6533b7d0fe1ef96bd125b6bf

RESEARCH PRODUCT

Measurement of the branching ratio and search for a CP violating asymmetry in the η→π+π−e+e−(γ) decay at KLOE

Massimo AntonelliP. BeltrameEnrico PasqualucciS. FioreD. LeoneG. FeliciE. GrazianiAchim DenigFilippo CeradiniS. BertolucciB. Di MiccoR. VersaciPaolo CiambroneT. SpadaroStefan E. MüllerS. MeolaF. BossiA. AntonelliS. BocchettaP. GauzziG. CaponL. TortoraA. PasseriG. F. XuC. Di DonatoPaolo SantangeloF. MurtasP. MassarottiBarbara SciasciaM. MartiniP. De SimoneF. NguyenF. PerfettoM. NapolitanoG. LanfranchiS. MiscettiVincenzo PateraM. PalutanA. Di DomenicoClaudio GattiC. BloiseM. MoulsonP. ValenteA. De SantisF. CrucianelliG. VenanzoniM. TestaG. De ZorziG. BencivenniCesare BiniF. AmbrosinoJuliet Lee-franziniS. GiovannellaP. FranziniP. BranchiniM. DreucciE. De LuciaFlavio ArchilliT. Capussela

subject

PhysicsNuclear and High Energy PhysicsParticle physicsMesonBranching fractionmedia_common.quotation_subjectGamma rayPiRadiative transferCP violationAsymmetrymedia_common

description

Abstract We have studied the η → π + π − e + e − ( γ ) decay using about 1.7 fb − 1 collected by the KLOE experiment at the DAΦNE ϕ -factory. This corresponds to about 72 millions η mesons produced in ϕ radiative decays. We have measured the branching ratio, inclusive of radiative effects, with 4% accuracy: BR ( η → π + π − e + e − ( γ ) ) = ( 26.8 ± 0.9 Stat . ± 0.7 Syst . ) × 10 − 5 . We have obtained the first measurement of the CP-odd ππ – ee decay planes angular asymmetry, A ϕ = ( − 0.6 ± 2.5 Stat . ± 1.8 Syst . ) × 10 − 2 .

yearjournalcountryeditionlanguage
2009-05-01Physics Letters B
https://doi.org/10.1016/j.physletb.2009.04.013