Study Of The Charmed Hadrons And The MDC Simulation Tuning Model At BES?

In the constituent quark model(CQM),a heavy-light meson is made up of a heavy anti-quark and a light quark.The CQM based Godfrey-Isgur(GI)model describes the low-lying heavy-light mesons well;but faces large discrepancies on higher excited states.By introducing the screening effect,the modified GI(MGI)model describes the heavy-light meson family much better.But masses of Ds0*(2317)and Ds1(2460)are still much lower than the MGI model predictions,which possibly because the flaws of the model or the possibility that they not belong to the heavy-light meson family.Further theoretical and experimental studies are required.Using the data taken at(?)=4.6 GeV by BESIII,the masses and widths of Ds1(2536)and Ds2*(2573)are measured as:M(Dsl(2536))=2537.7±0.5±3.0MeV/c2,?(Dsl(2536))=1.7±1.2±0.6 MeV;M(Ds2*(2573))=2571.6±0.7±1.4MeV/c2,?(Ds2*(2573))=13.5±2.0±1.0 MeV;the JP of Ds2*(2573)is determined to be 2+;In addition,the cross sections are also measured.Our results aggrees better with the modified GI model than GI model.The introduced screening effect describes the heavy-light mesons well.It doesn't do well for the Ds0*(2317)and Ds1(2460)mesons.The discovery of Zc(3900)+,which is widely regarded as a tetraquark candidate,is an important progress of multi-quark exotic states study.In experiment,searching for new exotic state,studying new decay modes and the relation between states will help us understand the physical mechanism of the exotic states.Based on the data samples taken at 4.23 GeV and 4.26 GeV,a neutral structure locating near the DD*threshold is observed through e+e-?(DD*)0?0 process.The mass and width are measured to be M=3885.7-5.7+4.3±8.4MeV/c2,r=34.6-11.8+11.4±14.7MeV,respectively.And the cross sections of ?-(e+e-Zc0?0)B(Zc0?DD*)are measured to be 77±13±17 pb,47±9±10 pb at 4.23 GeV and 4.26 GeV respectively.The production ratio R=(?)=0.96 ±0·18±0.12.Our results support that the newly found Zc0 state should be the isospin partner of the Zc±(3885);and to be the same particle with the Zc(3885)0,which couples with the ?0 J/?;no obvious isospin breaking effect observed in its two decay channels.The luminosity of BEPCII improves significantly after upgrading,small statistical uncertainty requires more precise simulation to reduce the systematic uncertainty.Based on deep understanding of the real data,a new MDC tuning model has been built,in which hits category method and a new method of extracting resolution from real data are performed.The tuning model saves manpower and improves the simulation precision significantly.The data quality checking results show that the average tracking efficiency difference between real data and simulation reduces from 1.0%to 0.5%in J/???+?-?0 control sample;and the agreement on momentum resolution improves significantly in J/?? pp control sample.