轻子散射实验是探索核子与原子核结构的理想工具。中国电子离子对撞机(Electron Ion Collider in China,EicC)建议书设想在已开建的强流重离子加速器装置(High Intensity heavy ion Accelerator Facility,HIAF)的基础上,升级质子束流为2...轻子散射实验是探索核子与原子核结构的理想工具。中国电子离子对撞机(Electron Ion Collider in China,EicC)建议书设想在已开建的强流重离子加速器装置(High Intensity heavy ion Accelerator Facility,HIAF)的基础上,升级质子束流为20 GeV的极化束流,并建造2.8~5 GeV极化电子束流,从而实现质心系能量为15~20 GeV的双极化电子-离子对撞。EicC设计的亮度为(2~4)×10^33cm^-2·s^-1,质子束流极化率达到70%,电子束流极化率达到80%。该装置除了能提供极化轻离子束流(例如:氦-3)外,也可产生非极化重离子束流(碳-12~铀-238)。EicC将聚焦核子海夸克部分子结构、原子核物质结构与性质、奇特强子态三个方面的物理研究。高亮度、高精度的对撞机有助于精确地测量核子结构函数并对核子进行三维成像,揭示强相互作用的动力学规律;原子核部分子分布包括核子短程关联以及原子核介质效应同样是该提案的重要科学目标;EicC能区接近重味夸克产生阈值,在研究重味强子谱方面拥有低背景的独特优势,有助于发现研究新的奇特强子态。质子质量起源问题也可以通过重味矢量介子的产生来研究。为了完成上述物理目标,我们将利用最先进的探测器技术建造接近全立体角覆盖的EicC对撞机谱仪。在准备EicC白皮书的过程中,我们得到世界各国专家的支持。EicC的物理与已有的实验和美国即将建设的EIC中的物理项目相互补充。EicC的建成及运行有望引领前沿的中高能核物理研究,使我国在加速器和探测器先进技术等领域实现跨越式发展,为我国核物理与强子物理以及相关科学领域提供大型综合实验平台与人才培养基地。展开更多
The property of σ-meson or f0(400-1200)is studied in the general color symmetry model(GCM)for quantum chromodynamics.With recent determined values of mσ,fσand fπin GCM,the isoscalarππS-wave amplitude is calculat...The property of σ-meson or f0(400-1200)is studied in the general color symmetry model(GCM)for quantum chromodynamics.With recent determined values of mσ,fσand fπin GCM,the isoscalarππS-wave amplitude is calculated without any free parameter.The T-matrix pole for f0(400-1200)is found to be 1011-i 284MeV,which is very close to the Particle Data Group value(400-1200)-i(300-500)MeV.展开更多
The pp → nK^＋E^＋ reaction is a very good isospin 3/2 filter for studying △^＋＋＊ decaying to K^＋E^＋. The proton beam experiment with a scheduled 4π hadron detector at Lanzhou Cooler Storage Ring （CSR） will m...The pp → nK^＋E^＋ reaction is a very good isospin 3/2 filter for studying △^＋＋＊ decaying to K^＋E^＋. The proton beam experiment with a scheduled 4π hadron detector at Lanzhou Cooler Storage Ring （CSR） will make the study of this reaction possible. Here, based on very limited available knowledge on the relevant ingredients for this reaction, we give theoretical prediction with Monte Carlo simulation for various observables for this reaction. This could serve as a reference for building the scheduled hadron detector and for identifying new physics in the following-on experiments at CSR.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
The possible hadronic molecules in D_(S)^(∗)+Ξ_(c)(′,∗)systems with J^(P)=1/2−,3/2−,and 5/2−are investigated with interactions described by light meson exchanges.By varying the cutoff in a phenomenologically reasona...The possible hadronic molecules in D_(S)^(∗)+Ξ_(c)(′,∗)systems with J^(P)=1/2−,3/2−,and 5/2−are investigated with interactions described by light meson exchanges.By varying the cutoff in a phenomenologically reasonable range of 1−2.5 GeV,we find ten near-threshold(bound or virtual)states in the single-channel case.After introducing the coupled-channel dynamics of D_(+)^(s)Ξ_(c)-D_(s)^(+)Ξ′c-D_(s)^(∗+)Ξ_(c-)D_(s)^(+)Ξ_(c)^(*)-D_(s)^(∗)+sΞ′_(c)-D_(s)^(∗)Ξ_(c)^(∗)systems,these states,except those below the lowest channels in each JP sector,move into the complex energy plane and become resonances in the mass range 4.43−4.76 GeV.Their spin-parities and nearby thresholds are 1/2−(D_(s)^(+)Ξ′_(c)),1/2^(−)(D_(s)^(++)Ξ_(c)^(*)),1/2−(D_(s)^(∗+)Ξ_(c)),1/2−(D_(s)^(∗+)Ξ_(c)^(′)),1/2−(D_(s)^(∗+)Ξ_(c)^(∗)),3/2−(D_(s)^(∗+)(Ξc),3/2−(D_(s)^(+)Ξ_(c)),3/2−(D_(s)^(∗+)Ξ′c),3/2−(D_(+s)^(∗)Ξ_(c)^(∗)),and 5/2−(D_(s)^(∗+)Ξ_(c)^(∗)).The impact of theδ(r)-term in the one-boson-exchange model on these states is presented.SettingΛ=1.5 GeV as an illustrative value,it is found that 1/2−(D_(s)^(*+)Ξ_(c))is a stable bound state(becoming unstable if the coupling to lower channels is turned on),1/2−(D∗+sΞc)and 3/2−(D_(s)^(∗+)Ξ_(c))are physical resonances in cases where theδ(r)-term is included or excluded,and the other seven states are physical resonances or"virtual-state-like"poles near thresholds,depending on whether theδ(r)-term is included.In addition,the partial decay widths of the physical resonances are provided.These double-charm hidden-strangeness pentaquark states,as the partners of the experimentally observed Pc and Pcs states,can be searched for in the D(∗)Λ_(c)final states in the future.展开更多
文摘轻子散射实验是探索核子与原子核结构的理想工具。中国电子离子对撞机(Electron Ion Collider in China,EicC)建议书设想在已开建的强流重离子加速器装置(High Intensity heavy ion Accelerator Facility,HIAF)的基础上,升级质子束流为20 GeV的极化束流,并建造2.8~5 GeV极化电子束流,从而实现质心系能量为15~20 GeV的双极化电子-离子对撞。EicC设计的亮度为(2~4)×10^33cm^-2·s^-1,质子束流极化率达到70%,电子束流极化率达到80%。该装置除了能提供极化轻离子束流(例如:氦-3)外,也可产生非极化重离子束流(碳-12~铀-238)。EicC将聚焦核子海夸克部分子结构、原子核物质结构与性质、奇特强子态三个方面的物理研究。高亮度、高精度的对撞机有助于精确地测量核子结构函数并对核子进行三维成像,揭示强相互作用的动力学规律;原子核部分子分布包括核子短程关联以及原子核介质效应同样是该提案的重要科学目标;EicC能区接近重味夸克产生阈值,在研究重味强子谱方面拥有低背景的独特优势,有助于发现研究新的奇特强子态。质子质量起源问题也可以通过重味矢量介子的产生来研究。为了完成上述物理目标,我们将利用最先进的探测器技术建造接近全立体角覆盖的EicC对撞机谱仪。在准备EicC白皮书的过程中,我们得到世界各国专家的支持。EicC的物理与已有的实验和美国即将建设的EIC中的物理项目相互补充。EicC的建成及运行有望引领前沿的中高能核物理研究,使我国在加速器和探测器先进技术等领域实现跨越式发展,为我国核物理与强子物理以及相关科学领域提供大型综合实验平台与人才培养基地。
基金supported in part by the Chinese Academy of Sciences(CAS)under Grant No.XDB34030000 and No.QYZDBSSW-SYS013the National Natural Science Foundation of China(NSFC)under Grant No.11835015,No.12047503 and No.11961141012+1 种基金the NSFC and the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)through the funds provided to the Sino-German Collaborative Research Center TRR110"Symmetries and the Emergence of Structure in QCD"(NSFC Grant No.12070131001,DFG Project-ID 196253076)the CAS Center for Excellence in Particle Physics(CCEPP).
基金Supported by the National Natural Science Foundation of China under Grant Nos.19335022 and 19675057the China Post-doctoral Science Foundation+1 种基金the Grant LWTZ 1298 of the Academy of Sciencesthe K.C.Wong Education Foundation.
文摘The property of σ-meson or f0(400-1200)is studied in the general color symmetry model(GCM)for quantum chromodynamics.With recent determined values of mσ,fσand fπin GCM,the isoscalarππS-wave amplitude is calculated without any free parameter.The T-matrix pole for f0(400-1200)is found to be 1011-i 284MeV,which is very close to the Particle Data Group value(400-1200)-i(300-500)MeV.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10225525 and 10435080, and the Knowledge Innovation Project of the Chinese Academy of Sciences under Grant No KJCX2-SW-N02.
文摘The pp → nK^＋E^＋ reaction is a very good isospin 3/2 filter for studying △^＋＋＊ decaying to K^＋E^＋. The proton beam experiment with a scheduled 4π hadron detector at Lanzhou Cooler Storage Ring （CSR） will make the study of this reaction possible. Here, based on very limited available knowledge on the relevant ingredients for this reaction, we give theoretical prediction with Monte Carlo simulation for various observables for this reaction. This could serve as a reference for building the scheduled hadron detector and for identifying new physics in the following-on experiments at CSR.
基金This work was supported by the Spanish Ministerio de Ciencia e Innovación(MICINN)and the European Regional Development Fund(ERDF)under Contract PID2020-112777 GB-I00by the EU STRONG-2020 Project under the Program H2020-INFRAIA-2018–1 with Grant Agreement No.824093+4 种基金by Generalitat Valenciana under Contract PROMETEO/2020/023by the Chinese Academy of Sciences under Grant No.XDB34030000by the National Natural Science Foundation of China(NSFC)under Grants No.12125507,No.11835015,No.12047503,and No.11961141012by the NSFC and the Deutsche Forschungsgemeinschaft(DFG)through the funds provided to the Sino-German Collaborative Research Center TRR110“Symmetries and the Emergence of Structure in QCD”(NSFC Grant No.12070131001,DFG Project-ID 196253076)M.A.is supported by Generalitat Valenciana under Grant No.CIDEGENT/2020/002.
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 by the Doctoral Program of Tian Chi Foundation of Xinjiang Uyghur Autonomous Region of China(51052300506)the NSFC and the Deutsche Forschungsgemeinschaftn(DFG,German Research Foundation)through the funds provided to the Sino-German Collaborative Research Center TRR110“Symmetries and the Emergence of Structure in QCD”(NSFC 12070131001,DFG Project-ID 196253076-TRR 110),the NSFC(11835015,12047503)the Chinese Academy of Sciences(CAS)(XDB34030000)。
文摘The possible hadronic molecules in D_(S)^(∗)+Ξ_(c)(′,∗)systems with J^(P)=1/2−,3/2−,and 5/2−are investigated with interactions described by light meson exchanges.By varying the cutoff in a phenomenologically reasonable range of 1−2.5 GeV,we find ten near-threshold(bound or virtual)states in the single-channel case.After introducing the coupled-channel dynamics of D_(+)^(s)Ξ_(c)-D_(s)^(+)Ξ′c-D_(s)^(∗+)Ξ_(c-)D_(s)^(+)Ξ_(c)^(*)-D_(s)^(∗)+sΞ′_(c)-D_(s)^(∗)Ξ_(c)^(∗)systems,these states,except those below the lowest channels in each JP sector,move into the complex energy plane and become resonances in the mass range 4.43−4.76 GeV.Their spin-parities and nearby thresholds are 1/2−(D_(s)^(+)Ξ′_(c)),1/2^(−)(D_(s)^(++)Ξ_(c)^(*)),1/2−(D_(s)^(∗+)Ξ_(c)),1/2−(D_(s)^(∗+)Ξ_(c)^(′)),1/2−(D_(s)^(∗+)Ξ_(c)^(∗)),3/2−(D_(s)^(∗+)(Ξc),3/2−(D_(s)^(+)Ξ_(c)),3/2−(D_(s)^(∗+)Ξ′c),3/2−(D_(+s)^(∗)Ξ_(c)^(∗)),and 5/2−(D_(s)^(∗+)Ξ_(c)^(∗)).The impact of theδ(r)-term in the one-boson-exchange model on these states is presented.SettingΛ=1.5 GeV as an illustrative value,it is found that 1/2−(D_(s)^(*+)Ξ_(c))is a stable bound state(becoming unstable if the coupling to lower channels is turned on),1/2−(D∗+sΞc)and 3/2−(D_(s)^(∗+)Ξ_(c))are physical resonances in cases where theδ(r)-term is included or excluded,and the other seven states are physical resonances or"virtual-state-like"poles near thresholds,depending on whether theδ(r)-term is included.In addition,the partial decay widths of the physical resonances are provided.These double-charm hidden-strangeness pentaquark states,as the partners of the experimentally observed Pc and Pcs states,can be searched for in the D(∗)Λ_(c)final states in the future.
