SnehaMalde,Oxford

1SnehaMaldeBESIIIPPAP

TheBESIIIexperimentandCollabora=on

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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

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•  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)

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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

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•  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

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•  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

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•  Valida=onofamplitudemodelsàinterestforQCD•  Phaseinforma=onpredictedbyamplitude

modelsishardtoverify•  BESIIIfuturemeasurementscouldallowfor

someverifica=on

Precisionbranchingfrac=ons(1)

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Doubletagtechnique

Doublecharmproduc1onatBESIIIallowsformeasurementofabsolutebranchingfrac=ons

•  AbsoluteBFmeasurementsarenotviableatLHCb

•  CurrentΛcandDsabsolutebranchingfrac=onsdo/willformleadingexperimentalsystema=cuncertain=esinLHCbmeasurementsof|Vub|.

Precisionbranchingfrac=ons(2)

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•  Poten=albackgroundsincludeanyDdecayto3chargedpions+Nneutralpar=cles(Ks,π0,KL,η,η’)

•  CannotbestudieddirectlyatLHCb.•  PossibleatBESIII,informa=onwouldbeveryusefulinconstrainingbkgsinthis

typeofanalysis.

•  Tes=ngleptonuniversalitywithB0àD(*)τν•  OneofthemoststrikinganomaliesinHEP•  Hadronic3prongdecayoftheτislookingverypromisingtoimprove

precision.

FutureplansforBESIII

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•  Lifeexpectancyoftheexperiment5-7years

•  Detectorageing•  Chinesefundingpriori=es

•  UKfocusisondataanalysisandso�wareimprovements.•  Desiredaccuracyofstrongphasemeasurementsrequiresmoreψ(3770)data•  Currentplansindicateaccumula=onin2021+2022

Groupcomposi=on&funding

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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

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•  OxfordandManchesterhavejoinedtheBESIIIcollabora=on•  StrengtheningofUK-China=esinHEP

•  Produc=onmechanismatBESIIIgivesaccesstoparametersdifficult/impossibletomeasureelsewhere.•  Manyvitalmeasurementsàcrucialtoachievingthegoalsof(LHCb),

LHCbUpgrade,BELLEII

•  PhysicsreachatBESIIIhasthepoten=altoprovidesignificantposi=veimpactontheUKBeautyandCharmflavourphysicsprogramme

Backup

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Bigger,Be�er,&BroaderversionoftheUKCLEO-cventure

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•  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