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Science Case for / Physics Goals of ALPS-II .

Science Case for / Physics Goals of ALPS-II . Strong case for p articles beyond the Standard Model. Standard Model (SM) of particle physics describes basic proper- ties of known matter and forces SM not a complete and fundamental theory :

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Science Case for / Physics Goals of ALPS-II .

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  1. Science Case for / Physics Goals of ALPS-II.

  2. Strong caseforparticlesbeyondthe Standard Model • Standard Model (SM) ofparticlephysicsdescribesbasic proper-tiesofknown matter andforces • SM not a completeand fundamental theory: • Nosatisfactoryexplanationforvaluesofitsmanyparameters • Noquantumgravity

  3. Strong caseforparticlesbeyondthe Standard Model • Standard Model (SM) ofparticlephysicsdescribesbasic proper-tiesofknown matter andforces • SM not a completeand fundamental theory: • Nosatisfactoryexplanationforvaluesofitsmanyparameters • Noquantumgravity • Noexplanationoftheoriginofdarkenergyanddark matter (wikipedia)

  4. Strong caseforparticlesbeyondthe Standard Model • Standard Model (SM) ofparticlephysicsdescribesbasic proper-tiesofknown matter andforces • SM not a completeand fundamental theory: • Nosatisfactoryexplanationforvaluesofitsmanyparameters • Noquantumgravity • Noexplanationoftheoriginofdarkenergyanddark matter • Leadingdark matter candidates: • NeutralinosandotherWeaklyInterac-ting Massive Particles (WIMPs) • AxionsandotherveryWeaklyInterac-ting Slim (=ultra-light) Particles (WISPs) (Kim,Carosi 10)

  5. Axionandaxion-likeparticles: Theory • Peccei-Quinnsolutionof strong CP puzzle: introduceaxionfield a(x) asdynamicalthetaparameter, enjoying a shiftsymmetry, brokenonlybyanomalouscouplingstogaugefields, • Effective theta parameter has zero expectation value: no strong CP violation • Elementary particle excitation of axion field: QCD axion(Weinberg 78; Wilczek 78) • For large decay constant : prime example of a WISP . . . (Kim 79; Shifman et al 80; Zhitnitsky80; Dine et al 81) • Axion-likeparticles(ALPs) : moreaxion-likefieldswithshiftsymmetryandanomalouscouplingstogaugebosons

  6. Axionandaxion-likeparticles: Theory

  7. Axionandaxion-likeparticles: Theory • In fieldtheoreticextensionsof SM, axionand ALP fieldsrealisedasphaseofcomplex SM singletscalarfieldswhosevacuumexpectationvalues break global anomalouschiral U(1) symmetries.(Peccei, Quinn 77) • Atenergiesmuchbelowthesymmetrybreaking,thelow-energyeffec-tivefieldtheoryisthatof (pseudo-)Nambu-Goldstone bosonswithdecayconstants • In models, in whichthe global PQ symmetriesare not imposedbyhand, but in whichtheyappearasautomaticconsequencesoflocalgaugein-variance, renormalisabilityandpatternofgaugesymmetrybreakdown: . (Georgi, Hall, Wise 81) • Big rangeofpossibilitiesdiscussedin literature:

  8. Axionandaxion-likeparticles: Theory • Particular strong motivationfortheexi-stenceoftheaxionand ALPs comesfromstringtheory • Low-energyeffectivefieldtheoryemer-ging fromstringtheorypredictsnaturalcandidatesforthe QCD axion, ofteneven an `axiverse´, containingmany additional ALPs (Witten 84; Conlon 06; Svrcek, Witten 06; Arvanitaki et al 09; Acharya et al 10; Cicoli,Goodsell,AR 12) • Numberof ALPs = numberofcyclesof extra-dimensional manifold • Big rangeofpossibilities, sinceitsvo-lumecantake a rangeofvalues:

  9. Axionandaxion-likeparticles: Theory

  10. Axionandaxion-likeparticles: Astrophysics • Strong boundson axions/ALPs comefromtheireffects on stellar evo-lutionandon thepropagationof SM particlesthroughastrophysicalen-vironments:(Raffelt 96) • Non-observation of an anomalousenergylossofHorizontal Branch (HB) stars due to ALP emission: • Absenseof a gamma-rayburst due toaxion/ALP-photon conversion in coincidencewithneutrinosfrom SN 1987A: (Brockway et al 96; Grifols et al 96) • Just behindtheboundaryofcurrentbounds, thereareintriguinghintssuggestingexistenceofaxionsand ALPs (Isern et al 08;12) • Evidencefor a non-standard energyloss in whitedwarfs, consistentwiththeexistenceof a subkeVmassaxionor ALP with

  11. Axionandaxion-likeparticles: Astrophysics • TeVphotonsfromdistantActiveGalactic Nuclei (AGN) shouldshowabsorptionfeatures due toe+e- pair productionattheExtragalactic Background Light (EBL)

  12. Axionandaxion-likeparticles: Astrophysics • TeVphotonsfromdistantActiveGalactic Nuclei (AGN) shouldshowabsorptionfeatures due toe+e- pair productionattheExtragalactic Background Light (EBL) • Not thecase: (e.g. Horns,Meyer) • Analysis of 50 spectra(HESS, MAGIC, Veritas): minimal EBL, absorptionexcludedbymorethan 4 sigma (Horns,Meyer 12)

  13. Axionandaxion-likeparticles: Astrophysics • TeVphotonsfromdistantActiveGalactic Nuclei (AGN) shouldshowabsorptionfeatures due toe+e- pair productionattheExtragalactic Background Light (EBL) • Not thecase: (e.g. Horns,Meyer) • Analysis of 50 spectra(HESS, MAGIC, Veritas): minimal EBL, absorptionexcludedbymorethan 4 sigma • Possibleexplanation in termsofphoton <-> ALP conversions in astrophysicalmagneticfields(Roncadelli et al 07; Simet et al 08; Sanchez-Conde et al 09; Horns et al 12)

  14. Axionandaxion-likeparticles: Astrophysics

  15. Axionandaxion-likeparticles: Dark matter • AxionsandotherbosonicWISPycolddark matter maybeprodu-ced non-thermally via vacuum-realignment in form ofclassical, spatiallycoherentoscillatingfields = coherentstateofextre-mely non-relativisticdark matter (Preskill et al 83; Abbott,Sikivie 83; Dine,Fischler 83; Cadamuro et al 12)

  16. Axionandaxion-likeparticles: Dark matter • AxionsandotherbosonicWISPycolddark matter maybeprodu-ced non-thermally via vacuum-realignment in form ofclassical, spatiallycoherentoscillatingfields = coherentstateofextre-mely non-relativisticdark matter • Axion (ALPs) cancontributesignifi-cantlytocolddark matter for . (a wider rangeofparameters) • Axionor ALP colddark matter may form rethermalising Bose Einstein Condensate (BEC) (Sikivie,Yang 09; Erken et al. 12; Sikivie 12) • Observational evidence for caustic rings of dark matter consistent with BEC, but not with WIMPy dark matter (Cadamuro et al. 12)

  17. Axionandaxion-likeparticles: Goals of ALPS-IIc • Chart thus-farunexploredparameterspace, surpassing, atlowmasses, eventhelimitsfromtheCERN Axion Solar Telescope (CAST) • Tackleregionswhicharefavoredbyastrophysicalhints, dark matter, andtheory

  18. Hidden photons: Theory • Most extensions of standard model based on supergravity or super-strings predict “hidden sector” of particles which are very weakly cou-pled to the “visible sector” standard model particles • Hidden-sectorAbelian gauge bosons (hidden photons) provide a win-dow to the hiddensectorsincetheycan mix kinetically with the visible sector hypercharge U(1) gauge boson, • Kinetic mixing generated at loop level via messenger exchange (Holdom 86; Dienes et al 97; Abel et al 08; Goodsell et al 09;12; Cicoli et al 11)

  19. Hidden photons: Dark radiation • FormeVscalemasses, photon <-> hiddenphotonoscillationsoccurresonantly after big bang nucleosynthesis, producing a hiddencosmicmicrowavebackground, leadingto an increaseofthecosmicenergydensity in invisible radiationatdecoupling (darkradiation), oftenquotedastheeffectivenumberofneutrinospecies(Jaeckel,Redondo,AR 08) • CMB observationsseemtofavour extra darkradiation: (Komatsu et al [WMAP] 10; Dunkley et al [AcatamaCosmologyTelescopeCollaboration] 10) • Requiredparameters:

  20. Hidden photons: Goals of ALPS-IIa/IIb • Conclusive test of hidden photon dark radiation hypothesis • Probe parameter region predicted in intermediate string scale scenarios • Tackle a fraction of hidden photon dark matter parameter space

  21. Summary • Strong physicscasefor WISPs fromtheory: • Solution of strong CP problemgivesparticularly strong motivationforexistenceof QCD axion • In many UV completionsof SM with a QCD axion, thereoccur also ALPs • Hidden sectorsareoftenexploited in supersymmetricextensionsofthe SM. In thesesectors, hiddenphotonsareverywellmotivated WISP candidatesproviding a windowtothehiddensector. • ALPs andhiddenphotonscansolvepuzzles in astrophysicsand cos-mology: • Anomalousenergylossofwhitedwarfs • AnomaloustransparencyoftheuniverseforTeVphotons • Extra darkradiation • WISPydark matter • ALPS-II cantacklecorrespondingregions in WISPyparameterspace!

  22. Backup • Study on ALP explanationofTeVtransparency in progress(Horns,Meyer): ALPS-II coversfiducialregion

  23. Backup • Projectedaxion/ALP sensitivitiesofotherexperiments: (Hewett et al 12)

  24. Backup • Projectedhiddenphotonsensitivitiesofotherexperiments: (Hewett et al 12)

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