IceCube searches for neutrinos from dark matter annihilations in the ...

M.RameezSwissPhysicalSocietyMeeting2016

23rd August2016

IceCube searches for neutrinos from dark matter annihilations in the Sun and Cosmic Accelerators

SPS– Lugano,M.Rameez 2

TheIceCube NeutrinoObservatory

Eν >100GeV

Eν >10GeV

~41oinice

Cherenkovradiation.


In-iceSignatures

Goodangularresolution:NeutrinoAstronomy◦ (~0.6o at10TeV)◦ Vertexcanbeoutsidethedetector:Increased

effectivevolume!

Muontracks→ νμ CC

𝜈𝜇 𝜈e

cascades →allflavors

• νe,ν𝞃 andall-flavorneutralcurrent• Fullyactivecalorimeter:Highenergyresolution• Angularreconstructionabove~50TeV

Inbothcases,𝜈 and�̅� areindistinguishable


DarkMatter• GalacticRotationCurves:

• GravitationalLensingduetogalaxyClusters:BulletCluster:astro-ph/0608247

• PrecisionCosmology• PlanckCMBMeasurements• CDMsimulationssuchasMillenium reproduceobservedLSS

Ω&' ≥ 0.1

Ω&'~0.2 − 0.4

Ω&' = 0.268 ± 0.02

WeknowDMexistsfrom:


WeaklyInteractingMassiveParticlesDarkMatterasathermalrelicoftheEarlyuniverse.

• Boltzmannequationoftheearlyuniverse• &56

&7+ 3𝐻𝑛< = − σ>55𝑣 𝑛<@ −𝑛AB<@

• RelicΩCD~0.27For σ>55𝑣 = 3. 10F@G𝑐𝑚J/𝑠

σ>55𝑣 ≈ NOP /QR P

DP ≈ 3. 10F@G𝑐𝑚J/𝑠

• StableWIMPSpresentinvarioustheories• Neutralino inSUSYtheories• Kaluza Kleinparticles. Freezeout

𝑋

𝑋T

𝑓

𝑓̅𝑀𝑔X 𝑔X

WIMPMiracle

WIMP Capture and Annihilation in the Sun

6

AtEarth:EnhancedneutrinofluxfromthedirectionoftheSun!

𝜒ScatteringCross

SectionNumberdensityofelementi ->SolarModel𝜎[C ∝ 𝐽(𝐽 + 1)

𝜎[` ∝ 𝐴@

Capture

Annihilation

ΓcABde =

12 𝐶gEquilibrium

SpinDependentscattering• OnlythehydrogenintheSuncontributes

significantly.• Lowereventratesindirectdetection

experiments• MoreinterestingforIceCube

SpinIndependentscattering• Heaviernucleicontributemoredueto∝ 𝐴@ enhancement.

• BettersensitivityusingdirectdetectionexperimentssuchasLUX,XENONetc

AllcalculationsperformedwithDarkSusy/WimpSim

𝑏T,𝑊F,𝜏F…

𝑏,𝑊k,𝜏k…

Primaryannihilationchannels De

cay

DenseMediumInteractions

MatterOscillations

….ν

….νT

prop

agation

Vacuumoscillations


EventsinIceCube

atmospheric µbackground

ν induced µ

Northern Skycosmic ray

νatm

atmospheric μOverwhelming background cosmic ray

Southern Sky

Austral Winter

Austral Summer

106 lowerbackgroundduringtheAustralWinter

Upgoingevents

Downgoingevents

ObserveddataMisreconstructed μ


EventSelectionStrategy

• HighEffectivevolume(IceCube)

• Goodangularresolution(<2O at1TeV)

• BadEnergyresolution(Onlyalowerlimit)

• >100GeV

• SmallerEffectivevolume(DeepCore)

• Worseangularresolution(8O at50GeV)

• GoodEnergyresolution~20%below100GeV

• <100GeV

• SmallerEffectivevolume(DeepCore)

• Worseangularresolution• (14O at30GeV)• GoodEnergyresolution~20%below60GeV

• <100GeV

AttemptstoisolateadowngoingIceCube dominatedsamplewerenotsuccessfulduetoμ background.

SPS– Lugano,M.Rameez9

Samples


Level4- Veto3

LowEnergy

μ

✘ ✓

μ

νμConeRT Veto

Muonssneakpastcutsonstartingvertex.(Falselyreconstructedstartingvertex)

Lookforhitswithina40degreecone.Sortthemintoclusters:within250metres and1μsofeachother

Countthesizeofthelargestcluster

Cutat3rejects>80%ofBkg,keeps90%ofSignal.

Level 5 – Boosted Decision Tree (contd)

2

BestBDTcutthresholdforsensitivitychosen- theModelRejectionFactormethod.



FinalSamplesSummary

SampleRate(mHz)

TotalMC(mHz)

Atmos𝝂𝝁 + 𝝂o𝝁(mHz)

Atmos𝝂𝒆 + 𝝂o𝒆(mHz)

Atmosμ

(mHz)

Energyrange(GeV)

Typicalsignalefficiency

WinterHighEnergy 2.9 3.0 2.1 0.1 0.8 100-2000 24%(5 TeV χχ toW+W-)

Winter LowEnergy 0.34 0.36 0.26 0.08 0.02 10-100 6%(50 GeVχχ toτ+τ-)

Summer 0.25 0.28 0.21 0.05 0.03 10-50 4%(20 GeVχχ toτ+τ-)

1

3

2

• Livetimes :Winter528.28days,Summer490.77days.Total1019.05daysofdata.• Nonoverlapping,noeventsincommon• Trueeventdirectionsnotexamined.Analysisisblind.


EventSelectionPerformance

EnergyReconstruction


Afullneutrinoenergyestimatorforcontainedtracks

Enhancessignaltobackgrounddiscrimination,andsensitivityfortheDeepCore dominatedsamples

and2 3

EventenergyinformationusedforaSolarWIMPanalysisforthefirsttimeinIceCube.


AnalysisMethodBackground(atmosphericν andμ):

• Uniformwithindeclinationband𝐵(𝛿e)

Signal(Astrophysicalν fromsource):• Clusteredaroundsource

Ktu = vwA

xwyz{ | }w~}�(�w)

@�(AxwFA~xw)FisherBinghamdistribution,(Gaussianindirectionalstatistics)

Eventbyeventangularresolution

Backgroundonly

Background+PSat120O,90O

Useeventdirection:

Andenergy:

St 𝑚�, 𝑐ℎ = 𝑃 𝐸e 𝑚�, 𝑐ℎ ∗ Ktu 𝐵e = 𝑃 𝐸e 𝜙>7' ∗ 𝐵 𝛿e

𝓛 𝑛� = �𝑛�𝑁 St 𝑚�, 𝑐ℎ + (1 −

𝑛�𝑁)𝐵e

�

e��

Likelihood:


AnalysisMethod(contd)

• 𝐵(𝛿e) and 𝑃 𝐸e 𝜙>7' areestimatedfromdata.• Robustagainstfalsediscovery

• 𝑃 𝐸e 𝑚�, 𝑐ℎ isestimatedfromMonteCarlo

• Ktu isanalytic.

• Loglikelihoodcanbemaximizedtofindthebestfit𝑛��• −2 log 𝓛 5��

𝓛 5��istheteststatisticsandis

distributedas𝜒@(1dof) – (Wilke’stheorem)• SignificancefrommanydatasetsscrambledinR.A.• Confidenceintervalson𝑛� - FeldmanandCousins.


1

2

3

Results• Nostatisticallysignificantexcess• Bestp– value~16%

500GeV𝜒𝜒 → 𝑏𝑏T𝑛�� = 24.4

PhD Thesis Defense - M. Rameez17PhD Thesis Defense - M. Rameez

1

2

3

Results

17

Improvements + More livetime + bugfix - > limits are lower by almost an order of magnitude w.r.t IC79

17M. Rameez – Universite de Geneve

Morelivetime +bettereventselection+betteranalysismethods+bugfix ->Resultsbetterby~1orderofmagnitudew.r.t IC79


AstrophysicalUncertainties

DMvelocitydistributionfunctions

Thereareuncertaintieson:• ThevelocityoftheSunw.r.tthehalo

• ThefractionofDMinaco-rotatingdarkdisk• Thegalacticescapevelocity

C.Rott etal.JCAP05(2014)049

Theuncertaintiesare20%(50%)atlow(high)WIMPmasses.

Conservativew.r.t.thedarkdiskfraction.


ComplementarityandDMModels

PhD Thesis Defense - M. Rameez18

Complementarity and DM models

Missing ET

<σannv>

σ�-N



Complementarity and DM models

Missing ET

<σannv>

σ�-N


< 𝜎>55𝑣 >

𝜎�F�

Missing𝐸�

ComplementarityinthepMSSM


Only pMSSM models not excluded by LHC Run 1 are shown Correct Higgs Mass and Relic density SI σχ-N not greater than LUX bounds Model colourcoded by hardness or softness of annihilation channels “PMSSM benchmark models for Snowmass 2013” arXiv:1305.2419,

148.3 GeV Bino-Higgsino WIMP can be excluded at >90% C.L



22M. Rameez – Universite de GeneveM. Rameez – Universite de GeneveM. Rameez – Universite de Geneve

arXiv:1505.06513



Complementarity of DM Searches in a Consistent Simplified Model: the Case of Z'T. Jacques et. al. arXiv:1605.06513

U(1)' extension of the standard model :

SU(3)C X SU(2)L X U(1)Y X U(1)'

One new gauge boson Z' (mass mz' given by SSB in a hidden sector)

Majorana DM, stable under Z2 symmetry

U(1)' charges for cancellation of SM X SM X U(1)' gauge anomaly. Higgs is charged

Full lagrangian in backup slides

SD WIMP-Nucleon scattering in the non relativistic limit – Direct Detection constraints

Z-Z' mixing

LHC constraints from Z' → l+l- and monojet constraints on DM

Strongest constraints are from LHC below 400 GeV WIMP mass, and IC above 400 GeV, except for θ = π/2


U(1)' extension of the standard model :

SU(3)C×SU(2)L ×U(1)Y×U(1)'

One new gauge boson Z'

(mass mz' given by SSB in a hidden sector) Majorana DM, stable under Z2 symmetry U(1)' charges for cancellation of SM X SM X U(1)' gauge anomaly. Higgs is charged Full lagrangian in backup slides SD WIMP-Nucleon scattering in the non relativistic limit –Direct Detection constraints Z-Z' mixing LHC constraints from Z' → l+l- and monojet constraints on DM Strongest constraints are from LHC below 400 GeV WIMP mass, and IC above 400 GeV, except for θ = π/2

Complementarity of DM Searches in a Consistent Simplified Model: the Case of Z' T. Jacques et. al. arXiv:1605.06513


TheEmerging750GeVdiphoton excess– portaltothedarksector?E.Morgante et.al.,JHEP1607(2016)141

Apseudoscalar,Pofmass750GeV:• ScatteringisSDattheNRlimit

750GeV>Ewk Scale• Lagrangian isSU(2)L invariant,PcouplestoB.• GuaranteesannihilationtoZZandZγ

Palsocouplestogluonsand/orquarks• Run1constraints

DMχ (fermion)orφ (scalar)stableunderZ2 symmetry.3scenarios.Pcouplesto :

• B,g,u,χ• B,g,u,χ,b• B,g,u,χ,t

WIMP-protonscatteringintheNRlimit𝑖(𝑆¡�.

B�'¢) forscalarDMand

(𝑆¡�.B�'¢) (𝑆¡�.

B�'¢) forfermionicDM

(IClimitscalculatedusingcaptureratesevaluatedinR.Catenaetal,JCAP1504(2015)04,042)andanalyticalsimplificationofICsensitivity.


TheEmerging750GeVdiphoton excess– portaltothedarksector?E.Morgante et.al.,JHEP1607(2016)141

Apseudoscalar,Pofmass750GeV:• ScatteringisSDattheNRlimit

750GeV>Ewk Scale• Lagrangian isSU(2)L invariant,PcouplestoB.• GuaranteesannihilationtoZZandZγ

Palsocouplestogluonsand/orquarks• Run1constraints

DMχ (fermion)orφ (scalar)stableunderZ2 symmetry.3scenarios.Pcouplesto :

• B,g,u,χ• B,g,u,χ,b• B,g,u,χ,t

WIMP-protonscatteringintheNRlimit𝑖(𝑆¡�.

B�'¢) forscalarDMand

(𝑆¡�.B�'¢) (𝑆¡�.

B�'¢) forfermionicDM

(IClimitscalculatedusingcaptureratesevaluatedinR.Catenaetal,JCAP1504(2015)04,042)andanalyticalsimplificationofICsensitivity.

No750GeVdiphoton Excess!


SearchesforneutrinosfromCosmicAccelerators

Galactic Extragalactic?


CosmicAcceleratorsandIceCubeCRs,wheredotheycomefrom?Whatacceleratesthem?• Galactic:SNRs,microquasars?• Extragalactic:AGNs,galaxyclusters,starburstgalaxies,

GRBs?Howaretheyaccelerated?Firstorderfermiacceleration–predictsparentprotonspectrumofpowerlaw𝐸F@ foranidealshock.• Neutrinosproducedatsourcewithsamepowerlaw

spectrumthroughp-pandp-γ interactions– piondecay–muondecay.

• 1:2:0atsource→1:1:1atEarth.

54eventsseenonanexpectedbackgroundof12.6± 5.1𝜇 and9.0F@.@k¤.�𝜈. Atmosphericonlyoriginrejectedat >6𝜎 Nostatisticallysignificant

clustering


~400000tracks,fromIC40,59,79and86(4yearsofIceCube)Northernsky:μ from𝜈³ + �̅�³ CCinteractionsSouthernsky:Atmosphericμ

Allskypointsourcesearches:nostatisticallysignificantexcess–correctingfortrials

TheIceCube samplesofeventsdedicatedtoPSsearches


TheStackingMethod

STACKING

Source1 Source2 Source3

r.a.

𝑆e7´7 =∑ ¶�·¸¹ º�,» [w

�¢��¼½

∑ ¶�·¸¹ º�,»¢��¼½

Theoreticalweight𝑊u,detectoracceptance𝑅`¿ 𝛿u, 𝛾

Sourcesthatareindividuallytooweakcanstillbedetectedasacatalog


StackingSearchExample:MilagroHotspots•6 TeV associations with supernova remnants based on Milagro observations. Models

from Halzen et al. Pvalue=1.99%inIC86+79+59

F.Halzen,A.Kappes andA.O’Murchadha (Phys.Rev.D78:063004,2008)

Compatiblewiththebackgroundonlyhypothesis.

Similarexcess(2%)observedinIC40aposteriori,henceexcluded.

Moredatarequired.

Update:Withmoredata,thesignificancehasreducedagain.25%pvalue(SeeTalkbyTessaCarver:TASKIIIsession1745hrs)

Probablyabackgroundfluctuation


Summary/Conclusions

Asearchwascarriedoutforν fromWIMPannihilationsintheSun:• 3yearsofIceCube data,Innovativebackgroundrejection,improvedreconstructions• Unbinned maximumlikelihoodmethodusingenergyestimators

Weobtained:• Nostatisticallysignificantexcess• Themoststringentboundson𝜇 fluxfromthedirectionoftheSunabove80GeV• ThemoststringentconstraintontheSpinDependentWIMP-Nucleonscatteringcrosssection.• Canconstraintheoriesofsymmetricdarkmatterwithcandidatein10GeV-10TeVrange

SimilarmethodwasusedtosearchforneutrinosfromcandidatesitesforCRacceleration,suchasSNRs

Nostatisticallysignificantexcesswasfoundinanysearches

BackupSlides


Results(contd)


ConstraintscanbederivedalsoonahostofotherSDandSIvelocityandmomentumsuppressedoperators.

(R.Catenaetal,JCAP1504(2015)04,042)

DirectdetectionbetterforSIscattering

𝜎�F�dgÁAd�𝛼𝐴@

Systematic Uncertainties

33

Mass(GeV) Channel uncertaintyin%(+/-)

AbsoluteDOMefficiency

20 τ+τ− -11/+29

50 τ+τ− -8/+23

100 W+W− -9/+19

500 bbT -7/+11

1000 W+W− -6/+9

Photonpropagationinice:AbsorptionandScattering

20 τ+τ− -13/+18

50 τ+τ− -9/+13

100 W+W− -9/+11

500 bbT -8/+7

1000 W+W− -6/+4


Photons>1cm ~1mm ~10μm ~1nm <0.1nm

10-6 eV 10-4 eV 10-1 eV ~1KeV > 100KeVPulsars,quasars,radiogalaxies TheBigBang(CMB) Nonthermalprocesses

MultimessengerAstronomy

CosmicRaysElectrons,protons,heavynuclei:108 - 1020 eV– Originsunknown.

GravitationalWavesPredictedbyGeneralrelativity– Observedfirstin2015BH-BHmerger~410MPc away.Phys.Rev.Lett.116(6):061102

Neutrinos

New

ProposedbyPauliin1930,detectedbyReines andCowans in1959,neutral,weaklyinteracting.TheSun,SN1987A– 10MeVDiffuseastrophysicalflux>50TeV ThisTalk


Region not observableIn photons orCharged particles

Themessengerhorizonγ-raysdonottraveltoofar• 1TeV :ClosestAGNsCRscannotpointback• Deflection:fewdegreesat~50EeV• Horizon~100MPc – interactionswithCMBTheneutrino- idealmessengerforthenonthermaluniverse• Neutral,undeflected

– canpointback• Interactsonlyweakly

– cantravelGpc distances– hardtodetect

• Wehopetosee• ThesitesofCRacceleration• DarkMatterannihilation

IceCube wasbuilttolookforastrophysicalneutrinos.

Copenhagen-2015

DM within our own Galaxy

36

DMHalo

BaryonicMatterDisk

LocalDMdensity

M.Pato – ICRC2015

GlobalMethod:Average𝜌CD atradiusoforbitofSun~0.4 ± 0.1𝐺𝑒𝑉/𝑐𝑚J

LocalMethod:𝜌CD atthepositionoftheSun‘Local’and‘Global’methodsnowstartingtoagreeonthelocalDMdensitySeeH.Silverwood etal,ICRC2015.

GlobalMethod


ν fromWIMPannihilationsintheSun

1TeV WIMP

FluxpredictionsfromWimpSim

Select:𝑊k𝑊F,𝜏k𝜏F (hardchannels)𝑏𝑏T (softchannel)

gg(evensofter)anddirectneutrino(evenharder)arenottheoreticallyfavoured


Level3Cutexamples1

Reducedloglikelihood.Cutonquality,rejectsbadlyreconstructedevents.

Explicitcutonreconstructeddirectiontoselectonlyhorizontaltracks.


Level3CutExamples(continued)

Zcoordinateofreconstructedstartingvertex.Selecteventsstartinglowerinthedetector.

2 3

DistancealongXYplanetostartingvertex.Selecteventsstartingnearcenterofthedetector.


Level5– BoostedDecisionTreeMultivariateclassificationalgorithm:

Giveseacheventascore between-1.0(background)and+1.0(signal)Trainedonasampleofsignallikeandbackgroundlikeeventsusingselectedvariables.

Variableshavetooffer:GoodSignaltobackgroundseparationGoodData/MCagreement(avoidsimulationartifacts)

ZenithofvectorbetweenCOGandVertex

2

ExampleBDTvariable


Level5– BoostedDecisionTree(contd)Prefervariablesthatarenotverycorrelatedwitheachother.

2

Signal Background

Ordifferentcorrelationsforsignalandbackground.


ComplementarityandEFTs

J.BlumenthaletalPhys.Rev.D91,035002(2015)– IceCube lineupdatedto3yearsbyme

Majorana FermionWIMP,UniversalCouplingstoquarks,AxialVectorInteractions

EFT

Equilibriumrevisited


Jungman andKamionkowsky (1996)

There’sathresholdσ[C belowwhichtheequilibriumconditionisnotavalidassumption

OurlimitswillremainabovethisthresholdforalongtimetocomeAssuming σc𝑣 ~ naturalscale.

UpcomingexperimentslikeCTAhavesensitivitytowardsDM σc𝑣 belowthenaturalscaleevenathighWIMPmasses


OtherStackingSearches(Nosignificantexcess)SNRsyoungerthan10000years(Sedov TaylorPhase)

Starburstgalaxiesinthenearbyuniverse:Contribute<1%ofthediffuseastrophysicalflux

Supermassiveblackholes withintheGZKhorizon,fromthe2MASScatalog:Contribute<2%ofthediffuseflux

NearbyGalaxyClusters:Theoreticalpredictionsarebelowcurrentsensitivity.

ArrivaldirectionsofAugerandTAUHECRsabove85EeV

LimitsbetterthanAntaresanalysisbyafactorof25

UHECRsabove85EeV


Periodicsearch– GammaRaybinaries

1)X-Ray binaries. characteristic radio emission believed to come from relativistic jets.Star

to observer

2) The neutrino flux expected at earth depends upon the orientation of our line of sight to these precessing jets.

3)Neutrino emission from these sources will follow the source PERIODICITY.

Trialfactorreduction:10microquasarsselected• Northernsky:detectedinGeV orhigher• Southernsky:detectedinTeV

TheHypothesis:AneutrinosignalwillhavethesameperiodicityastheopticalandX-rayobservations.(notnecessarilyinphasewithgamma)

Method:Lookforadirectionalexcessofeventsalsoclusteredinphase.


PeriodicSearch(Results)

Pretrialpvalue:8.67%,Nosignificantexcess

Source HESS J0632+057

Posttrialpvalue44.3%

Backgroundonlyhypothesis.

IceCube searches for neutrinos from dark matter annihilations in the ...

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