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1、PreprintsubmittedtoHEAVYIONActaPhys.Hung.A22/1(2005)000–000PHYSICSMassgenerationincoalescence-effectsonhadronspectraThomasPeitzmann11UtrechtUniversity/NIKHEF,3508TAUtrecht,TheNetherlandsReceived1January2005Abstract.Differentscenariosforthecreationofconstituentmassinthehadronformationprocessarediscu
2、ssed.Effectsofthesemaybeobservableinhadronmomentumspectra.Keywords:coalescence,recombination,heavy-ioncollisions,hadronmassPACS:25.75.-q1.IntroductionIthasbeenproposedthattheparticlespeciesdependencesobservedintheinterme-diatepTregime(2−6GeV/c)ofheavyioncollisions[1,2,3,4,5]maybeexplainedbyacollec
3、tiveproductionmechanism,namelyrecombinationorcoalescence[6,7].Inmostcoalescencemodelshadronsareassumedtoformfromessentiallycollinearpartons.Theoverlapfunctionissometimessimplyassumedtobeadeltafunction,insomecasesfinitewidthshavebeenused,usuallyverysmallinthetransversedirectionandassuminganxdistrib
4、utionlikeoneexpectstoseeinthefinalstatearXiv:nucl-th/0511022v17Nov2005hadron,suchthatthepartonsdonothavetoundergoachangeinmomentumwhenformingahadron.Thereisnowaythatthiskindofcoalescencecouldproducehadronswiththesamequarkcontentbutdifferentmasses,ifonedoesn’tassumethatquarksofthesameflavormaycarrydi
5、fferentconstituentmasses.Hadronsofdifferentmassmaybeproduced,ifoneallowsforrelativemomentumofthepartonsatthemomentofcoalescence.Thenanaturalstepistoallowquarkstohavesmallermasses-maybeeventheircurrentmasses-allowingthemtoalsoformpions.Itmaybeusefultorelaxtheassumptionofquarkshavingtheirconstituentm
6、assandinvestigatewhatdifferenceachangeinthequarkmassesmakes.Onemayenvisagetwodifferentextremescenariosforthegenerationofmasses:1.Quarksmayobtaintheirconstituentmassesearlybeforeconfinementsetsin.Thesedressedquarkswouldthenformhadronsbycoalescence.2.Quarksremainmasslessuntilconfinement.Constituentmass
7、esaregeneratedatthemomentofhadroncreation,i.e.coalescence.2T.PeitzmannAlthoughtherealsituationmaybesomewhatintermediatebetweenthetwoex-tremesgivenabove,Iwillforsimplicityconcentrateondiscussingtheseextremecases.Inbothc
