π0e+e+ decay rate.
Original languageEnglish
Article number137172
Number of pages10
JournalPhysics Letters B
Publication statusPublished - 10 Jul 2022


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