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SnehaMalde,Oxford
1SnehaMaldeBESIIIPPAP
TheBESIIIexperimentandCollabora=on
SnehaMaldeBESIIIPPAP 2
LocatedinBeijing@BEPCIIacceleratore+e-collider√s=2-4.6GeVHerme=cdetectorThirdgenera=onofBESexperimentsBESIIIfirsthadronsdetected18/7/2008
-10yearsago!Collabora=onsize~450authors38ins=tutesfromChina16fromEurope12fromUSA/OtherAsia
CornerstoneoftheChineseexperimentalpar1clephysics
programme
OxfordandManchesterjoinedinDecember2017,specificallyduetoexper1seincharmstrongphasemeasurements
Broadphysicsprogramme
SnehaMaldeBESIIIPPAP 3
RangeofenergiesàRangeofphysicsinterestsLightquarkstudies,QCD,charm,charmonium,tau,“XYZstates”,newphysicsTopcitedpublica=on
Observa=onofachargedcharmoniumlikestateZ(3900)PRL110(2013)252001
SpecificUKinterests
SnehaMaldeBESIIIPPAP 4
• UKinterestsinBESIIIareprimarily=edtotheinterestsofsomeflagshipLHCbUpgrade(andBELLEII)measurements.
• Produc=onmechanismsatBESIIIallowforunique,precise,andvital,charmmeasurementswhichessen=allycannotbeperformedelsewhere.
• CKManglegamma• CharmCPVandmixing• |Vub|• LeptonFlavourViola=on
• JointLHCb-BESIIIworkshopinFeb2018toexploremutualbenefit(LHCB-PUB-2016-025)• PerfectfitwiththeEuropeanstrategy• ReplicatethesuccessoftheUKCLEO-ccontribu=on
Charmstrong-phaseparametersBranchingfrac=ons
}}
Strongphaseparametersfromψ(3770)
SnehaMaldeBESIIIPPAP
5
StrongphaseparametersrelatetodifferencesintheamplitudesandphasesbetweenD0andD0toacommonfinalstate
• Phasemeasurementrequiressystemwithinterference
• e+e-àψ(3770)àDD• TwoDmesonsarequantumcorrelated.
ψ(3770)D1
D2
Signaldecay
Tagdecay
DàKSππ
∝| A |2 + | A |2 −2 | A || A | cos(δ)Densityofsignal
e.g.DàKSππ
e.g.CP+eigenstate
DàKSππisonedecaymode,ofinterest.TherearemanymoreofinteresttoLHCbandBELLEII
Strongphaseparameteruses
SnehaMaldeBESIIIPPAP 6
• CKMangleγismeasuredinavarietyofBdecays• Mostofthesemeasurementsincludeadecayofa
neutralD• Strongphaseparametersprovideinputonthis
partofthedecayinamodel-independentwayàcrucialforprecisionmeasurement.
• AnalysesofBESIIIdatawouldopennewchannelsandmethodsforγmeasurement.
• AnumberofcurrentinputsonlypossibleduetotheUKinvolvementinCLEO-c
Dataset Contribu1ontoσ(γ) Comment
CLEO-c0.8t-1 2° Notpreciseenough+limitedobservables
BESIII3t-1(2010+2011) Projected:1° Dataanalysisnowunderway
BESIII10-20t-1(planned) Projected:0.5° Essen=alforLHCbupgradeandBELLEII
CLEO-cpreciseenoughfor2010s,BESIIIrequiredfor2020sand2030s
Otherusesofstrongphaseparameters
SnehaMaldeBESIIIPPAP 7
• KnowledgeofcharmstrongphaseparametersalsoopensnewchannelsandmethodsforCPviola=onincharmmixing• Asyetunobserved,andanotherkeygoal
ofLHCb
|q/p|0.6 0.8 1 1.2 1.4 1.6
Arg
(q/p
) [de
g.]
−60
−40
−20
0
20
40
60m 1 m 2 m 3 m 4 m 5
�� ���������
• Valida=onofamplitudemodelsàinterestforQCD• Phaseinforma=onpredictedbyamplitude
modelsishardtoverify• BESIIIfuturemeasurementscouldallowfor
someverifica=on
Precisionbranchingfrac=ons(1)
SnehaMaldeBESIIIPPAP 8
Doubletagtechnique
Doublecharmproduc1onatBESIIIallowsformeasurementofabsolutebranchingfrac=ons
• AbsoluteBFmeasurementsarenotviableatLHCb
• CurrentΛcandDsabsolutebranchingfrac=onsdo/willformleadingexperimentalsystema=cuncertain=esinLHCbmeasurementsof|Vub|.
Precisionbranchingfrac=ons(2)
SnehaMaldeBESIIIPPAP 9
• Poten=albackgroundsincludeanyDdecayto3chargedpions+Nneutralpar=cles(Ks,π0,KL,η,η’)
• CannotbestudieddirectlyatLHCb.• PossibleatBESIII,informa=onwouldbeveryusefulinconstrainingbkgsinthis
typeofanalysis.
• Tes=ngleptonuniversalitywithB0àD(*)τν• OneofthemoststrikinganomaliesinHEP• Hadronic3prongdecayoftheτislookingverypromisingtoimprove
precision.
FutureplansforBESIII
SnehaMaldeBESIIIPPAP 10
• Lifeexpectancyoftheexperiment5-7years
• Detectorageing• Chinesefundingpriori=es
• UKfocusisondataanalysisandso�wareimprovements.• Desiredaccuracyofstrongphasemeasurementsrequiresmoreψ(3770)data• Currentplansindicateaccumula=onin2021+2022
Groupcomposi=on&funding
SnehaMaldeBESIIIPPAP 11
Oxford• PI:SnehaMalde(RSandERCfunded)• GuyWilkinson• LeiLi(2yrNewtonInterna=onalFellow)• Postdoc(ERCfunded)fromAutumn2018
Manchester
• PI:EvaGersabeck(RSfunded)• 2StudentsfromAutumn2018(RSfunded)• UseofHEP-Blacke�ClusterforBESIIIjobs
• Bothgroupsac=velypursuingfurtherexternalfundingforpostdocs&students• Primaryfocusforbothgroupsischarmstrongphaseparameters• Addi=onalresourcesrequiredtofollowotherinteres=ngavenues
• CurrentbulkfundingendsforbothPIinearly2023• Closetoendofaccumula=onofthelargerψ(3770)sample
• Dataanalysiswouldcon=nueforafewyears• ideallywithaddi=onalfundsforpersonpowerandtravel
• Expectimportantphysicsresultsformodestinvestment.
Summary
SnehaMaldeBESIIIPPAP 12
• OxfordandManchesterhavejoinedtheBESIIIcollabora=on• StrengtheningofUK-China=esinHEP
• Produc=onmechanismatBESIIIgivesaccesstoparametersdifficult/impossibletomeasureelsewhere.• Manyvitalmeasurementsàcrucialtoachievingthegoalsof(LHCb),
LHCbUpgrade,BELLEII
• PhysicsreachatBESIIIhasthepoten=altoprovidesignificantposi=veimpactontheUKBeautyandCharmflavourphysicsprogramme
Backup
SnehaMaldeBESIIIPPAP 13
Bigger,Be�er,&BroaderversionoftheUKCLEO-cventure
SnehaMaldeBESIIIPPAP 14
• In2006UKins=tutesjoinedCLEO-cwiththepurposeofmakingcharmstrongphasemeasurements.12publica=ons
• Providedinputsessen=altothefirstphaseofγstudiesatLHCb
• CLEOdatasetprovidessufficientprecisionfor2010s
• BESIIIdatarequiredfor2020s
&2030s
1. arXiv:1710.10086Quantum-correlatedmeasurementsofD→K0Sπ+π−π0decaysandconsequencesforthedetermina=onoftheCKMangleγ
2. arXiv:1709.03467Model-independentdetermina=onofthestrongphasedifferencebetweenD0andD¯0→π+π−π+π−amplitudes
3. arXiv:1703.08505AmplitudeAnalysesofD0→π+π−π+π−andD0→K+K−π+π−Decays
4. arXiv:1611.09253AmplitudeanalysisofD0→π+π−π+π−decaysusingCLEO-cdata
5. arXiv:1602.07430Improveddetermina=onoftheD→K−π+π+π−coherencefactorandassociatedhadronicparametersfromacombina=onofe+e−→ψ(3770)→cc¯andpp→cc¯Xdata
6. arXiv:1504.05878Firstdetermina=onoftheCPcontentofD→π+π−π+π−andupdateddetermina=onoftheCPcontentsofD→π+π−π0andD→K+K−π0
7. arXiv:1410.3964Firstdetermina=onoftheCPcontentofD->pi+pi-pi0andD->K+K-pi0
8. arXiv:1401.1904Newdetermina=onoftheD0->K-pi+pi0andD0->K-pi+pi+pi-coherencefactorsandaveragestrong-phasedifferences
9. arXiv:1203.3804StudiesofthedecaysD^0àK_S^0K^-π^+andD^0àK_S^0K^+π^-
10. arXiv:1010.2817Model-independentdetermina=onofthestrong-phasedifferencebetweenD^0andD^0-bar->K^0_S,Lh^+h^-(h=pi,K)anditsimpactonthemeasurementoftheCKManglegamma/phi_3
11. arXiv:1201.5716AmplitudeanalysisofD0->K+K-pi+pi-12. arXiv:0903.4853Determina=onoftheD0->K-pi+pi0andD0->K-pi+pi+pi-
CoherenceFactorsandAverageStrong-PhaseDifferencesUsingQuantum-CorrelatedMeasurements
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