abstract

• A sample of 3984 candidates of the K →π γγ decay, with an estimated background of 291±14 events, was collected by the NA62 experiment at CERN during 2017–2018. In order to describe the observed di-photon mass spectrum, the next-to-leading order contribution in chiral perturbation theory was found to be necessary. The decay branching ratio in the full kinematic range is measured to be (9.61±0.17)×10−7. The first search for production and prompt decay of an axion-like particle with gluon coupling in the process K →π a, a→γγ is also reported.

authors

• Engelfried Jatzkowski Jurgen
• Engelfried Jatzkowski Jurgen
• The NA62 Collaboration
• The NA62 Collaboration

publication date

• 2024-01-01

funding provided via

• CECI; Collaboration Institutes; Czech Republic; Ministry of Education, Science, Research and Sport; National Science Foundation, NSF, (1506088, 1806430); National Science Foundation, NSF; Univerzita Karlova v Praze, UK, (PRIMUS 23/SCI/025, UNCE/SCI/013); Univerzita Karlova v Praze, UK; H2020 Marie Skłodowska-Curie Actions, MSCA, (101023808, 701386, 754496, 842407, 893101); H2020 Marie Skłodowska-Curie Actions, MSCA; CERN; Enseignement Supérieur et de la Recherche Scientifique, MESRS; European Resuscitation Council, ERC, (802836); European Resuscitation Council, ERC; Natural Sciences and Engineering Research Council of Canada, NSERC, (SAPPJ-2018-0017); Natural Sciences and Engineering Research Council of Canada, NSERC; Science and Technology Facilities Council, STFC, (ST/J00412X/1, ST/M005798/1); Science and Technology Facilities Council, STFC; Royal Society, (UF0758946, UF100308); Royal Society; European Research Council, ERC, (268062, 336581); European Research Council, ERC; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, (LM 2018104); Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Grantová Agentura České Republiky, GA ČR, (23-06770S); Grantová Agentura České Republiky, GA ČR; Bundesministerium für Bildung und Forschung, BMBF, (05H12UM5, 05H15UMCNA, 05H18UMCNA); Bundesministerium für Bildung und Forschung, BMBF; Fonds De La Recherche Scientifique - FNRS, FNRS, (2.5020.11); Fonds De La Recherche Scientifique - FNRS, FNRS; Consejo Nacional de Ciencia y Tecnología, CONACYT; Ministero dell’Istruzione, dell’Università e della Ricerca, MIUR, (RBFR12JF2Z); Ministero dell’Istruzione, dell’Università e della Ricerca, MIUR; Instituto Nazionale di Fisica Nucleare, INFN; Horizon 2020; Institutul de Fizică Atomică, IFA, (1/16.03.2016, PN 19 06 01 04); Institutul de Fizică Atomică, IFA  Grant

published in

• Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics  Journal

keywords

Digital Object Identifier (DOI)

• 10.1016/j.physletb.2024.138513

PubMed ID

start page

end page

volume

• 850

issue