We study the hadronic decays of ∧c^+ to the final states ∑^+η and ∑^+η, using an e^+e^- annihilation data sample of 567 pb^-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII col...We study the hadronic decays of ∧c^+ to the final states ∑^+η and ∑^+η, using an e^+e^- annihilation data sample of 567 pb^-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII collider. We find evidence for the decays ∧^+→∑^+η and ∑^+η' and with statistical significance of and , respectively. Normalizing to the reference decays ∧^+→∑^+π^0 and ∑^+ω, we obtain the ratios of the branching fractions B(∧C^+→∑^+η)/V(∧^→∑^+π^0)and B(∧C^+→∑^+η)/B(∧C^+→∑^+ω)to be and , respectively. The upper limits at the 90% confidence level are set to be B(∧C^→∑^+η)/V(∧^+→∑^+π^0)<0.58 and B(∧C^+→∑^+η)/B(∧C^+→∑^+ω)<1.2. Using BESIII measurements of the branching fractions of the reference decays, we determine B(∧C^+→∑^+η)=(0.41±019±0.05)%(<0.68%) and B(∧C^+→∑^+η)=(1.34+0.53+0.19)%(<1.9%). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of ∧C^+→∑^+η is consistent with the previous measurement, and the branching fraction of ∧C^+→∑^+η is measured for the first time.展开更多
By analyzing 2.93 fb-1 data collected at the center-of-mass energy s1/2=3.773 GeV with the BESⅢdetector,we measure the absolute branching fraction of the semileptonic decay D+→K0e+ve to be B（D+→K0e+ve） =（8.59 &#...By analyzing 2.93 fb-1 data collected at the center-of-mass energy s1/2=3.773 GeV with the BESⅢdetector,we measure the absolute branching fraction of the semileptonic decay D+→K0e+ve to be B（D+→K0e+ve） =（8.59 ±0.14 ±0.21）%using K0→KS0→π0π0,where the first uncertainty is statistical and the second systematic.Our result is consistent with previous measurements within uncertainties..展开更多
From December 2011 to May 2014, about 5 fb-1of data were taken with the BESIII detector at center-ofmass energies between 3.810 Ge V and 4.600 Ge V to study the charmonium-like states and higher excited charmonium sta...From December 2011 to May 2014, about 5 fb-1of data were taken with the BESIII detector at center-ofmass energies between 3.810 Ge V and 4.600 Ge V 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
The number of ψ’ events accumulated by the BESⅢ experiment from March 3 through April 14, 2009, is determined by counting inclusive hadronic events. The result is 106.41×(1.00±0.81%)×106 . The error ...The number of ψ’ events accumulated by the BESⅢ experiment from March 3 through April 14, 2009, is determined by counting inclusive hadronic events. The result is 106.41×(1.00±0.81%)×106 . The error is systematic dominant; the statistical error is negligible.展开更多
Data sets were collected with the BES detector at the BEPC collider at the center-of-mass energy of√s=3.650 GeV during May 2009 and at√s=3.773 GeV from January 2010 to May 2011.By analyzing the large angle Bhabha sc...Data sets were collected with the BES detector at the BEPC collider at the center-of-mass energy of√s=3.650 GeV during May 2009 and at√s=3.773 GeV from January 2010 to May 2011.By analyzing the large angle Bhabha scattering events,the integrated luminosities of the two data sets are measured to be(44.49±0.02±0.44)pb 1and(2916.94±0.18±29.17)pb 1,respectively,where the first error is statistical and the second error is systematic.展开更多
The decay channel ψ→π+π-J/ψ(J/ψ→γp) is studied using a sample of 1.06×108 ψ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the p invariant mass ...The decay channel ψ→π+π-J/ψ(J/ψ→γp) is studied using a sample of 1.06×108 ψ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the p invariant mass spectrum. The enhancement can be fitted with an S-wave Breit-Wigner resonance function with a resulting peak mass of M =1861+6-13 (stat)+7-26 (syst) MeV/c2 and a narrow width that is Γ <38 MeV/c2 at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with well established mesons.展开更多
There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B fac...There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESⅢ, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESⅢ during the remaining operation period of BEPCⅡ. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCⅡ to higher luminosity.展开更多
Studies of e+e?→D+sDˉˉˉˉ(?)0K?e+e?→Ds+Dˉ(?)0K?and the PP-wave charmed-strange mesons are performed based on an e+e?e+e?collision data sample corresponding to an integrated luminosity of 567 pb?1 collected with ...Studies of e+e?→D+sDˉˉˉˉ(?)0K?e+e?→Ds+Dˉ(?)0K?and the PP-wave charmed-strange mesons are performed based on an e+e?e+e?collision data sample corresponding to an integrated luminosity of 567 pb?1 collected with the BESIII detector at s√=4.600s=4.600 GeV.The processes of e+e?→D+sDˉˉˉˉ?0K?e+e?→Ds+Dˉ?0K?and D+sDˉˉˉˉ0K?Ds+Dˉ0K?are observed for the first time and are found to be dominated by the modes D+sDs1(2536)?Ds+Ds1(2536)?and D+sD?s2(2573)?Ds+Ds2?(2573)?,respectively.The Born cross sections are measured to beσB(e+e?→D+sDˉˉˉˉ?0K?)=(10.1±2.3±0.8)σB(e+e?→Ds+Dˉ?0K?)=(10.1±2.3±0.8)pb andσB(e+e?→D+sDˉˉˉˉ0K?)=(19.4±2.3±1.6)σB(e+e?→Ds+Dˉ0K?)=(19.4±2.3±1.6)pb,and the products of Born cross section and the decay branching fraction are measured to beσB(e+e?→D+sDs1(2536)?+c.c.)?σB(e+e?→Ds+Ds1(2536)?+c.c.)?B(Ds1(2536)?→Dˉˉˉˉ?0K?)=(7.5±1.8±0.7)B(Ds1(2536)?→Dˉ?0K?)=(7.5±1.8±0.7)pb andσB(e+e?→D+sD?s2(2573)?+c.c.)?B(D?s2(2573)?→Dˉˉˉˉ0K?)=σB(e+e?→Ds+Ds2?(2573)?+c.c.)?B(Ds2?(2573)?→Dˉ0K?)=(19.7±2.9±2.0)(19.7±2.9±2.0)pb.For the Ds1(2536)?Ds1(2536)?and D?s2(2573)?Ds2?(2573)?mesons,the masses and widths are measured to be M(Ds1(2536)?)=(2537.7±0.5±3.1)MeV/c2M(Ds1(2536)?)=(2537.7±0.5±3.1)MeV/c2,Γ(Ds1(2536)?)=(1.7±1.2±0.6)Γ(Ds1(2536)?)=(1.7±1.2±0.6)MeV,and M(D?s2(2573)?)=M(Ds2?(2573)?)=(2570.7±2.0±1.7)MeV/c2,(2570.7±2.0±1.7)MeV/c2,Γ(D?s2(2573)?)=(17.2±3.6±1.1)Γ(Ds2?(2573)?)=(17.2±3.6±1.1)MeV.The spin-parity of the D?s2(2573)?Ds2?(2573)?meson is determined to be JP=2+JP=2+.In addition,the processes e+e?→D+sDˉˉˉˉ(?)0K?e+e?→Ds+Dˉ(?)0K?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
To study the nature of the state Y(2175),a dedicated data set of e~ + e~-collision data was collected at the center-of-mass energy of 2.125 GeV with the BESⅢ detector at the BEPCⅡ collider.By analyzing large-angle B...To study the nature of the state Y(2175),a dedicated data set of e~ + e~-collision data was collected at the center-of-mass energy of 2.125 GeV with the BESⅢ detector at the BEPCⅡ collider.By analyzing large-angle Bhabha scattering events,the integrated luminosity of this data set is determined to be 108.49±0.02±0.85 pb~(-1),where the first uncertainty is statistical and the second one is systematic.In addition,the center-of-mass energy of the data set is determined with radiative dimuon events to be 2126.55±0.03±0.85 MeV,where the first uncertainty is statistical and the second one is systematic.展开更多
A measurement of the number of J/ψ events collected with the BESⅢ detector in 2009 and 2012 is performed using inclusive decays of the J/ψ. The number of J/ψ events taken in 2009 is recalculated to be(223.7±1...A measurement of the number of J/ψ events collected with the BESⅢ detector in 2009 and 2012 is performed using inclusive decays of the J/ψ. The number of J/ψ events taken in 2009 is recalculated to be(223.7±1.4)×10~6, which is in good agreement with the previous measurement, but with significantly improved precision due to improvements in the BESⅢ software. The number of J/ψ events taken in 2012 is determined to be(1086.9±6.0)×10~6. In total, the number of J/ψ events collected with the BESⅢ detector is measured to be(1310.6±7.0)×106, where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.展开更多
由分析散布事件 e <SUP>+</SUP 的大角度的 Bhabha > e <SUP></SUP>() e <SUP>+</SUP > e <SUP></SUP>和 diphoton 事件 e <SUP>+</SUP > e <SUP></SUP>(...由分析散布事件 e <SUP>+</SUP 的大角度的 Bhabha > e <SUP></SUP>() e <SUP>+</SUP > e <SUP></SUP>和 diphoton 事件 e <SUP>+</SUP > e <SUP></SUP>()为数据，集合与升级的北京在 center-of-mass ( c.m )收集了在 2.2324 和 4.5900 GeV (总共的 131 个精力点)之间的精力在北京电子正电子 Collider ( BEPCII )的分光计( BESIII )，综合光明个别地在不同 c.m 精力被测量了。结果是为 R 价值和 J/ 回声参数大小的重要输入。展开更多
From 2011 to 2014,the BESIII experiment collected about 5 fb-1 data at center-of-mass energies around 4 GeV for the studies of the charmonium-like and higher excited charmonium states.By analyzing the di-muon process ...From 2011 to 2014,the BESIII experiment collected about 5 fb-1 data at center-of-mass energies around 4 GeV for the studies of the charmonium-like and higher excited charmonium states.By analyzing the di-muon process e+e- → Yisr/fsr μ+μ-,the center-of-mass energies of the data samples are measured with a precision of 0.8 MeV.The center-of-mass energy is found to be stable for most of the time during data taking.展开更多
Using data samples collected at center-of-mass energies of √s=4.009, 4.230, 4.260, and 4.360 Ge V with the BES detector operating at the BEPC collider, we perform a search for the process e+e-→γχc J(J =0, 1, 2)and...Using data samples collected at center-of-mass energies of √s=4.009, 4.230, 4.260, and 4.360 Ge V with the BES detector operating at the BEPC collider, we perform a search for the process e+e-→γχc J(J =0, 1, 2)and find evidence for e+e-→γχc1 and e+e-→γχc2 with statistical significances of 3.0σ and 3.4σ, respectively. The Born cross sections σB(e+e-→γχc J), as well as their upper limits at the 90% confidence level(C.L.) are determined at each center-of-mass energy.展开更多
The number of J/ψ events collected with the BES detector at the BEPC from June 12 to July 28, 2009 is determined to be (225.3 ± 2.8) × 10 6 using J/ψ→inclusive events, where the uncertainty is the systema...The number of J/ψ events collected with the BES detector at the BEPC from June 12 to July 28, 2009 is determined to be (225.3 ± 2.8) × 10 6 using J/ψ→inclusive events, where the uncertainty is the systematic error and the statistical one is negligible.展开更多
基金National Key Basic Research Program of China (2015CB856700)National Natural Science Foundation of China (NSFC)(11235011,11275266,11335008,11425524,11625523,11635010)+16 种基金the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics (CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1332201,U1532257,U1532258)CAS (KJCX2-YW-N29,KJCX2-YW-N45,QYZDJ-SSW-SLH003)100 Talents Program of CASNational 1000 Talents Program of ChinaINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG (Collaborative Research Center CRC 1044,FOR 2359)Istituto Nazionale di Fisica Nucleare,ItalyKoninklijke Nederlandse Akademie van Wetenschappen (KNAW)(530-4CDP03)Ministry of Development of Turkey (DPT2006K-120470)National Science and Technology fundThe Swedish Research CouncilU. S. Department of Energy under (DE-FG02-05ER41374,DE-SC-0010118,DE-SC-0010504,DE-SC-0012069)University of Groningen (RuG)the Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI),DarmstadtWCU Program of National Research Foundation of Korea (R32-2008-000-10155-0).
文摘We study the hadronic decays of ∧c^+ to the final states ∑^+η and ∑^+η, using an e^+e^- annihilation data sample of 567 pb^-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII collider. We find evidence for the decays ∧^+→∑^+η and ∑^+η' and with statistical significance of and , respectively. Normalizing to the reference decays ∧^+→∑^+π^0 and ∑^+ω, we obtain the ratios of the branching fractions B(∧C^+→∑^+η)/V(∧^→∑^+π^0)and B(∧C^+→∑^+η)/B(∧C^+→∑^+ω)to be and , respectively. The upper limits at the 90% confidence level are set to be B(∧C^→∑^+η)/V(∧^+→∑^+π^0)<0.58 and B(∧C^+→∑^+η)/B(∧C^+→∑^+ω)<1.2. Using BESIII measurements of the branching fractions of the reference decays, we determine B(∧C^+→∑^+η)=(0.41±019±0.05)%(<0.68%) and B(∧C^+→∑^+η)=(1.34+0.53+0.19)%(<1.9%). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of ∧C^+→∑^+η is consistent with the previous measurement, and the branching fraction of ∧C^+→∑^+η is measured for the first time.
基金Supported by National Key Basic Research Program of China （2009CB825204, 2015CB856700）, National Natural Science Foundation of China （NSFC） （10935007, 11125525, 11235011, 11305180, 11322544, 11335008, 11425524, 11475123）, Chinese Academy of Sciences （CAS） Large-Scale Scientific Facility Program, CAS Center for Excellence in Particle Physics （CCEPP）, Collaborative Innovation Center for Particles and Interactions （CICPI）, Joint Large-Scale Scientific Facility Funds of NSFC and CAS （11179007, U1232201, U1332201, U1532101）, CAS （KJCX2-YW-N29, KJCX2-YW-N45）, 100 Talents Program of CAS, National 1000 Talents Program of China, IN- PAC and Shanghai Key Laboratory for Particle Physics and Cosmology, German Research Foundation DFG （Collaborative Research Center CRC-1044）, Istituto Nazionale di Fisica Nucleare, Italy, Koninklijke Nederlandse Akademie van Wetenschappen （KNAW） （530- 4CDP03）, Ministry of Development of Turkey （DPT2006K-120470）, National Natural Science Foundation of China （NSFC） （11405046, U1332103）, Russian Foundation for Basic Research （14-07-91152）, Swedish Resarch Council, U. S. Department of Energy （DE-FG02- 04ER41291, DE-FG02-05ER41374, DF~SC0012069, DESC0010118）, U.S. National Science Foundation, University of Groningen （RUG） and Helmholtzzentrum fuer Schwerionenforschung GmbH （GSI）, Darmstadt, WCU Program of National Research Foundation of Korea （R32-2008-000-10155-0）.
文摘By analyzing 2.93 fb-1 data collected at the center-of-mass energy s1/2=3.773 GeV with the BESⅢdetector,we measure the absolute branching fraction of the semileptonic decay D+→K0e+ve to be B（D+→K0e+ve） =（8.59 ±0.14 ±0.21）%using K0→KS0→π0π0,where the first uncertainty is statistical and the second systematic.Our result is consistent with previous measurements within uncertainties..
基金Supported by National Key Basic Research Program of China （2015CB856700）, National Natural Science Foundation of China （NSFC） （11125525, 11235011, 11322544, 11335008, 11425524）, Chinese Academy of Sciences （CAS） Large-Scale Scientific Facility Pro- gram, 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, Italy Ministry 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）
文摘From December 2011 to May 2014, about 5 fb-1of data were taken with the BESIII detector at center-ofmass energies between 3.810 Ge V and 4.600 Ge V 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 by Ministry of Science and Technology of China （2009CB825200）, National Natural Science Foundation of China （NSFC） （10625524, 10821063, 10825524, 10835001, 10935007, 11125525, 10975143, 10979058）, Joint Funds of the National Natural Science Foundation of China （11079008, 11179007）, Chinese Academy of Sciences （CAS） Large-Scale Scientific Facility Program CAS （KJCX2- YW-N29, KJCX2-YW-N45）, 100 Talents Program of CAS, Istituto Nazionale di Fisica Nucleare, Italy, Ministry of Development of Turkey （DPT2006K-120470）, U. S. Department of Energy （DE-FG02-04ER41291, DE-FG02-91ER40682, DE-FG02-94ER40823）, U.S. National Science Foundation, University of Groningen （RUG） and the Helmholtzzentrum fuer Schwerionenforschung GmbH （GSI）, Darmstadt, WCU Program of National Research Foundation of Korea （R32-2008-000-10155-0） The BESIII collaboration thanks the staff of BEPC II and the computing center for their hard efforts.
文摘The number of ψ’ events accumulated by the BESⅢ experiment from March 3 through April 14, 2009, is determined by counting inclusive hadronic events. The result is 106.41×(1.00±0.81%)×106 . The error is systematic dominant; the statistical error is negligible.
基金Supported by the Ministry of Science and Technology of China （2009CB825204）, National Natural Science Foundation of China （10625524, 10821063, 10825524, 10835001, 10935007, 11125525, 11235011）, Joint Funds of the National Natural Science Foundation of China （11079008, 11179007）, Chinese Academy of Sciences Large-Scale Scientific Facility Program, CAS （KJCX2-YW-N29, KJCX2-YW- N45）, 100 Talents Program of CAS, Geiman Research Foundation DFG （Collaborative Research Center CRC-1044）, Istituto Nazionale di Fisica Nucleate, Italy, Ministry of Development of Turkey （DPT2006K-120470）, U. S. Department of Energy （DE-FG02-04ER41291, DE- FG02-05ER41374, DE-FG02-94ER40823）, U.S. National Science Foundation, University of Groningen （RUG） and the Helmholtzzentrum fuer Schwerionenforschung GmbH （GSI）, Darmstadt, WCU Program of National Research Foundation of Korea （R32-2008-000-10155-0）
文摘Data sets were collected with the BES detector at the BEPC collider at the center-of-mass energy of√s=3.650 GeV during May 2009 and at√s=3.773 GeV from January 2010 to May 2011.By analyzing the large angle Bhabha scattering events,the integrated luminosities of the two data sets are measured to be(44.49±0.02±0.44)pb 1and(2916.94±0.18±29.17)pb 1,respectively,where the first error is statistical and the second error is systematic.
基金Supported by Ministry of Science and Technology of China （2009CB825200）, National Natural Science Foundation of China （NSFC） （10625524, 10821063, 10825524, 10835001, 10935007）, Chinese Academy of Sciences （CAS） Large-Scale Scientific Facility Program, CAS （KJCX2-YW-N29, KJCX2-YW-N45）, 100 Talents Program of CAS Istituto Nazionale di Fisica Nucleare, Italy, Russian Foundation for Basic Research （08-02-92221, 08-02-92200-NSFC-a）, Siberian Branch of Russian Academy of Science, joint project No 32 with CAS, Chinese University of Hong Kong Focused Investment Grant （3110031）, U. S. Department of Energy （DE-FG02-04ER41291, DE-FG02-91ER40682, DE-FG02-94ER40823）, WCU Program of National Research Foundation of Korea （R32-2008-000-10155-0）. D. Cronin-Hennessy thanks the A.P. Sloan Foundation
The BESⅢ collaboration thanks the staff of BEPCH and the computing center for their hard efforts.
文摘The decay channel ψ→π+π-J/ψ(J/ψ→γp) is studied using a sample of 1.06×108 ψ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the p invariant mass spectrum. The enhancement can be fitted with an S-wave Breit-Wigner resonance function with a resulting peak mass of M =1861+6-13 (stat)+7-26 (syst) MeV/c2 and a narrow width that is Γ <38 MeV/c2 at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with well established mesons.
基金Supported in part by National Key Basic Research Program of China (2015CB856700)National Natural Science Foundation of China (NSFC) (11335008,11425524, 11625523, 11635010, 11735014, 11822506, 11935018)+18 种基金the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics (CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1532257, U1532258, U1732263)CAS Key Research Program of Frontier Science (QYZDJ-SSW-SLH003, QYZDJ-SSW-SLH040)100 Talents Program of CASCAS PIFIthe Thousand Talents Program of ChinaIN-PAC and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG under Contracts NosCollaborative Research Center CRC 1044, FOR 2359Istituto Nazionale di Fisica Nucleare, ItalyKoninklijke Nederlandse Akademie van Wetenschappen (KNAW) (530-4CDP03)Ministry of Development of Turkey (DPT2006K-120470)National Science and Technology fundThe Knut and Alice Wallenberg Foundation (Sweden) (2016.0157)The Swedish Research CouncilU. S. Department of Energy (DE-FG02-05ER41374, DESC-0010118, DE-SC-0012069)University of Groningen (Ru G) and the Helmholtzzentrum fuer Schwerionenforschung Gmb H (GSI), Darmstadtthe Russian Ministry of Science and Higher Education (14.W03.31.0026).
文摘There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESⅢ, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESⅢ during the remaining operation period of BEPCⅡ. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCⅡ to higher luminosity.
基金Supported in part by National Key Basic Research Program of China(2015CB856700)National Natural Science Foundation of China(NSFC)(11335008,11425524,11625523,11635010,11735014)+9 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Program,the CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1532257,U1532258,U1732263)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASINPAC,Shanghai Key Laboratory for Particle Physics and Cosmology,German Research Foundation DFG under Contracts Nos.Collaborative Research Center CRC 1044,FOR 2359Istituto Nazionale di Fisica Nucleare,Italy,Koninklijke Nederlandse Akademie van Wetenschappen(KNAW)(530-4CDP03)Ministry of Development of Turkey(DPT2006K-120470)National Science and Technology fund,The Swedish Research CouncilU.S.Department of Energy(DE-FG02-05ER41374,DE-SC-0010118,DE-SC-0010504,DE-SC-0012069),University of Groningen(RuG)the Helmholtzzentrum fuer Schwerionenforschung GmbH(GSI),Darmstadt.
文摘Studies of e+e?→D+sDˉˉˉˉ(?)0K?e+e?→Ds+Dˉ(?)0K?and the PP-wave charmed-strange mesons are performed based on an e+e?e+e?collision data sample corresponding to an integrated luminosity of 567 pb?1 collected with the BESIII detector at s√=4.600s=4.600 GeV.The processes of e+e?→D+sDˉˉˉˉ?0K?e+e?→Ds+Dˉ?0K?and D+sDˉˉˉˉ0K?Ds+Dˉ0K?are observed for the first time and are found to be dominated by the modes D+sDs1(2536)?Ds+Ds1(2536)?and D+sD?s2(2573)?Ds+Ds2?(2573)?,respectively.The Born cross sections are measured to beσB(e+e?→D+sDˉˉˉˉ?0K?)=(10.1±2.3±0.8)σB(e+e?→Ds+Dˉ?0K?)=(10.1±2.3±0.8)pb andσB(e+e?→D+sDˉˉˉˉ0K?)=(19.4±2.3±1.6)σB(e+e?→Ds+Dˉ0K?)=(19.4±2.3±1.6)pb,and the products of Born cross section and the decay branching fraction are measured to beσB(e+e?→D+sDs1(2536)?+c.c.)?σB(e+e?→Ds+Ds1(2536)?+c.c.)?B(Ds1(2536)?→Dˉˉˉˉ?0K?)=(7.5±1.8±0.7)B(Ds1(2536)?→Dˉ?0K?)=(7.5±1.8±0.7)pb andσB(e+e?→D+sD?s2(2573)?+c.c.)?B(D?s2(2573)?→Dˉˉˉˉ0K?)=σB(e+e?→Ds+Ds2?(2573)?+c.c.)?B(Ds2?(2573)?→Dˉ0K?)=(19.7±2.9±2.0)(19.7±2.9±2.0)pb.For the Ds1(2536)?Ds1(2536)?and D?s2(2573)?Ds2?(2573)?mesons,the masses and widths are measured to be M(Ds1(2536)?)=(2537.7±0.5±3.1)MeV/c2M(Ds1(2536)?)=(2537.7±0.5±3.1)MeV/c2,Γ(Ds1(2536)?)=(1.7±1.2±0.6)Γ(Ds1(2536)?)=(1.7±1.2±0.6)MeV,and M(D?s2(2573)?)=M(Ds2?(2573)?)=(2570.7±2.0±1.7)MeV/c2,(2570.7±2.0±1.7)MeV/c2,Γ(D?s2(2573)?)=(17.2±3.6±1.1)Γ(Ds2?(2573)?)=(17.2±3.6±1.1)MeV.The spin-parity of the D?s2(2573)?Ds2?(2573)?meson is determined to be JP=2+JP=2+.In addition,the processes e+e?→D+sDˉˉˉˉ(?)0K?e+e?→Ds+Dˉ(?)0K?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 by National Key Basic Research Program of China（2015CB856700） National Natural Science Foundation of China（NSFC）（11235011,11335008,11425524,11625523,11635010）+13 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 CAS（U1332201,U1532257,U1532258） CAS Key Research Program of Frontier Sciences（QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040） 100 Talents Program of CAS National 1000 Talents Program of China,INPAC Shanghai Key Laboratory for Particle Physics and Cosmology,German Research Foundation DFG under Contracts Nos.Collaborative Research Center CRC 1044,FOR 2359 Istituto 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 Council,U.S.Department of Energy（DEFG02-05ER41374,DE-SC-0010118,DE-SC-0010504,DE-SC-0012069） University of Groningen（RuG） and the Helmholtzzentrum fuer Schwerionenforschung GmbH（GSI） Darmstadt,WCU Program of National Research Foundation of Korea（R32-2008-000-10155-0）
基金Supported by the Ministry of Science and Technology of China（2009CB825200） National Natural Science Foundation of China（NSFC）（11235011,11322544,11335008,11425524,11475207）+16 种基金 the Chinese Academy of Sciences（CAS）Large-Scale Scientific Facility Program the Collaborative Innovation Center for Particlcs and Interactions（CICPI） Joint Large-Scale Scientific Facility Funds of the NSFC and CAS（11179014）Joint Large-Scale Scientific Facility Funds of the NSFC and CAS（11179007,U1232201,U1532257,U1532258） Joint Funds of the National Natural Science Foundation of China（11079008） CAS（KJCX2-YW-N29,KJCX2-YW-N45） 100 Talents Program of CAS National 1000 Talents Program of China German Research Foundation DFG（Collaborative Research Center CRC 1044） Istituto Nazionale di Fisica Nucleare,Italy Koninklijke Nederlandse Akademie van Wetenschappen（KNAW）（530-4CDP03） Ministry of Development of Turkey（DPT2006K-120470） National Natural Science Foundation of China（11205082） The Swedish Research Council,U.S.Department of Energy（DE-FG02-05ER41374,DE-SC-0010118,DE-SC-0010504） U.S.National Science Foundation,University of Groningen（RuG） the Helmholtzzentrum fuer Schwerionenforschung GmbH（GSI） Darmstadt,WCU Program of National Research Foundation of Korea（R32-2008-000-10155-0）
基金Supported in part by National Key Basic Research Program of China（2015CB856700）National Natural Science Foundation of China（NSFC）（11235011,11322544,11335008,11425524,11635010,11675184,11735014）+18 种基金the Chinese Academy of Sciences（CAS）Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics（CCEPP）the Collaborative Innovation Center for Particles and Interactions（CICPI）Joint Large-Scale Scientific Facility Funds of the NSFC and CAS（U1232201,U1332201,U1532257,U1532258）CAS（KJCX2-YW-N29,KJCX2-YW-N45）100 Talents Program of CASNational 1000 Talents Program of ChinaINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG（Collaborative Research Center CRC 1044,FOR 2359）Istituto Nazionale di Fisica Nucleare,ItalyKoninklijke Nederlandse Akademie van Wetenschappen（KNAW）（530-4CDP03）Ministry of Development of Turkey（DPT2006K-120470）National Natural Science Foundation of China（NSFC）（11505010）The Swedish Resarch CouncilU.S.Department of Energy（DE-FG02-05ER41374,DE-SC-0010118,DE-SC-0010504,DE-SC-0012069）U.S.National Science FoundationUniversity of Groningen（RuG）the Helmholtzzentrum fuer Schwerionenforschung GmbH（GSI）,DarmstadtWCU Program of National Research Foundation of Korea（R32-2008-000-10155-0）
文摘To study the nature of the state Y(2175),a dedicated data set of e~ + e~-collision data was collected at the center-of-mass energy of 2.125 GeV with the BESⅢ detector at the BEPCⅡ collider.By analyzing large-angle Bhabha scattering events,the integrated luminosity of this data set is determined to be 108.49±0.02±0.85 pb~(-1),where the first uncertainty is statistical and the second one is systematic.In addition,the center-of-mass energy of the data set is determined with radiative dimuon events to be 2126.55±0.03±0.85 MeV,where the first uncertainty is statistical and the second one is systematic.
基金Supported by National Key Basic Research Program of China（2015CB856700） National Natural Science Foundation of China（NSFC）（10805053,11125525,11175188,11235011,11322544,11335008,11425524）+15 种基金 Chinese Academy of Sciences（CAS）Large-Scale Scientific Facility Program the CAS Center for Excellence in Particle Physics（CCEPP） Collaborative Innovation Center for Particles and Interactions（CICPI） Joint Large-Scale Scientific Facility Funds of NSFC and CAS（11179007,U1232201,U1232107,U1332201） CAS（KJCX2-YW-N29,KJCX2-YW-N45） 100 Talents Program of CAS,INPAC Shanghai Key Laboratory for Particle Physics and Cosmology German Research Foundation DFG（Collaborative Research Center CRC-1044） Istituto Nazionale di Fisica Nucleare,Italy Ministry 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） the Helmholtzzentrum fuer Schwerionenforschung GmbH（GSI）,Darmstadt WCU Program of National Research Foundation of Korea（R32-2008-000-10155-0）
The BESIII collaboration thanks the staff of BEPCII and the IHEP computing center for their hard efforts.
文摘A measurement of the number of J/ψ events collected with the BESⅢ detector in 2009 and 2012 is performed using inclusive decays of the J/ψ. The number of J/ψ events taken in 2009 is recalculated to be(223.7±1.4)×10~6, which is in good agreement with the previous measurement, but with significantly improved precision due to improvements in the BESⅢ software. The number of J/ψ events taken in 2012 is determined to be(1086.9±6.0)×10~6. In total, the number of J/ψ events collected with the BESⅢ detector is measured to be(1310.6±7.0)×106, where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.
基金Supported by National Key Basic Research Program of China （2015CB856700）, National Natural Science Foundation of China （NSFC） （10935007, 11121092, 11125525, 11235011, 11322544, 11335008, 11375170, 11275189, 11079030, 11475164, 11475169, 11005109, 10979095, 11275211）, Chinese Academy of Sciences （CAS） Large-Scale Scientific Facility Program Joint Large-Scale Scientific Facility Funds of the NSFC and CAS （11179007, U1232201, U1332201, U1532102）. （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, Italy, Ministry 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, WCU Program of National Research Foundation of Korea （R32-2008-000-10155-0）
文摘由分析散布事件 e <SUP>+</SUP 的大角度的 Bhabha > e <SUP></SUP>() e <SUP>+</SUP > e <SUP></SUP>和 diphoton 事件 e <SUP>+</SUP > e <SUP></SUP>()为数据，集合与升级的北京在 center-of-mass ( c.m )收集了在 2.2324 和 4.5900 GeV (总共的 131 个精力点)之间的精力在北京电子正电子 Collider ( BEPCII )的分光计( BESIII )，综合光明个别地在不同 c.m 精力被测量了。结果是为 R 价值和 J/ 回声参数大小的重要输入。
基金Supported by National Key Basic Research Program of China （2015CB856700）, National Natural Science Foundation of China （11125525, 11235011, 11322544, 11335008, 11425524, Y61137005C）, Chinese Academy of Sciences （CAS） Large-Scale Scientific Facility Program, CAS Center for Excellence in Particle Physics （CCEPP）, Collaborative Innovation Center for Particles and Interactions （CICPI）, Joint Large-Scale Scientific Facility Funds of NSFC and CAS （11179007, U1232201, U1332201）, CAS （KJCX2-YW-N29, KJCX2-YW- N45）, 100 Talents Program of CAS, National 1000 Talents Program of China, INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology, German Research Foundation DFG （Collaborative Research Center CRC-1044）, Istituto Nazionale di Fisica Nucleare, Italy, Ministry of Development of Turkey （DPT2006K-120470）, Russian Foundation for Basic Research （14-07-91152）, Swedish Research Council, U. S. Department of Energy （DE-FGO2-O4ER41291, DE-FG02-05ER41374, DE-FG02-94ER40823, DESC0010118）, U.S. National Science Foundation, University of Groningen （RUG） and Helmholtzzentrum fuer Schwerionenforschung GmbH （GSI）, Darmstadt, WCU Program of National Research Foundation of Korea （R32-2008-000-10155-0）.
文摘From 2011 to 2014,the BESIII experiment collected about 5 fb-1 data at center-of-mass energies around 4 GeV for the studies of the charmonium-like and higher excited charmonium states.By analyzing the di-muon process e+e- → Yisr/fsr μ+μ-,the center-of-mass energies of the data samples are measured with a precision of 0.8 MeV.The center-of-mass energy is found to be stable for most of the time during data taking.
基金Supported by National Key Basic Research.Program of China （2015CB856700）, Joint Funds of National Natural Science Foundation of China （11079008, 11179007, U1232201, UF332201, U1232107）, National Natural Science Foundation of China （NSFC） （10935007, 11121092, 11125525, 11235011, 11322544, 11335008）, Chinese Academy of Sciences （CAS） Large-Scale Scientific Facility Program, 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, Italy, Ministry of Development of Turkey （DPT2006K-120470）, Russian Foundation for Basic Research （14-07-91152）, U. S. Department of En- ergy （DE-FG02-04ER41291, DE-FG02-05ER41374, DE-FG02-94ER40823, DESC0010118）, U.S. National Science Foundation, University of Groningen （RUG） and Helmholtzzentrum fuer Schwerionenforschung GmbH （GSI）, Darmstadt, WCU Program of National Research Foundation of Korea （R32-2008-000-10155-0）
文摘Using data samples collected at center-of-mass energies of √s=4.009, 4.230, 4.260, and 4.360 Ge V with the BES detector operating at the BEPC collider, we perform a search for the process e+e-→γχc J(J =0, 1, 2)and find evidence for e+e-→γχc1 and e+e-→γχc2 with statistical significances of 3.0σ and 3.4σ, respectively. The Born cross sections σB(e+e-→γχc J), as well as their upper limits at the 90% confidence level(C.L.) are determined at each center-of-mass energy.
