FLAVOUR PHYSICS AT TAU-C FACTORIES在头-C工厂味物理

StefanoBiancoLaboratoriNazionalidiFrascatidell’INFNFrascati,January19th,2006FlavourPhysics

att-cFactoriesFrascatiJan19th,20061CONTENTSPast,PresentandForeseeableFutureforTauCfactoriesFlavour(Charm)Physics(seeAntonio’stalkforonium)AListOfOpenQuestionsandAFewAnswersFrascatiJan19th,20062

Past,PresentandForeseeableFuture

forTauCfactories

FrascatiJan19th,20063Charmdiscovery

K.Niu,E.Mikumo,Y.Maeda

Prog.Theor.Phys.46(1971)1644

D+K+

p0FirstobservationofDmesons

ataccelerators

I.Peruzzietal.,Phys.Rev.Lett.

37(1976)569.FrascatiJan19th,20064Charmquarkdetectors

overtheyears

R704

E760

E835NA14ARGUSMARKI

IIIE691CLEO2CLEO-CPANDANOWBABAR,BELLECDF,D0BESNA1BNLSPEARADONECOMPASSFrascatiJan19th,20065√s=3.770GeV(y’’)coherentproductionofDmesonpair

e+e-

y(3770)DD

WHY?Larges,lowmultiplicityPureinitialstate:nofragmentationDoubletagmeasurements:nobackgroundCleanneutrinoreconstructionCoherentinitialstateCLEO-cFrascatiJan19th,20066Tau-charmFactoriesproposedinthepast1987proposedatCERN1989proposedatSLAC1990proposedinSpain1992proposedinITEP1994proposedatArgonne1996micro-workshopatFrascati(G.CaponConvener)…2005astudyinFrascatiFrascatiJan19th,20067THECHARMINGCOMPETITIONCLEO-ctau-charmfactory,running.goal=3fb-1DDstartedSep2003,asofApril2005265pb-1integratedaty’’.Luminositybelowprojectgoal=31032cm-2s-1.Endin2021.Beijingtau-charmfactoryBEPC-II,design1033cm-2s-1,commissioningin2006BABAR(endin2021)BELLESBELLE???Frascatitau-charmStudy(2005):2x108reconstructedDDeventsL=1034cm-2s-1100fb-1/ystartin202130xCLEO-c2xBEPC-IIafter1y~10xBABAR/SBELLEwithmuchbettersystematicsFrascatiJan19th,20068Detector

(CLEOIII–like)

VERY

CHALLENGING

AND

AMBITIOUStrackerRICHECALsolenoidermetic4pgeometrypotentDAQopentrigger1.5Tnow,...1.0Tlater93%of4psp/p=0.35%@1GeVdE/dx:5.7%p@minI93%of4psE/E=2%@1GeV=4%@100MeV83%of4p87%KaonIDwith0.2%pfake@0.9GeV85%of4pForp>1GeVTrigger:Tracks&ShowersPipelinedLatency=2.5msDataAcquisition:Eventsize=25kBThruput<6MB/sFrascatiJan19th,200692.

FlavourPhysics

atatau-CFactory

(seeAntonio’stalkforonium)

FrascatiJan19th,200610High-impactPhysics&EngineeringDatabaseCPV,mixingandraredecaysinCharmsectorareaprobeforNewPhysicsWhy(only)3families?QuarkcistheonlyHQup-typeprobeInthecharmsector,SMcontributionstoCPV,mixingandraredecaysaresmall(GIM)Buthowsmall?CPVasimm10-3D0D0barmixing10-3—10-10Raredecays10-9–10-19Higgs?

HIENERGYSMFSIcorrectionsareimportantQuantitativepredictionsvia1/mQexpansionsarepossible

QuarkcisthelightestheavyquarkStudyingthec-quarkprovidessensitivityanddiscoverypotentialforNewPhysics.Afterthediscovery(?)ofHiggs@LHC,NewPhysicsmanifestationsinc-quark(andinb-quark)importanttodistinguishamongmodels.FSIcorrectionsareimportantc-QCD

LOENERGYFrascatiJan19th,200611√s=3.770GeV(y’’)coherentproductionofDmesonpairsL~1034cm-2s-1,100fb-1/y2x108DDpairsdetected(30%eff*acc,extrap.fromCLEO-c),inuniquelycleanenvironment,peryear.SearchforNewPhysics:DirectCPViolationinSCSDasymmetries,anddirectlyinintegratedrates.Sensitivity10-4,SMPREDICTION10-3.SearchfordirectCPVinCFDand/orDCSD,whereSMPREDICTSNOCPVMixingexploitingcoherence,uniquefeatureofthresholdproduction.Cannotstudymixingintimeevolutionofrates,butonlyinintegratedrates.Inmostchannels,DCSDconcurrentprocessdoesnotexistthankstoBose-Einsteinstatistics(coherentC=-1quantumstate).Bycomparingsemileptandhadronic,measurestrongphaseshiftd.Raredecays:FCNCD+hl+l-,D0l+l-,SMPREDICTION10-9

Sensitivity10-7-10-8e+e-y(3770)DD

“NEWPHYSICS〞PROGRAMMEBibliography:SB,Fabbri,Benson,Bigi

Riv.Nuovo

Cim.26,7-8,2003hep-ex/0309021.I.BigiandA.SandaCPViolation,Cambridge,2000.CLEO-cproposal(2001).BurdmanShipseyAnnu.Rev.Nucl.Part.Sci.2003.53:431–99FrascatiFuturoreport(Antonelli,SB,Bloise,Bossi,Miscettietal.)FrascatiJan19th,200612Also,tauphysics

e+e-

y’’t+t-√s=3.770GeV(y’’)productionoftauleptonpairs,s~3nb.L~1034cm-2s-1,100fb-1/yLNVdecaytmgsensitivetoSUSY,(109events)/(threeyears).BABARbestlimit7x10-8(90%cl)dominatedbysystematics,backgroundttg.Runningatthresholdreducessystematics.RobustStandardModelphysicsprogramme:precisemeasurementofmassweakcouplings(purelyleptonicandsemileptonicdecays)testofCVCrule,andimplicationsonanom.magn.momentofmuon.etc(seeGinoIsidori’stalkApril2005Frascati,andFuturoreportSect.5.5)FrascatiJan19th,200613CPVASYMMETRIESFrascatiJan19th,200614Foratwo-amplitudedecaydi

=strongphaseCPasymmetry:2differentweakamplitudesstrongphase-shiftAtot

=g1M1eid1+g2M2eid2CPconjugateAtot

=g1M1eid1+g2M2eid2**aCP=2Im(g2g1*)sin(d1-d2)M1M2|g1|2M12+|g2|2M22+2Re(g2g1*)cos(d1-d2)M1M2|Atot|2-|Atot|2|Atot|2+|Atot|2=CPVIOLATINGINTEGRATEDASYMMETRIESareneededforCPVasymmetrySingleCabibbo-suppresseddecaysInDSCDandCFDonlyoneweakamplitudeNOCPVWITHINSMFrascatiJan19th,200615Inplainwords…SMpredictsCPVatthe10-3levelinSCSDobservationwouldbea***resultSMpredictsZEROCPVinCFDandDCSDobservationofCPVinthosedecaysisa*****discoveryofNewPhysicsFrascatiJan19th,200616SearchforCPviolationviaDalitzplotanalysis

ofSingly-Cabibbo-suppressedDecays

Usefulldecayinfo,notonlyBRmustdetermineamplitudecoefficientsandphases

FinalstateresultsfromtheinterferenceofallintermediatestatesDifferencesbetweenamplitudeand/orphasespatternsinaDalitzanalysisbetwconjugatestates(i.e.,D+vsD-),wouldbeevidenceofCPviolation(ref.I.Bigi,A.Sanda“CPViolation〞)FrascatiJan19th,200617Ds,

D+

KK

Ds+

K+K-p+D+

K+K-p+FrascatiJan19th,200618K+K

-projectionK-

p+projectionYieldD±=710692S/ND±=8.62DecayFractionandphases

K*(892)=20.71.0%(0fixed)

f(1020)=27.80.7%(243.15.2)°K*(1410)=10.71.9%(-47.44.9)

°K*

(1430)=66.56.0%(61.83.8)°

f0(1370)=7.01.1%(60.05.3)°a0(980)=27.04.8%(145.64.3)°f2(1270)=0.80.2%(11.67.0)°f(1680)=1.60.4%(-74.37.5)°Preliminary

D±

KK

FrascatiJan19th,200619Coefficients:D±,

D+,

D-

Phases:

D±,

D+,

D-

D+/D-splitsampleanalysisPreliminary!NoevidenceofCPVFrascatiJan19th,200620D0D0MIXINGFrascatiJan19th,200621ProcesseswhichallowmixingappearinH12and

H21.ThetimeevolutionofflavoureigenstatesisgivenbytheSchrödingerequation

Ifarenotmasseigenstates.Masseigenstatesare(assumingCPconservation),andmixingamplitudeisMassandwidthdifferencesareparametrizedbyFormalismofP0-P0mixing

mixingcanbedescribedbytheratio

r

|x|>0mixingiscausedbygenuinetransitions(Df=2)xsplitsmasses

|y|>0mixingiscausedbytheshort-livedcomponentdisappearingrapidly,leavingbehindthelong-livedcomponent,madeofand

y

splits

lifetimes

FrascatiJan19th,200622SHORTDISTANCEKK,ppp0,hLONGDISTANCEqSD/LDx=Dm/Gy=DG/(2G)

c

SD~LD0.48100%

sSD<<LD<5%<1%

tSD>>LD

0.75?

tSD>>LD>22?K0,D0,B0_Where’sTheDifference?FrascatiJan19th,200623Theoretical“guidance〞FromcompilationofH.N.Nelsonhep-ex/9908021TrianglesareSM

x

SquaresareSM

y

CirclesareNSM

x“D0D0

mixingisawindowonNewPhysics”_FrascatiJan19th,200624

2_MeasureyCP,theyparameterforCPeigenstates

Measurer

HADRONICDECAYSSEMILEPTONICDECAYS(1+2)/2TECHNIQUESFORSTUDYINGD0D0MIXING(I)FrascatiJan19th,200625_Measurer

HADRONICDECAYSD*tagsD0

flavourmixingCabibbo-FavouredDecayDoubleCabibbo-SuppressedDecayStrongphase

d

betweenCFDandDCSDmixes

x

and

yvia

TECHNIQUESFORSTUDYINGD0D0MIXING(II)FrascatiJan19th,200626_Measurer

D*tagsD0

flavourmixingCabibbo-FavouredDecaySEMILEPTONICDECAYSvia

TECHNIQUESFORSTUDYINGD0D0MIXING(III)FrascatiJan19th,200627DirectmeasurementofyCPrequiresgoodlifetimeresolution

MeasuringrwsinhadronicdecaysrequirestodisuntanglerDCSfromr;andtheknowledgeofd

Measuringrwsinsemileptonicdecaysprovidestherparameter,butitisexperimentallymoredifficultMEASURINGrwsattau-CPROVIDESTHErPARAMETER,SINCEQUANTUMCORRELATIONSFORBIDDECAYTOIDENTICALFINALSTATES(NODCSDPOLLUTION).TECHNIQUESFORSTUDYINGD0D0MIXING(Concl.)_FrascatiJan19th,200628STATUSOF

D0D0

MIXING

ASOF

SPRING

2004dFrascatiJan19th,200629√s=3.770GeV(y’’)coherentproductionofDmesonpairs,L~1034cm-2s-1,100fb-1/y2x108DDpairsdetected(30%eff*acc,extrap.fromCLEO-c),inuniquelycleanenvironment,peryear.StandardModelphysicsprogramme:Absolutebranchingratios;Vcd,Vcsfromsemileptonicdecays;SLFormFactors;CharmdecayconstantsfDfromD

mn;lightquarksinDalitzplots;etc.e+e-

y(3770)DD

STANDARDMODELFLAVOURPHYSICS

Ref:SB,Fabbri,Benson,BigiRiv.NuovoCim.26,7-8,2003hep-ex/0309021.I.BigiandA.SandaCPViolation,Cambridge,2000.FrascatiJan19th,200630CharmoniumspectroscopyQCDHybrids,glueballs

e+e-J/ygX

FrascatiJan19th,200631QUESTIONS,ANDMYVERYFEWANSWERSPhysicsIsthetcFasignificanthelptodisentangleamongnon-SMmodelsafterthediscoveryofSUSY?AretheSMmeasurementssignificantinthefieldofbandcphysics?IstheSMprogrammeofatcFstrongenoughtoallowsuccessevenisSUSYisnotdiscoveredatLHC?Detectormustbeall-purposedetector!Canwestartdesign?ImpactonFrascatiinfrastructure?VERYBIG,INTERNATIONALENTERPRISECost?MachineImpactonFrascatiinfrastructure?VERYBIG,INTERNATIONALENTERPRISEsymmetric/asymmetric?FitsDAFNEbuilding?NOCost100MEuro?M