We report a search for a heavier partner of the recently observed Z_(cs)(3985)^(-) state,denoted as Z_(cs)^('-),in the process e^(+)e^(−)→K^(+)D_(s)^(∗−) D^(∗0 )+ c.c.,based on e^(*)e^(-)collision data collected ...We report a search for a heavier partner of the recently observed Z_(cs)(3985)^(-) state,denoted as Z_(cs)^('-),in the process e^(+)e^(−)→K^(+)D_(s)^(∗−) D^(∗0 )+ c.c.,based on e^(*)e^(-)collision data collected at the center-of-mass energies of √s=4.661,4.682 and 4.699 GeV with the BESIII detector.The Z_(cs)^('-) is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark.A partial-reconstruction technique is used to isolate K^(+)recoil-mass spectra,which are probed for a potential contribution from Z_(cs)^('-)→D_(s)^(∗−) D^(∗0 )+ c.c.We find an excess of Z_(cs)^('-)→D_(s)^(*-)-D^(*0)(c.c.)candidates with a significance of 2.1o,after considering systematic uncertainties,at a mass of(4123.5±0.7_(sat)±4.7_(syst.))MeV/c^(2).As the data set is limited in size,the upper limits are evaluated at the 90%confidence level on the product of the Born cross sections(σ^(Borm))and the branching fraction(B)of Z_(cs)^('-)→D_(s)^(*-)-D^(*0),under different assumptions of the Z_(cs)^('-) mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV at the three center-of-mass energies.The upper limits of σ^(Born).B are found to be at the level of O(1)pb at each energy.Larger data samples are needed to confirm the Z_(cs)^('-) state and clarify its nature in the coming years.展开更多
The complete and incomplete fusion cross sections for ^(6)Li+^(209)Bi were measured using the in-beamγ-ray method around the Coulomb barrier.The cross sections of(deuteron captured)incomplete fusion(ICF)products were...The complete and incomplete fusion cross sections for ^(6)Li+^(209)Bi were measured using the in-beamγ-ray method around the Coulomb barrier.The cross sections of(deuteron captured)incomplete fusion(ICF)products were re-quantified experimentally for this reaction system.The results reveal that the ICF cross section is equivalent to that of complete fusion(CF)above the Coulomb barrier and dominant near or below the Coulomb barrier.A theoretical calculation based on the continuum discretized coupled channel(CDCC)method was performed for the aforementioned CF and ICF cross sections;the result is consistent with the experiments.The universal fusion function(UFF)was also compared with the measured CF cross section for different barrier parameters,demonstrating that the CF suppression factor is significantly influenced by the choice of potential,which can reflect both dynamic and static effects of breakup on the fusion process.展开更多
Fatigue crack growth behaviors in electron beam weldments of a nickel-base superalloy are studied. The objective of this paper is to discuss effects of the inhomogeneity of mechanical performance on fatigue crack grow...Fatigue crack growth behaviors in electron beam weldments of a nickel-base superalloy are studied. The objective of this paper is to discuss effects of the inhomogeneity of mechanical performance on fatigue crack growth (FCG) rate and crack path deviation (CPD). The base metal served in a turbine disk of aerospace engine was selected to fabricate bead-on-plate weldments by using electron beam welding. Some wedge-type opening loading specimens, notched in three different zone of weld metal, HAZ and base metal, were employed and performed fatigue crack growth tests at 650℃. The results show that the fatigue crack growth of electron beam welded joints is instable due to the influence of mechanical heterogeneities. Owing to the crack deviation at the weld metal and heat-affected-zone (HAZ), the effective growth driving force at the tip of fatigue crack was reduced with the reduction of the effective stress intensity factor (SIF) which finally causes fatigue crack rate decrease. Fatigue crack was strongly affected by size and the symmetrical characteristics of the plastic zone at the crack tip, which means that the integrity of the welded structure containing the fatigue crack mainly depended on the toughness of the low strength zone.展开更多
In this study,we adopt the self-consistent Hartree-Fock-Bogoliubov(HFB) theory with the proton-neutron quasi-particle random phase approximation(pnQRPA) based on the Skyrme force for calculation of the β^(-) -decay h...In this study,we adopt the self-consistent Hartree-Fock-Bogoliubov(HFB) theory with the proton-neutron quasi-particle random phase approximation(pnQRPA) based on the Skyrme force for calculation of the β^(-) -decay half-lives for nuclei with N~82 and 126 on possible r-process paths.In the calculations,the Skyrme interaction(e.g.,SKO’) is adopted,and the tensor interaction is added self-consistently in both HFB and QRPA calculations.We systematically study how the half-life is changed by varying the strength of the triplet-even(TE) and triplet-odd(TO) components as well as the IS pairing.We find that a variation in strength of the IS pairing of approximately 20% does not produce a substantial effect on β-decay rates with or without the tensor force,while a strength variation of the TO tensor force considerably affects the change in the β-decay half-lives for the very neutron rich N~82 and 126 isotonic chains.In addition,with the inclusion of the tensor force,the GT decay becomes dominant for very neutron-rich nuclei.展开更多
Using e^(+)e^(−)annihilation data corresponding to an integrated luminosity of 2.93 fb^(−1)taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays...Using e^(+)e^(−)annihilation data corresponding to an integrated luminosity of 2.93 fb^(−1)taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η).The fit fractions of individual components are obtained,and large interferences among the dominant components of the decays D^(0)→a_(1)(1260)π,D^(0)→π(1300)π,D^(0)→ρ(770)ρ(770),and D^(0)→2(ππ)_(S)are observed in both channels.With the obtained amplitude model,the CP-even fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are determined to be(75.2±1.1_(stat).±1.5_(syst.))%and(68.9±1.5_(stat).±2.4_(syst.))%,respectively.The branching fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are measured to be(0.688±0.010_(stat.)±0.010_(syst.))%and(0.951±0.025_(stat.)±0.021_(syst.))%,respectively.The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of D^(0)→4πwhen used to determine the CKM angleγ(ϕ_(3))via the B^(−)→DK^(−)decay.展开更多
Background The Jiangmen Underground Neutrino Observatory(JUNO),a 20-kton multipurpose underground liquid scintillator detector,was proposed with the determination of the neutrino mass hierarchy as a primary physics go...Background The Jiangmen Underground Neutrino Observatory(JUNO),a 20-kton multipurpose underground liquid scintillator detector,was proposed with the determination of the neutrino mass hierarchy as a primary physics goal.To veto the cosmogenic background and shield the central detector from the environmental radioactivity,a multi-veto system,which consists of a water Cherenkov detector and a top tracker detector,is required.In order to keep the water quality good and remove the radon from water,an ultrapure water system,a radon removal system and radon concentration measurement system have been designed.Method The JUNO ultrapure water system was designed on the basis of the water system of the Daya Bay experiment.By installing the degassing membrane devices on the water system of JUNO prototype and Daya Bay experiment which can remove radon from water,the radon removal efficiency has been measured at the conditions of different gas–liquid phase pressures and different gas concentrations in water using the radon measurement system.Result Loading carbon dioxide into the water and increasing the inlet water pressure could help to improve the radon removal efficiency of the degassing membrane devices,and the radon concentration in water can be reduced to∼0.1 Bq/m^(3).Conclusion A reliable ultrapure water production and circulation system has been designed to keep the water quality good and to reduce the radon concentration in water for JUNO water Cherenkov detector.The radon concentration in water can satisfy the requirement of JUNO by using the Liqui-Cel degassing membrane devices.展开更多
Typhoon-generated waves pose a serious threat to the development of offshore wind power; therefore typical wave parameters caused by typhoon near Donghai Bridge, a demonstration area of offshore wind farm, were analys...Typhoon-generated waves pose a serious threat to the development of offshore wind power; therefore typical wave parameters caused by typhoon near Donghai Bridge, a demonstration area of offshore wind farm, were analysed. We pay particular attention to the dissipation term which is one of the source terms of governing equation for windwave evolution in WAVEWATCH llI. Anisotropic energy dissipation in the wave propagation direction is considered and further applied in our model. A good agreement is observed by comparison with in situ data. Furthermore, the new improved model is used to simulate and forecast wave evolution caused by Chan-Hom （201509）. The evolution of typical wave parameters i.e. significant wave height and mean wave period were discussed in the East China Sea, especially near Donghai Bridge.展开更多
基金Supported in part by National Key R&D Program of China(Grant Nos.2020YFA0406400,2020YFA0406300)National Natural Science Foundation of China(NSFC)(Grant Nos.11635010,11735014,11805086,11835012,11935015,11935016,11935018,11961141012,12022510,12025502,12035009,12035013,12192260,12192261,12192262,12192263,12192264,12192265)+18 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(Grant No.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)and Shanghai Key Laboratory for Particle Physics and CosmologyERC(Grant No.758462)European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement(Grant No.894790)German Research Foundation DFG(Grant No.443159800),Collaborative Research Center CRC 1044,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(Grant No.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(Grant No.B16F640076)Olle Engkvist Foundation(Grant No.200-0605)STFC(United Kingdom)Suranaree University of Technology(SUT),Thailand Science Research and Innovation(TSRI),and National Science Research and Innovation Fund(NSRF)(Grant No.160355)The Royal Society,UK(Grant Nos.DH140054,DH160214)The Swedish Research CouncilU.S.Department of Energy(Grant No.DE-FG02-05ER41374)。
文摘We report a search for a heavier partner of the recently observed Z_(cs)(3985)^(-) state,denoted as Z_(cs)^('-),in the process e^(+)e^(−)→K^(+)D_(s)^(∗−) D^(∗0 )+ c.c.,based on e^(*)e^(-)collision data collected at the center-of-mass energies of √s=4.661,4.682 and 4.699 GeV with the BESIII detector.The Z_(cs)^('-) is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark.A partial-reconstruction technique is used to isolate K^(+)recoil-mass spectra,which are probed for a potential contribution from Z_(cs)^('-)→D_(s)^(∗−) D^(∗0 )+ c.c.We find an excess of Z_(cs)^('-)→D_(s)^(*-)-D^(*0)(c.c.)candidates with a significance of 2.1o,after considering systematic uncertainties,at a mass of(4123.5±0.7_(sat)±4.7_(syst.))MeV/c^(2).As the data set is limited in size,the upper limits are evaluated at the 90%confidence level on the product of the Born cross sections(σ^(Borm))and the branching fraction(B)of Z_(cs)^('-)→D_(s)^(*-)-D^(*0),under different assumptions of the Z_(cs)^('-) mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV at the three center-of-mass energies.The upper limits of σ^(Born).B are found to be at the level of O(1)pb at each energy.Larger data samples are needed to confirm the Z_(cs)^('-) state and clarify its nature in the coming years.
基金Supported by the National Nature Science Foundation of China(U2167204,11975040,1832130)The Brazilian authors thank the partial financial support from CNPq,FAPERJ,and INCT-FNA(Instituto Nacional de Ciência e Tecnologia,Física Nuclear e Aplicações),research Project No.(464898/2014-5)+4 种基金supported by(M.S.)the U.S.Department of Energy,Office of Science,and Office of Nuclear Physics(DE-AC02-06CH11357)supported By the Key Research and Development Program of Guangdong Province,China(2020B040420005)the Basic and Applied Basic Research Foundation of Guangdong Province,China(2021B1515120027)LingChuang Research Project of China National Nuclear Corporation(20221024000072F6-0002-7)the Nuclear Energy Development and Research Project(HNKF202224(28)),and the'111'Center(B20065).
文摘The complete and incomplete fusion cross sections for ^(6)Li+^(209)Bi were measured using the in-beamγ-ray method around the Coulomb barrier.The cross sections of(deuteron captured)incomplete fusion(ICF)products were re-quantified experimentally for this reaction system.The results reveal that the ICF cross section is equivalent to that of complete fusion(CF)above the Coulomb barrier and dominant near or below the Coulomb barrier.A theoretical calculation based on the continuum discretized coupled channel(CDCC)method was performed for the aforementioned CF and ICF cross sections;the result is consistent with the experiments.The universal fusion function(UFF)was also compared with the measured CF cross section for different barrier parameters,demonstrating that the CF suppression factor is significantly influenced by the choice of potential,which can reflect both dynamic and static effects of breakup on the fusion process.
基金National Defense Key Lab for High Energy Density Beam Technology in China for the financial support.
文摘Fatigue crack growth behaviors in electron beam weldments of a nickel-base superalloy are studied. The objective of this paper is to discuss effects of the inhomogeneity of mechanical performance on fatigue crack growth (FCG) rate and crack path deviation (CPD). The base metal served in a turbine disk of aerospace engine was selected to fabricate bead-on-plate weldments by using electron beam welding. Some wedge-type opening loading specimens, notched in three different zone of weld metal, HAZ and base metal, were employed and performed fatigue crack growth tests at 650℃. The results show that the fatigue crack growth of electron beam welded joints is instable due to the influence of mechanical heterogeneities. Owing to the crack deviation at the weld metal and heat-affected-zone (HAZ), the effective growth driving force at the tip of fatigue crack was reduced with the reduction of the effective stress intensity factor (SIF) which finally causes fatigue crack rate decrease. Fatigue crack was strongly affected by size and the symmetrical characteristics of the plastic zone at the crack tip, which means that the integrity of the welded structure containing the fatigue crack mainly depended on the toughness of the low strength zone.
基金Supported by the National Natural Science Foundation of China(11575120,11822504)Science Specialty Program of Sichuan University(2020SCUNL210)。
文摘In this study,we adopt the self-consistent Hartree-Fock-Bogoliubov(HFB) theory with the proton-neutron quasi-particle random phase approximation(pnQRPA) based on the Skyrme force for calculation of the β^(-) -decay half-lives for nuclei with N~82 and 126 on possible r-process paths.In the calculations,the Skyrme interaction(e.g.,SKO’) is adopted,and the tensor interaction is added self-consistently in both HFB and QRPA calculations.We systematically study how the half-life is changed by varying the strength of the triplet-even(TE) and triplet-odd(TO) components as well as the IS pairing.We find that a variation in strength of the IS pairing of approximately 20% does not produce a substantial effect on β-decay rates with or without the tensor force,while a strength variation of the TO tensor force considerably affects the change in the β-decay half-lives for the very neutron rich N~82 and 126 isotonic chains.In addition,with the inclusion of the tensor force,the GT decay becomes dominant for very neutron-rich nuclei.
基金Supported in part by the National Key R&D Program of China(2020YFA0406300,2020YFA0406400)the National Natural Science Foundation of China(NSFC)(11625523,11635010,11735014,11835012,11935015,11935016,11935018,11961141012,12025502,12035009,12035013,12061131003,12105276,12122509,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017)+15 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(U1732263,U1832103,U1832207,U2032111)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyEuropean Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement(894790)German Research Foundation DFG(455635585),Collaborative Research Center CRC 1044,FOR5327,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation of Thailand(B16F640076)Polish National Science Centre(2019/35/O/ST2/02907)The Swedish Research CouncilU.S.Department of Energy(DE-FG02-05ER41374)。
文摘Using e^(+)e^(−)annihilation data corresponding to an integrated luminosity of 2.93 fb^(−1)taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η).The fit fractions of individual components are obtained,and large interferences among the dominant components of the decays D^(0)→a_(1)(1260)π,D^(0)→π(1300)π,D^(0)→ρ(770)ρ(770),and D^(0)→2(ππ)_(S)are observed in both channels.With the obtained amplitude model,the CP-even fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are determined to be(75.2±1.1_(stat).±1.5_(syst.))%and(68.9±1.5_(stat).±2.4_(syst.))%,respectively.The branching fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are measured to be(0.688±0.010_(stat.)±0.010_(syst.))%and(0.951±0.025_(stat.)±0.021_(syst.))%,respectively.The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of D^(0)→4πwhen used to determine the CKM angleγ(ϕ_(3))via the B^(−)→DK^(−)decay.
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA10010300).
文摘Background The Jiangmen Underground Neutrino Observatory(JUNO),a 20-kton multipurpose underground liquid scintillator detector,was proposed with the determination of the neutrino mass hierarchy as a primary physics goal.To veto the cosmogenic background and shield the central detector from the environmental radioactivity,a multi-veto system,which consists of a water Cherenkov detector and a top tracker detector,is required.In order to keep the water quality good and remove the radon from water,an ultrapure water system,a radon removal system and radon concentration measurement system have been designed.Method The JUNO ultrapure water system was designed on the basis of the water system of the Daya Bay experiment.By installing the degassing membrane devices on the water system of JUNO prototype and Daya Bay experiment which can remove radon from water,the radon removal efficiency has been measured at the conditions of different gas–liquid phase pressures and different gas concentrations in water using the radon measurement system.Result Loading carbon dioxide into the water and increasing the inlet water pressure could help to improve the radon removal efficiency of the degassing membrane devices,and the radon concentration in water can be reduced to∼0.1 Bq/m^(3).Conclusion A reliable ultrapure water production and circulation system has been designed to keep the water quality good and to reduce the radon concentration in water for JUNO water Cherenkov detector.The radon concentration in water can satisfy the requirement of JUNO by using the Liqui-Cel degassing membrane devices.
基金supported by the National Science Foundation for the Youth of China (11102212)the State Key Program of National Science of China (11232012)
文摘Typhoon-generated waves pose a serious threat to the development of offshore wind power; therefore typical wave parameters caused by typhoon near Donghai Bridge, a demonstration area of offshore wind farm, were analysed. We pay particular attention to the dissipation term which is one of the source terms of governing equation for windwave evolution in WAVEWATCH llI. Anisotropic energy dissipation in the wave propagation direction is considered and further applied in our model. A good agreement is observed by comparison with in situ data. Furthermore, the new improved model is used to simulate and forecast wave evolution caused by Chan-Hom （201509）. The evolution of typical wave parameters i.e. significant wave height and mean wave period were discussed in the East China Sea, especially near Donghai Bridge.
