Supernova neutrino spectra and applications to flavor oscillations [Elektronische Ressource] / Mathias Thorsten Keil

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DissertationSupernova Neutrino Spectraand Applications toFlavor OscillationsbyMathias Thorsten KeilInstitut fu¨r Theoretische Physik T30Univ.-Prof. Dr. Manfred LindnerMax-Planck-Institut fu¨r Physik(Werner-Heisenberg-Institut)Advisor: Dr. habil. Georg G. Raffeltsupported by the grant SFB 375Institut fu¨r Theoretische Physik T30, Univ.-Prof. Dr. Manfred LindnerSupernova Neutrino Spectraand Applications toFlavor OscillationsMathias Thorsten KeilVollsta¨ndiger Abdruck der von der Fakult¨at fu¨r Physik der Technischen Universit¨atMu¨nchen zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften(Dr. rer. nat.) genehmigten Dissertation.Vorsitzender: Univ.-Prof. Dr. F. v. FeilitzschPru¨fer der Dissertation: 1. Univ.-Prof. Dr. M. Lindner2. Univ.-Prof. Dr. M. DreesDie Dissertation wurde am 27.05.2003 bei der Technischen Universit¨at Mu¨ncheneingereicht und durch die Fakulta¨t fu¨r Physik am 25.06.2003 angenommen.SummaryWe study the flavor-dependent neutrino spectra formation in the core ofa supernova (SN) by means of Monte Carlo simulations. Several neutrinodetectors around the world are able to detect a high-statistics signal from agalactic SN. From such a signal one may extract information that severelyconstrains the parameter space for neutrino oscillations. Therefore, reliablepredictions for flavor-dependent fluxes and spectra are urgently needed.

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• Astronomie

Informations

• Publié par: technische_universitat_munchen
• Publié le: 01 janvier 2003
• Nombre de lectures: 20
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Dissertation

SupernovaNeutrinoSpectra
andApplicationsto
FlavorOscillations

ybMathiasThorstenKeil

Institutfu¨rTheoretischePhysikT30
Univ.-Prof.Dr.ManfredLindner
Max-Planck-Institutfu¨rPhysik
(Werner-Heisenberg-Institut)
Advisor:Dr.habil.GeorgG.Raelt
supportedbythegrantSFB375

Institutfu¨rTheoretischePhysikT30,Univ.-Prof.Dr.ManfredLindner

SupernovaNeutrinoSpectra
andApplicationsto
FlavorOscillations

MathiasThorstenKeil

Vollsta¨ndigerAbdruckdervonderFakulta¨tfu¨rPhysikderTechnischenUniversita¨t
Mu¨nchenzurErlangungdesakademischenGradeseinesDoktorsderNaturwissenschaften
(Dr.rer.nat.)genehmigtenDissertation.

Vorsitzender:Univ.-Prof.Dr.F.v.Feilitzsch
Pru¨ferderDissertation:1.Univ.-Prof.Dr.M.Lindner
2.Univ.-Prof.Dr.M.Drees

DieDissertationwurdeam27.05.2003beiderTechnischenUniversita¨tMu¨nchen
eingereichtunddurchdieFakulta¨tfu¨rPhysikam25.06.2003angenommen.

SummaryWestudytheflavor-dependentneutrinospectraformationinthecoreof
asupernova(SN)bymeansofMonteCarlosimulations.Severalneutrino
detectorsaroundtheworldareabletodetectahigh-statisticssignalfroma
galacticSN.Fromsuchasignalonemayextractinformationthatseverely
constrainstheparameterspaceforneutrinooscillations.Therefore,reliable
predictionsforflavor-dependentfluxesandspectraareurgentlyneeded.
Inallhydrodynamicsimulationsthetreatmentofνµ,τandν¯µ,τisrather
schematic,withtheexceptionofthemostrecentGarching-Groupsimulation,
wheretheinteractionprocesseswereupdatedpartlybasedonourresults.The
interactionscommonlyincludedintraditionalsimulationsareiso-energetic
scatteringonnucleonsNν→νN,scatteringonelectronsandpositrons
e±ν→νe±,andelectron-positronpairannihilatione+e−→νµ,τν¯µ,τ.Inour
MonteCarlosimulationswevarythestaticstellarbackgroundmodelsinad-
ditiontosystematicallyswitchingonandoffoursetofinteractionprocesses,
i.e.,recoilandweakmagnetisminNν→νN,scatteringone±andνe/¯νe,
e+e−andνeν¯eannihilationintoνµ,τν¯µ,τpairs,andneutrinobremsstrahlung
offnucleonsNN→NNνν¯.Asνµ,τandν¯µ,τsources,NN→NNνν¯and
νeν¯e→νµ,τν¯µ,τdominate.Thelatterprocesshasneverbeenstudiedbefore
inthecontextofSNeandturnsouttobealwaysmoreimportantthanthe
traditionale+e−annihilationprocessbyafactorof2–3.Forenergytransfer,
themostimportantreactionsareNν→νNwithrecoil,andscatteringon
e±.Weakmagnetismhasaverysmalleffectandscatteringonνeandν¯eis
negligible.Thechargedcurrentreactionse−p→νenande+n→ν¯epdominateforνe
andν¯e.Incomparingournumericalresultsforallflavorswefindthestandard
<hierarchyofmeanenergiesνe<ν¯e∼νµ,τ,with,however,verysimilar
valuesforνµ,τandν¯e.Theluminositiesofνµ,τandν¯ecandifferbyupto
afactorof2fromLν¯e≈Lνe.TheGarchingGroupobtainssimilarresults
fromtheirself-consistentsimulationwiththefullsetofinteractions.These
resultsarealmostorthogonaltothepreviousstandardpictureofexactly
equalluminositiesofallflavorsanddifferencesinmeanenergiesofuptoa
2.ofortfacExistingconceptsforidentifyingoscillationeffectsinaSNneutrinosignal
needtoberevised.Wepresenttwomethodsfordetectingtheearth-matter
effectthatareratherindependentofpredictionsfromSNsimulations.An
earth-inducedfluxdifferencecanbemeasuredbythefutureIceCubedetector
inAntarcticaandaco-detectorlikeSuper-orHyper-Kamiokande.Atasingle
detectorwithhighenergyresolutiontheFouriertransformoftheinverse-
energyspectrumcanrevealthemodulationsofthespectrum.Bothmethods
aresensitivetothesmallmixingangleθ13andtheneutrinomasshierarchy.

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Acknowledgments
Mantience,ypeandoplekconindness.tributedIetoxpressthismydissertagratitudetiontowitheveryotheirneawhodvice,helpesuppdmort,akingpa-
thisworkcometrue.
ForemostIamindebtedtomyadvisor,GeorgRaffelt,notonlyforpropos-
ingtheprojectandtherebygettingmeintoAstroparticlePhysics,buteven
moreforhisgreatsupportandadviceinsomanyways.Ibenefitedverymuch
fromourcloseandveryinspiringcollaboration.Alsofortheproofreadingand
uncountablevaluablesuggestionsonthemanuscriptIamverygrateful.
Thenumericalpartofthisworkwasonlypossiblewiththecodethat
Hans-ThomasJankahaddevelopedandkindlyintroducedmeto.Ienjoyed
thecollaborationwithThomasandappreciatehispatiencewithmyques-
tionsandhisexhaustiveanswersonallkindsofcode-andsupernova-related
questions.ThomasandhisGarchingSupernovaGroup,i.e.,RobertBuras
andMarkusRampp,contributedveryvaluableresultsfromtheirhydrody-
namicsimulations.IalsothankRobertforourmanylongdiscussionsand
hisvaluablesuggestionsonpartsofthemanuscript.
WithAmolDigheIhadawonderfulcollaborationontheneutrino-
oscillationpart.ButalsoforallotherquestionsanddiscussionsIfound
manAmol’suscriptdoorbywidehisopproen.oInafreadingddition,andIstuhankggestions.AmolAforlsoifmproorvingdiscussionspartsofwtheith
MichaelKachelrieß,SergioPastor,DimitrySemikoz,andRicardTom´asIam
verygrateful.
myAsfamilyimpowhortanstuppastheortedsauppndortatencouragedthemeinstitutetwehroughoutreallatllhosetheyfriendsears,eveandn
mywhendeepIwestastfarhanksawatyo.Fmoyrptarenheirtslovaseweandllsasuppmyortibrothernanyapndossiblesister.wCayIhristophowe
evenfittedsomeproofreadingintohisbusyconferenceschedule,thankyou.
andFeovreyourrythinglovyeo,usuppdidort,formande,weoncrdsouragecannotmenet,yxpressourpmyatiencegratitude,yourandsmlileovs,e
foryou,Meike.

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Partsofthisdissertationhavealreadybeenpublishedas:

•M.“MonT.teCKeil,arloG.sG.tudyofRaffelt,supaendrnovH.anT.eutrinoJanka,spectraformation,”
Astrophys.J.inpress,
tro-ph/0208035.as

•R.“Electron-Buras,H.neutrinoT.Jankpaira,M.T.annihilatiKeil,on:G.AG.newRaffelt,sourceandforM.muonRampp,andtau
Asneutrinostrophys.inJ.sup587ernov(2003)ae,”320[astro-ph/0205006].

•M.T.Keil,G.G.Raffelt,andH.T.Janka,
“SupernovaNeutrinoSpectraFormation,”
Nucl.Phys.BProc.Suppl.118(2003)506.

•G.G.Raffelt,M.T.Keil,R.Buras,H.T.Janka,andM.Rampp,
“Supernovaneutrinos:Flavor-dependentfluxesandspectra,”
tro-ph/0303226.as

•A.S.Dighe,M.T.Keil,andG.G.Raffelt,
“DetectingtheneutrinomasshierarchywithasupernovaatIceCube,”
JCAP,inpress(2003),hep-ph/0303210.

•A.“IdenS.tDigheifying,M.earthT.Kematteril,andeGffects.Go.nRsaffeuplt,ernovaneutrinosatasingle
detector,”p-ph/0304150.he

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tsentCon

1Introduction

2TheCore-CollapseParadigm
2.1TheLifeofaStar:BalancingForces.............
2.2TheDeathofaMassiveStar:CoreCollapse........
2.3Reincarnation:AProto-NeutronStarEmerges.......
2.4Self-ConsistentSimulations..................
2.5Flavor-DependentNeutrinoEmission............

3NeutrinoInteractions
3.1Beta-Processes........................
3.2Neutrino-NucleonScattering.................
3.3WeakMagnetism.......................
3.4Bremsstrahlung........................
3.5PairAnnihilation.......................
3.6ScatteringonElectronsandElectronNeutrinos......
3.7OtherReactions........................

4SettingtheStageforNeutrinoTransport
4.1CharacterizingProto-NeutronStars.............
4.2Proto-Neutron-StarProfiles.................
4.3OpticalDepthvs.ThermalizationDepth..........
4.4ThermalizationDepthsinOurStellarModels.......

5CharacterizingNon-ThermalNeutrinoSpectra
5.1GlobalParameters......................
5.2AnalyticFits.........................

6RelativeImportanceofNeutral-CurrentReactions
6.1MonteCarloSetup......................
6.2Accretion-PhaseModelI...................

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........

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7701113161

1212326272282343

3553639324

949415

757595

6.3SteepPowerLaw.........................
6.4ShallowPowerLaw........................
6.5Summary.............................
7ComparisonofAllFlavors
7.1ResultsfromOurMonteCarloStudy..............
7.2PreviousLiterature........................
7.3SpectralShape..........................
7.4Summary.............................
8DetectingOscillationsofSNNeutrinos
8.1OscillationsofSNNeutrinos...................
8.2DetectingOscillationsWithTwoDistantDetectors......
8.2.1TheBasicPrinciple....................
8.2.2TheSNSignalatIceCube................
8.2.3TheOscillationSignalatIceCube...........
8.2.4Super-orHyper-KamiokandeandIceCube.......
8.3DetectingtheEarth-MatterEffectataSingleDetector....
8.4Summary.............................
9DiscussionandSummary

tionsbbreviaAA

BMonteCarloCode
B.1GeneralConcept.........
B.2StructureoftheCode.......

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1Chapter

ductiontroIn

Thephysicsofneutrinooscillationshasreceivedtremendousattentiondur-
ingthepastyearsandtodayoscillationsarethoughttobeestablished.A
largenumberofexperimentshascontributedtoourpresentknowledgeof
thetheamllowixingedrscangeshemesareandknown.parameters.WithinForthesenveextralfewofthedecadesmixtingheparametersmagnitude
ofthesmallmixingangleθ13andthequestionwhethertheneutrinomass
hierarchyisnormalorinvertedwillremainopenandcanbesettledonlyby
futureprecisionmeasurementsatdedicatedlong-baselineoscillationexper-
iments(Bargeretal.2001,Cerveraetal.2000,Freund,Huber,&Lindner
2001)ortheobservationofafuturegalacticsupernova(SN).
Alongwithth