Spectroscopy and pentaquarks at HERA

Results of the H1 and ZEUS Collaborations on spectroscopy of light and charmed mesons and on pentaquark searches, obtained using the HERA I data, are summarised.

SpectroscopyandpentaquarksatHERA

LeonidGladilin

(onbehalfoftheH1andZEUSCollaborations)

arXiv:hep-ex/0412014v1 5 Dec 2004

DESY,ZEUSexperiment,Notkestr.85,22607Hamburg,Germany

E-mail:gladilin@mail.desy.de

OnleavefromMoscowStateUniversity,supportedbytheU.S.-IsraelBSF

Abstract.

ResultsoftheH1andZEUSCollaborationsonspectroscopyoflightandcharmedmesonsandonpentaquarksearches,obtainedusingtheHERAIdata,aresummarised.Keywords:spectroscopy,pentaquarks

PACS:13.60.Le,13.60.Rj,14.20.Lq,14.40.Lb

INTRODUCTION

Lightandcharmedhadronsareproducedcopiouslyinepcollisionswithacentre-of-massenergyof318GeVatHERA.During rstphaseofHERAoperation(1992-2000),theH1andZEUSCollaborationsaccumulateddatasamplescorrespondingto~120pb 1each.TheH1andZEUSresultsonhadronspectroscopyandpentaquarksearchesaresummarisedinthisnote.

SPECTROSCOPYOFLIGHTANDCHARMEDMESONS

Inclusivephotoproductionofη,ρ0,f0(980)andf2(1270)mesonswasmeasuredatanaveragephoton-protoncentre-of-massenergyW=210GeVThedifferentialcrosssectionsforthosemesonsandforchargedpionsasafunctionofpT+m,wheremisthemeson’snominalmass,showsimilarpower-lawbehaviour.Theresultssuggestasimilarmechanismofthemesonsproductioninfragmentationprocesses.

0K0productionindeepinelasticscattering(DIS)revealedMeasurementofinclusiveKss

′(1525),andanotherat1726MeV[2].Thestateastateat1537MeV,consistentwithf2

at1726MeVhasamassconsistentwithf0(1710),andisfoundinagluon-richregionofphasespace.Thisobservationindicatesthatf0(1710)hasasizeablegluoniccomponent.Theproductionofexcitedcharmedandcharmed-strangemesonswasstudiedusingtheirdecaysto nalstatesinvolvingD ±Themeasuredratesofcquarkshadronis- 0andD±mesonsagreewiththoseobtainedine+e annihilations.TheingasD0,D12s1

measuredvalueofthehelicityparameterforD±s1mesonsisconsistentwiththeobserva-+tionoftheCLEOCollaborationthatthespin-parityoftheD±s1is1.AsearchfortheradiallyexcitedD ′±mesonrevealednosignal.TheupperlimitontheproductofthefractionofcquarkshadronisingasaD ′+mesonandthebranchingratiooftheD ′+decaytoD +π+π wasestimatedtobe0.7%(95%C.L.).

Word文档免费下载Word文档免费下载:Spectroscopy and pentaquarks at HERA (共3页,当前第1页)

Spectroscopy and pentaquarks at HERA相关文档

最新文档

返回顶部