乌鲁木齐市儿童医院Title备课讲稿.ppt

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1、乌鲁木齐市儿童医院TitlePreviousstudyofpolarizedfragmentationfunctionSU(6)DIS(Boros,Liang,PRD’98)fragmentationE.g.,attheZ0pole,=-0.94forf=s,d,b;=-0.67forf=u,c.2004-8-13,CCAST2QinghuaXu,ShandongUniversityTheDISdataavailable:HERMES(PRD01),E665(EPC00)-----largeerror!N

2、OMAD(NPB00),betterstatistics,butenergytoolow!RHICspinprogram(ppcollision)ispromising:(a)highstatistics(highluminosity)(b)highenergy(200-500GeV).Availabletheoreticalstudiesinppcollisions:D.deFlorian,M.Stratmann,W.Vogelsang,Phys.Rev.Lett.81(1998);C.Boros,J.T.Londer

3、gan,A.W.Thomas,Phys.Rev.D62(2000);B.Q.Ma,I.Schmidt,J.Soffer,J.J.Yang,Nucl.Phys.A703(2002);XuQ.H.,LiuC.X,LiangZ.T.,Phys.Rev.D65,114008(2002).2004-8-13,CCAST3QinghuaXu,ShandongUniversityPHinhighpTjetsatRHICHyperonproductionwithhighpT:helicitydistributionfunctionlon

4、gitudinallypolarizedfragmentationfunction2004-8-13,CCAST4QinghuaXu,ShandongUniversityContributionofgluonandquarkjet(s)toproductionQuarkjetsdominatetheHyperonproductionwithhighPT!FromgluonfragmentationFromquarkfragmentationPYTHIADifferentsubprocess:qqqq,qgqg,gg

5、gg……,but:2004-8-13,CCAST5QinghuaXu,ShandongUniversitypolarizedfragmentationfunctionWedividetheproducedHi’sinintofourgroups:(a)directlyproducedandcontaintheqf;(b)decayproductsofpolarizedheavierhyperons;(c)directlyproducedbutdon’tcontaintheqf;(d)decayproductsofunp

6、olarizedheavierhyperons.Thosefrom(a)and(b)canbepolarized,(c)and(d)arenot!Hence::spintransferfactor:fractionofspincarriedbyqfinHi(qf….)SU(6),DISfor(b)qfHj+XdecayspintransferfactorinHjHi+X’.canbeobtainedfromgenerator(e.g.PYTHIA)2004-8-13,CCAST6QinghuaXu,Shandong

7、UniversityResultsofhyperonpolarizationSU(6),setIISU(6),setI(GRSV00)DIS,setIDIS,setII(GRSV96)SU(6),setIDIS,setISU(6),setIIDIS,setIIThedecaycontributionofisverylarge,whileoriginof+ismuchcleaner!(1)Pisverysmall.(2)DifferencebetweenresultsofSU(6)andDISissmall.(3)P

8、hasastrongdependenceofdifferentsetsoff(x)!P+islarge.DifferencebetweenresultsofSU(6)andDISislarge.P+hasaweakdependenceofdifferentsetsoff(x)!2004-8-13,CCAST