Based on(10087±44)×106J/ψevents collected with the BESⅢdetector,we search for the lepton number violating decay J/ψ→K+K+e-e-+c.c.for the first time.The upper limit on the branching fractio...Based on(10087±44)×106J/ψevents collected with the BESⅢdetector,we search for the lepton number violating decay J/ψ→K+K+e-e-+c.c.for the first time.The upper limit on the branching fraction of this decay is set to 2.1×10-9at the 90%confidence level with a frequentist method.This is the first search for J/ψdecays with a lepton number change by two,offering valuable insights into the underlying physical processes.展开更多
By analyzingψ(3686)data sample containing(107.7±0.6)×106events taken with the BESIII detector at the BEPCII storage ring in 2009,theχ_(c 0)resonance parameters are precisely measured usingχ_(c 0,c 2)→...By analyzingψ(3686)data sample containing(107.7±0.6)×106events taken with the BESIII detector at the BEPCII storage ring in 2009,theχ_(c 0)resonance parameters are precisely measured usingχ_(c 0,c 2)→π+π−/K+K−events.The mass ofχ_(c 0)is determined to be M(χ_(c 0))=(3415.63±0.07±0.07±0.07)MeV/c2,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 fromχ_(c 2)mass uncertainty.These measurements improve the precision ofχ_(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)×106(3686)data events taken in 2012,the decay branching fractions ofχ_(c 0,c 2)→π+π−/K+K−are measured as well,with precision improved by a factor of three compared to previous measurements.Theseχ_(c 0)decay branching fractions provide important inputs for the study of glueballs.展开更多
Using 20.3 fb-1of 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-1of 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 Eγ>10 MeV was determined to be 1.2×10-5at 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
Utilizing 4.5 fb-1ofe+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-1ofe+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 decaysΛc+→Σ0K+π0andΛc+→Σ0K+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 5.0×10-4for and forΛc+→Σ0K+π0and 6.5×10-4forΛc+→Σ0K+π+π−.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)×1010J/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)×1010J/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
Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×1010events 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)×1010events 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 1.3×10-5at the 90%confidence level.展开更多
We search for the leptonic decay D+→e+νeusing 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+νeusing 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+νeis 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
Based on a sample of 2.7x 109ψ(3686)events collected by the BESIII detector operating at the BEP-CII collider,the decay 4(3686)→YXcJ,XcJ→ηηη’is analyzed.The decay modes Xc1and Xc2→ηηη’are ob...Based on a sample of 2.7x 109ψ(3686)events collected by the BESIII detector operating at the BEP-CII collider,the decay 4(3686)→YXcJ,XcJ→ηηη’is analyzed.The decay modes Xc1and Xc2→ηηη’are observed for the first time,and their corresponding branching fractions are determined to be B(Xc1→ηηη’)=(1.40±0.13(stat.)±0.09(sys.))×10-4and B(Xc2→ηηη’)=(4.18±0.84(stat.)±0.48(sys.))×10-5.An upper limit on the branching fraction of xco→ηηη’is set as 2.59×10-5at a 90%confidence level(CL).A partial wave analys-is(PWA)of the decay Xc1→ηηη’is performed to search for the 1-+exotic stateη1(1855).The PWA result indic-ates that the structure in theηη’mass spectrum is attributed to f0(1500),while in the m mass spectrum,it is attrib-uted to the 0++phase space.The upper limit of B(xcl→η1(1855)η)·B(η1(1855)→ηη')<9.79×10-5is set based on the PWA at 90%CL.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 BESⅢand B facto...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 BESⅢand 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 BESⅢduring 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 BEPCⅡto higher luminosity.展开更多
The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of...The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5×1035cm–2·s–1or higher.The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory—the BEPCII,providing a unique platform for exploring the asymmetry of matter-antimatter(charge-parity violation),in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions,as well as searching for exotic hadrons and physics beyond the Standard Model.The STCF project in China is under development with an extensive R&D program.This document presents the physics opportunities at the STCF,describes conceptual designs of the STCF detector system,and discusses future plans for detector R&D and physics case studies.展开更多
The integrated luminosities of data samples collected in the BESⅢexperiment 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...The integrated luminosities of data samples collected in the BESⅢexperiment 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
The cross sections of e+e-→K+K-J/Ψat center-of-mass energies from 4.127 to 4.600 GeV are measured based on 15.6 fb-1data collected with the BESⅢdetector operating at the BEPCⅡstorage ring.Two resonant ...The cross sections of e+e-→K+K-J/Ψat center-of-mass energies from 4.127 to 4.600 GeV are measured based on 15.6 fb-1data collected with the BESⅢdetector operating at the BEPCⅡstorage ring.Two resonant structures are observed in the line shape of the cross sections.The mass and width of the first structure are measured to be(4225.3±2.3±21.5)MeV and(72.9±6.1±30.8)MeV,respectively.They are consistent with those of the established Y(4230).The second structure is observed for the first time with a statistical significance greater than 8σ,denoted as Y(4500).Its mass and width are determined to be(4484.7±13.3±24.1)MeV and(111.1±30.1±15.2)MeV,respectively.The first presented uncertainties are statistical and the second ones are systematic.The product of the electronic partial width with the decay branching fractionΓ(Y(4230)→e+e−)B(Y(4230)→K+K−J/Ψ)is reported.展开更多
Using inclusive decays of J/ψaprecise determination of the number of J/ψevents collected with the BESIII detector was performed.For the two data sets taken in 2009 and 2012,the numbers of J/ψevents were recalculate...Using inclusive decays of J/ψaprecise determination of the number of J/ψevents collected with the BESIII detector was performed.For the two data sets taken in 2009 and 2012,the numbers of J/ψevents were recalculated to be(224.0±1.3)×106and(1088.5±4.4)×106,respectively;these numbers are in good agreement with the previous measurements.For the J/ψsample taken in 2017-2019,the number of events was determined to be(8774.0±39.4)×106.The total number of J/ψevents collected with the BESIII detector was determined to be(10087±44)×106,where the uncertainty is dominated by systematic effects,and the statistical uncertainty is negligible.展开更多
The number ofψ(3686)events collected by the BESⅢdetector during the 2021 run period is determined to be(2259.3±11.1)×10~6 by counting inclusiveψ(3686)hadronic events.The uncertainty is systematic and the ...The number ofψ(3686)events collected by the BESⅢdetector during the 2021 run period is determined to be(2259.3±11.1)×10~6 by counting inclusiveψ(3686)hadronic events.The uncertainty is systematic and the statistical uncertainty is negligible.Meanwhile,the numbers ofψ(3686)events collected during the 2009 and 2012run periods are updated to be(107.7±0.6)×10~6 and(345.4±2.6)×10~6,respectively.Both numbers are consistent with the previous measurements within one standard deviation.The total number ofψ(3686)events in the three data samples is(2712.4±14.3)×10~6.展开更多
We report a search for a heavier partner of the recently observed Zcs(3985)-state,denoted as Zcs'-,in the process e+e−→K+Ds∗−D∗0+c.c.,based on e*e-collision data collected at t...We report a search for a heavier partner of the recently observed Zcs(3985)-state,denoted as Zcs'-,in the process e+e−→K+Ds∗−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 Zcs'-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 Zcs'-→Ds∗−D∗0+c.c.We find an excess of Zcs'-→Ds*--D*0(c.c.)candidates with a significance of 2.1o,after considering systematic uncertainties,at a mass of(4123.5±0.7sat±4.7syst.)MeV/c2.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(σBorm)and the branching fraction(B)of Zcs'-→Ds*--D*0,under different assumptions of the Zcs'-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 ofσBorn.B are found to be at the level of O(1)pb at each energy.Larger data samples are needed to confirm the Zcs'-state and clarify its nature in the coming years.展开更多
From December 2011 to May 2014,about 5 fb^-1 of data were taken with the BESIII detector at center-of-mass energies between 3.810 GeV and 4.600 GeV to study the charmonium-like states and higher excited charmonium sta...From December 2011 to May 2014,about 5 fb^-1 of data were taken with the BESIII detector at center-of-mass energies between 3.810 GeV and 4.600 GeV to study the charmonium-like states and higher excited charmonium states.The time-integrated luminosity of the collected data sample is measured to a precision of 1%by analyzing events produced by the large-angle Bhabha scattering process.展开更多
We present a measurement of the integrated luminosity of e+e-collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm=3.773 GeV.The integrated luminosities of the ...We present a measurement of the integrated luminosity of e+e-collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm=3.773 GeV.The integrated luminosities of the datasets taken from December 2021 to June 2022,from November 2022 to June 2023,and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1,8.157±0.031 fb-1,and 4.191±0.016 fb-1,respectively,by analyzing large angle Bhabha scattering events.The uncertainties are dominated by systematic effects,and the statistical uncertainties are negligible.Our results provide essential input for future analyses and precision measurements.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 s1/2=4.600 GeV. The processes of e^+e^-→D_s^+■*0K^- and D_s^+■~0K^- are observed for the first time and are found to be dominated by the modes D_s^+Ds1(2536)^-and D_s^+Ds2~*(2573)^-, respectively. The Born cross sections are measured to be σ~B(e^+e^-→D_s^+■*0K^-) =(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^+Ds1(2536)^-+c.c.)·B(Ds1(2536)^-→■*0K^-)=(7.5±1.8±0.7) pb and σ~B(e^+e^-→D_s^+Ds2~*(2573)^-+ c.c.)·B(Ds2~*(2573)^-→■~0 K^-)=(19.7 ± 2.9 ±2.0) pb. For the Ds1(2536)^-and Ds2~*(2573)^-mesons, the masses and widths are measured to be M(Ds1(2536)^-)=(2537.7±0.5 ±3.1) MeV/c2, Γ(Ds1(2536)^-) =(1.7 ±1.2 ±0.6)MeV, and M(Ds2~*(2573)^-)=(2570.7±2.0 ±1.7) MeV/c^2, Γ(Ds2~*(2573)^-)=(17.2 ±3.6 ±1.1) MeV. The spin-parity of the Ds2~*(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
Using e+e−annihilation data corresponding to an integrated luminosity of 2.93 fb−1taken 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−1taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays D0→π+π−π+π−and D0→π+π−π0π0(non-η).The fit fractions of individual components are obtained,and large interferences among the dominant components of the decays D0→a1(1260)π,D0→π(1300)π,D0→ρ(770)ρ(770),and D0→2(ππ)Sare observed in both channels.With the obtained amplitude model,the CP-even fractions of D0→π+π−π+π−and D0→π+π−π0π0(non-η)are determined to be(75.2±1.1stat.±1.5syst.)%and(68.9±1.5stat.±2.4syst.)%,respectively.The branching fractions of D0→π+π−π+π−and D0→π+π−π0π0(non-η)are measured to be(0.688±0.010stat.±0.010syst.)%and(0.951±0.025stat.±0.021syst.)%,respectively.The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of D0→4πwhen used to determine the CKM angleγ(ϕ3)via the B−→DK−decay.展开更多
From December 2019 to June 2021,the BESⅢexperiment collected approximately 5.85 fb−1of data at center-of-mass energies between 4.61 and 4.95 GeV.This is the highest collision energy BEPCⅡhas reached to date.The a...From December 2019 to June 2021,the BESⅢexperiment collected approximately 5.85 fb−1of data at center-of-mass energies between 4.61 and 4.95 GeV.This is the highest collision energy BEPCⅡhas reached to date.The accumulated e+e−annihilation data samples are useful for studying charmonium(-like)states and charmed-hadron decays.By adopting a novel method of analyzing the production of Ac+Ac-pairs in e+e−annihilation,the center-of-mass energies are measured with a precision of 0.6 MeV.Integrated luminosities are measured with a precision of better than 1%by analyzing the events of large-angle Bhabha scattering.These measurements provide important inputs to analyses based on these data samples.展开更多
基金supported in part by National Key R&D Program of China under Contracts Nos.2023YFA1606000,2023YFA1606704National Natural Science Foundation of China(NSFC)under Contracts Nos.12035009,11635010,11935015,11935016,11935018,12025502,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819+15 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramCAS under Contract No.YSBR-101100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG under Contract No.FOR5327Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation under Contracts Nos.2021.0174,2021.0299Ministry of Development of Turkey under Contract No.DPT2006K-120470National Research Foundation of Korea under Contract No.NRF-2022R1A2C1092335National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional DevelopmentResearch and Innovation of Thailand under Contract No.B50G670107Polish National Science Centre under Contract No.2024/53/B/ST2/00975Swedish Research Council under Contract No.2019.04595U.S.Department of Energy under Contract No.DE-FG02-05ER41374。
摘要Based on(10087±44)×106J/ψevents collected with the BESⅢdetector,we search for the lepton number violating decay J/ψ→K+K+e-e-+c.c.for the first time.The upper limit on the branching fraction of this decay is set to 2.1×10-9at the 90%confidence level with a frequentist method.This is the first search for J/ψdecays with a lepton number change by two,offering valuable insights into the underlying physical processes.
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)。
摘要By analyzingψ(3686)data sample containing(107.7±0.6)×106events taken with the BESIII detector at the BEPCII storage ring in 2009,theχ_(c 0)resonance parameters are precisely measured usingχ_(c 0,c 2)→π+π−/K+K−events.The mass ofχ_(c 0)is determined to be M(χ_(c 0))=(3415.63±0.07±0.07±0.07)MeV/c2,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 fromχ_(c 2)mass uncertainty.These measurements improve the precision ofχ_(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)×106(3686)data events taken in 2012,the decay branching fractions ofχ_(c 0,c 2)→π+π−/K+K−are measured as well,with precision improved by a factor of three compared to previous measurements.Theseχ_(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)。
摘要Using 20.3 fb-1of 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 Eγ>10 MeV was determined to be 1.2×10-5at 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 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)。
摘要Utilizing 4.5 fb-1ofe+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 decaysΛc+→Σ0K+π0andΛc+→Σ0K+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 5.0×10-4for and forΛc+→Σ0K+π0and 6.5×10-4forΛc+→Σ0K+π+π−.
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)。
摘要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)×1010J/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(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).
摘要Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×1010events 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 1.3×10-5at the 90%confidence level.
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)。
摘要We search for the leptonic decay D+→e+νeusing 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+νeis 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National Key R&D Program of China(2023YFA1606000,2023YFA1606704)National Natural Science Foundation of China(NSFC)(11635010,11935015,11935016,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+14 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramCAS(YSBR-101)100 Talents Program of CASThe 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(2024/53/B/ST2/00975)Swedish Research Council(2019.04595)U.S.Department of Energy(DE-FG02-05ER41374)。
摘要Based on a sample of 2.7x 109ψ(3686)events collected by the BESIII detector operating at the BEP-CII collider,the decay 4(3686)→YXcJ,XcJ→ηηη’is analyzed.The decay modes Xc1and Xc2→ηηη’are observed for the first time,and their corresponding branching fractions are determined to be B(Xc1→ηηη’)=(1.40±0.13(stat.)±0.09(sys.))×10-4and B(Xc2→ηηη’)=(4.18±0.84(stat.)±0.48(sys.))×10-5.An upper limit on the branching fraction of xco→ηηη’is set as 2.59×10-5at a 90%confidence level(CL).A partial wave analys-is(PWA)of the decay Xc1→ηηη’is performed to search for the 1-+exotic stateη1(1855).The PWA result indic-ates that the structure in theηη’mass spectrum is attributed to f0(1500),while in the m mass spectrum,it is attrib-uted to the 0++phase space.The upper limit of B(xcl→η1(1855)η)·B(η1(1855)→ηη')<9.79×10-5is set based on the PWA at 90%CL.
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).
摘要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 BESⅢand 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 BESⅢduring 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 BEPCⅡto higher luminosity.
基金supported by the National Key R&D Program of China under Contract No.2022YFA1602200the International Partnership Program of the Chineses Academy of Sciences under Grant No.211134KYSB20200057the STCF Key Technology Research and Development Project.
摘要The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5×1035cm–2·s–1or higher.The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory—the BEPCII,providing a unique platform for exploring the asymmetry of matter-antimatter(charge-parity violation),in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions,as well as searching for exotic hadrons and physics beyond the Standard Model.The STCF project in China is under development with an extensive R&D program.This document presents the physics opportunities at the STCF,describes conceptual designs of the STCF detector system,and discusses future plans for detector R&D and physics case studies.
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)。
摘要The integrated luminosities of data samples collected in the BESⅢexperiment 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)under Contracts Nos.(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 under Contracts Nos.(U1732263,U1832207)CAS Key Research Program of Frontier Sciences under Contract No.(QYZDJ-SSW-SLH040)100 Talents Program of CASINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyERC under Contract No.(758462)European Union Horizon 2020 research and innovation programme under Contract No.Marie Sklodowska-Curie grant agreement No(894790)German Research Foundation DFG under Contracts Nos.(443159800),Collaborative Research Center CRC 1044,FOR 2359,GRK 214Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey under Contract No.(DPT2006K-120470)National Science and Technology fundOlle Engkvist Foundation under Contract No.(200-0605)STFC(United Kingdom)The Knut and Alice Wallenberg Foundation(Sweden)under Contract No.(2016.0157)The Royal Society,UK under Contracts Nos.(DH140054,DH160214)The Swedish Research CouncilU.S.Department of Energy under Contracts Nos.(DE-FG02-05ER41374,DE-SC-001206)。
摘要The cross sections of e+e-→K+K-J/Ψat center-of-mass energies from 4.127 to 4.600 GeV are measured based on 15.6 fb-1data collected with the BESⅢdetector operating at the BEPCⅡstorage ring.Two resonant structures are observed in the line shape of the cross sections.The mass and width of the first structure are measured to be(4225.3±2.3±21.5)MeV and(72.9±6.1±30.8)MeV,respectively.They are consistent with those of the established Y(4230).The second structure is observed for the first time with a statistical significance greater than 8σ,denoted as Y(4500).Its mass and width are determined to be(4484.7±13.3±24.1)MeV and(111.1±30.1±15.2)MeV,respectively.The first presented uncertainties are statistical and the second ones are systematic.The product of the electronic partial width with the decay branching fractionΓ(Y(4230)→e+e−)B(Y(4230)→K+K−J/Ψ)is reported.
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)
摘要Using inclusive decays of J/ψaprecise determination of the number of J/ψevents collected with the BESIII detector was performed.For the two data sets taken in 2009 and 2012,the numbers of J/ψevents were recalculated to be(224.0±1.3)×106and(1088.5±4.4)×106,respectively;these numbers are in good agreement with the previous measurements.For the J/ψsample taken in 2017-2019,the number of events was determined to be(8774.0±39.4)×106.The total number of J/ψevents collected with the BESIII detector was determined to be(10087±44)×106,where the uncertainty is dominated by systematic effects,and the statistical uncertainty is negligible.
基金supported in part by National Key R&D Program of China under Contracts Nos.2020YFA0406300,2020YFA0406400National Natural Science Foundation of China(NSFC)under Contracts Nos.12150004,11635010,11735014,11835012,11935015,11935016,11935018,11961141012,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017+17 种基金the Program of Science and Technology Development Plan of Jilin Province of China under Contract Nos.20210508047RQ and 20230101021JCthe 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 under Contract No.U1832207CAS Key Research Program of Frontier Sciences under Contracts Nos.QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)Shanghai Key Laboratory for Particle Physics and CosmologyEuropean Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement under Contract No.894790German Research Foundation DFG under Contracts Nos.455635585,Collaborative Research Center CRC 1044,FOR5327,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey under Contract No.DPT2006K-120470National Research Foundation of Korea under Contract No.NRF-2022R1A2C1092335National 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 under Contract No.B16F640076Polish National Science Centre under Contract No.2019/35/O/ST2/02907The Swedish Research CouncilU.S.Department of Energy under Contract No.DE-FG02-05ER41374。
摘要The number ofψ(3686)events collected by the BESⅢdetector during the 2021 run period is determined to be(2259.3±11.1)×10~6 by counting inclusiveψ(3686)hadronic events.The uncertainty is systematic and the statistical uncertainty is negligible.Meanwhile,the numbers ofψ(3686)events collected during the 2009 and 2012run periods are updated to be(107.7±0.6)×10~6 and(345.4±2.6)×10~6,respectively.Both numbers are consistent with the previous measurements within one standard deviation.The total number ofψ(3686)events in the three data samples is(2712.4±14.3)×10~6.
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)。
摘要We report a search for a heavier partner of the recently observed Zcs(3985)-state,denoted as Zcs'-,in the process e+e−→K+Ds∗−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 Zcs'-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 Zcs'-→Ds∗−D∗0+c.c.We find an excess of Zcs'-→Ds*--D*0(c.c.)candidates with a significance of 2.1o,after considering systematic uncertainties,at a mass of(4123.5±0.7sat±4.7syst.)MeV/c2.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(σBorm)and the branching fraction(B)of Zcs'-→Ds*--D*0,under different assumptions of the Zcs'-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 ofσBorn.B are found to be at the level of O(1)pb at each energy.Larger data samples are needed to confirm the Zcs'-state and clarify its nature in the coming years.
基金Supported by National Key Basic Research Program of China(2015CB856700)National Natural Science Foundation of China(NSFC)(11125525,11235011,11322544,11335008,11425524)+5 种基金Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Program,Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(11179007,U1232201,U1332201)CAS(KJCX2-YW-N29,KJCX2-YW-N45)100 Talents Program of CAS,INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology,German Research Foundation DFG(Collaborative Research Center CRC-1044),Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(DPT2006K-120470)Russian Foundation for Basic Research(14-07-91152)U.S.Department of Energy(DE-FG02-04ER41291,DE-FG02-05ER41374,DE-FG02-94ER40823,DESC0010118)U.S.National Science Foundation,University of Groningen(RUG)and the Helmholtzzentrum fuer Schwerionenforschung GmbH(GSI),Darmstadt and WCU Program of National Research Foundation of Korea(R32-2008-000-10155-0)
摘要From December 2011 to May 2014,about 5 fb^-1 of data were taken with the BESIII detector at center-of-mass energies between 3.810 GeV and 4.600 GeV to study the charmonium-like states and higher excited charmonium states.The time-integrated luminosity of the collected data sample is measured to a precision of 1%by analyzing events produced by the large-angle Bhabha scattering process.
基金Supported in part by the National Key R&D Program of China(2020YFA0406400,2020YFA0406300,2023YFA1606000)the National Natural Science Foundation of China(123B2077,12035009,11635010,11735014,11875054,11935015,11935016,11935018,11961141012,12025502,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+8 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Program,the CAS Center for Excellence in Particle Physics(CCEPP),the Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U2032104,U1832207)the Excellent Youth Foundation of Henan Scientific Commitee(242300421044)100 Talents Program of CASthe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and Cosmology,German Research Foundation DFG(455635585,FOR5327,GRK 2149)Istituto Nazionale di Fisica Nucleare,Italy,Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of Mongolia,National 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)。
摘要We present a measurement of the integrated luminosity of e+e-collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm=3.773 GeV.The integrated luminosities of the datasets taken from December 2021 to June 2022,from November 2022 to June 2023,and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1,8.157±0.031 fb-1,and 4.191±0.016 fb-1,respectively,by analyzing large angle Bhabha scattering events.The uncertainties are dominated by systematic effects,and the statistical uncertainties are negligible.Our results provide essential input for future analyses and precision measurements.
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
摘要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 s1/2=4.600 GeV. The processes of e^+e^-→D_s^+■*0K^- and D_s^+■~0K^- are observed for the first time and are found to be dominated by the modes D_s^+Ds1(2536)^-and D_s^+Ds2~*(2573)^-, respectively. The Born cross sections are measured to be σ~B(e^+e^-→D_s^+■*0K^-) =(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^+Ds1(2536)^-+c.c.)·B(Ds1(2536)^-→■*0K^-)=(7.5±1.8±0.7) pb and σ~B(e^+e^-→D_s^+Ds2~*(2573)^-+ c.c.)·B(Ds2~*(2573)^-→■~0 K^-)=(19.7 ± 2.9 ±2.0) pb. For the Ds1(2536)^-and Ds2~*(2573)^-mesons, the masses and widths are measured to be M(Ds1(2536)^-)=(2537.7±0.5 ±3.1) MeV/c2, Γ(Ds1(2536)^-) =(1.7 ±1.2 ±0.6)MeV, and M(Ds2~*(2573)^-)=(2570.7±2.0 ±1.7) MeV/c^2, Γ(Ds2~*(2573)^-)=(17.2 ±3.6 ±1.1) MeV. The spin-parity of the Ds2~*(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 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)。
摘要Using e+e−annihilation data corresponding to an integrated luminosity of 2.93 fb−1taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays D0→π+π−π+π−and D0→π+π−π0π0(non-η).The fit fractions of individual components are obtained,and large interferences among the dominant components of the decays D0→a1(1260)π,D0→π(1300)π,D0→ρ(770)ρ(770),and D0→2(ππ)Sare observed in both channels.With the obtained amplitude model,the CP-even fractions of D0→π+π−π+π−and D0→π+π−π0π0(non-η)are determined to be(75.2±1.1stat.±1.5syst.)%and(68.9±1.5stat.±2.4syst.)%,respectively.The branching fractions of D0→π+π−π+π−and D0→π+π−π0π0(non-η)are measured to be(0.688±0.010stat.±0.010syst.)%and(0.951±0.025stat.±0.021syst.)%,respectively.The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of D0→4πwhen used to determine the CKM angleγ(ϕ3)via the B−→DK−decay.
基金Supported in part by National Key R&D Program of China(2020YFA0406400,2020YFA0406300)National Natural Science Foundation of China(NSFC)(11635010,11735014,11805086,11835012,11935015,11935016,11935018,11961141012,12022510,12025502,12035009,12035013,12192260,12192261,12192262,12192263,12192264,12192265)+17 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)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH040)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(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&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)。
摘要From December 2019 to June 2021,the BESⅢexperiment collected approximately 5.85 fb−1of data at center-of-mass energies between 4.61 and 4.95 GeV.This is the highest collision energy BEPCⅡhas reached to date.The accumulated e+e−annihilation data samples are useful for studying charmonium(-like)states and charmed-hadron decays.By adopting a novel method of analyzing the production of Ac+Ac-pairs in e+e−annihilation,the center-of-mass energies are measured with a precision of 0.6 MeV.Integrated luminosities are measured with a precision of better than 1%by analyzing the events of large-angle Bhabha scattering.These measurements provide important inputs to analyses based on these data samples.