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.
We present the physics program of the open charm and heavy c states above the DD production energy threshold,which will be studied with the BES-Ⅲ detector at the BEPC-Ⅱ collider in the coming years.Based on some full Monte Carlo simulations with the BES-Ⅲ detector,we predict the accuracy levels on measuring some physical quantities related to D0,D+ and D+s decays as well as some non-charmed decays of the heavy c states.
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.
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.
麦迪娜M. N. Achasov安磊安琪安正华白景芝班勇N. Berger边渐鸣I. BoykoR. A. BriereV. Bytev蔡啸曹国富曹学香常劲帆G. Chelkov陈刚陈和生陈江川陈丽平陈玛丽陈鹏陈申见陈元柏初元萍D. Cronin-Hennessy代洪亮代建平D. Dedovich邓子艳I. DenysenkoM. Destefanis丁勇董燎原董明义杜书先段麦英方建封常青傅成栋傅金林高原宁耿聪K. Goetzen龚文煊M. GrecoS. Grishin顾运厅郭爱强郭立波郭玉萍韩少卿F. A. Harris何康林何苗何振亚衡月昆侯治龙胡海明胡继峰胡涛胡小为黄彬黄光明黄金书黄性涛黄燕萍姬长胜纪全季晓斌季筱璐贾卢魁姜丽丽江晓山焦健斌金大鹏金山S. KomamiyaW. KuehnS. Lange梁干庄李澄李翠李德民李飞李刚李海波李捷李家才李蕾李陆李秋菊李卫东李卫国李晓玲李小男李学潜李秀荣李玉晓李志兵梁昊梁泰然Y.T. Liang梁勇飞廖广睿廖小涛刘北江刘春秀刘春燕刘福虎刘芳刘峰刘冠川刘虎刘宏邦刘怀民刘红薇刘健刘觉平刘坤刘魁勇刘树彬刘晓海刘玉斌刘艳芳刘衍文刘勇刘振安鲁公儒吕军光吕绮雯吕晓睿卢云鹏罗成林罗民兴Zhejiang University罗涛罗小兰马长利马凤才马海龙马秋梅马想马骁妍M. Maggiora冒亚军毛泽普闵建莫晓虎N. Yu. MuchnoiY. Nefedov宁飞鹏S. L. Olsen欧阳群M. PelizaeusK. Peters
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.
麦迪娜M. N. AchasovD. J. Ambrose安芬芬安琪安正华白景芝班勇J. BeckerN. BergerM. Bertani边渐鸣E. BogerO. BondarenkoI. BoykoR. A. BriereV. Bytev蔡啸A. Calcaterra曹国富常劲帆G. Chelkov陈刚陈和生陈江川陈玛丽陈申见陈晔陈元柏程和平初元萍D. Cronin-Hennessy代洪亮代建平D. Dedovich邓子艳A. DenigI. DenysenkoM. Destefanis丁伟民丁勇董燎原董明义杜书先方建房双世L. FavaF. Feldbauer封常青R. B. Ferroli傅成栋傅金林高原宁耿聪K. Goetzen龚文煊W. GradlM. Greco顾旻皓顾运厅管颖慧郭爱强郭立波郭玉萍韩艳良郝喜庆F. A. Harris何康林何苗何振亚T. Held衡月昆侯治龙胡海明胡继峰胡涛黄彬黄光明黄金书黄性涛黄燕萍T. Hussain姬长胜纪全季晓斌季筱璐贾卢魁姜丽丽江晓山焦健斌焦铮金大鹏金山景繁凡N. Kalantar-NayestanakiM. KavatsyukW. Kuehn赖蔚J. S. Lange潘振声李春花李澄李翠李德民李飞李刚李海波李家才李康李蕾李宁博李秋菊李绍莉李卫东李卫国李晓玲李小男李学潜李秀荣李志兵梁昊梁勇飞梁羽铁廖广瑞廖小涛刘北江C. L. Liu刘春秀刘春燕刘福虎刘芳刘峰刘虎刘宏邦刘汇慧刘怀民刘红薇刘觉平刘魁勇刘凯刘坤刘佩莲刘树彬刘翔刘晓海刘勇刘豫斌刘振安刘志强刘智青H. Loehner鲁公儒吕海江吕军光
By analyzing 2.93 fb^(^(-1)) data collected at the center-of-mass energy s^(1/2)=3.773 GeV with the BESⅢdetector,we measure the absolute branching fraction of the semileptonic decay D^+→K^0e+v_e to be B(D^+→K^0e^+v_e) =(8.59 ±0.14 ±0.21)%using K^0→K_S^0→π~0π~0,where the first uncertainty is statistical and the second systematic.Our result is consistent with previous measurements within uncertainties..
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.
