2
nism .Inordertoclarifyfinallywhatistheunderlying mechanism behindtheobservedZ 3900 struc tureandotherexoticstructures moreexperimentalandtheoreticaleffortsarerequired. Fig.1ThetypicaldiagramsdepictingY 4260 ψ π π decay.Here ,( denotesY 4260 directdecay into ψ π π ;( describestheintermediatehadronicloopcontributiontoY 4260 ψ π π ;( and arefromtheISPEmechanism. Fig.2Thedistributionsoftheψ π andπ π invariantmassspectraofY 4260 π π ψ .The fullcirclesandtriangleswitherrorbarsaretheexperimentaldatagivenbyBESIII andBelle re spectively.TheredhistogramsareourresultsconsideringcontributionsoftheISPE mechanismtothe 4260 π π ψ decay. 犚犲犳犲狉犲狀犮犲狊 M.Ablikim etal. ,[ BESIIICollaboration ], Phys.Rev.Lett. 110 2013 252001. D.Y.Chen X.Liu Phys.Rev. D84 2011 034032. D.Y.Chen X.Liu T.Matsuki arXiv 1208.2411 hepph D.Y.Chen X.Liu T.Matsuki Phys.Rev. D88 2013 036008. Z.Q.Liu etal. ,[ BelleCollaboration ], Phys.Rev.Lett. 110 2013 252002. 17 犘狉犲犱犻犮狋犻狅狀狊狅犳犆犺犪狉 犲犱犆犺犪狉犿狅狀犻狌犿犾犻犽犲犛狋狉狌犮狋狌狉犲狊 ChenDianyong Thenew experimentalobservationgivenbyBESIII notonlybringsusexcitement sincetheob servedcharmoniumlikestructureZ 3900 isverysimilartoourpredictionsbytheInitialSinglePion Emission ISPE mechanism butalsofurtherstimulatesustothinkabouthowtoincorporatetheISPE mechanism withotherphenomena i.e. itsapplicationto moredecayprocessesandgive moretheoretical predictions.Alongthisway wenoticethatbothofpionandkaoncanbecategorizedaschiralparticles. Thus hiddencharmdikaondecaysofahighercharmoniumaretheintriguingprocesses wheretheInitial SingleChiralparticleEmission ISChE mechanismcanplayanimportantroleinthesedecays whichisa naturalextensionoftheISPE mechanism.Tosomeextent theISPE mechanism canbeincludedinthe ISChEmechanism. ApplyingtheISChE mechanismtotheprocessesofdikaondecayofhighercharmonium orcharmoni umlikestate onerequirestworelations ψ and ψ ψ which providethecriteriatochoosesuitableprocesses.Theminimum ofthesum ofthemassesofkaon and isabout4331MeV.Thus the massofaninitialhighercharmonium mustbehigherthan4331 2013 IMP& HIRFLAnnualReport

犘狉犲犱犻犮狋犻狅狀狊狅犳犆犺犪狉犵犲犱犆犺犪狉犿狅狀 …english.imp.cas.cn/sp/ap/ap/2013nb2/201501/P...[3]D.Y.Chen,X.Liu,T.Matsuki,Phys.Rev.Lett.,110(2013)232001.

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Page 1: 犘狉犲犱犻犮狋犻狅狀狊狅犳犆犺犪狉犵犲犱犆犺犪狉犿狅狀 …english.imp.cas.cn/sp/ap/ap/2013nb2/201501/P...[3]D.Y.Chen,X.Liu,T.Matsuki,Phys.Rev.Lett.,110(2013)232001.

nism[4].InordertoclarifyfinallywhatistheunderlyingmechanismbehindtheobservedZc(3900)struc

tureandotherexoticstructures,moreexperimentalandtheoreticaleffortsarerequired.

Fig.1ThetypicaldiagramsdepictingY(4260)→犑/ψπ+π- decay.Here,(a)denotesY(4260)directdecay

into犑/ψπ+π-;(b)describestheintermediatehadronicloopcontributiontoY(4260)→犑/ψπ

+π-;(c)and

(d)arefromtheISPEmechanism.

Fig.2Thedistributionsofthe犑/ψπ+andπ

+π-invariantmassspectraofY(4260)→π

+π-犑/ψ.The

fullcirclesandtriangleswitherrorbarsaretheexperimentaldatagivenbyBESIII[1]andBelle

[5],respectively.TheredhistogramsareourresultsconsideringcontributionsoftheISPEmechanismtothe

Y(4260)→π+π-犑/ψdecay.

犚犲犳犲狉犲狀犮犲狊

[1]M.Ablikim,etal.,[BESIIICollaboration],Phys.Rev.Lett.,110(2013)252001.[2]D.Y.Chen,X.Liu,Phys.Rev.,D84(2011)034032.[3]D.Y.Chen,X.Liu,T.Matsuki,arXiv:1208.2411[hepph].[4]D.Y.Chen,X.Liu,T.Matsuki,Phys.Rev.,D88(2013)036008.[5]Z.Q.Liu,etal.,[BelleCollaboration],Phys.Rev.Lett.,110(2013)252002.

17 犘狉犲犱犻犮狋犻狅狀狊狅犳犆犺犪狉犵犲犱犆犺犪狉犿狅狀犻狌犿犾犻犽犲犛狋狉狌犮狋狌狉犲狊ChenDianyong

  ThenewexperimentalobservationgivenbyBESIII[1]notonlybringsusexcitement,sincetheob

servedcharmoniumlikestructureZc(3900)isverysimilartoourpredictionsbytheInitialSinglePionEmission(ISPE)mechanism

[2],butalsofurtherstimulatesustothinkabouthowtoincorporatetheISPEmechanismwithotherphenomena,i.e.,itsapplicationtomoredecayprocessesandgivemoretheoreticalpredictions.Alongthisway,wenoticethatbothofpionandkaoncanbecategorizedaschiralparticles.Thus,hiddencharmdikaondecaysofahighercharmoniumaretheintriguingprocesses,wheretheInitialSingleChiralparticleEmission(ISChE)mechanismcanplayanimportantroleinthesedecays,whichisanaturalextensionoftheISPEmechanism.Tosomeextent,theISPEmechanismcanbeincludedintheISChEmechanism.

ApplyingtheISChEmechanismtotheprocessesofdikaondecayofhighercharmoniumorcharmoni

umlikestate,onerequirestworelations犿ψ犻 >犿犓 +犿犇 +犿犇狊and 犿ψ犻 >犿ψ犳 +犿犓+ +犿犓- ,which

providethecriteriatochoosesuitableprocesses.Theminimumofthesumofthemassesofkaon,犇(),

and犇()狊 isabout4331MeV.Thus,themassofaninitialhighercharmonium mustbehigherthan4331

11 2013 IMP& HIRFLAnnualReport

Page 2: 犘狉犲犱犻犮狋犻狅狀狊狅犳犆犺犪狉犵犲犱犆犺犪狉犿狅狀 …english.imp.cas.cn/sp/ap/ap/2013nb2/201501/P...[3]D.Y.Chen,X.Liu,T.Matsuki,Phys.Rev.Lett.,110(2013)232001.

MeV,whenwestudythehiddencharmdikaondecaysofahighercharmoniumbytheISChEmechanism.Thus,inthisworkthehiddencharmdikaondecaysofhighercharmoniaorcharmoniumlikestatesinclude

Y(4660)→珡K[犇犛()珡犇

()]/K[珡犇犛()犇

()]→犑/ψK+K-,

ψ(4790)→珡K[犇犛()珡犇

()]/K[珡犇犛()犇

()]→犑/ψK+K-.

Fig.1Dependenceofthedistributionof犱Γ/犱犿犑/ψK+ onthe犑/ψK+invariantmassspectrum

[3].The

diagrams(a)and(d),diagrams(b)and(e),anddiagrams(c)and(f),aretheresultsconsideringthe

intermediate犇珡犇犛+H.C.,犇珡犇犛+犇珡犇犛+H.C.,and犇珡犇犛

+H.C.contributions,respectively.Here,thelineshapeofdistributionofdΓ/犱犿犑/ψK+ isnormalizedto1.

  WepresentthelineshapeofthedikaondecayofY(4660)andψ(4790)resultedfromtheISChEmech

anisminFig.1.Theverticallinesindicatethethresholdsof犇()珡犇犛

().Ifconsideringtheintermediate犇

珡犇犛+犇珡犇犛+H.C.contributiontoY(4660)→犑/ψK

+K-,wenoticethatthereexisttwostructuresinthe

lineshapeshowninFig.1(b).Thehigheroneisasharppeakstructurenearthe犇犛珡犇/珡犇狊

犇thresholds,

whiletheloweroneisabroadstructureasareflectionofthehigherone.Ifonlyincludingtheintermediate

犇珡犇犛+H.C.,theresultantdistributionof犱Γ/犱犿犑/ψ犓+ ofY(4660)→犑/ψK

+K- givesasmallsharp

peakstructurearoundthe犇珡犇犛

threshold.Inaddition,itsreflectionraisedas3.7GeVisobscure(seeFig.1(c)formoredetails).Asfortheψ(4790)→犑/ψK

+K- decay,wepresentthecorrespondingline

shapesof犱Γ/犱犿犑/ψK+ distributionbyconsideringtheintermediates犇珡犇犛+犇珡犇

犛 +H.C.and犇

珡犇犛 +H.

C.contributionsindiagrams(e)and(f)ofFig.1.TheFig.1(e)showsanenhancementstructureexisting

inthe犱Γ/犱犿犑/ψK+ distribution,whichiscomposedofasharppeaknearthe犇犛珡犇/珡犇

狊犇thresholdandits

reflection.ThissituationisdifferentfromthatofY(4660)→犑/ψK+K-justmentionedabove.Fig.1(f)in

dicatesasharppeakstructureclosetothe犇珡犇

犛thresholdandabroadstructurecorrespondingtoitsre

flection,whicharemoreclearcomparedwiththestructuresshowninFig.1(c).

犚犲犳犲狉犲狀犮犲狊

[1]M.Ablikim,etal.,[BESIIICollaboration],Phys.Rev.Lett.,110(2013)252001.[2]D.Y.Chen,X.Liu,Phys.Rev.,D84(2011)034032.[3]D.Y.Chen,X.Liu,T.Matsuki,Phys.Rev.Lett.,110(2013)232001.

21 IMP& HIRFLAnnualReport 2013