Search results for " Charmonium"

showing 4 items of 4 documents

Observation of ψ(3686)→η′e+e−

2018

Abstract Using a data sample of 448.1 × 10 6 ψ ( 3686 ) events collected with the BESIII detector at the BEPCII collider, we report the first observation of the electromagnetic Dalitz decay ψ ( 3686 ) → η ′ e + e − , with significances of 7.0σ and 6.3σ when reconstructing the η ′ meson via its decay modes η ′ → γ π + π − and η ′ → π + π − η ( η → γ γ ), respectively. The weighted average branching fraction is determined to be B ( ψ ( 3686 ) → η ′ e + e − ) = ( 1.90 ± 0.25 ± 0.11 ) × 10 − 6 , where the first uncertainty is statistical and the second systematic.

Dalitz decayNuclear and High Energy PhysicsMesonElectron–positron annihilationBESIII; Charmonium; Dalitz decay; e+e− Annihilation; Nuclear and High Energy Physicse + e − Annihilation01 natural sciencesOmegaNOlaw.inventionBESIII; Charmonium; Dalitz decay; e+e−Annihilation; Nuclear and High Energy PhysicsNuclear physicslaw0103 physical sciencese+e−Annihilation010306 general physicsColliderCharmoniumPhysics010308 nuclear & particles physicsGenerator (category theory)Branching fractionBESIIIe+e− AnnihilationPseudoscalarBESIII; Charmonium; Dalitz decay; e + e − Annihilation ; Nuclear and High Energy PhysicsPhysics Letters B
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J / psi production in the hadronic decays of the Z.

1994

Abstract: J/psi mesons have been reconstructed from their decay to mu(+)mu(-) and e(+)e(-), using the data collected by the DELPHI experiment during 1991 and 1992 at the LEP collider. From about 1 million hadronic Z decays 153 +/- 17 J/psi were found, 5.4 +/- 2.3 psi' were obtained in the channel J/psi(--> mu(+)mu(-))pi(+)pi(-) and 6.4 +/- 2.7 chi(c) in the channel J/psi(--> mu(+)mu(-))gamma. As the dominant source of J/psi mesons is from b quarks, the following branching ratios: Br(b-->J/psi X) = (1.12 +/- 0.12 (stat.) +/- 0.10 (syst.))%, Br(b --> psi' X) = (0.48 +/- 0.22 (stat.) +/- 0.10 (syst.))%, Br(b-->chi(cl) X) = (1.4 +/- 0.6 (stat.)(-0.2)(+0.4) (syst.))% were measured. From the prop…

Nuclear and High Energy PhysicsParticle physicsMesonLUND MONTE-CARLO; B-MESON DECAYS; HEAVY-QUARKONIUM; JET FRAGMENTATION; TRANSITIONS; CHARMONIUM; PHYSICS; SYSTEMS; BOSONLUND MONTE-CARLOElectron–positron annihilationHadronTRANSITIONSAstrophysics::Cosmology and Extragalactic AstrophysicsB meson01 natural sciencesb taggingJET FRAGMENTATIONPartícules (Física nuclear)law.inventionNuclear physicsPHYSICSB-MESON DECAYSlawSYSTEMSCHARMONIUM0103 physical sciences[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]B mesonNuclear Experiment010306 general physicsColliderBosonDELPHIHEAVY-QUARKONIUMPhysics010308 nuclear & particles physicsPhysicsHigh Energy Physics::PhenomenologyZ0 decayBOSONb-taggingHigh Energy Physics::ExperimentDELPHI; B meson; b tagging; Z0 decayParticle Physics - Experiment
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An improved limit for Γee of X(3872) and Γee measurement of ψ(3686)

2015

Using the data sets taken at center-of-mass energies above 4 GeV by the BESIII detector at the BEPCII storage ring, we search for the reaction e+e−→γISRX(3872)→γISRπ+π−J/ψ via the Initial State Radiation technique. The production of a resonance with quantum numbers JPC=1++ such as the X(3872) via single photon e+e− annihilation is forbidden, but is allowed by a next-to-leading order box diagram. We do not observe a significant signal of X(3872) , and therefore give an upper limit for the electronic width times the branching fraction ΓeeX(3872)B(X(3872)→π+π−J/ψ)<0.13 eV at the 90% confidence level. This measurement improves upon existing limits by a factor of 46. U…

Nuclear and High Energy PhysicsX(3872)BESIII; Charmonium spectroscopy; X(3872); Γ; ee; ψ(3686)ψ(3686)ΓBESIIIBESIII; Charmonium spectroscopy; X(3872); Γee; ψ(3686); Nuclear and High Energy PhysicsCharmonium spectroscopyΓeeeelcsh:Physicslcsh:QC1-999
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Determination of the $X(3872)$ meson quantum numbers

2013

The quantum numbers of the X(3872) meson are determined to be J(PC) = 1(++) based on angular correlations in B+ -> X(3872)K+ decays, where X(3872) -> pi(+) pi(-) j/psi and J/psi -> pi(+) mu(-). The data correspond to 1.0 fb(-1) of pp collisions collected by the LHCb detector. The only alternative assignment allowed by previous measurements J(PC) = 2(-+) is rejected with a confidence level equivalent to more than 8 Gaussian standard deviations using a likelihood-ratio test in the full angular phase space. This result favors exotic explanations of the X(3872) state.

Particle physicsCOLLISIONSMesonExotic mesonHigh Energy Physics::LatticeGaussian14.40.NdNuclear TheoryGeneral Physics and AstronomyFOS: Physical sciences01 natural sciencesSettore FIS/04 - Fisica Nucleare e SubnucleareHigh Energy Physics - ExperimentNuclear physicsPhysics and Astronomy (all)symbols.namesakeHigh Energy Physics - Experiment (hep-ex)14.40.RtHadronic decays of bottom meson0103 physical sciences13.25.GvPi[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]CollisionsNuclear Experiment010306 general physicsPhysics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyParticle physicsState (functional analysis)Exotic hadrons Charmonium Hadron ColliderQuantum numberLHCbFIS/01 - FISICA SPERIMENTALEPhase space13.25.HwsymbolsBottom mesons (|B|>0)TetraquarkFísica nuclearHigh Energy Physics::ExperimentLHCFísica de partículesExperimentsFIS/04 - FISICA NUCLEARE E SUBNUCLEAREParticle Physics - ExperimentHadronic decays of J/ψ Υ and other quarkoniaX(3872)
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