中国高能物理学会第十届全国粒子物理学术会议, 南京.ppt

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1、中国高能物理学会第十届全国粒子物理学术会议,南京ObservationofX(1835)in房双世“晨光杯”论文报告OutlineIntroductionEventSelectionBackgroundStudyResultsSummaryandDiscussionAnarrowenhancementisobservedin.AssumingthatthesystemisinanS-waveresultedinaresonancemassofMeVandatotalwidthofMeV.M=1859MeV/c2G<30MeV/c2(

2、90%CL)+3+5-10-25M(pp)-2mp(GeV)00.10.20.3IntroductionIntroductionItcanbeinterpretedasappbarboundstate.Insuchacase,itisdesirabletoobservesuchastateinotherdecaymodes.ManypossibledecaymodessuggestedinC.S.CaoandS.L.ZhuCommun.Theory.Phys.42,844(2004)C.J.DingandM.L.Yan,Phys.R

3、ev.C72(2005)Onepossibledecaymodes,neverstudiedbeforeatBESeasytotagusingChargedtracks4goodchargedtrackswith

4、cos

5、<0.8inMDC;Thetotalchargeisrequiredtobe0;PID:atleastthreeofthemareidentifiedaspionswithTOFanddE/Dx;PhotonselectionEnergydepositedinBSCgreaterthan60MeVIsolated

6、fromchargedtracksbymorethan5oN=3forN=2forEventSelectionusedtoimprovethemassresolutionEventSelectionforAnalysisofX(1835)EventSelectionforAnalysisofX(1835)mass-sidebandeventsMainbackground,60MdecaysbyLUNDmodelCheckefficiencycurvephasespaceBackgroundStudyBkg.studyforLUN

7、DMCsidebandsdatadataBkg.StudyforPhasespaceeventsEfficiencycurveMCBkg.StudyforLUNDMCsidebandsdatadataBkg.StudyforEfficiencycurvePhasespaceeventsMCObservationofX(1835)inThesum+-massspectrumfordecayinginto+-andMassspectrumfitting5.1The+-massspect

8、rumforMassspectrumfitting6.0The+-massspectrumforMassspectrumfitting7.7Thesum+-massspectrumfordecayinginto+-andMassandwidthfromm=1827.48.1MeV/c2,=54.234.5MeV/c2Massandwidthfromm=1836.37.9MeV/c2,=70.323.1MeV/c2Thesumofmassspectrumfortwodecaym

9、odesm=1833.76.12.7MeV/c2,=67.720.37.7MeV/c2ThesumofmassspectrumfortwodecaymodesThemass,widthandbranchingfractionsobtainedfromtwodifferentdecaymodesareconsistentwitheachother.ResultsofmassspectrumfittingPaperpublishedinPhys.Rev.Lett.95,262001(2005)(Received11Augus

10、t2005;published28December2005)SPIRES-HEPsearch(2008-04-01)39timescited首次在以我国科学家为主进行的北京谱仪实验中发现新粒子。国际权威《粒子数据手册》PDG2006