32c 31c Figure1TheDalitzplotofthe1769BKKKand1730chargeconjugatecandidatesTheDalitzplotsignalmodelisanisobarmodel67consistingofsixdi erentcontributions1020f0980f01 ID: 326747
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WorksupportedinpartbyDepartmentofEnergycontractDE-AC02-76SF00515. 32c/ 31c/ Figure1:TheDalitzplotofthe1769B+!K+K+K and1730chargeconjugatecandidates.TheDalitzplotsignalmodelisanisobarmodel[6,7]consistingofsixdi erentcontributions: (1020),f0(980),f0(1710), c0andtwobroadscalarcomponents.The rstisanonresonantcomponentwhichhasadependenceontheK+K massoftheforme s23+e s13where isashapeparameter\roatedin t.ThesecondisaresonancedubbedX0(1550),whosemassandwidthare\roatedinthe t.Thiscomponentisincludedinanattemptto tanobservedenhancementinthemK+K spectrumandfollowsthetreatmentusedbytheBelleCollaborationintheirsimilaranalysis[8].ThetotalbranchingfractionismeasuredtobeB(B+!K+K+K )=(35:20:91:6)10 6.Thetotalchargeasymmetryisconsistentwithzero:ACP=( 1:72:61:5)%.TheresultsoftheDalitz-plot tareshowninTable1.4SearchforB KEvidenceforB+! K+hasalreadybeenreportedbytheBellecollaboration[9]butthereisnomeasurementoftheneutralmode.Theanalysisisperformedintheregionm 2:85GeV=c2inordertoavoidtheregiondominatedbythecresonance.FulldetailsaregiveninRef.[10].Inthechargedmode649signaleventsareobserved,correspondingtoapartialbranchingfractionofB(B+! K+)=(7:51:00:7)10 6.Them distributionshowsnoevidenceofglueballproduction.Intheneutralmode10:0+4:1 3:4signaleventsareobserved,withasigni canceof4:2,correspondingtoapartialbranchingfractionofB(B0! K0)=(4:1+1:7 1:40:4)10 6.Thisanalysisprovidesthe rstobservationofthechargedmodeand rstevidenceoftheneutralmode.5SearchforB00KNeitherthechargednorneutralmodeshavebeenstudiedbefore.Theneutralmodecouldpoten-tiallybeinterestingforCPviolationstudiessinceitisbothab!spenguinandade niteCPeigenstate[11].ItalsoprovidesanadditionalhandletounderstandthelargecharmlessB!0Xsbranchingfraction,seeRef.[12]andreferencestherein.TheanalysisisfullydocumentedinRef.[13].Unfortunatelynosigni cantsignalisobservedineithertheneutralorchargeddecaymode.IntheneutralmodethemeasuredbranchingfractionisB(B0!00K0)=(5+14 91)10 6,whichcorrespondstoa90%con dencelevelupperlimitof3110 6.InthechargedmodethemeasuredbranchingfractionisB(B+!00K+)=(11+9 71)10 6,whichcorrespondstoa90% B+!K+ andB+!K+0.InthisanalysistheK+isreconstructedinitsdecaytoK0S+.ThesPlotstechniqueisagainusedtocorrectlyaccountforthevariationinsignaleciencyovertheDalitzplotinthemeasurementofthebranchingfractionsandasymmetries.Thebranchingfractionresultsareasfollows:B(B+!K++ )=(75:36:08:1)10 6,B(B+!K+K+ )6:210 6,B(B+!K++K )11:810 6andB(B+!K+K+K )=(36:23:33:6)10 6.Theasymmetrymeasurementsarebothconsistentwithzero:ACP(B+!K++ )=(774)%,ACP(B+!K+K+K )=(1183)%.9SearchforinclusiveBKXdecaysThisinclusiveanalysisofB!KXdecays,fullydocumentedinRef.[25],isthe rstuseoftherecoilanalysistechniqueinacharmlesshadronicBdecay.InarecoilanalysisoneBisfullyreconstructedinadecaytoaDorDmesonplusanumberofpionsand/orkaons.ThetracksandneutralsnotassociatedwiththisfullyreconstructedBarethenanalysedinanattemptto ndthesignatureofasignaldecay.Thismethodleadstoaveryhighsignalpuritysincecontinuumbackgroundisdramaticallyreduced,howeverthereisacostintermsofthesignaleciency.InthisanalysisthesignalsignatureisaK+orK0ScandidatewithamomentumintheBrestframeofp(K)&#x-0.1;隔2:34GeV=c.Thismomentumrequirementisusedtoeliminateb!cevents.Amaximumlikelihood tisthenperformedusingmES,Eandp(K).Thepartialbranchingfractionresultsare:B(B!K+X)=(196+37 34+31 30)10 6B(B!K0X)=(154+55 48+55 41)10 6(26610 6)10SummarySeveralrecentmeasurementsfromBABARofcharmlessmulti-bodyBdecayshavebeenpresentedinawidevarietyofmodes.Withthegreatlyincreasingstatisticsandmoresophisticatedanalysistechniques(e.g.Dalitzplotandrecoil)beingappliedtheareaofcharmlessBdecayslookstohaveaveryrichfuture.11AcknowledgmentsManythankstothevariousprimaryauthorsoftheanalysesandtoTimGershonfortheiradviceandguidanceinpreparingboththissummaryandtheconferencepresentation.IwouldalsoliketoacknowledgethelateProf.RichardDalitzwhosadlypassedawayearlierthisyear.Hiscontributionstothe eldareessentialtotheanalysespresentedhereandtosomanyothersperformedbytheB-factoriesandotherexperiments.References[1]M.KobayashiandT.Maskawa,Prog.Theor.Phys.,652-657(1973).[2]R.H.Dalitz,Phil.Mag.,1068(1953).[3]E.Barberioetal.(HeavyFlavourAveragingGroup),hep-ex/0603003andonlineupdateathttp://www.slac.stanford.edu/xorg/hfag[4]B.Aubertetal.(BABARCollaboration),Nucl.Instrum.Meth.A479,1-116(2002). 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