6533b7dafe1ef96bd126e3db

RESEARCH PRODUCT

Observation of the decay KS→π+π−e+e−

C. CheshkovU. KochG. GoviW. KubischtaE. IacopiniP. GrafströmG. BocquetYu. PotrebenikovNadia PastroneA. WinhartA. LaiMauro PicciniB. VallageP. DebuR. FantechiAndrea FormicaLydia Iconomidou-fayardMilene CalvettiJ. C. CholletI. MannelliA. NappiM. EppardI.g. KnowlesMichal SzleperM. SavrieE. MenichettiR.s. DosanjhF. CostantiniG.e. KalmusSandro PalestiniM. De BeerP. LubranoH. DibonS. GiudiciGiacomo GrazianiA. PetersS. WronkaM. WittgenM. HolderBenedetto GoriniS.a. SchmidtD. MarrasR. TurlayS. A. WottonM. ContalbrigoK. HoltzJ. CoganManfred JeitlerM. SozziM. BenderG.d. BarrWojciech WislickiE. ImbergamoH. D. WahlE. OlaiyaJ. DuclosD.j. MundayG. AnzivinoJ. NassalskiMichael Andrew ParkerM. CirilliN. A. MolokanovaJ. OcarizNiels DobleB. RenkP. F. DalpiazP. HristovE. RondioI. PellmannE. MazzucatoI. AugustinG. FischerM. PepeG. D'agostiniT.o. WhiteG. UnalT.j. GershonM.d. NeedhamB. PeyaudAnton TaurokB. HayR. SaccoFabrizio PetrucciL. KöpkeA. GonidecAugusto CeccucciV. SchönhartingM. MarkytanM. LentiP.l. FrabettiG. CollazuolJ.b. ChezeVladimir KekelidzeVictoria Jane MartinG.m. PierazziniG. TatishviliLau GatignonMayda VelascoMichael ZiolkowskiA. MestvirishviliA. TkatchevM. MartiniH. ParsonsLouis FayardF. MarchettoAlan W. WalkerA. I. ZinchenkoKonrad KleinknechtP. CenciH. TauregH.g. BeckerH. BlümerA. GianoliC. LazzeroniA. KalterR. Granier De CassagnacCristina BiinoIvan MikulecG. NeuhoferS. CrépéV. FalaleevR. CarosiD. MadigojineLuciano MusaM. PernickaRoberta ArcidiaconoD.c. CundyAndrea BizzetiR. CasaliA. NortonY. SchuéB. Panzer-steindelH. FoxA. LacourtC. CerriI. Wingerter-seezAdrian John Bevan

subject

mesoni K; decadimenti rarimesoni KPhysicsNuclear physicsNuclear and High Energy Physicsdecadimenti rariBranching fractionBremsstrahlungNA48 experiment

description

Abstract We present the first observation of the decay KS→π+π−e+e− based upon the data collected in 1998 by the NA48 experiment at CERN. We have identified a clean sample of 56 events with negligible background contamination. Using KL→π+π−π0D decays as normalization sample, the branching ratio is measured to be BR(KS→π+π−e+e−)=[4.5±0.7(stat)±0.4(syst)]×10−5. This result is in good agreement with the theoretical expectations from the mechanism of inner bremsstrahlung.

https://doi.org/10.1016/s0370-2693(00)01300-9