Spring Semester 2015 Final Oral Exam –...

SpringSemester2015

FinalOralExam–9/10.06.2015

1.  Theφ(1020)-meson1.  Towhichmesonfamilybelongstheφ-meson?Quantumnumbersandquark

content?2.  Explainwhytheφ mesondecaysmostlyintokaonsandseldomintopions.3.  Explainwhytheφ doesnotdecayintoποπο

2.  Massparabola,odd-massnuclei

1.  Commenttheattachedfigure“excessmass=f(Z)”anddiscussthedecaysequencesoftheA=101isobars.

3.  Newphysics?

1.  Double-betadecaysoccurs,e.g. ..Feynmangraph?2.  Whataboutneutrino-lessdouble-betadecay?Feynmangraph.

Consequences?

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3482Se→36

82Kr + 2e− + 2ν e

1.  CPviolation1.  Whatisaneutralkaon?Howdoesitdecay?2.  HowwasCPviolationdiscoveredin1964inK0-decays.3.  Formalism?

2.  Spinandparityofnuclei1.  Whatisthespinandparityoftheradioisotope179F?(figureavailable)2.  ThefirstexcitedstatehasJP=1/2-.Suggest1possibleconfigurationofthat

state.3.  Mass

1.  Howisbeta-decayusedtosetalimitontheelectron-neutrinomass?DiscussTritiumdecay.

2.  Give2waystheHiggsisproducedattheLHC–Feynmandiagrams.


1.  Stronginteraction1.  Howwasthegluondiscovered?2.  Comparethefollowingreactions(Feynmandiagrams,signatureindetectors)

3.  Inferthemaindifferencesbetweenαsandαqed.

2.  Nuclearmodels1.  PresenttheFermi-gasmodel.2.  Successandlimitations?

3.  Reactorneutrinos

1.  Whichneutrinoflavorsareproducedinanuclearreactor?2.  Givetheprincipleofdetectionandtheexperimentalsignatureofreactor

neutrinos.


qq→ qqγγ and qq→ qqgg

1.  Stronginteraction1.  Buildthelowest-massmesons(L=0)madeofthefirst3quarks(u,d,s).What

arethecorrespondingJPC?2.  Comparethedecaywidthsofthechargedpionandchargedkaonintomuon-

neutrinofinalstate.

2.  Nuclearmodels1.  Presentthenuclearshellmodelanditspotential.2.  Explainhowmagicnumbersarepredicted.3.  Predictspinandparityof4120Ca–makeuseoftheattachedscheme.

3.  Solarneutrinos?

1.  WhichreactionsareresponsibleforneutrinoproductionintheSun?2.  HowcantheybedetectedonEarth?Feynmandiagramofreaction?Principle.


1.  QCDproperties1.  Giveoneevidencefortheexistenceofthecolorquantumnumber.2.  Comparethefollowingreactions(Feynmandiagrams,signaturein

detectors).Drawconclusiononthebehavioroftheelectromagneticandstrongcouplingconstants.

2.  Rutherfordscattering1.  WhatisthefeatureofRutherfordscattering?2.  Explainbrieflyhowthecrosssectionformulaischangedinordertoaccount

forthecomplexityofnuclei(andlaternucleons).3.  Neutrinodiscovery

1.  Whichflavor(s)ofneutrinosis/areproducedinareactor?2.  Howwasthefirstdiscoverymade?ProcessandFeynmangraph?Detection

principle?


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gg→gg and γγ →γγ

1.  Weakgaugebosons1.  HowareW+,W-bosonsproducedinproton-protoncollisions?2.  CompareWproductioninppandppbar:atlowandatveryhighenergies.3.  HowoftendoestheWdecayintojets?Intoleptons?Youmaywanttowriteall

possibledecaysfirst.

2.  Semi-empiricalmassformulaandnuclearstability1.  DescribethevarioustermsoftheSemiEmpiricalMassFormula2.  Predictionsandlimitations?

3.  CPviolationinKaondecays

1.  Explainthephenomenonofstrangenessoscillations.2.  HowwasCPviolationdiscoveredinKaondecays?


1.  Higgsboson1.  HowistheHiggsbosonproducedine+e-andppcollisions?GiveoneFeynman

diagramforeach.2.  Studytheinvariantmassof4leptonsmeasuredbyATLAS.Attached.3.  WhichprocessescontributetotheStandardModelbackground?

2.  DiscussnuclearfissionwithintheLiquidDropmodel1.  WhichtermofSEMFplaysacrucialrole?2.  Howdifferentare23592Uand23892Uwithrespecttofission?

3.  DeepInelasticScattering(DIS)

1.  WhatisDISscattering?Feynmandiagram(s).2.  Howdiditleadtothestructureofnucleonsintermsofquarks?


1.  HiggsObservationatLHC1.  HowistheHiggsproducedinproton-protoncollisions.Feynmandiagram.2.  DiscusstheInvariantmassof4leptons(attached)withemphasison

(i)theHiggssignaland(ii)theotherfeaturesofthedistribution.

2.  QCDpredictsanewstateofmatter1.  Whataretheconditionsforaquark-gluonplasma?2.  Commentthephasediagram–seefigureattached

3.  Natureofneutrinos:DiracorMajorana?2.  Whataretheconditionsforneutrino-lessdoublebetadecaytohappen?

Feynmandiagram.3.  HowisTritiumbeta-decayusedtosetalimitontheelectronneutrino?


1.  Neutrino-nucleonDeepInelasticScattering1.  Whichprocessescontributetoneutrino-nucleonandantineutrino-nucleon

scatteringatthequarklevel?2.  Justifytheformsofcross-sections:

2.  Quark-gluonplasma1.  Whatisit?Commentthephasediagram–seefigureattached.

3.  Whichquantumnumbersarenotconservedin:1.  DrawFeynmangraphsleadingtoprotondecayinGrandUnification(GUT).2.  Whatistheexperimentalsignature?

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p→π 0e+ ; π 0 →γγγ

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dx dy=2GF

2MEνπ

xq(x)+ xq(x) 1− y( )2"#

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d 2σ νN

dx dy=2GF

2MEνπ

xq(x) 1− y( )2 + xq(x)"#

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1.  TheZweakneutralboson1.  HowistheZbosonproducedinproton-protoncollisions?2.  WhatareallpossibledecaysoftheZ-boson?3.  ExplainhowtheLEP-Ie+e-colliderexperiments(COMenergy~91±3GeV)set

alimitonthenumberoflightneutrinos?Howlight? 2.  Strongnuclearforce

1.  Giveasimplepotentialaccountingforthenuclearforce.2.  Discussstrangenessenhancementassignatureofquark-gluonplasma

3.  η meson

1.  QuantumnumbersJPCoftheη meson?2.  Discuss ηdecaysto2and3photons?


1.  TheHiggsbosonandtheZ-boson1.  Feynmangraphfore+e-àZZ?Whatisthethresholdofthisreaction?2.  Feynmangraphfore+e-àHZ?Whatisthethresholdofthisreaction?3.  HiggsatLHC:DiscusstheInvariantmassof4leptons(attached)with

emphasison(i)theHiggssignaland(ii)theotherfeaturesofthedistribution.2.  Massparabola,even-massnuclei

1.  Commenttheattachedfigure“excessmass=f(Z)”anddiscussthedecaysequencesoftheA=106isobars.Whichnucleiarebeta-stable?

3.  Fusionreactions1.  Whataretheconditionsforfusion?2.  Give3differentfusionreactionsinstarsleadingtoHelium-4.


1.  TheHiggsboson1.  Whatarepossibledecaysofa125-GeVHiggsboson?DrawFeynmangraphs

ofthedecayinto2photons.2.  Studyandcommenttheattachedinvariantmassdistributionof2photons.3.  Inparticulargive2processesresponsibleforthelarge“background”under

theHiggssignal2.  Massparabola,odd-massnuclei

1.  Commenttheattachedfigure“excessmass=f(Z)”anddiscussthedecaysequencesoftheA=111isobars.

2.  Writedownthedifferentbeta-decayreactions–oneexampleperkind.3.  Fusionreactions

1.  Whataretheconditionsforfusion?2.  Give3differentfusionreactionsinstarsleadingtoHelium-4.


1.  J/ψparticle1.  Howwasitdiscovered?GiveFeynmangraph(s)ofproductionine+e-and

decaytoleptons.2.  Whatareitsquantumnumbers(JPC)?3.  Explainwhytheparticleisverynarrow(widthΓ~90keVinsteadof~100MeV

fornormalhadrons)?2.  Interactionsatwork

1.  WritetheFeynmandiagramsofthedecaysoftheΔ++resonance:

1.  Estimatethedecayfractionratio

3.  Heavyioncollisions1.  WhatisQCDandwhatdoesitpredictathighdensitiesandenergies?2.  DiscussCharmoniumandstrangenessproductioninsuchanenvironment.


Γ(Δ++ → pe+νe )Γ(Δ++ → pπ + )

1.  Time-reversalviolationinkaondecays1.  K0productioninlowenergyprotonantiprotonannihilationsproceeds

through .Whataboutanti-K0?2.  HowdoK0andanti-K0decaysemi-leptonically?Feynmangraphs?3.  ExplainhowcanT-violationbemeasured?Howwilltheeffectbecomparedto

CPviolation?2.  α decay

1.  Drawaschematicdiagramofthepotentialenergyofanα particleasafunctionofitsdistancerfromthecentreofthenucleus.Discussα decay.

2.  Explainwhyfastneutronsareneededtoinducefissionof238U,contraryto235U.

3.  Neutrinos

1.  WhichneutrinoflavoursareproducedintheSun?2.  HowcantheseneutrinosbedetectedonEarth?


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pp →K −π +K 0

1.  Piondecays1.  Howdothechargedandneutralpionsdecay?GiveFeynmandiagrams.2.  Comparethedecaybranchingratiosofthechargedpionintoelectronand

muonfinalstates.

2.  Nuclearmodels1.  DescribetheNuclearshellmodel.2.  Successandlimitations?Examples.

3.  StronginteractionsandGrandUnifiedTheories(GUT)1.  Give2evidencesfortheexistenceofthecolorquantumnumber.2.  WhatisthesymmetrybehindGUT?Give2predictionsofthetheory.2.  Discussonepossibleprotondecay.Feynmandiagramandexperimental

detectionprinciple.


1.  Muondecay1.  Howdoesthemuondecay?Feynmandiagram?2.  Whatisparticularwithmuonsproducedinchargedpiondecaysatrest?

Consequencesontheangulardistributionofelectron/positron?3.  DiscussParity(P)andC-parity(C)violationsinmuondecay.Consequences?

2.  Chargedistributionandspatialextensionofnucleus

1.  Commenttheresultsofelectron-Nucleusscattering–seefigureattached.Whatistheinterpretationoftheminima?Whynotzeros?

2.  Whataboutprobingthematterdensityofnuclei?3.  Protondecay

1.  Howcanaprotondecay?2.  Whatistheprincipleofdetectionandmeasurement?


1.  Allowedhadrons1.  Formesons,whataretheallowedJPC?2.  Buildthemesonfamiliesexpectedforthefirst3quarks(u,d,s)andforangular

momentumL=1.

2.  Nuclearmodels1.  Presentbrieflythenuclearshellmodelandexplainhowmagicnumbersare

predicted.2.  Predictspinandparityof178O–makeusoftheattachedscheme

3.  Matter-antimatterasymmetryintheUniverse

1.  HowisCPviolationimplementedintheStandardModel?2.  Whatistheexperimentalstatus?3.  Whatarethe3necessaryconditionstoachieveMatter-Antimatter

asymmetryintheUniverse?


1.  Accordingtothequarkmodel,mesonsarequark-antiquarkboundstatesandbaryons3-quarkboundstates.

1.  Whatistherelationbetweenelectriccharge,isospinandhypercharge?2.  ForBaryons,whataretheallowedJPC?3.  Deducethebaryonfamiliesexpectedforthefirst3quarks(u,d,s)andforL=0.

2.  α decay1.  Drawaschematicdiagramofthepotentialenergyofanα particleasa

functionofitsdistancerfromthecentreofthenucleus.Discussα decay.2.  Explainwhyfastneutronsareneededtoinducefissionof238U,contraryto

235U.

3.  Oscillationsandraredecays1.  GiveFeynmangraphofoscillationintheKaonandD-mesonsystems.2.  WhyareK0andD0decaystoapairofleptonssuppressed?


1.  Chargedpiondecayatrest1.  Howdoesthechargedpiondecay?Feynmandiagram(s).2.  Comparethedecaystomuonandtoelectron?3.  Discussparity,C-parityandCPinpiondecay.

2.  ConfinementandQuark-gluonplasma1.  Discussasymptoticfreedomandconfinement.2.  Commentthephasediagram–seefigureattached.3.  Discuss“jet-quenching”assignatureofquark-gluonplasma

3.  Oscillations1.  DescribetheneutralB-mesonsystem.2.  GiveFeynmangraphsofoscillationsintheB-mesonandD-mesonsystems.


1.  Neutrinoelectronscattering1.  Feynmandiagramsofreactionsand2.  Comparethe(electron)angulardistributions?3.  Consequenceonthetotalcrosssections?

2.  Chargedistributionandspatialextensionofnucleus1.  DescribeRutherfordscattering2.  Commenttheresultsofelectron-Nucleusscattering–seefigureattached

3.  Doublebetadecay1.  Whatarethe2possibilities?Feynmangraphs.2.  Consequences?


−− → evev ee−− → evev ee

1.  CPviolationinB-decays1.  GiveaFeynmangraphofasemi-leptonicdecaywhereaB0transformstoa

D0.2.  ExplaintheprincipleofmeasurementofCP-asymmetryinthedecay

Makeuseoftheattachedfigure

2.  ConfinementandQuark-gluonplasma1.  Discussasymptoticfreedomandconfinement.2.  Explainhow“jet-quenching”couldbeasignatureofquark-gluonplasma

3.  Leptonnumberandbaryonnumber1.  IstheprocessallowedintheStandardModel?Feynmangraph.2.  Discusspossibilitiesforsimultaneousviolationofleptonandbaryonnumber

beyondSM.Exampleofprocess.


e+µ− → µ+e−

B0 / B0 → J /ΨKS → µ+µ−−π +π −

1.  WeakdecaysofBmesons1.  Howdothefollowingdecaysproceed?Feynmangraphs?

2.  Estimatetheratioofthetwodecaywidths3.  CompareCPviolationexpectedinBmesonsandinKmesons.

2.  Massparabola,even-massnuclei1.  Commenttheattachedfigure“excessmass=f(Z)”anddiscussthedecay

sequencesoftheA=102isobars.2.  Discussthepossibletransition

3.  CPviolation

1.  HowisCPviolationmeasuredine+e-àB0-B0bar.ConsiderthedecayoftheneutralB-mesonsintoJ/PsiKs.

2.  Youmayusetheattachedfigure


Γ B− →D0K *−( )Γ B− →D0ρ−( )

B− →D0K *− and B− →D0ρ−

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(A,Z)→(A,Z - 2)

46102Pd + ?→44

102Ru+ ?

1.  StandardModelinteractions?1.  Whichofprocesses1,2,3areallowed?2.  Ifyes,Feynmangraphsandinteractionatwork?

2.  Chargedistributionandspatialextensionofnucleus1.  Commenttheresultsofelectron-Nucleusscattering–seefigureattached.

Whatistheinterpretationoftheminima?Whynotzeros?2.  Howtoprobematterdensityofnuclei?

3.  CPviolation

1.  HowisCPviolationmeasuredinB-mesondecays?2.  HowisCPviolationmeasuredinK-mesondecays?


µ+ +µ− → γ +γ

νµ +νe →νe +νµ

K − + p→ π 0 +Λ0

1.  WeakdecaysofDmesons1.  Howdothefollowingdecaysproceed?Feynmangraphs?

2.  Estimatetheratioofthetwodecaywidths3.  ComparemixinginDmesonsandinKmesons.

2.  DeepInelasticScatteringandstructurefunctions1.  Give2electron-protonprocesses,onemediatedbyneutralcurrentsandone

bychargedcurrents.2.  DescribetheQ2dependenceofstructurefunctionsbyconsidering(i)free

quarks,(ii)gluonexchangeand(iii)gluonemission

3.  Stronginteractions1.  DescribetheYukawamodelofstrongnuclearforce.2.  ComparetheYukawamodeltotheQCDpictureofstronginteraction.


Γ D0 → K +K –( )Γ D0 → π +K –( )

D0 → K +K – and D0 → K –π +

1.  Charmonium1.  HowisJ/ψproducedine+e-andepcollisions?Feynmangraphs?2.  ExplainwhythewidthoftheJ/ψissomuchsmallerthannormalhadrons.

2.  DeepInelasticScatteringandstructurefunctions1.  Whatistheprotonmadeof?2.  Howistheprotonmomentumdistributedamongitsconstituents?

3.  RunningcouplingconstantsandUnification1.  Whatisthedifferencebetweenelectromagneticandstronginteractions?2.  Whataboutweakinteractions?3.  Discussthepossibilityofunificationofall3forces.


1.  Weakdecaysofleptons1.  Howdothefollowingdecaysproceed?Feynmangraphs?

2.  Estimatetheratioofthetwodecaywidths3.  ComparemixinginDmesonsandinKmesons.

2.  Conservationlaws1.  Howdoesthefollowinginteractionproceedandwhy?2.  Showthefollowingresult:

3.  SMandbeyond2.  GivetwoexperimentalfactsthatsuggestphysicsbeyondtheSM?3.  Tellaboutonepossiblesolutionwhichaddressestheseshortcomings.


Γ D0 → K +π –( )Γ D0 → π +K –( )

D0 → K +π – and D0 → K –π +

d + d→4 He+π 0

σ pp→ dπ +( )σ pn→ dπ 0( )

= 2

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45111Rb 51

111Sb

46111Pd 50

111Sn

47111Ag 49

111In

48111Cd

•  Even-evennuclei(data)-Uppercurve(SEMF)

o  Odd-oddnuclei(data)-Lowercurve(SEMF)

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Q(x) = d(x) + u(x)Q (x) = d (x) + u (x)Qv (x) ≡Q(x) −Q (x)

Tem

pera

ture

ρ0 baryon density

Spring Semester 2015 Final Oral Exam –...

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