A measurement of the K+→ π+μ+μ− decay

E Cortina Gil,A Kleimenova,E Minucci,S Padolski,P Petrov,A Shaikhiev,R Volpe,T Numao,Y Petrov,B Velghe,V W S Wong,D Bryman,J Fu,T Husek,M Zamkovsky,R Aliberti,G Khoriauli,J Kunze,D Lomidze,L Peruzzo,M Vormstein,R Wanke,P Dalpiaz,M Fiorini,A Norton,F Petrucci,H Wahl,A Cotta Ramusino,A Gianoli,E Iacopini,G Latino,M Lenti,A Parenti,A Bizzeti,F Bucci,A Antonelli,G Georgiev,V Kozhuharov,G Lanfranchi,S Martellotti,M Moulson,T Spadaro,G Tinti,F Ambrosino,T Capussela,M Corvino,D Di Filippo,R Fiorenza,P Massarotti,M Mirra,M Napolitano,G Saracino,G Anzivino,E Imbergamo,R Lollini,R Piandani,C Santoni,M Barbanera,P Cenci,B Checcucci,P Lubrano,M Lupi,M Piccini,F Costantini,L Di Lella,N Doble,S Giudici,G Lamanna,E Pedreschi,M Sozzi,C Cerri,R Fantechi,L Pontisso,F Spinella,I Mannelli,G D’Agostini,M Raggi,A Biagioni,E Leonardi,A Lonardo,P Valente,P Vicini,V Bonaiuto,A Fucci,A Salamon,F Sargeni,R Arcidiacono,B Bloch-Devaux,M Boretto,E Menichetti,E Migliore,D Soldi,C Biino,A Filippi,F Marchetto,J Engelfried,N Estrada-Tristan,A M Bragadireanu,D Emelyanov,T Enik,V Falaleev,V Kekelidze,A Korotkova,L Litov,D Madigozhin,M Misheva,N Molokanova,S Movchan,I Polenkevich,Yu Potrebenikov,S Shkarovskiy,A Zinchenko,S Fedotov,E Gushchin,A Khotyantsev,Y Kudenko,V Kurochka,M Medvedeva,A Mefodev,S Kholodenko,V Kurshetsov,V Obraztsov,A Ostankov,V Semenov,H O Danielsson ,M Pepé ,Ryan Page ,Aigul Baeva ,Ovidiu Emanuel Hutanu ,Francesco Brizioli ,M A Giorgi ,P S Cooper ,Jan Jerhot ,Joel Swallow ,Ilaria Neri ,Babette Döbrich ,Dosbol Baigarashev ,Eva Barbara Holzer ,H F Heath ,Karol Kampf ,V Černý ,Stefan Alexandru Ghinescu ,Karim Massri ,Joseph Carmignani ,Paolo Cretaro ,Maria Brigida Brunetti ,Matteo Turisini ,C J Parkinson ,Enrico Lari ,Ottorino Frezza ,Valentin Sugonyaev ,Jack Henshaw ,Roger Jones ,Z Kučerová ,Roberto Ammendola ,Stoyan Miroslavov Trilov ,T Blažek ,O Yushchenko,L Bician,J Bernhard,A Ceccucci,N De Simone,F Duval,L Federici,E Gamberini,L Gatignon,R Guida,F Hahn,B Jenninger,M Koval,P Laycock,G Lehmann Miotto,P Lichard,A Mapelli,R Marchevski,M Noy,V Palladino,M Perrin-Terrin,J Pinzino,V Ryjov,S Schuchmann,S Venditti,T Bache,V Duk,V Fascianelli,J R Fry,F Gonnella,E Goudzovski,L Iacobuzio,C Lazzeroni,N Lurkin,F Newson,A Romano,A Sergi,A Sturgess,A Tomczak,B Angelucci,D Britton,C Graham,D Protopopescu,J B Dainton,G Ruggiero,L Fulton,D Hutchcroft,E Maurice,B Wrona,A Conovaloff,D Coward,P Rubin

doi:10.1007/jhep11(2022)011

Abstract

A sample of 2.8 × 104K+ → π+μ+μ− candidates with negligible background was collected by the NA62 experiment at the CERN SPS in 2017–2018. The model-independent branching fraction is measured to be (9.15 ± 0.08) × 10−8, a factor three more precise than previous measurements. The decay form factor is presented as a function of the squared dimuon mass. A measurement of the form factor parameters and their uncertainties is performed using a description based on Chiral Perturbation Theory at mathcal{O} (p6).

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