Ústav technické a experimentální fyziky Institute of Experimental and Applied Physics

Pionium as a source of false events in the K -> pi nu nubar decays.

NázevTitle
Pionium as a source of false events in the K -> pi nu nubar decays.Pionium as a source of false events in the K -> pi nu nubar decays.
Druh výsledkuResult type
Článek v časopiseJournal article
AutořiAuthors
P. Lichard
DOIDOI
10.1103/PhysRevD.102.113005
Časopis / citaceJournal / citation
Physical Review D. 2020, 102(11), 113005-1-113005-5. ISSN 2470-0010.
RokYear
2020
JazykLanguage
eng
WoSWoS
000600276500002
ScopusScopus
2-s2.0-85098151581
RIVRIV
RIV/68407700:21670/20:00344922!RIV21-MSM-21670___
ProjektProject
Institucionální podpora na rozvoj výzkumné org.Institucionální podpora na rozvoj výzkumné org.

AbstraktAbstract

We suggest that the decay modes of kaons with a pion and a pionium (pi+ pi− atom) in the final state can constitute a not yet considered background to the very rare decay K → π ν ν̄. In fact, a part of pioniums may escape the decay region before decaying into two π0s (or to π0 π0 γ in the case of excited pionium). To illustrate the importance of this background, we show that it may even explain, under some assumptions, the unexpected K L decay events that appeared in the KOTO experiment.

We suggest that the decay modes of kaons with a pion and a pionium (pi+ pi− atom) in the final state can constitute a not yet considered background to the very rare decay K → π ν ν̄. In fact, a part of pioniums may escape the decay region before decaying into two π0s (or to π0 π0 γ in the case of excited pionium). To illustrate the importance of this background, we show that it may even explain, under some assumptions, the unexpected K L decay events that appeared in the KOTO experiment.