A new technology-rotationally accelerated shot peening（RASP）, was developed to prepare gradient structured materials. By using centrifugal acceleration principle and large steel balls, the RASP technology can produc...A new technology-rotationally accelerated shot peening（RASP）, was developed to prepare gradient structured materials. By using centrifugal acceleration principle and large steel balls, the RASP technology can produce much higher impact energy compared to conventional shot peening. As a proof-of-concept demonstration, the RASP was utilized to refine the surface layer in pure copper（Cu） with an average grain size of 85 nm. The grain size increases largely from surface downwards the bulk, forming an800 ？m thick gradient-structured surface layer and consequently a micro-hardness gradient. The difference between the RASP technology and other established techniques in preparing gradient structured materials is discussed. The RASP technology exhibits a promoting future for large-scale manufacturing of gradient materials.展开更多
The current work models a weak(soft) interface between two elastic materials as containing a periodic array of micro-crazes. The boundary conditions on the interfacial micro-crazes are formulated in terms of a system ...The current work models a weak(soft) interface between two elastic materials as containing a periodic array of micro-crazes. The boundary conditions on the interfacial micro-crazes are formulated in terms of a system of hypersingular integro-differential equations with unknown functions given by the displacement jumps across opposite faces of the micro-crazes. Once the displacement jumps are obtained by approximately solving the integro-differential equations, the effective stiffness of the micro-crazed interface can be readily computed. The effective stiffness is an important quantity needed for expressing the interfacial conditions in the spring-like macro-model of soft interfaces. Specific case studies are conducted to gain physical insights into how the effective stiffness of the interface may be influenced by the details of the interfacial micro-crazes.展开更多
We report an experimental investigation on laser ablation and associated surface structuring of CdZnTe by femtosecond Ti:Sa laser pulses(laser wavelengthλ≈800 nm,≈35 fs,10 Hz),in air.By exploiting different static ...We report an experimental investigation on laser ablation and associated surface structuring of CdZnTe by femtosecond Ti:Sa laser pulses(laser wavelengthλ≈800 nm,≈35 fs,10 Hz),in air.By exploiting different static irradiation conditions,the fluence threshold and the incubation effect in CdZnTe are estimated.Interestingly,surface treatment with a low laser fluence(laser pulse energy E≈5-10_μJ)and number of shots(5<N<50)show the formation of well-defined cracks in the central part of the shallow crater,which is likely associated to a different thermal expansion coefficients of Te inclusions and matrix during the sample heating and cooling processes ensuing femtosecond laser irradiation.Irradiation with a larger number of pulses(N≈500,1000)with higher pulse energies(E≈30-50μJ)results in the formation of welldefined laser-induced periodic surface structures(LIPSS)in the outskirts of the main crater,where the local fluence is well below the material ablation threshold.Both low spatial frequency and high spatial frequency LIPSS perpendicular to the laser polarization are found together and separately depending on the irradiation condition.These are ascribed to a process of progressive aggregation of randomly distributed nanoparticles produced during laser ablation of the deep crater in the region of the target irradiated by a fluence below the ablation threshold with many laser pulses.展开更多
A boundary integral method with radial basis function approximation is proposed for numerically solving an important class of boundary value problems governed by a system of thermoelastostatic equations with variable ...A boundary integral method with radial basis function approximation is proposed for numerically solving an important class of boundary value problems governed by a system of thermoelastostatic equations with variable coe?cients. The equations describe the thermoelastic behaviors of nonhomogeneous anisotropic materials with properties that vary smoothly from point to point in space. No restriction is imposed on the spatial variations of the thermoelastic coe?cients as long as all the requirements of the laws of physics are satis?ed. To check the validity and accuracy of the proposed numerical method, some speci?c test problems with known solutions are solved.展开更多
The structure, crystallization kinetics and magnetic property of as-quenched Fe_(73.5)Si_(13.5)B_9Nb_3Cu_1 amorphous ribbon(R0) as well as ribbons after autoclave treatment at 100°C and 150°C(R1 and R2) have...The structure, crystallization kinetics and magnetic property of as-quenched Fe_(73.5)Si_(13.5)B_9Nb_3Cu_1 amorphous ribbon(R0) as well as ribbons after autoclave treatment at 100°C and 150°C(R1 and R2) have been systematically studied by various techniques. With increasing autoclave treatment temperature,the measured structural, kinetic and magnetic parameters of samples increase firstly, i.e. R0 < R1; and then decrease or recover to the as-quenched sample, i.e. R2 < R1 or R2 ≈ R0. These results indicate that the SROs in R1 samples increased by transforming from fcc to bcc structure during the autoclave treatment and that the autoclave treatment can decrease the large radius(r_M) MRO(medium range order),but increase the small rMMRO. The measured structural, thermal and magnetic parameters of R2 sample have a tendency to recover toward as-quenched R0 sample. The thermal and magnetic parameters of samples after solely annealing treatment at higher temperature have no obvious recover phenomenon.The uneven actions of pressure and temperature in autoclave treatment may be helpful for us to search a new method to improve the magnetic properties of Fe-based glasses.展开更多
Ocean wave energy conversion as one of the renewable clean energy sources is attracting the research interests of many people.This review introduces different types of power take-off(PTO)technology of wave energy conv...Ocean wave energy conversion as one of the renewable clean energy sources is attracting the research interests of many people.This review introduces different types of power take-off(PTO)technology of wave energy converters.The novelty of this paper is to present advantages and disadvantages of the linear direct and indirect drive PTO devices for ocean wave energy conversion.The designs and optimizations of PTO systems of ocean wave energy converters have been studied from reviewing the recently published literature.The novel mechanical designs of the PTO systems have been compared and investigated in order to increase the energy harvesting efficiency.展开更多
Learning the Hamiltonian of a quantum system is indispensable for prediction of the system dynamics and realization of high fidelity quantum gates.However,it is a significant challenge to efficiently characterize the ...Learning the Hamiltonian of a quantum system is indispensable for prediction of the system dynamics and realization of high fidelity quantum gates.However,it is a significant challenge to efficiently characterize the Hamiltonian which has a Hilbert space dimension exponentially growing with the system size.Here,we develop and implement an adaptive method to learn the effective Hamiltonian of an 11-qubit quantum system consisting of one electron spin and ten nuclear spins associated with a single nitrogen-vacancy center in a diamond.We validate the estimated Hamiltonian by designing universal quantum gates based on the learnt Hamiltonian and implementing these gates in the experiment.Our experimental result demonstrates a well-characterized 11-qubit quantum spin register with the ability to test quantum algorithms,and shows our Hamiltonian learning method as a useful tool for characterizing the Hamiltonian of the nodes in a quantum network with solid-state spin qubits.展开更多
Grazing incident X-ray diffraction at different grazing angles for self-organized Ge dots grown on Si(001) are carried out and lattice constant expansions of 1.2?parallel to the surface as compared with the Si lattice...Grazing incident X-ray diffraction at different grazing angles for self-organized Ge dots grown on Si(001) are carried out and lattice constant expansions of 1.2?parallel to the surface as compared with the Si lattice are found within the Ge dots.A 3.1?lattice expansion of the Ge dots along the growth direction is also fund by ordinary X-ray(004) diffraction.According to the Poisson equation and the Vegard law,our results infer that the Ge dot should be a partially strain relaxed SiGe alloy with Ge content of abuot 55?2001 Elsevier Science B.V.All rights reserved.展开更多
Biological materials with various outstanding properties have been studied for a long time by investigators.As a kind of natural biological material,sea shells exhibiting the complexity and unique architectures have d...Biological materials with various outstanding properties have been studied for a long time by investigators.As a kind of natural biological material,sea shells exhibiting the complexity and unique architectures have drawn much attention in recent years.In the present work,Pinctada shell was selected as the target material,and its展开更多
Two dimensional layered films such as graphene and layered inorganic materials are promising for future nanoscale electronics and optics.We also performance of dielectric layer and metal contacts on the performces of ...Two dimensional layered films such as graphene and layered inorganic materials are promising for future nanoscale electronics and optics.We also performance of dielectric layer and metal contacts on the performces of field展开更多
Due to its far-reaching scientific impact and broad applications, coherent resonant tunneling effect in magnetic tunnel junctions has aroused intensive interest from spintronic and semiconductor communities. Actually,...Due to its far-reaching scientific impact and broad applications, coherent resonant tunneling effect in magnetic tunnel junctions has aroused intensive interest from spintronic and semiconductor communities. Actually, resonant tunneling effect has been verified and utilized in semiconductor-based multiquantum wells, such as resonant tunneling diode and light-emitting diodes with multiple quantum wells and etc.展开更多
By analyzing ψ(3686) data sample containing (107.7±0.6)×10^(6) events taken with the BESIII detector at the BEPCII storage ring in 2009,the χ_(c 0) resonance parameters are precisely measured using χ_(c 0...By analyzing ψ(3686) data sample containing (107.7±0.6)×10^(6) events taken with the BESIII detector at the BEPCII storage ring in 2009,the χ_(c 0) resonance parameters are precisely measured using χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) events.The mass of χ_(c 0) is determined to be M (χ_(c 0))=(3415.63±0.07±0.07±0.07)MeV/c^(2),and its full width is F (χ_(c 0))=(12.52±0.12±0.13)MeV,where the first uncertainty is statistical,the second systematic,and the third for mass comes from χ_(c 2) mass uncertainty.These measurements improve the precision of χ_(c 0) mass by a factor of four and width by one order of magnitude over the previous individual measurements,and significantly boost our knowledge about the charmonium spectrum.Together with additional (345.4±2.6)×10^(6)(3686) data events taken in 2012,the decay branching fractions of χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) are measured as well,with precision improved by a factor of three compared to previous measurements.These χ_(c 0) decay branching fractions provide important inputs for the study of glueballs.展开更多
Using 20.3 fb^(-1)of e^(+)e^(-)annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESⅢdetector,we report on an improved search for the radiative leptonic decay D^(+)→γe^(+)ve.An upper limi...Using 20.3 fb^(-1)of e^(+)e^(-)annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESⅢdetector,we report on an improved search for the radiative leptonic decay D^(+)→γe^(+)ve.An upper limit on its partial branching fraction for photon energies E_(γ)>10 MeV was determined to be 1.2×10^(-5)at a 90%confidence level;this excludes most current theoretical predictions.A sophisticated deep learning approach,which includes thorough validation and is based on the Transformer architecture,was implemented to efficiently distinguish the signal from massive backgrounds.展开更多
Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×10^(10)events collected using the BESIII detector at the BEPCII collider,we firstly search for the lepton number violation de...Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×10^(10)events collected using the BESIII detector at the BEPCII collider,we firstly search for the lepton number violation decayφ→π^(+)π^(+)e^(-)e^(-)via J/ψ→φη.No obviously signals are found.The upper limit on the branching fraction ofφ→π^(+)π^(+)e^(-)e^(-)is set to be 1.3×10^(-5)at the 90%confidence level.展开更多
Lepton number violation decayω→π^(+)π^(+)e^(-)e^(-)+c.c.is searched for via J/ψ→ωηusing a data sample of(1.0087±0.0044)×10^(10)J/ψevents collected via the BESIII detector at the BEPCII collider.No s...Lepton number violation decayω→π^(+)π^(+)e^(-)e^(-)+c.c.is searched for via J/ψ→ωηusing a data sample of(1.0087±0.0044)×10^(10)J/ψevents collected via the BESIII detector at the BEPCII collider.No significant signal is observed,and the upper limit on the branching fraction ofω→π^(+)π^(+)e^(-)e^(-)+c.c.at the 90%confidence level is determined for the first time to be 2.8×10^(-6).展开更多
We search for the leptonic decay D^(+)→e^(+)ν_(e)using an e+e-collision data sample with an integrated luminosity of 20.3 fb-1collected with the BESIII detector at a center-of-mass energy of 3.773 GeV.Significant si...We search for the leptonic decay D^(+)→e^(+)ν_(e)using an e+e-collision data sample with an integrated luminosity of 20.3 fb-1collected with the BESIII detector at a center-of-mass energy of 3.773 GeV.Significant signal is not observed,and an upper limit on the branching fraction of D^(+)→e^(+)ν_(e)is set as 9.7×10^(-7),at a confidence level of 90%.Our upper limit is an order of magnitude smaller than the previous limit for this decay mode.展开更多
Utilizing 4.5 fb^(-1)ofe^(+)e^(-)annihilation data collected at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV by the BESIII detector at the BEPCII collider,we searched for singly Cabibbo-suppressed h...Utilizing 4.5 fb^(-1)ofe^(+)e^(-)annihilation data collected at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV by the BESIII detector at the BEPCII collider,we searched for singly Cabibbo-suppressed hadronic decaysΛ_(c)^(+)→Σ^(0)K^(+)π^(0)andΛ_(c)^(+)→Σ^(0)K^(+)π^(+)π^(−)and with a single-tag method.No significant signals were observed for both decays.The upper limits on the branching fractions at the 90%confidence level were determined to be 5.0×10^(-4)for and forΛ_(c)^(+)→Σ^(0)K^(+)π^(0)and 6.5×10^(-4)forΛ_(c)^(+)→Σ^(0)K^(+)π^(+)π^(−).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
基金supports from the National Natural Science Foundation of China (Grant No. 51301092)Pangu Foundation are acknowledged
文摘A new technology-rotationally accelerated shot peening（RASP）, was developed to prepare gradient structured materials. By using centrifugal acceleration principle and large steel balls, the RASP technology can produce much higher impact energy compared to conventional shot peening. As a proof-of-concept demonstration, the RASP was utilized to refine the surface layer in pure copper（Cu） with an average grain size of 85 nm. The grain size increases largely from surface downwards the bulk, forming an800 ？m thick gradient-structured surface layer and consequently a micro-hardness gradient. The difference between the RASP technology and other established techniques in preparing gradient structured materials is discussed. The RASP technology exhibits a promoting future for large-scale manufacturing of gradient materials.
文摘The current work models a weak(soft) interface between two elastic materials as containing a periodic array of micro-crazes. The boundary conditions on the interfacial micro-crazes are formulated in terms of a system of hypersingular integro-differential equations with unknown functions given by the displacement jumps across opposite faces of the micro-crazes. Once the displacement jumps are obtained by approximately solving the integro-differential equations, the effective stiffness of the micro-crazed interface can be readily computed. The effective stiffness is an important quantity needed for expressing the interfacial conditions in the spring-like macro-model of soft interfaces. Specific case studies are conducted to gain physical insights into how the effective stiffness of the interface may be influenced by the details of the interfacial micro-crazes.
文摘We report an experimental investigation on laser ablation and associated surface structuring of CdZnTe by femtosecond Ti:Sa laser pulses(laser wavelengthλ≈800 nm,≈35 fs,10 Hz),in air.By exploiting different static irradiation conditions,the fluence threshold and the incubation effect in CdZnTe are estimated.Interestingly,surface treatment with a low laser fluence(laser pulse energy E≈5-10_μJ)and number of shots(5<N<50)show the formation of well-defined cracks in the central part of the shallow crater,which is likely associated to a different thermal expansion coefficients of Te inclusions and matrix during the sample heating and cooling processes ensuing femtosecond laser irradiation.Irradiation with a larger number of pulses(N≈500,1000)with higher pulse energies(E≈30-50μJ)results in the formation of welldefined laser-induced periodic surface structures(LIPSS)in the outskirts of the main crater,where the local fluence is well below the material ablation threshold.Both low spatial frequency and high spatial frequency LIPSS perpendicular to the laser polarization are found together and separately depending on the irradiation condition.These are ascribed to a process of progressive aggregation of randomly distributed nanoparticles produced during laser ablation of the deep crater in the region of the target irradiated by a fluence below the ablation threshold with many laser pulses.
文摘A boundary integral method with radial basis function approximation is proposed for numerically solving an important class of boundary value problems governed by a system of thermoelastostatic equations with variable coe?cients. The equations describe the thermoelastic behaviors of nonhomogeneous anisotropic materials with properties that vary smoothly from point to point in space. No restriction is imposed on the spatial variations of the thermoelastic coe?cients as long as all the requirements of the laws of physics are satis?ed. To check the validity and accuracy of the proposed numerical method, some speci?c test problems with known solutions are solved.
基金financially supported by the National Key Research Program of China(No.2016YFB0300501)the Key Research Project of Shandong Province(No.2016GGX102010)the National Natural Science Foundation of China(Nos.51471099,51571132,51511140291 and 51771103)
文摘The structure, crystallization kinetics and magnetic property of as-quenched Fe_(73.5)Si_(13.5)B_9Nb_3Cu_1 amorphous ribbon(R0) as well as ribbons after autoclave treatment at 100°C and 150°C(R1 and R2) have been systematically studied by various techniques. With increasing autoclave treatment temperature,the measured structural, kinetic and magnetic parameters of samples increase firstly, i.e. R0 < R1; and then decrease or recover to the as-quenched sample, i.e. R2 < R1 or R2 ≈ R0. These results indicate that the SROs in R1 samples increased by transforming from fcc to bcc structure during the autoclave treatment and that the autoclave treatment can decrease the large radius(r_M) MRO(medium range order),but increase the small rMMRO. The measured structural, thermal and magnetic parameters of R2 sample have a tendency to recover toward as-quenched R0 sample. The thermal and magnetic parameters of samples after solely annealing treatment at higher temperature have no obvious recover phenomenon.The uneven actions of pressure and temperature in autoclave treatment may be helpful for us to search a new method to improve the magnetic properties of Fe-based glasses.
基金Australia Research Council Discovery Project(Grant DPI70101039)for financial support.
文摘Ocean wave energy conversion as one of the renewable clean energy sources is attracting the research interests of many people.This review introduces different types of power take-off(PTO)technology of wave energy converters.The novelty of this paper is to present advantages and disadvantages of the linear direct and indirect drive PTO devices for ocean wave energy conversion.The designs and optimizations of PTO systems of ocean wave energy converters have been studied from reviewing the recently published literature.The novel mechanical designs of the PTO systems have been compared and investigated in order to increase the energy harvesting efficiency.
基金Supported by the Frontier Science Center for Quantum Information of the Ministry of Education of China,Tsinghua University Initiative Scientific Research Program,and the National Key Research and Development Program of China(2016YFA0301902)
文摘Learning the Hamiltonian of a quantum system is indispensable for prediction of the system dynamics and realization of high fidelity quantum gates.However,it is a significant challenge to efficiently characterize the Hamiltonian which has a Hilbert space dimension exponentially growing with the system size.Here,we develop and implement an adaptive method to learn the effective Hamiltonian of an 11-qubit quantum system consisting of one electron spin and ten nuclear spins associated with a single nitrogen-vacancy center in a diamond.We validate the estimated Hamiltonian by designing universal quantum gates based on the learnt Hamiltonian and implementing these gates in the experiment.Our experimental result demonstrates a well-characterized 11-qubit quantum spin register with the ability to test quantum algorithms,and shows our Hamiltonian learning method as a useful tool for characterizing the Hamiltonian of the nodes in a quantum network with solid-state spin qubits.
文摘Grazing incident X-ray diffraction at different grazing angles for self-organized Ge dots grown on Si(001) are carried out and lattice constant expansions of 1.2?parallel to the surface as compared with the Si lattice are found within the Ge dots.A 3.1?lattice expansion of the Ge dots along the growth direction is also fund by ordinary X-ray(004) diffraction.According to the Poisson equation and the Vegard law,our results infer that the Ge dot should be a partially strain relaxed SiGe alloy with Ge content of abuot 55?2001 Elsevier Science B.V.All rights reserved.
文摘Biological materials with various outstanding properties have been studied for a long time by investigators.As a kind of natural biological material,sea shells exhibiting the complexity and unique architectures have drawn much attention in recent years.In the present work,Pinctada shell was selected as the target material,and its
文摘Two dimensional layered films such as graphene and layered inorganic materials are promising for future nanoscale electronics and optics.We also performance of dielectric layer and metal contacts on the performces of field
基金financially supported by the National natural Science Foundation of China(NSFC)the State Key R&D Projects sponsored by the Ministry of Science and Technology(MOST)of Chinathe China France bilateral Cooperation and Exchange Projects,and the CAS
文摘Due to its far-reaching scientific impact and broad applications, coherent resonant tunneling effect in magnetic tunnel junctions has aroused intensive interest from spintronic and semiconductor communities. Actually, resonant tunneling effect has been verified and utilized in semiconductor-based multiquantum wells, such as resonant tunneling diode and light-emitting diodes with multiple quantum wells and etc.
基金Supported in part by National Key R&D Program of China(2020YFA0406300,2020YFA0406400,2023YFA1606000)National Natural Science Foundation of China(NSFC)(11635010,11735014,11935015,11935016,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+17 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(U1832207)100 Talents Program of CAS(ZR2022JQ02,ZR2024QA151)supported by Shandong Provincial Natural Science Foundationsupported by the China Postdoctoral Science Foundation(2023M742100)The Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG(FOR5327,GRK 2149)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry 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,B50G670107)Polish National Science Centre(2019/35/O/ST2/02907)Swedish Research Council(2019.04595)The Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘By analyzing ψ(3686) data sample containing (107.7±0.6)×10^(6) events taken with the BESIII detector at the BEPCII storage ring in 2009,the χ_(c 0) resonance parameters are precisely measured using χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) events.The mass of χ_(c 0) is determined to be M (χ_(c 0))=(3415.63±0.07±0.07±0.07)MeV/c^(2),and its full width is F (χ_(c 0))=(12.52±0.12±0.13)MeV,where the first uncertainty is statistical,the second systematic,and the third for mass comes from χ_(c 2) mass uncertainty.These measurements improve the precision of χ_(c 0) mass by a factor of four and width by one order of magnitude over the previous individual measurements,and significantly boost our knowledge about the charmonium spectrum.Together with additional (345.4±2.6)×10^(6)(3686) data events taken in 2012,the decay branching fractions of χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) are measured as well,with precision improved by a factor of three compared to previous measurements.These χ_(c 0) decay branching fractions provide important inputs for the study of glueballs.
基金supported in part by National Key R&D Program of China(2020YFA0406400,2023YFA1606000,2020YFA0406300)National Natural Science Foundation of China(NSFC)(11635010,11735014,11935015,11935016,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+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(U1832207)CAS(YSBR-101)100 Talents Program of CASCAS Project for Young Scientists in Basic Research(YSBR-117)The Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyAgencia Nacional de Investigación y Desarrollo de Chile(ANID),Chile(ANID PIA/APOYO AFB230003)German Research Foundation DFG(FOR5327)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry 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(B50G670107)Polish National Science Centre(2019/35/O/ST2/02907)Swedish Research Council(2019.04595)The Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘Using 20.3 fb^(-1)of e^(+)e^(-)annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESⅢdetector,we report on an improved search for the radiative leptonic decay D^(+)→γe^(+)ve.An upper limit on its partial branching fraction for photon energies E_(γ)>10 MeV was determined to be 1.2×10^(-5)at a 90%confidence level;this excludes most current theoretical predictions.A sophisticated deep learning approach,which includes thorough validation and is based on the Transformer architecture,was implemented to efficiently distinguish the signal from massive backgrounds.
基金supported in part by the National Key R&D Program of China(2020YFA0406300,2020YFA0406400)National Natural Science Foundation of China(NSFC)(12035009,11635010,11735014,11835012,11935015,11935016,11935018,11961141012,12025502,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017)+17 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(U1832207)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 Cosmologythe European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement(894790)the German Research Foundation DFG(455635585),the Collaborative Research Center CRC 1044,FOR5327,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF2022R1A2C1092335)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)Swedish Research Council(2019.04595)the Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)the U.S.Department of Energy(DE-FG02-05ER41374).
文摘Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×10^(10)events collected using the BESIII detector at the BEPCII collider,we firstly search for the lepton number violation decayφ→π^(+)π^(+)e^(-)e^(-)via J/ψ→φη.No obviously signals are found.The upper limit on the branching fraction ofφ→π^(+)π^(+)e^(-)e^(-)is set to be 1.3×10^(-5)at the 90%confidence level.
基金Supported in part by National Key R&D Program of China(2023YFA1606000,2023YFA1606704)National Natural Science Foundation of China(NSFC)(12035009,11875170,11635010,11935015,11935016,11935018,12025502,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+16 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Program,CAS(YSBR-101)100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)Shanghai Key Laboratory for Particle Physics and CosmologyAgencia Nacional de Investigación y Desarrollo de Chile(ANID)Chile(ANID PIA/APOYO AFB230003)ERC(758462)German Research Foundation DFG(FOR5327)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of MongoliaPolish National Science Centre(2024/53/B/ST2/00975)STFC(United Kingdom)Swedish Research Council(2019.04595)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘Lepton number violation decayω→π^(+)π^(+)e^(-)e^(-)+c.c.is searched for via J/ψ→ωηusing a data sample of(1.0087±0.0044)×10^(10)J/ψevents collected via the BESIII detector at the BEPCII collider.No significant signal is observed,and the upper limit on the branching fraction ofω→π^(+)π^(+)e^(-)e^(-)+c.c.at the 90%confidence level is determined for the first time to be 2.8×10^(-6).
基金Supported in part by the National Key R&D Program of China(2023YFA1606000,2020YFA0406400,2020YFA0406300)the National Natural Science Foundation of China(NSFC)(11635010,11735014,11935015,11935016,11875054,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+12 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)the Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U2032104,U1832207)the 100 Talents Program of CAS,the Excellent Youth Foundation of Henan Scientific Commitee(242300421044)the Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and Cosmology,the German Research Foundation DFG(FOR5327)the Istituto Nazionale di Fisica Nucleare,Italy,the Knut and Alice Wallenberg Foundation(2021.0174,2021.0299)the Ministry of Development of Turkey(DPT2006K-120470),the National Research Foundation of Korea(NRF-2022R1A2C1092335)the National Science and Technology Fund of Mongoliathe National Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research,and Innovation of Thailand(B16F640076,B50G670107)the Polish National Science Center(2019/35/O/ST2/02907)the Swedish Research Council(2019.04595)the Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)the US Department of Energy(DE-FG02-05ER41374)。
文摘We search for the leptonic decay D^(+)→e^(+)ν_(e)using an e+e-collision data sample with an integrated luminosity of 20.3 fb-1collected with the BESIII detector at a center-of-mass energy of 3.773 GeV.Significant signal is not observed,and an upper limit on the branching fraction of D^(+)→e^(+)ν_(e)is set as 9.7×10^(-7),at a confidence level of 90%.Our upper limit is an order of magnitude smaller than the previous limit for this decay mode.
基金supported in part by National Key R&D Program of China(2020YFA0406300,2020YFA0406400,2023YFA1606000)National Natural Science Foundation of China(NSFC)(12205141,11635010,11735014,11935015,11935016,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+16 种基金Natural Science Foundation of Hunan Province(2024JJ2044)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(U1832207)100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG(FOR5327)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF2022R1A2C1092335)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,B50G670107)Polish National Science Centre(2019/35/O/ST2/02907)Swedish Research Council(2019.04595)The Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘Utilizing 4.5 fb^(-1)ofe^(+)e^(-)annihilation data collected at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV by the BESIII detector at the BEPCII collider,we searched for singly Cabibbo-suppressed hadronic decaysΛ_(c)^(+)→Σ^(0)K^(+)π^(0)andΛ_(c)^(+)→Σ^(0)K^(+)π^(+)π^(−)and with a single-tag method.No significant signals were observed for both decays.The upper limits on the branching fractions at the 90%confidence level were determined to be 5.0×10^(-4)for and forΛ_(c)^(+)→Σ^(0)K^(+)π^(0)and 6.5×10^(-4)forΛ_(c)^(+)→Σ^(0)K^(+)π^(+)π^(−).
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.
