Using the SG-III prototype laser at China Academy of Engineering Physics,Mianyang,we irradiated polystyrene(CH)samples with a thermal radiation drive,reaching conditions on the principal Hugoniot up to P≈1 TPa(10 Mba...Using the SG-III prototype laser at China Academy of Engineering Physics,Mianyang,we irradiated polystyrene(CH)samples with a thermal radiation drive,reaching conditions on the principal Hugoniot up to P≈1 TPa(10 Mbar),and away from the Hugoniot up to P≈300 GPa(3 Mbar).The response of each sample was measured with a velocity interferometry diagnostic to determine the material and shock velocity,and hence the conditions reached,and the reflectivity of the sample,from which changes in the conductivity can be inferred.By applying the selfimpedance mismatch technique with the measured velocities,the pressure and density of thermodynamic points away from the principal Hugoniot were determined.Our results show an unexpectedly large reflectivity at the highest shock pressures,while the off-Hugoniot points agree with previous work suggesting that shock-compressed CH conductivity is primarily temperature-dependent.展开更多
The interaction between{112}<111>deformation twinning and grain boundary in coaxial polycrystalline tantalum under shock compression was studied with molecular dynamics simulation under different grain pair miso...The interaction between{112}<111>deformation twinning and grain boundary in coaxial polycrystalline tantalum under shock compression was studied with molecular dynamics simulation under different grain pair misorientation angles(MA)and geometric compatibility factor(m’).Generally,in the coaxial polycrystal,the value of MA determines the occurrence of twin transfer(TT)or twin blockage(TB),i.e.,twin transfer occurs at MA≤29°with twin blockage otherwise.Under TT,the value of m’affects the selection of twin variants.,i.e.,the twin system with a larger m’is easier to active.The morphology of twin pairs is ruler-shaped and lenticular under TT and TB,respectively,with different thickening mechanisms,including grain boundary dislocation emission.展开更多
Using data taken at 29 center-of-mass energies between 4.16 and 4.70 GeV with the BESⅢdetector at the Beijing Electron Positron Collider corresponding to a total integrated luminosity of approximately 18.8 fb^(-1),th...Using data taken at 29 center-of-mass energies between 4.16 and 4.70 GeV with the BESⅢdetector at the Beijing Electron Positron Collider corresponding to a total integrated luminosity of approximately 18.8 fb^(-1),the process e^(+)e^(-)→pppñπ+c.c.is observed for the first time with a statistical significance of 11.5σ.The average Born cross sections in the energy ranges of(4.160,4.380)GeV,(4.400,4.600)GeV and(4.610,4.700)GeV are measured to be(21.5±5.7±1.2)fb,(46.3±10.6±2.5)fb and(59.0±9.4±3.2)fb,respectively,where the first uncertainties are statistical and the second are systematic.The line shapes of the pñ and ppπ^(-)invariant mass spectra are consistent with phase space distributions,indicating that no hexaquark or di-baryon state is observed.展开更多
Using(448.1±2.9)×10^(6)ψ(3686)for the weak baryonic decayψ(3686)→Λc+∑-+c.c..The analysis procedure is optimized using a blinded method.No significant signal is observed,and the upper limit on the branch...Using(448.1±2.9)×10^(6)ψ(3686)for the weak baryonic decayψ(3686)→Λc+∑-+c.c..The analysis procedure is optimized using a blinded method.No significant signal is observed,and the upper limit on the branching fraction(B)ofψ(3686)→Λc+∑-+c.c.is set as 1.4×10^(-5)at the 90%confidence level.展开更多
Using electron-positron annihilation data samples corresponding to an integrated luminosity of 4.5 fb-1,collected by the BESⅢdetector in the energy region between 4599.53 MeV and 4698.82 MeV,we report the first obser...Using electron-positron annihilation data samples corresponding to an integrated luminosity of 4.5 fb-1,collected by the BESⅢdetector in the energy region between 4599.53 MeV and 4698.82 MeV,we report the first observations of the Cabibbo-suppressed decaysΛ_(c)^(+)→nπ^(+)π^(0),Λ_(c)^(+)→nπ^(+)π^(-)π^(+),and the Cabibbo-favored decayΛ_(c)^(+)→nK^(-)π^(+)π^(+)with statistical significances of 7.9σ,7.8σ,and>10σ,respectively.The branching fractions of these decays are measured to be B(Λ_(c)^(+)→nπ^(+)π^(0))=(0.64±0.09±0.02)%,B(Λ_(c)^(+)→nπ^(+)π^(-)π^(+))=(0.45±0.07±0.03)%,and B(Λ_(c)^(+)→nK^(-)π^(+)π^(+))=(1.90±0.08±0.09)%,where the first uncertainties are statistical and the second are systematic.We find that the branching fraction of the decayΛ_(c)^(+)→nπ^(+)π^(0)is about one order of magnitude higher than that ofΛ_(c)^(+)→nπ^(+).展开更多
A new search for two-neutrino double-beta(2νββ)decay of^(136)Xe to the 0+1 excited state of 136Ba is performed with the full EXO-200 dataset.A deep learning-based convolutional neural network is used to discriminat...A new search for two-neutrino double-beta(2νββ)decay of^(136)Xe to the 0+1 excited state of 136Ba is performed with the full EXO-200 dataset.A deep learning-based convolutional neural network is used to discriminate signal from background events.Signal detection efficiency is increased relative to previous searches by EXO-200 by more than a factor of two.With the addition of the Phase II dataset taken with an upgraded detector,the median 90%confidence level half-life sensitivity of 2νββdecay to the 0+1 state of 136Ba is 2.9×10^(24)yr using a total^(136)Xe exposure of 234.1 kg yr.No statistically significant evidence for 2νββdecay to the 0^(+)_(1)state is observed,leading to a lower limit of T2ν1/2(0^(+)→0^(+)_(1))>1.4×10^(24)yr at 90%confidence level,improved by 70%relative to the current world's best constraint.展开更多
During the 2016-17 and 2018-19 running periods,the BESIII experiment collected 7.5 fb of e^(+)e^(-)collision data at center-of-mass energies ranging from 4.13 to 4.44 GeV.These data samples are primarily used for the ...During the 2016-17 and 2018-19 running periods,the BESIII experiment collected 7.5 fb of e^(+)e^(-)collision data at center-of-mass energies ranging from 4.13 to 4.44 GeV.These data samples are primarily used for the study of excited charmonium and charmoniumlike states.By analyzing the di-muon process e^(+)e^(-)→(γISR=FSR)μ^(+)μ^(-),we measure the center-of-mass energies of the data samples with a precision of 0.6 MeV.Through a run-by-run study,we find that the center-of-mass energies were stable throughout most of the data-collection period.展开更多
There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B fac...There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESⅢ, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESⅢ during the remaining operation period of BEPCⅡ. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCⅡ to higher luminosity.展开更多
Using a dedicated data sample taken in 2018 on the J/ψpeak,we perform a detailed study of the trigger efficiencies of the BESIII detector.The efficiencies are determined from three representative physics processes,na...Using a dedicated data sample taken in 2018 on the J/ψpeak,we perform a detailed study of the trigger efficiencies of the BESIII detector.The efficiencies are determined from three representative physics processes,namely Bhabha scattering,dimuon production and generic hadronic events with charged particles.The combined efficiency of all active triggers approaches 100%in most cases,with uncertainties small enough not to affect most physics analyses.展开更多
To study the temperature distribution and thermal-stress field in different service stages, a two-dimensional model of a turbine blade with thermal barrier coatings is developed, in which the conjugate heat transfer a...To study the temperature distribution and thermal-stress field in different service stages, a two-dimensional model of a turbine blade with thermal barrier coatings is developed, in which the conjugate heat transfer analysis and the decoupled thermal-stress calculation method are adopted. Based on the simulation results, it is found that a non-uniform distribution of temperature appears in different positions of the blade surface, which has directly impacted on stress field. The maximum temperature with a value of 1030 ℃ occurs at the leading edge. During the steady stage, the maximum stress of thermally grown oxide （TGO） appears in the middle of the suction side, reaching 3.75 GPa. At the end stage of cooling, the maximum compressive stress of TGO with a value of-3.5 GPa occurs at the leading edge. Thus, it can be predicted that during the steady stage the dangerous regions may locate at the suction side, while the leadine edge mav be more Drone to failure on cooling.展开更多
In this paper, a finite element model was developed for a turbine blade with thermal barrier coatings to investigate its failure behavior under cyclic thermal loading. Based on temperature and stress fields obtained f...In this paper, a finite element model was developed for a turbine blade with thermal barrier coatings to investigate its failure behavior under cyclic thermal loading. Based on temperature and stress fields obtained from finite element simulations, dangerous regions in ceramic coating were determined in terms of the maximum principal stress criterion. The results show that damage preferentially occurs in the chamfer and rabbet of a turbine blade with thermal barrier coatings and its thermal fatigue life decreases with the increase of thermal stress induced by high service temperature.展开更多
The formation and dissociation of Er deuteride grains were investigated by using scanning electron microscopy, in-situ X-ray diffraction and thermal desorption spectroscopy. Pure Er film shows classic columnar structu...The formation and dissociation of Er deuteride grains were investigated by using scanning electron microscopy, in-situ X-ray diffraction and thermal desorption spectroscopy. Pure Er film shows classic columnar structure, while the Er deuteride film was observed as bamboo-like morphology. The in-situ X-ray diffraction results demonstrate that the diffraction peaks of 27.39°, 28.43°, 31.71°, and 39.95° are ascribed to the crystal planes of （002）, （110）, （111）, and （112） of ErD3 phase, respectively. It is also confirmed that by in-situ X-ray diffraction technique, ErD3 grains would be dissociated at temperature exceeding 400 ℃. This result is consistent with the conclusion obtained by thermal desorption spectroscopy.展开更多
The establishment of a possible connection between neutrino emission and gravitational-wave(GW)bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge.In t...The establishment of a possible connection between neutrino emission and gravitational-wave(GW)bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge.In the Daya Bay experiment,using the data collected from December 2011 to August 2017,a search was per-formed for electron-antineutrino signals that coincided with detected GW events,including GW150914,GW151012,GW151226,GW170104,GW170608,GW 170814,and GW 170817.We used three time windows of±10,±500,and±1000 s relative to the occurrence of the GW events and a neutrino energy range of 1.8 to 100 MeV to search for correlated neutrino candidates.The detected electron-antineutrino candidates were consistent with the expected background rates for all the three time windows.Assuming monochromatic spectra,we found upper limits(90%confidence level)of the electron-antineutrino fluence of(1.13-2.44)×10^(11)cm^(-2)at 5 MeV to 8.0×10^(7)cm^(-2)at 100 MeV for the three time w indows.Under the assumption of a Fermi-Dirac spectrum,the upper limits were found to be(5.4-7.0)×10^(9)cm^(2)for the three time windows.展开更多
Studies of e^+e~→D_s^+■^((*)0)K^-and the P-wave charmed-strange mesons are performed based on an e^+e^-collision data sample corresponding to an integrated luminosity of 567 pb^(-1) collected with the BESIII detecto...Studies of e^+e~→D_s^+■^((*)0)K^-and the P-wave charmed-strange mesons are performed based on an e^+e^-collision data sample corresponding to an integrated luminosity of 567 pb^(-1) collected with the BESIII detector at s^(1/2)=4.600 GeV. The processes of e^+e^-→D_s^+■^(*0)K^- and D_s^+■~0K^- are observed for the first time and are found to be dominated by the modes D_s^+D_(s1)(2536)^-and D_s^+D_(s2)~*(2573)^-, respectively. The Born cross sections are measured to be σ~B(e^+e^-→D_s^+■^(*0)K^-) =(10.1±2.3±0.8) pb and σ~B(e^+e^-→D_s^+■~0K^-) =(19.4±2.3± 1.6) pb, and the products of Born cross section and the decay branching fraction are measured to be σ~B(e^+e^-→D_s^+D_(s1)(2536)^-+c.c.)·B(D_(s1)(2536)^-→■^(*0)K^-)=(7.5±1.8±0.7) pb and σ~B(e^+e^-→D_s^+D_(s2)~*(2573)^-+ c.c.)·B(D_(s2)~*(2573)^-→■~0 K^-)=(19.7 ± 2.9 ±2.0) pb. For the D_(s1)(2536)^-and D_(s2)~*(2573)^-mesons, the masses and widths are measured to be M(D_(s1)(2536)^-)=(2537.7±0.5 ±3.1) MeV/c2, Γ(D_(s1)(2536)^-) =(1.7 ±1.2 ±0.6)MeV, and M(D_(s2)~*(2573)^-)=(2570.7±2.0 ±1.7) MeV/c^2, Γ(D_(s2)~*(2573)^-)=(17.2 ±3.6 ±1.1) MeV. The spin-parity of the D_(s2)~*(2573)^-meson is determined to be J^p= 2^+. In addition, the processes e^+e^-→D_s^+■^((*)0)K^-are searched for using the data samples taken at four(two) center-of-mass energies between 4.416(4.527) and 4.575 GeV, and upper limits at the 90% confidence level on the cross sections are determined.展开更多
We study the hadronic decays of ∧c+ to the final states ∑+η and ∑+η’,using an e+e-annihilation data sample of 567 pb-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCⅡ collider....We study the hadronic decays of ∧c+ to the final states ∑+η and ∑+η’,using an e+e-annihilation data sample of 567 pb-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCⅡ collider.We find evidence for the decays ∧c+→∑+η and ∑+η’ with statistical significance of 2.5σ and 3.2σ,respectively.Normalizing to the reference decays ∧c+→∑+π0 and ∑+ω,we obtain the ratios of the branching fractions■and ■to be 0.35±0.16±0.02 and 0.86±0.34±0.04,respectively.The upper limits at the 90% confidence level are set to be■and■.Using BESIII measurements of the branching fractions of the reference decays,we determine B（∧c+→∑+η）=（0.41±0.19±0.05）%（<0.68%）and B（∧c+→∑+η’）=（1.34±0.53 ±0.19）%（<1.9%）.Here,the first uncertainties are statistical and the second systematic.The obtained branching fraction of ∧c+→∑+η is consistent with the previous measurement,and the branching fraction of ∧c+→∑+η’ is measured for the first time.展开更多
The prediction of reactor antineutrino spectra will play a crucial role as reactor experiments enter the precision era.The positron energy spectrum of 3.5 million antineutrino inverse beta decay reactions observed by ...The prediction of reactor antineutrino spectra will play a crucial role as reactor experiments enter the precision era.The positron energy spectrum of 3.5 million antineutrino inverse beta decay reactions observed by the Daya Bay experiment,in combination with the fission rates of fissile isotopes in the reactor,is used to extract the positron energy spectra resulting from the fission of specific isotopes.This information can be used to produce a precise,data-based prediction of the antineutrino energy spectrum in other reactor antineutrino experiments with different fission fractions than Daya Bay.The positron energy spectra are unfolded to obtain the antineutrino energy spectra by removing the contribution from detector response with the Wiener-SVD unfolding method.Consistent results are obtained with other unfolding methods.A technique to construct a data-based prediction of the reactor antineutrino energy spectrum is proposed and investigated.Given the reactor fission fractions,the technique can predict the energy spectrum to a 2%precision.In addition,we illustrate how to perform a rigorous comparison between the unfolded antineutrino spectrum and a theoretical model prediction that avoids the input model bias of the unfolding method.展开更多
The Er Al2@Al2O3 nanocapsules with Er Al2core and Al2O3 shell were synthesized by modified arc-charge technique.The typical core-shell structure of the nanocapsules was confirmed by high resolution transmission electr...The Er Al2@Al2O3 nanocapsules with Er Al2core and Al2O3 shell were synthesized by modified arc-charge technique.The typical core-shell structure of the nanocapsules was confirmed by high resolution transmission electron microscopy and X-ray photoelectron spectroscopy.Transmission electron microscopy analysis shows the irregular sphere of the nanocapules with an average diameter of 26 nm.Magnetic investigation revealed the Curie temperature of Er Al2@Al2O3 nanocapsules at 20 K and the typical superparamagnetic behavior between blocking temperature and Curie temperature.Based on the blocking temperature and average diameter,the magnetocrystalline anisotropy constant of Er Al2@Al2O3nanocapsules was estimated to illustrate the magnetic contribution to the-SM.The large-SMof 14.25 J/（kg K）was obtained under 50 k Oe at 5 K.A vital parameter β was introduced in the present work to scale the optimized magnetic characteristics and the optimized mechanism was discussed in detail according to classical superparamagnetic theory.The results demonstrate that the optimal-SMwill be obtained when the magnetic parameter β is close to the theoretical coefficient.展开更多
The integrated luminosities of data samples collected in the BESⅢ experiment in 2016-2017 at centerof-mass energies between 4.19 and 4.28 GeV are measured with a precision better than 1% by analyzing large-angle Bhab...The integrated luminosities of data samples collected in the BESⅢ experiment in 2016-2017 at centerof-mass energies between 4.19 and 4.28 GeV are measured with a precision better than 1% by analyzing large-angle Bhabha scattering events.The integrated luminosities of old datasets collected in 2010-2014 are updated by considering corrections related to detector performance,offsetting the effect of newly discovered readout errors in the electromagnetic calorimeter,which can haphazardly occur.展开更多
Using inclusive decays of J/ψ aprecise determination of the number of J/ψ events collected with the BESIII detector was performed.For the two data sets taken in 2009 and 2012,the numbers of J/ψ events were recalcul...Using inclusive decays of J/ψ aprecise determination of the number of J/ψ events collected with the BESIII detector was performed.For the two data sets taken in 2009 and 2012,the numbers of J/ψ events were recalculated to be(224.0±1.3)×10^(6) and(1088.5±4.4)×10^(6),respectively;these numbers are in good agreement with the previous measurements. For the J/ψ sample taken in 2017-2019,the number of events was determined to be(8774.0±39.4)×10^(6).The total number of J/ψ events collected with the BESIII detector was determined to be(10087±44)×10^(6),where the uncertainty is dominated by systematic effects,and the statistical uncertainty is negligible.展开更多
基金The authors would like to thank the technical teams at LFRC for their invaluable work producing the targets and operating the facility.N.J.H.and D.K.were supported by the Helmholtz Association under Grant No.VH-NG-1141.Y.L.was supported by the National Natural Science Foundation of China(Grant No.11605189).
文摘Using the SG-III prototype laser at China Academy of Engineering Physics,Mianyang,we irradiated polystyrene(CH)samples with a thermal radiation drive,reaching conditions on the principal Hugoniot up to P≈1 TPa(10 Mbar),and away from the Hugoniot up to P≈300 GPa(3 Mbar).The response of each sample was measured with a velocity interferometry diagnostic to determine the material and shock velocity,and hence the conditions reached,and the reflectivity of the sample,from which changes in the conductivity can be inferred.By applying the selfimpedance mismatch technique with the measured velocities,the pressure and density of thermodynamic points away from the principal Hugoniot were determined.Our results show an unexpectedly large reflectivity at the highest shock pressures,while the off-Hugoniot points agree with previous work suggesting that shock-compressed CH conductivity is primarily temperature-dependent.
基金financially supported by the Key-Area Re-search and Development Program of GuangDong Province(No.2019B010941001)National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact(No.6142902220301)+1 种基金Shanghai Engineering Research Center of High-Performance Medical Device Materials(No.20DZ2255500)the Major Science and Technology Infrastructure Project of Material Genome Bigscience Facilities Platform supported by Municipal Development and Reform Commission of Shenzhen.
文摘The interaction between{112}<111>deformation twinning and grain boundary in coaxial polycrystalline tantalum under shock compression was studied with molecular dynamics simulation under different grain pair misorientation angles(MA)and geometric compatibility factor(m’).Generally,in the coaxial polycrystal,the value of MA determines the occurrence of twin transfer(TT)or twin blockage(TB),i.e.,twin transfer occurs at MA≤29°with twin blockage otherwise.Under TT,the value of m’affects the selection of twin variants.,i.e.,the twin system with a larger m’is easier to active.The morphology of twin pairs is ruler-shaped and lenticular under TT and TB,respectively,with different thickening mechanisms,including grain boundary dislocation emission.
基金Supported in part by National Key R&D Program of China under Contracts Nos.Supported in part by National Key R&D Program of China(2020YFA0406300,2020YFA0406400)National Natural Science Foundation of China(NSFC)(11975118,11625523,11635010,11735014,11822506,11835012,11935015,11935016,11935018,11961141012,12022510,12025502,12035009,12035013,12061131003,12075252,12192260,12192261,12192262,12192263,12192264,12192265)+19 种基金the Natural Science Foundation of Hunan Province of China(2019JJ30019)the Science and Technology Innovation Program of Hunan Province(2020RC3054)the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1732263,U1832207)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH040)100 Talents Program of CASINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyERC(758462)European Union Horizon 2020 research and innovation programme under Contract No.Marie Sklodowska-Curie grant agreement(894790)German Research Foundation DFG(43159800)Collaborative Research Center CRC 1044,FOR 2359,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(DPT2006K-120470)National Science and Technology fundOlle Engkvist Foundation(200-0605)STFC(United Kingdom)The Knut and Alice Wallenberg Foundation(Sweden)(2016.0157)The Royal Society,UK(DH140054,DH160214)The Swedish Research CouncilU.S.Department of Energy(DE-FG02-05ER41374,DE-SC-0012069)。
文摘Using data taken at 29 center-of-mass energies between 4.16 and 4.70 GeV with the BESⅢdetector at the Beijing Electron Positron Collider corresponding to a total integrated luminosity of approximately 18.8 fb^(-1),the process e^(+)e^(-)→pppñπ+c.c.is observed for the first time with a statistical significance of 11.5σ.The average Born cross sections in the energy ranges of(4.160,4.380)GeV,(4.400,4.600)GeV and(4.610,4.700)GeV are measured to be(21.5±5.7±1.2)fb,(46.3±10.6±2.5)fb and(59.0±9.4±3.2)fb,respectively,where the first uncertainties are statistical and the second are systematic.The line shapes of the pñ and ppπ^(-)invariant mass spectra are consistent with phase space distributions,indicating that no hexaquark or di-baryon state is observed.
基金supported in part by National Key Research and Development Program of China(2020YFA0406400,2020YFA0406300)National Natural Science Foundation of China(NSFC,11975118,11635010,11735014,11835012,11935015,11935016,11935018,11961141012,12022510,12025502,12035009,12035013,12192260,12192261,12192262,12192263,12192264,12192265,12061131003)+18 种基金the Natural Science Foundation of Hunan Province of China(2019JJ30019)the Science and Technology Innovation Program of Hunan Province(2020RC3054)the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1832207)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH040)100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and Cosmology,ERC(758462)European Union’s Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement(894790)German Research Foundation DFG(443159800)Collaborative Research Center CRC 1044,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(DPT2006K-120470)National Science and Technology fundNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources and Institutional Development,Research and Innovation(B16F640076)STFC(United Kingdom)Suranaree University of Technology(SUT),Thailand Science Research and Innovation(TSRI),and National Science Research and Innovation Fund(NSRF,160355)The Royal Society,UK(DH140054,DH160214)The Swedish Research CouncilU.S.Department of Energy(DE-FG02-05ER41374)。
文摘Using(448.1±2.9)×10^(6)ψ(3686)for the weak baryonic decayψ(3686)→Λc+∑-+c.c..The analysis procedure is optimized using a blinded method.No significant signal is observed,and the upper limit on the branching fraction(B)ofψ(3686)→Λc+∑-+c.c.is set as 1.4×10^(-5)at the 90%confidence level.
基金Supported in part by National Key R&D Program of China(2020YFA0406400,2020YFA0406300)National Natural Science Foundation of China(NSFC)(11635010,11735014,11805086,11835012,11935015,11935016,11935018,11975011,11961141012,12022510,12025502,12035009,12035013,12192260,12192261,12192262,12192263,12192264,12192265)+20 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1832207)the CAS Center for Excellence in Particle Physics(CCEPP)100 Talents Program of CASFundamental Research Funds for the Central Universities,Lanzhou University,University of Chinese Academy of SciencesThe Institute of Nuclear and Particle Physics(INPAC)Shanghai Key Laboratory for Particle Physics and CosmologyERC(758462)German Research Foundation DFG(443159800)Collaborative Research Center CRC 1044,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(DPT2006K-120470)National Science and Technology fundNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation(B16F640076STFC)(United Kingdom)Suranaree University of Technology(SUT)Thailand Science Research and Innovation(TSRI)National Science Research and Innovation Fund(NSRF)(160355)The Royal Society,UK(DH140054,DH160214)The Swedish Research CouncilU.S.Department of Energy(DEFG02-05ER41374)。
文摘Using electron-positron annihilation data samples corresponding to an integrated luminosity of 4.5 fb-1,collected by the BESⅢdetector in the energy region between 4599.53 MeV and 4698.82 MeV,we report the first observations of the Cabibbo-suppressed decaysΛ_(c)^(+)→nπ^(+)π^(0),Λ_(c)^(+)→nπ^(+)π^(-)π^(+),and the Cabibbo-favored decayΛ_(c)^(+)→nK^(-)π^(+)π^(+)with statistical significances of 7.9σ,7.8σ,and>10σ,respectively.The branching fractions of these decays are measured to be B(Λ_(c)^(+)→nπ^(+)π^(0))=(0.64±0.09±0.02)%,B(Λ_(c)^(+)→nπ^(+)π^(-)π^(+))=(0.45±0.07±0.03)%,and B(Λ_(c)^(+)→nK^(-)π^(+)π^(+))=(1.90±0.08±0.09)%,where the first uncertainties are statistical and the second are systematic.We find that the branching fraction of the decayΛ_(c)^(+)→nπ^(+)π^(0)is about one order of magnitude higher than that ofΛ_(c)^(+)→nπ^(+).
文摘A new search for two-neutrino double-beta(2νββ)decay of^(136)Xe to the 0+1 excited state of 136Ba is performed with the full EXO-200 dataset.A deep learning-based convolutional neural network is used to discriminate signal from background events.Signal detection efficiency is increased relative to previous searches by EXO-200 by more than a factor of two.With the addition of the Phase II dataset taken with an upgraded detector,the median 90%confidence level half-life sensitivity of 2νββdecay to the 0+1 state of 136Ba is 2.9×10^(24)yr using a total^(136)Xe exposure of 234.1 kg yr.No statistically significant evidence for 2νββdecay to the 0^(+)_(1)state is observed,leading to a lower limit of T2ν1/2(0^(+)→0^(+)_(1))>1.4×10^(24)yr at 90%confidence level,improved by 70%relative to the current world's best constraint.
基金Supported in part by National Key Research and Development Program of China(2020YFA0406300,2020YFA0406400)National Natural Science Foundation of China(NSFC)(11625523,11635010,11735014,11822506,11835012,11935015,11935016,11935018,11961141012)+12 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1732263,U1832207)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040)100 Talents Program of CAS,INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology,ERC(758462)European Union Horizon 2020 research and innovation programme(Marie Sklodowska-Curie grant agreement No 894790)German Research Foundation DFG(443159800)Collaborative Research Center CRC 1044,FOR 2359,FOR 2359,GRK 214Istituto Nazionale di Fisica Nucleare,Italy,Ministry of Development of Turkey(DPT2006K-120470)National Science and Technology fund,Olle Engkvist Foundation(200-0605)STFC(United Kingdom)The Knut and Alice Wallenberg Foundation(Sweden)(2016.0157)The Royal Society,UK(DH140054,DH160214)The Swedish Research Council,U.S.Department of Energy(DE-FG02-05ER41374,DE-SC-0012069)。
文摘During the 2016-17 and 2018-19 running periods,the BESIII experiment collected 7.5 fb of e^(+)e^(-)collision data at center-of-mass energies ranging from 4.13 to 4.44 GeV.These data samples are primarily used for the study of excited charmonium and charmoniumlike states.By analyzing the di-muon process e^(+)e^(-)→(γISR=FSR)μ^(+)μ^(-),we measure the center-of-mass energies of the data samples with a precision of 0.6 MeV.Through a run-by-run study,we find that the center-of-mass energies were stable throughout most of the data-collection period.
基金Supported in part by National Key Basic Research Program of China (2015CB856700)National Natural Science Foundation of China (NSFC) (11335008,11425524, 11625523, 11635010, 11735014, 11822506, 11935018)+18 种基金the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics (CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1532257, U1532258, U1732263)CAS Key Research Program of Frontier Science (QYZDJ-SSW-SLH003, QYZDJ-SSW-SLH040)100 Talents Program of CASCAS PIFIthe Thousand Talents Program of ChinaIN-PAC and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG under Contracts NosCollaborative Research Center CRC 1044, FOR 2359Istituto Nazionale di Fisica Nucleare, ItalyKoninklijke Nederlandse Akademie van Wetenschappen (KNAW) (530-4CDP03)Ministry of Development of Turkey (DPT2006K-120470)National Science and Technology fundThe Knut and Alice Wallenberg Foundation (Sweden) (2016.0157)The Swedish Research CouncilU. S. Department of Energy (DE-FG02-05ER41374, DESC-0010118, DE-SC-0012069)University of Groningen (Ru G) and the Helmholtzzentrum fuer Schwerionenforschung Gmb H (GSI), Darmstadtthe Russian Ministry of Science and Higher Education (14.W03.31.0026).
文摘There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESⅢ, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESⅢ during the remaining operation period of BEPCⅡ. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCⅡ to higher luminosity.
基金Supported in part by National Key Basic Research Program of China(2015CB856700)National Natural Science Foundation of China(NSFC)(11625523,11635010,11735014,11822506,11835012,11935015,11935016,11935018,11961141012)+15 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(U 1732263,U 1832207)CAS Key Research Program of Frontier Sciences(QYZDJ-SSWSLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyERC(758462)German Research Foundation DFG under Contracts Nos.Collaborative Research Center CRC 1044,FOR 2359Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development o f Turkey(DPT2006K-120470)National Science and Technology fundOlle Engkvist Foundation(200-0605)STFC(United Kingdom)The Knut and Alice Wallenberg Foundation(Sweden)(2016.0157)The Royal Society,UK(DH140054,DH160214)The Swedish Research CouncilU.S.Department of Energy(DEFG02-05ER41374,DE-SC-0012069)。
文摘Using a dedicated data sample taken in 2018 on the J/ψpeak,we perform a detailed study of the trigger efficiencies of the BESIII detector.The efficiencies are determined from three representative physics processes,namely Bhabha scattering,dimuon production and generic hadronic events with charged particles.The combined efficiency of all active triggers approaches 100%in most cases,with uncertainties small enough not to affect most physics analyses.
基金supported by the National Natural Science Foundation of China(Grant Nos.51172192,11272275 and 11002122)the Natural Science Foundation of Hunan Province(Grant No.11JJ4003)the Doctoral Scientific Research Foundation of Xiangtan University(Grant Nos.KZ08022,KZ03013 and KF20140303)
文摘To study the temperature distribution and thermal-stress field in different service stages, a two-dimensional model of a turbine blade with thermal barrier coatings is developed, in which the conjugate heat transfer analysis and the decoupled thermal-stress calculation method are adopted. Based on the simulation results, it is found that a non-uniform distribution of temperature appears in different positions of the blade surface, which has directly impacted on stress field. The maximum temperature with a value of 1030 ℃ occurs at the leading edge. During the steady stage, the maximum stress of thermally grown oxide （TGO） appears in the middle of the suction side, reaching 3.75 GPa. At the end stage of cooling, the maximum compressive stress of TGO with a value of-3.5 GPa occurs at the leading edge. Thus, it can be predicted that during the steady stage the dangerous regions may locate at the suction side, while the leadine edge mav be more Drone to failure on cooling.
基金supported by the National Natural Science Foundation of China(Nos.11002122,51172192,11272275 and 11002121)the Natural Science Foundation of Hunan Province, China(No.11JJ4003)the Key Project of Scientific Research Conditions in Hunan Province,China(No.2012TT2040)
文摘In this paper, a finite element model was developed for a turbine blade with thermal barrier coatings to investigate its failure behavior under cyclic thermal loading. Based on temperature and stress fields obtained from finite element simulations, dangerous regions in ceramic coating were determined in terms of the maximum principal stress criterion. The results show that damage preferentially occurs in the chamfer and rabbet of a turbine blade with thermal barrier coatings and its thermal fatigue life decreases with the increase of thermal stress induced by high service temperature.
基金supported by the Fundamental Research Funds for the Central Universities of Ministry of Education of China(No.ZYGX2012YB017)the National Natural Science Foundation of China(No.91126001)
文摘The formation and dissociation of Er deuteride grains were investigated by using scanning electron microscopy, in-situ X-ray diffraction and thermal desorption spectroscopy. Pure Er film shows classic columnar structure, while the Er deuteride film was observed as bamboo-like morphology. The in-situ X-ray diffraction results demonstrate that the diffraction peaks of 27.39°, 28.43°, 31.71°, and 39.95° are ascribed to the crystal planes of （002）, （110）, （111）, and （112） of ErD3 phase, respectively. It is also confirmed that by in-situ X-ray diffraction technique, ErD3 grains would be dissociated at temperature exceeding 400 ℃. This result is consistent with the conclusion obtained by thermal desorption spectroscopy.
基金Daya Bay is supported in part by the Ministry of Science and Technology o f China, the U.S. Department o f Energy, the Chinese Academy of Sciences, the CASCenter for Excellence in Particle Physics, the National Natural Science Foundation of China, the Guangdong provincial government, the Shenzhen municipal government,the China General Nuclear Power Group, Key Laboratory of Particle and Radiation Imaging (Tsinghua University), the Ministry of Education, Key Laboratory ofParticle Physics and Particle Irradiation (Shandong University), the Ministry o f Education, Shanghai Laboratory for Particle Physics and Cosmology, the ResearchGrants Council o f the Hong Kong Special Administrative Region of China, the University Development Fund of the University of Hong Kong, the MOE program forResearch of Excellence at National Taiwan University, National Chiao-Tung University, NSC fund support from Taiwan, the U.S. National Science Foundation, the AlfredP. Sloan Foundation, the Ministry o f Education, Youth, and Sports of the Czech Republic, the Charles University GAUK (284317), the Joint Institute o f NuclearResearch in Dubna, Russia, the National Commission of Scientific and Technological Research of Chile, and the Tsinghua University Initiative Scientific Research Program.
文摘The establishment of a possible connection between neutrino emission and gravitational-wave(GW)bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge.In the Daya Bay experiment,using the data collected from December 2011 to August 2017,a search was per-formed for electron-antineutrino signals that coincided with detected GW events,including GW150914,GW151012,GW151226,GW170104,GW170608,GW 170814,and GW 170817.We used three time windows of±10,±500,and±1000 s relative to the occurrence of the GW events and a neutrino energy range of 1.8 to 100 MeV to search for correlated neutrino candidates.The detected electron-antineutrino candidates were consistent with the expected background rates for all the three time windows.Assuming monochromatic spectra,we found upper limits(90%confidence level)of the electron-antineutrino fluence of(1.13-2.44)×10^(11)cm^(-2)at 5 MeV to 8.0×10^(7)cm^(-2)at 100 MeV for the three time w indows.Under the assumption of a Fermi-Dirac spectrum,the upper limits were found to be(5.4-7.0)×10^(9)cm^(2)for the three time windows.
基金Supported in part by National Key Basic Research Program of China(2015CB856700)National Natural Science Foundation of China(NSFC)(11335008,11425524,11625523,11635010,11735014)+9 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Program,the CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1532257,U1532258,U1732263)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASINPAC,Shanghai Key Laboratory for Particle Physics and Cosmology,German Research Foundation DFG under Contracts Nos.Collaborative Research Center CRC 1044,FOR 2359Istituto Nazionale di Fisica Nucleare,Italy,Koninklijke Nederlandse Akademie van Wetenschappen(KNAW)(530-4CDP03)Ministry of Development of Turkey(DPT2006K-120470)National Science and Technology fund,The Swedish Research CouncilU.S.Department of Energy(DE-FG02-05ER41374,DE-SC-0010118,DE-SC-0010504,DE-SC-0012069),University of Groningen(RuG)the Helmholtzzentrum fuer Schwerionenforschung GmbH(GSI),Darmstadt
文摘Studies of e^+e~→D_s^+■^((*)0)K^-and the P-wave charmed-strange mesons are performed based on an e^+e^-collision data sample corresponding to an integrated luminosity of 567 pb^(-1) collected with the BESIII detector at s^(1/2)=4.600 GeV. The processes of e^+e^-→D_s^+■^(*0)K^- and D_s^+■~0K^- are observed for the first time and are found to be dominated by the modes D_s^+D_(s1)(2536)^-and D_s^+D_(s2)~*(2573)^-, respectively. The Born cross sections are measured to be σ~B(e^+e^-→D_s^+■^(*0)K^-) =(10.1±2.3±0.8) pb and σ~B(e^+e^-→D_s^+■~0K^-) =(19.4±2.3± 1.6) pb, and the products of Born cross section and the decay branching fraction are measured to be σ~B(e^+e^-→D_s^+D_(s1)(2536)^-+c.c.)·B(D_(s1)(2536)^-→■^(*0)K^-)=(7.5±1.8±0.7) pb and σ~B(e^+e^-→D_s^+D_(s2)~*(2573)^-+ c.c.)·B(D_(s2)~*(2573)^-→■~0 K^-)=(19.7 ± 2.9 ±2.0) pb. For the D_(s1)(2536)^-and D_(s2)~*(2573)^-mesons, the masses and widths are measured to be M(D_(s1)(2536)^-)=(2537.7±0.5 ±3.1) MeV/c2, Γ(D_(s1)(2536)^-) =(1.7 ±1.2 ±0.6)MeV, and M(D_(s2)~*(2573)^-)=(2570.7±2.0 ±1.7) MeV/c^2, Γ(D_(s2)~*(2573)^-)=(17.2 ±3.6 ±1.1) MeV. The spin-parity of the D_(s2)~*(2573)^-meson is determined to be J^p= 2^+. In addition, the processes e^+e^-→D_s^+■^((*)0)K^-are searched for using the data samples taken at four(two) center-of-mass energies between 4.416(4.527) and 4.575 GeV, and upper limits at the 90% confidence level on the cross sections are determined.
基金Supported in part by National Key Basic Research Program of China(2015CB856700)National Natural Science Foundation of China(NSFC)(11235011,11275266,11335008,11425524,11625523,11635010)+16 种基金the Chinese Academy of Sciences(CAS) Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1332201,U1532257,U1532258)CAS(KJCX2-YW-N29,KJCX2-YW-N45,QYZDJ-SSW-SLH003)100 Talents Program of CASNational 1000 Talents Program of ChinaINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG(Collaborative Research Center CRC 1044,FOR 2359)Istituto Nazionale di Fisica Nucleare,ItalyKoninklijke Nederlandse Akademie van Wetenschappen(KNAW)(530-4CDP03)Ministry of Development of Turkey(DPT2006K-120470)National Science and Technology fundThe Swedish Research CouncilU.S. Department of Energy under(DE-FG02-05ER41374,DE-SC-0010118,DE-SC-0010504,DE-SC-0012069)University of Groningen(RuG)the Helmholtzzentrum fuer Schwerionenforschung GmbH(GSI),DarmstadtWCU Program of National Research Foundation of Korea(R32-2008-000-10155-0)
文摘We study the hadronic decays of ∧c+ to the final states ∑+η and ∑+η’,using an e+e-annihilation data sample of 567 pb-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCⅡ collider.We find evidence for the decays ∧c+→∑+η and ∑+η’ with statistical significance of 2.5σ and 3.2σ,respectively.Normalizing to the reference decays ∧c+→∑+π0 and ∑+ω,we obtain the ratios of the branching fractions■and ■to be 0.35±0.16±0.02 and 0.86±0.34±0.04,respectively.The upper limits at the 90% confidence level are set to be■and■.Using BESIII measurements of the branching fractions of the reference decays,we determine B（∧c+→∑+η）=（0.41±0.19±0.05）%（<0.68%）and B（∧c+→∑+η’）=（1.34±0.53 ±0.19）%（<1.9%）.Here,the first uncertainties are statistical and the second systematic.The obtained branching fraction of ∧c+→∑+η is consistent with the previous measurement,and the branching fraction of ∧c+→∑+η’ is measured for the first time.
基金Supported in part by the Ministry of Science and Technology of Chinathe U.S.Department of Energy,the Chinese Academy of Sciences,the CAS Center for Excellence in Particle Physics,the National Natural Science Foundation of China+3 种基金the Guangdong provincial governmentthe Shenzhen municipal government,the China General Nuclear Power Group,the Research Grants Council of the Hong Kong Special Administrative Region of China,the Ministry of Education in TWthe U.S.National Science Foundation,the Ministry of Education,Youth,and Sports of the Czech Republic,the Charles University Research Centre UNCE,the Joint Institute of Nuclear Research in Dubna,Russiathe National Commission of Scientific and Technological Research of Chile。
文摘The prediction of reactor antineutrino spectra will play a crucial role as reactor experiments enter the precision era.The positron energy spectrum of 3.5 million antineutrino inverse beta decay reactions observed by the Daya Bay experiment,in combination with the fission rates of fissile isotopes in the reactor,is used to extract the positron energy spectra resulting from the fission of specific isotopes.This information can be used to produce a precise,data-based prediction of the antineutrino energy spectrum in other reactor antineutrino experiments with different fission fractions than Daya Bay.The positron energy spectra are unfolded to obtain the antineutrino energy spectra by removing the contribution from detector response with the Wiener-SVD unfolding method.Consistent results are obtained with other unfolding methods.A technique to construct a data-based prediction of the reactor antineutrino energy spectrum is proposed and investigated.Given the reactor fission fractions,the technique can predict the energy spectrum to a 2%precision.In addition,we illustrate how to perform a rigorous comparison between the unfolded antineutrino spectrum and a theoretical model prediction that avoids the input model bias of the unfolding method.
基金financially supported by the National Natural Science Foundation of China (Nos.51271178,51571195,51331006,51590883)
文摘The Er Al2@Al2O3 nanocapsules with Er Al2core and Al2O3 shell were synthesized by modified arc-charge technique.The typical core-shell structure of the nanocapsules was confirmed by high resolution transmission electron microscopy and X-ray photoelectron spectroscopy.Transmission electron microscopy analysis shows the irregular sphere of the nanocapules with an average diameter of 26 nm.Magnetic investigation revealed the Curie temperature of Er Al2@Al2O3 nanocapsules at 20 K and the typical superparamagnetic behavior between blocking temperature and Curie temperature.Based on the blocking temperature and average diameter,the magnetocrystalline anisotropy constant of Er Al2@Al2O3nanocapsules was estimated to illustrate the magnetic contribution to the-SM.The large-SMof 14.25 J/（kg K）was obtained under 50 k Oe at 5 K.A vital parameter β was introduced in the present work to scale the optimized magnetic characteristics and the optimized mechanism was discussed in detail according to classical superparamagnetic theory.The results demonstrate that the optimal-SMwill be obtained when the magnetic parameter β is close to the theoretical coefficient.
基金Supported in part by National Key R&D Program of China(2020YFA0406300,2020YFA0406400)National Natural Science Foundation of China(NSFC)(11625523,11635010,11735014,11822506,11835012,11935015,11935016,11935018,11961141012,12022510,12025502,12035009,12035013,12061131003)+16 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1732263,U1832207)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH040)100 Talents Program of CASINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyERC(758462)European Union Horizon 2020 research and innovation programme(Marie Sklodowska-Curie grant agreement No 894790)German Research Foundation DFG(443159800),Collaborative Research Center CRC 1044,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(DPT2006K-120470)National Science and Technology fundOlle Engkvist Foundation(200-0605)STFC(United Kingdom)The Knut and Alice Wallenberg Foundation(Sweden)(2016.0157)The Royal Society,UK(DH140054,DH160214)The Swedish Research CouncilU.S.Department of Energy(DE-FG02-05ER41374,DE-SC-0012069)。
文摘The integrated luminosities of data samples collected in the BESⅢ experiment in 2016-2017 at centerof-mass energies between 4.19 and 4.28 GeV are measured with a precision better than 1% by analyzing large-angle Bhabha scattering events.The integrated luminosities of old datasets collected in 2010-2014 are updated by considering corrections related to detector performance,offsetting the effect of newly discovered readout errors in the electromagnetic calorimeter,which can haphazardly occur.
基金Supported in part by National Key R&D Program of China(2020YFA0406300, 2020YFA0406400)National Natural Science Foundation of China(NSFC)(11625523, 11635010, 11735014, 11822506, 11835012, 11935015, 11935016, 11935018, 11961141012, 12022510, 12025502, 12035009, 12035013,12061131003,12075252)+16 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1732263, U1832207)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH040)100 Talents Program of CASINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyERC(758462)European Union Horizon 2020 research and innovation programme Marie Sklodowska-Curie grant agreement(894790)German Research Foundation DFG(443159800), Collaborative Research Center CRC 1044, FOR 2359, GRK 214Istituto Nazionale di Fisica Nucleare, ItalyMinistry of Development of Turkey under Contract No. DPT2006K-120470National Science and Technology fundOlle Engkvist Foundation(200-0605)STFC(United Kingdom)The Knut and Alice Wallenberg Foundation(Sweden)(2016.0157)The Royal Society, UK(DH140054, DH160214)The Swedish Research CouncilU. S. Department of Energy(DE-FG02-05ER41374, DE-SC-0012069)
文摘Using inclusive decays of J/ψ aprecise determination of the number of J/ψ events collected with the BESIII detector was performed.For the two data sets taken in 2009 and 2012,the numbers of J/ψ events were recalculated to be(224.0±1.3)×10^(6) and(1088.5±4.4)×10^(6),respectively;these numbers are in good agreement with the previous measurements. For the J/ψ sample taken in 2017-2019,the number of events was determined to be(8774.0±39.4)×10^(6).The total number of J/ψ events collected with the BESIII detector was determined to be(10087±44)×10^(6),where the uncertainty is dominated by systematic effects,and the statistical uncertainty is negligible.
