POST-Electroweak physics and BSM at the EIC YuxiangZhao · particles" Discovery of Parity...

ElectroweakandBSMphysicsatanEICYuxiangZhao

POETIC7@TempleUniversity

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Abhay Deshpande,KrishnaKumar,SeamusRiordan(SBU)Jin Huang(BNL)

Outline•IntroductionofElectroweakinteractions•ElectroweakphysicsatanEICqNucleonspinstructureqTheweakmixinganglesin2Өw

•ChargedLeptonFlavorViolation(CLFV)studyatanEIC

•Summary2

Chen-Ning YangTsung-Dao Lee

Chien-Shiung Wu

Symmetries play a central role in physics. Parity, Time Reversal, Charge Conjugation, …, were naturally assumed to be conserved until

T.D. Lee and C.N. Yang first suggested parity violation. Awarded Nobel Prize 1957 after experimental confirmation.

"for their penetrating investigation of the so-called parity laws which has led to important discoveries regarding the elementary particles"

DiscoveryofParityViolation

C. S. Wu led the experiment confirmed parity violation in nuclear β-decay

Glashow-Weinberg-Salam (GWS) theory yields the unification of electroweak interaction and predicts Z boson 3

Electro-weakinteractions

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Spin-1/2particlescarrytwotypesofcouplings:AxialandVectorAxial:differenceofstrengthforleft/righthandedstatesVector:Averageofthetwo

Nodifferenceforleft/rightparticleVectorcoupling=Q

Onlyinteractwithleft-handedfermions

Interactwithbothleftandrighthandedfermions

ParityViolatingElectronScattering--- Neutralcurrent

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NoPV YesPV

TodetectPV:long.pol.Electron+unpol.Nucl.

IncontextofSMTreelevel…

ParityViolatingElectronScattering--- Neutralcurrent

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NoPV YesPV

IncontextofSMTreelevel…

TodetectPV:long.pol.Electron+unpol.Nucl.

SpinstructurestudyBeforeEIC---StructurefunctionsandPDFsine-p(n)DISprocesses

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Experimental observables PDFs

Unpolarized structure functions

F1ү F2

ү

Unpolarized cross section

ALL ALT

Polarized structure functions

g1ү g2

ү

Unpolarized pdfs:f(x)=q↑(x) + q↓(x)

Quark-Parton ModelQPM

Polarized pdfs:Helicity distribution ∆q=q↑(x) - q↓(x)

No g2 interpretation in QPM

~50%

~30%Spin crisis

SIDIStoaccessTMDs,DVCStoaccessGPDs…3Dera…ongoingefforts

FlavorDecompositions--- anexampleforpolarizedcase

• Withpureү exchangeininclusiveDIS:

• Assumption:SU(3)flavorsymmetry

Δu+Δd-2 Δsü Additionalinputsfromβ-decayofneutronandhyperons

ü SIDISmeasurementsalsoprovidesomeinformation,fragmentationprocessisinvolved

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Hmm…Nothirdkindofnucleon…

Δu+Δd

ElectroweakinteractionsinDISregionatanEICcanhavenewinputs…

EICoffersnewopportunitieswithweakneutralcurrents

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Anselmino,Efremov,Leader,Ji…Phys.Rep.216(1995)

pol.electron&unpol.nucleon:

WithparityviolationandQ2 <<Z2

unpol.electron&pol.nucleon:

Inclusiveelectronmeasurements

Newstructurefunctions---ү-Zinterferencestructurefunctions

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pol.electron&unpol.nucleon: unpol.electron&pol.nucleon:

NewanduniquecombinationsofindividualPDFs

Newstructurefunctions---ү-Zinterferencestructurefunctions

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pol.electron&unpol.nucleon: unpol.electron&pol.nucleon:

WexchangeinDISregion

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Parity-violatingasymmetriesine-Dcollisions

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§ Deuteronhassameamountofuanddinx>0.2region§ APV~20/3sin2Өw -1§ FundamentalquantityinSM,constraintsonnewphysics,suchasnewZbosonetc.

1loopcalculationCzarneckl andMarciano

Parity-violatingasymmetriesine-Dcollisions

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§ Deuteronhassameamountofuanddinx>0.2region§ APV~20/3sin2Өw -1§ FundamentalquantityinSM,constraintsonnewphysics,suchasnewZbosonetc.

Simulations• DJANGOHgeneratorsimulatesDISprocessesincludingQEDandQCDradiationüDevelopedbyHubertSpiesberger andusedatBNLfortheEICChargedCurrentstudy

• Electron-protoncollisionstostudynewstructurefunctionsüThedataisbinnedin(x,Q2)twodimensionsüDoingYdependentfittoextractprojectionsonF1үZ ,F3үZ ,g1үZ ,g5үZ

• sin2Өw projectionsarefromelectronbeamasymmetriesine-Dcollisions• Highlightsoftheprojections:

ü Cuts:q Q2>1GeV2,Wh>2GeV,y>0.1,pcutforstructurefunctionstudiesq Q2<6400GeV2 andx>0.2inadditionforsin2Өw projections

ü Unfoldingforkinematicalmigrationduetoradiationandfinitedetectorresolution 15

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ePHENIX

PleaserefertoePHENIX LOIforthedetails

Detectorsmearing

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Reference[2] Reference[1]

Tracking

EMCal:

e-p collisions 10x100,10x250,15x100,15x250

Runtimeluminosity 1034 /cm2/s

Detector efficiency 70%

Beam efficiency 70%

Beam timeforrunning 2.5 years5monthsperyear=12.5months

luminosityafterallefficiencies 40 fb-1 permonth

Integratedluminosity 500fb-1Proton(electron)beampolarization 70%(80%)

Uncertaintyofproton(electron)beampolarization 5%(2%)

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Luminosityandpolarizationtable(e-pcollisions)

e-D collisions 10x100,10x250,15x100,15x250,20x250

Runtimeluminosity(pernucleon) 1034 /cm2/s

Detector efficiency 70%

Beam efficiency 70%

Beam timeforrunning 200 days

luminosityafterallefficiencies 40fb-1 permonth

Integratedluminosity 267fb-1Electronbeampolarization 80%

Uncertainty ofelectronbeampolarization 2%19

Luminosityandpolarizationtable(e-Dcollisions)

•Unpolarized structurefunctionsqe-pcollisionsqelectron:longitudinallypolarizedqproton:unpolarizedqIntegratedluminosity:500fb-1

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Predictedasymmetries

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F1үZ dominatestheasymmetry

δA/Aasafunctionofx

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δA(sys)/A<0.5%Diff.Lumi.Sys.~5x10-4

Unpol.SFsprojectionsafterunfolding

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•Polarizedstructurefunctionsqe-pcollisionsqe:unpolarizedqp:longitudinallypolarizedqIntegratedluminosity:500fb-1

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Predictedasymmetries

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Predictedasymmetries

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δA/Aasafunctionofx

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δA(sys)/A<3%Diff.Lumi.Sys.~3x10-4

Pol.SFsprojectionsafterunfolding

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•Weakmixingangleqe-Dcollisionsqe:longitudinallypolarizedqD:unpolarizedqIntegratedluminosity:267fb-1(200days)

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δA/Afore-Dcollisions

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Diff.Lumi.Sys.~5x10-4

• Achallengeforpolarimeter

• Polarimetry~1%atthebeginningandthen0.5%forhigherenergyandhigherluminosity

• R&Dproposal:targetat1%inthefirststage

Worlddataofsin2ӨwincludingEICprojections

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• 200daysofdedicatedrun

• CanreachsimilarprecisiontoSoLID measurement

• InterestingQ2 regionneverbeenmeasuredorplanned

ChargedLeptonFlavorViolationatanEIC

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LeptonFlavorViolation• Solidevidencesshowingthatneutrinoshavesmallbutnon-zeromasses• Neutrinooscillationswithlargemixingangles• LeptonFlavorViolationoccursinChargedLeptonstoo…

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SUSYSM

Slepton-neutralino loops Chargino-sneutrino loops

BR(μàe)~10-15BR(μàe)<10-54

Neutrinooscillation

Canbeobservable…Extremelysmall… Atheoryreview:PRD77,113010(2008)

SearchforLeptonFlavorViolation• Majorexperimentalsearchesareongoing

üNeutrinoless conversionofstoppedmuonstoelectronsinnuclei(μ↔e)üRaredecayofafreemuontoanelectronandphoton(μ↔e)üRaredecayofakaontoanelectronandmuon(μ↔e)üTaudecaysate+e- colliders(τ↔e)

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Needveryhighfluxesforrequiredstatisticalreach

Doableatnewhighintensitykaon&muonbeamsandhighluminositye+e- collidersallovertheworld

EICcanalsocontribute…EspeciallyafterpioneereffortsatHERA

LeptonFlavorViolationsearchatepcollider

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e↔μ ore↔τ

Mediatedbyleptoquark containingbothLeptonandbaryonquantumnumbers

NullresultatHERAwithlumi.of410pb-1 assumingλ=0.3

LeptonFlavorViolationsearchatanEIC

36 1e-00

5

0.00

01

0.00

1

0.01 0.

1 1 10 100 11

12 13

21 22

23 31

32 33

Ratio: λi λj / MLQ2 (TeV-2)

(q i q j)

Lepto

-Quar

k: e q

i --> τ q

j

EIC- S

malles

t ratio

can e

xplor

eHE

RA - U

pper

exclu

sion l

imits

0.0001

0.001

0.01

0.1

1

10

100

10 100 1000 10000 100000

Rat

io: �

i �j /

MLQ

2 (TeV

-2)

Mass for (qi qj) generation (GeV)

Lepto-Quark: e qi --> � qjEIC- Smallest ratio can exploreHERA - Upper exclusion limits

10fb-1

Arecentstudy,JHEP11,045(2010),showedthattheupperlimit

on!"#!$%&'() byHERAcouldbeextendedby2ordersofmagnitudeatanEIC

Assuming100%efficiency

MCgeneratorlevelstudies….Sofar• Standardmodelbackgroundsgenerated:Neutral&ChargedcurrentDIS,photo-production,lepton-pairproduction&Wproduction….CompareeventtopologieswiththeLQevents

• t hasacleansignature:AnalysissimilartothoseperformedinH1andZEUSindicatesthatreliableidentificationofTauiscertainlypossiblebothforüLeptonic DecaysoftüHadronicDecays:Narrow“pencil”likejetswith1-3pions

• VerycleardifferencesintopologiesofSMandLQeventsestablished.GEANTdetectorsimulationsnowunderway… 37

Eventtopology

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Topology:neutralcurrentDISevent;exceptthattheelectronisreplacedbytaulepton

• Ifforwardintheincidentelectrondirection,thetauwouldbeisolated• Ifmixedinwithhadronremnants,thetauwouldbeboosted• Potentialforcleanidentificationwithhighefficiency:

v lookforsinglepion,threepions inanarrowcone,singlemuon:shouldbeabletodeviseseveralgoodtriggers

vtauvertexdisplaced200to3000microns:wouldgreatlyhelpbackgroundrejectionandmaintainhighefficiencyifvertexdetectorisincludedinEICdetectordesign

JetsatGeneratorLevel(firstlook)

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Analysis

Jets at generator level

Figure: Plot (a) Angular distribution of hadronic � decay products in LQ data.Plot (b) shows the corresponding distribution using leading charged pions thatwere not associated with the known � jet

Raghav Kunnawalkam Elayavalli (SBU) Beyond the Standard Model � jet at the EIC detector December 18th 2012 24 / 36

t decayjet Normalhadronic jetinDIS

DISJetwidthisabout2timestothet-jetwidth

Analysis

� Projection

(a) LQ, �� projection in the detector (b) DIS, �� projection in the detector

Figure: �� projection of the widths of the di⇥erent jets in the detector for similarnumber of events : Hits collected by the EM calorimeter

Raghav Kunnawalkam Elayavalli (SBU) Beyond the Standard Model � jet at the EIC detector December 18th 2012 26 / 36

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Analysis

Jets in the Detector

Figure: Angular Distribution of the di�erent jets in the detector: Hits collected bythe EM calorimeter

Raghav Kunnawalkam Elayavalli (SBU) Beyond the Standard Model � jet at the EIC detector December 18th 2012 25 / 36

Analysis

Jets in the Detector

Figure: Angular Distribution of the di�erent jets in the detector: Hits collected bythe EM calorimeter

Raghav Kunnawalkam Elayavalli (SBU) Beyond the Standard Model � jet at the EIC detector December 18th 2012 25 / 36

t decayjet Normalhadronic jetinDIS

“pencil-like”jets,comparedto“hadronicjets”

VeryearlyG4simulationcoupledtoeventgeneratorη

φ

η

φ

Summary•Presentedtheprojectionsofnewunpol./pol.SFsqUniquecombinationsofPDFsqBrandnew,neverbeenmeasuredbeforeqIndependinputstotheworlddatafitwithhighprecision

•PresentedtheprojectionsofweakmixingangleqReachrelativehighprecisioninaninterestingQ2 regionqDedicated200daysofbeamtime

• Impactstudyonindividualunpol-pdfs/pol-pdfs areunderwaywithCJ-Collaboration/DSSVgroup

•CLFV: PotentialtodiscoverBSMphysicsatanEIC 41

Backups

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Center-of-masstable

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Beamenergyconfiguration(exp,GeV) CenterofMass (GeV)

10x100 63

10x250 100

15x100 77

15x250 122

20x250 141

Whatholds/glueshadronstogether

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Spinstructure

Massstructure

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=12�⌃ + LQ

�+ [�g + LG]

Weknowverylittle…

Nuclei

qaversatilerangeofkinematicsqbeampolarizationsqhighluminosityqdifferentbeamspecies

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qpreciselyimagetheseaquarksandgluonsinnucleonsandnuclei

qexplorethenewQCDfrontierofstrongcolorfieldsinnuclei

qresolveoutstandingissuesinunderstandingnucleonsandnucleiintermsoffundamentalbuildingblocksofQCD

AnewlyproposedFacility,ElectronIonCollider

With TO

EIC:theworldwideinterests

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Germany CERN US China Germany

Checkofdetectorsmearing---theta

Inputresolutionis10mrad

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Checkofdetectorsmearing---phi

Inputresolutionis0.3mrad

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Checkofdetectorsmearing---dp/p(for5+/- 0.1GeVparticles)

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Parametrizeddetectionresolutionsforinclusiveelectrons

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Projectionsonthemeasuredyield(beforeunfolding)

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Projectionsonthemeasuredyield(beforeunfolding)

Duetothesignchangeofg1gzfunction

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Projectionsonmeasuredyield

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Projectionsconsideringbinmigration

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10x250

20x325

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Acoplanarity:Dfmiss-tjet

10x250

20x325

EventTopology:LQvsSMMissingPT

Flavordecompositions• Withpureү exchangeininclusiveDIS:

• Assumption:SU(3)flavorsymmetry

Δu+Δd-2 ΔsAdditionalinputsfromβ-decayofneutronandhyperons

Δ∑ =Δu+Δd+ΔsOnlytwocombinationsofΔu,Δd,Δs

Otherprocessescanalsocontribute,butwithadditionalsys.errorsandassumptions 56

Hmm…Nothirdkindofnucleon…

Δu+Δd

Δ∑ (p)=0.15Δ∑ (N)=0.35Schemedependent…