0000000000300640

AUTHOR

Kejun Zhu

showing 11 related works from this author

Precision measurement of the D*(0) decay branching fractions

2015

WOS: 000349437800001

PhysicsNuclear and High Energy PhysicsBESIII детекторPhysics and Astronomy (miscellaneous)Mesonквантовая хромодинамикаAnalytical chemistryFOS: Physical sciencesNuclear and High Energy Physics; Physics and Astronomy (miscellaneous)Branching (polymer chemistry)QCD7. Clean energyMESONSHigh Energy Physics - ExperimentNONuclear physicsHigh Energy Physics - Experiment (hep-ex)бозоныPiPhysical Review D
researchProduct

Search forηandη′invisible decays inJ/ψ→ϕηandϕη′

2013

Using a sample of (225.3 +/- 2.8) x 10(6) J/psi decays collected with the BESIII detector at BEPCII, searches for invisible decays of eta and eta ' in J/psi -> phi eta and phi eta ' are performed. Decays of phi -> K+K- are used to tag the eta and eta ' decays. No signals above background are found for the invisible decays, and upper limits at the 90% confidence level are determined to be 2.6 x 10(-4) for the ratio B(eta -> invisible)/B(eta ->gamma gamma) and 2.4 x 10(-2) for B(eta '-> invisible)/B(eta '->gamma gamma). These limits may be used to constrain light dark matter particles or spin-1 U bosons. DOI: 10.1103/PhysRevD.87.012009

PhysicsNuclear and High Energy PhysicsParticle physicsElectron–positron annihilationHigh Energy Physics::ExperimentNuclear ExperimentLight dark matterBosonGamma gammaPhysical Review D
researchProduct

Radioactivity control strategy for the JUNO detector

2021

JUNO is a massive liquid scintillator detector with a primary scientific goal of determining the neutrino mass ordering by studying the oscillated anti-neutrino flux coming from two nuclear power plants at 53 km distance. The expected signal anti-neutrino interaction rate is only 60 counts per day, therefore a careful control of the background sources due to radioactivity is critical. In particular, natural radioactivity present in all materials and in the environment represents a serious issue that could impair the sensitivity of the experiment if appropriate countermeasures were not foreseen. In this paper we discuss the background reduction strategies undertaken by the JUNO collaboration…

Nuclear and High Energy PhysicsPhysics - Instrumentation and DetectorsPhysics::Instrumentation and DetectorsNuclear engineeringMonte Carlo methodControl (management)measurement methodsFOS: Physical sciencesQC770-798Scintillator7. Clean energy01 natural sciencesNOPE2_2Nuclear and particle physics. Atomic energy. Radioactivity0103 physical sciences[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]ddc:530Sensitivity (control systems)010306 general physicsPhysicsJUNOliquid [scintillation counter]010308 nuclear & particles physicsbusiness.industryDetectorSettore FIS/01 - Fisica Sperimentaleradioactivity [background]suppression [background]Instrumentation and Detectors (physics.ins-det)Monte Carlo [numerical calculations]Nuclear powerthreshold [energy]sensitivityNeutrino Detectors and Telescopes (experiments)GEANTNeutrinobusinessEnergy (signal processing)
researchProduct

Precise Measurement of the e+e−→π+π−J/ψ Cross Section at Center-of-Mass Energies from 3.77 to 4.60 GeV

2017

The cross section for the process e(+)e(-)-> pi(+) pi(-) J/psi is measured precisely at center-of-mass energies from 3.77 to 4.60 GeV using 9 fb(-1) of data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in a fit to the cross section. The first resonance has a mass of (222.0 +/- 3.1 +/- 1.4) MeV/ c(2) and a width of (44.1 +/- 4.3 +/- 2.0)MeV, while the second one has a mass of (4320.0 +/- 10.4 +/- 7.0)MeV/c(2) and a width of (101.4(- 19.7)(+25.3) +/- 10.2) MeV, where the first errors are statistical and second ones are systematic. The first resonance agrees with the Y(4260) resonance reported by previous experiments. The precisi…

Nuclear physicsPhysicsCross section (physics)010308 nuclear & particles physics0103 physical sciencesGeneral Physics and AstronomySigmaCenter of mass010306 general physics01 natural sciencesResonance (particle physics)Belle experimentStorage ringPhysical Review Letters
researchProduct

Search for the rare decaysJ/ψ→Ds−ρ+andJ/ψ→D¯0K¯*0

2014

A search for the rare decays of J/psi -> D-S(-) rho(+) + c.c. and J/psi -> D-S(-)rho(+) + c.c.) <(D)over bar(0)<(K)over bar*(0) + c.c.) < 2.5 x 10(-6) at the 90% confidence level.

Nuclear physicsPhysicsNuclear and High Energy PhysicsBranching fractionElectron–positron annihilationHigh Energy Physics::ExperimentAstrophysicsBar (unit)Physical Review D
researchProduct

Observation ofη′→ωe+e−

2015

Based on a sample of eta' mesons produced in the radiative decay J/psi -> gamma eta' in 1.31 x 10(9) J/psi events collected with the BESIII detector, the decay eta' -> omega e(+)e(-) is observed for the first time, with a statistical significance of 8 sigma. The branching fraction is measured to be B(eta' -> omega e(+)e(-)) = (1.97 +/- 0.34(stat) +/- 0.17(syst)) x 10(-4), which is in agreement with theoretical predictions. The branching fraction of eta' -> omega gamma is also measured to be (2.55 +/- 0.03(stat) +/- 0.16(syst)) x 10(-2), which is the most precise measurement to date, and the relative branching fraction B(eta' -> omega e(+)e(-))/B(eta' -> omega gamma) is determined to be (7.7…

PhysicsNuclear physicsNuclear and High Energy PhysicsMesonBranching fractionElectron–positron annihilationAnalytical chemistryRadiative decayHigh Energy Physics::ExperimentVector meson dominanceNuclear ExperimentOmegaPhysical Review D
researchProduct

Measurement of thee+e−→ηJ/ψcross section and search fore+e−→π0J/ψat center-of-mass energies between 3.810 and 4.600 GeV

2015

Using data samples collected with the BESIII detector operating at the BEPCII collider at 17 center-of-mass energies from 3.810 to 4.600 GeV, we perform a study of e(+)e(-) -> eta J/psi and pi(0)J/psi The Born cross sections of these two processes are measured at each center-of-mass energy. The measured energy-dependent Born cross section for e(+)e(-) -> eta J/psi shows an enhancement around 4.2 GeV. The measurement is compatible with an earlier measurement by Belle.

PhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsElectron–positron annihilation01 natural scienceslaw.inventionMass enhancementNuclear physicsCross section (physics)law0103 physical sciencesHigh Energy Physics::ExperimentCenter of massNuclear Experiment010306 general physicsColliderPhysical Review D
researchProduct

Observation of a Charged Charmoniumlike Structure ine+e−→(D*D¯*)±π∓ats=4.26  GeV

2014

We study the process e(+)e(-) -> (D* (D) over bar*)(+/-)pi(-/+) at a center-of-mass energy of 4.26 GeV using a 827 pb(-1) data sample obtained with the BESIII detector at the Beijing Electron Positron Collider. Based on a partial reconstruction technique, the Born cross section is measured to be (137 +/- 9 +/- 15) pb. We observe a structure near the (D* (D) over bar*)(+/-) threshold in the pi(-/+) recoil mass spectrum, which we denote as the Z(c)(+/-) (4025). The measured mass and width of the structure are (4026.3 +/- 2.6 +/- 3.7) MeV/c(2) and (24.8 +/- 5.6 +/- 7.7) MeV, respectively. Its production ratio sigma(e(+)e(-) -> Z(c)(+/-)(4025)pi(-/+)-> (D* (D) over bar*)(+/-)pi(-/+)/sigma(e(+)e…

PhysicsHigh energyPositronRecoilElectron–positron annihilationMass spectrumAnalytical chemistryPiGeneral Physics and AstronomyHigh Energy Physics::ExperimentBar (unit)Physical Review Letters
researchProduct

Precise Measurement of the e+e− → π+π−J/ψ Cross Section at Center-of-Mass Energies from 3.77 to 4.60 GeV

2020

The cross section for the process e(+)e(-)-> pi(+) pi(-) J/psi is measured precisely at center-of-mass energies from 3.77 to 4.60 GeV using 9 fb(-1) of data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in a fit to the cross section. The first resonance has a mass of (222.0 +/- 3.1 +/- 1.4) MeV/ c(2) and a width of (44.1 +/- 4.3 +/- 2.0)MeV, while the second one has a mass of (4320.0 +/- 10.4 +/- 7.0)MeV/c(2) and a width of (101.4(- 19.7)(+25.3) +/- 10.2) MeV, where the first errors are statistical and second ones are systematic. The first resonance agrees with the Y(4260) resonance reported by previous experiments. The precisi…

Nuclear physicsPhysicsCross section (physics)SigmaCenter of massResonance (particle physics)Belle experimentStorage ring30 Years of BES Physics
researchProduct

The Design and Sensitivity of JUNO's scintillator radiopurity pre-detector OSIRIS

2021

The European physical journal / C 81(11), 973 (2021). doi:10.1140/epjc/s10052-021-09544-4

Liquid scintillatorPhysics - Instrumentation and DetectorsPhysics and Astronomy (miscellaneous)Physics::Instrumentation and Detectorsscintillation counter: liquidmeasurement methodsQC770-798Astrophysics01 natural sciencesthorium: nuclidedesign [detector]neutrinoRadioactive purityPhysicsLow energy neutrinoJUNOliquid [scintillation counter]biologySettore FIS/01 - Fisica SperimentaleDetectorInstrumentation and Detectors (physics.ins-det)3. Good healthQB460-466Physics::Space Physicsnuclide [uranium]FOS: Physical sciencesScintillatornuclide [thorium]530NONuclear physicsPE2_2uranium: nuclideNuclear and particle physics. Atomic energy. Radioactivity0103 physical sciencesddc:530Sensitivity (control systems)[PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det]010306 general physicsJUNO neutrino physics liquid scintillatorEngineering (miscellaneous)background: radioactivitydetector: designMeasurement method010308 nuclear & particles physicsradioactivity [background]biology.organism_classificationsensitivityHigh Energy Physics::ExperimentReactor neutrinoOsiris
researchProduct

JUNO sensitivity to low energy atmospheric neutrino spectra

2021

Atmospheric neutrinos are one of the most relevant natural neutrino sources that can be exploited to infer properties about cosmic rays and neutrino oscillations. The Jiangmen Underground Neutrino Observatory (JUNO) experiment, a 20 kton liquid scintillator detector with excellent energy resolution is currently under construction in China. JUNO will be able to detect several atmospheric neutrinos per day given the large volume. A study on the JUNO detection and reconstruction capabilities of atmospheric $\nu_e$ and $\nu_\mu$ fluxes is presented in this paper. In this study, a sample of atmospheric neutrino Monte Carlo events has been generated, starting from theoretical models, and then pro…

Physics and Astronomy (miscellaneous)Physics::Instrumentation and Detectorsscintillation counter: liquidenergy resolutionAtmospheric neutrinoQC770-798Astrophysics7. Clean energy01 natural sciencesneutrino: fluxHigh Energy Physics - ExperimentHigh Energy Physics - Experiment (hep-ex)particle source [neutrino]neutrinoneutrino: atmosphere[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]Cherenkovneutrino/e: particle identificationenergy: low [neutrino]Jiangmen Underground Neutrino ObservatoryPhysicsJUNOphotomultiplierliquid [scintillation counter]primary [neutrino]neutrino: energy spectrumDetectoroscillation [neutrino]neutrinosMonte Carlo [numerical calculations]atmosphere [neutrino]QB460-466observatorycosmic radiationComputer Science::Mathematical Softwareproposed experimentNeutrinonumerical calculations: Monte CarloComputer Science::Machine LearningParticle physicsdata analysis methodAstrophysics::High Energy Astrophysical PhenomenaFOS: Physical sciencesCosmic rayScintillatorComputer Science::Digital LibrariesNOStatistics::Machine LearningPE2_2neutrino: primaryneutrino: spectrumNuclear and particle physics. Atomic energy. Radioactivity0103 physical sciencesddc:530structure010306 general physicsNeutrino oscillationEngineering (miscellaneous)Cherenkov radiationparticle identification [neutrino/mu]Scintillationneutrino/mu: particle identificationflavordetectorparticle identification [neutrino/e]010308 nuclear & particles physicsneutrino: energy: lowHigh Energy Physics::Phenomenologyspectrum [neutrino]resolutionenergy spectrum [neutrino]flux [neutrino]neutrino: particle source13. Climate actionHigh Energy Physics::Experimentneutrino: oscillationneutrino detector
researchProduct