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Searching for axions and ALPs from string theory .

Searching for axions and ALPs from string theory . Particles beyond the Standard Model?!. Standard Model of P article Physics : Fundamental des- cription of known matter par- ticles and gauge forces. Particles beyond the Standard Model?!.

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Searching for axions and ALPs from string theory .

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  1. SearchingforaxionsandALPs fromstringtheory.

  2. Particlesbeyondthe Standard Model?! • Standard Model ofParticlePhysics: Fundamental des-criptionofknown matter par-ticlesandgaugeforces

  3. Particlesbeyondthe Standard Model?! • Standard Model ofParticlePhysics: Fundamental des-criptionofknown matter par-ticlesandgaugeforces • Standard Model ofCosmolo-gy: onlyabout 5 % ofenergycontentofpresentuniverseconsistsofknownparticles

  4. Particlesbeyondthe Standard Model?! • Standard Model ofParticlePhysics: Fundamental des-criptionofknown matter par-ticlesandgaugeforces • Standard Model ofCosmolo-gy: onlyabout 5 % ofenergycontentofpresentuniverseconsistsofknownparticles • Extensionsofthe Standard Model ofParticlePhysics: severalgoodmotivatedcan-didatesforconstituentsofdark matter • SUSY: Neutralino, Gravitino • Peccei Quinn: Axion

  5. Peccei-Quinn extensionofthe Standard Model • Motivation: Explanation ofunnaturalsmallness, ,, ofCP-violatingtopologicalterm in QCDLagrangian, • Axionfield

  6. Peccei-Quinn extensionofthe Standard Model • Motivation: Explanation ofunnaturalsmallness, ,, ofCP-violatingtopologicalterm in QCDLagrangian, • Axionfield • Axion: ultralightparticle, cf. Weinberg `78; Wilczek `78

  7. Peccei-Quinn extensionofthe Standard Model • Motivation: Explanation ofunnaturalsmallness, ,, ofCP-violatingtopologicalterm in QCDLagrangian, • Axionfield • Axion: ultralightparticle, cf. Weinberg `78; Wilczek `78 • extremelyweakinteractionswith Standard Model particles

  8. Peccei-Quinn extensionofthe Standard Model • Motivation: Explanation ofunnaturalsmallness, ,, ofCP-violatingtopologicalterm in QCDLagrangian, • Axionfield • Axion: ultralightparticle, cf. Weinberg `78; Wilczek `78 • extremelyweakinteractionswith Standard Model particles • Welcome sideeffect: • Axion: candidatefordark matter: created non-thermally via misa-lignmentmechanism in form ofcoherentoscillationsofaxionfield

  9. Coexistence: SUSY and PQ extension in stringtheory • Particularlystronglymotivatedextensionsof Standard Model based on stringtheory: • Unificationof all forces • Quantum gravity

  10. Coexistence: SUSY and PQ extension in stringtheory • Particularlystronglymotivatedextensionsof Standard Model based on stringtheory: • Unificationof all forces • Quantum gravity • Spectrumoflow-energyeffec-tivetheory in (3+1)-dimensionsissupersymmetricandpossiblycontainsseveralkindsofveryweaklyinteractingslimparticles (WISPs): Axion, ALPs (Axion-LikeParticles • ifthecompactspacecomprisedofthe 6 extra dimensionshascertaingeometricalandtopological proper-ties (Calabi-Yau; severalcycles)

  11. Axions in stringtheory • String compactificationsgenericallycontain pseudo-scalarfieldswithaxioniccouplingtogaugefieldsandanomalous global shiftsymmetry • These axionandaxion-likeparticle (ALP) candidatesarise in stringcompactificationsas KK zeromodesofantisymmetrictensorfields: cf. Witten `84

  12. Axions in IIB stringtheory • Concentrate on IIB case (moduli stabilisation best understood): Realisationof brane-world scenarios in string theory • KK reduction (expansion in harmonicforms): • Numberofaxionicfieldsdeterminedbyto-pologyof CY orientifold: numberoftopolo-gically non-equivalent 2-cycles or 4-cycles

  13. Axions in IIB stringtheory • Numberofcyclesgenerically O(100):

  14. Axions in IIB stringtheory • Cycles can be wrapped by space-time filling D-branes • Each of these branes gives rise to a gauge theory at low energy • Visible sector gauge theory realized by stacks of D7 branes wrapping small 4-cycles • Hidden sectors, in particular hidden photons, realized by branes wrapping cycles not intersecting visible sector branes

  15. Axions in IIB stringtheory • Eachaxionicfieldcomesalongwith a real scalarfield– saxion– whichis real partoflowestcomponentofchiralsuperfield, • … Kähler modulusmeasuringthevolumeof 4-cycle • 4D EFT from KK reductionof D-braneaction • isgaugekineticfunctionfortheory on D7-brane: • volumemeasuresgaugecoupling, • hasaxioniccoupling,

  16. Axions in IIB stringtheory • 4D effectivefieldtheory, cf. Jockers, Louis `05 • Decayconstantsandcouplingtogaugebosons via canonicalnormali-zationofaxionandgaugekinetictermsandmatchingto:

  17. IIB axiverse • An axiverse - QCD axion plus possiblymanyultra-light ALPs whosemassspectrumislogarithmicallyhierarchical – maynaturallyarisefromstrings, cf. Arvanitaki et al. `09 • Challengestoobtain an axiverse: • Onlyaxionswhichare not projected out byorientifoldprojectionappear in LE EFT • Onlyaxionswhich do not gettoo heavy by Kähler modulistabilisationcanbecandidatesfor QCD axionandother light ALPs, cf. Conlon `06 • Onlyaxionswhichare not eatenbyStückelbergmechanismtogivemassestobrane-localizedanomalous U(1) gaugebosons will appear in LE EFT • Acharya, Bobkov, Kumar `11: Modulistabilisation via single non-pertur-bativecorrectionto superpotential (cf. Bobkov,Braun, Kumar, Raby `10) fixes all Kähler moduli plus oneaxioncombination: axiversewithand • Cicoli, Goodsell, AR, 1206.0819: Modulistabilisationofthe so-called LARGE Volume Scenario (LVS) whichexploitsbothperturbativeand non-perturbativeeffectsto fix Kähler moduligivesriseto an axiversewithand

  18. LVS axiverse • Strategyto fix moduli in LVS: (cf. Cicoli, Mayrhofer, Valandro `11) • Exploit del Pezzofour-cyclesupportingsingle non-perturbativeeffect; dPmodulusfixedatsmallsize, dPsaxionandaxion heavy; interplaywithleadingorderalpha´ correctionyieldsexponentially large CY volume • Visible sectorwithchiralitybuiltbywrapping mag-netised D7-branes around rigid but not del Pezzofourcycles; D-term conditionsstabilise d combi-nationsof Kähler moduli, leaving . flat directions; latterfixedbypert. corrections • LVS requires : oneoftheremainingcyclesshouldbesmalltoobtaincorrectvalueof . , whilethereshouldbeat least onefurtherwhichcanbelarge; latterfixedat • More on this: talkbyMichele Cicoli

  19. LVS axiverse • Massscalesfor : • Nocosmologicalmoduliproblemsincedilutedbyentropyproduction due todecayof . reheatinguniverseto O(GeV)

  20. LVS axiverse • Scalingofaxiondecayconstantsandcouplings: • : QCD axionwith • : essentiallymassless ALP with , but nearlydecoupled,

  21. LVS axiverse • Scalingofaxiondecayconstantsandcouplings: • : QCD axionwith • : essentiallymassless ALP with , but nearlydecoupled, • Possiblymoreultralight, , ALPs with

  22. Axionand ALPs with intermediate scaledecayconstant? • Currentlimitsandpossiblehintsfromastrophysicsandcosmology:

  23. Hintsforaxionor ALP effects in propagationofTeVphotonsthroughuniverse? • TeVphotonsofdistantActiveGa-lactic Nuclei (AGN) shouldfeatureabsorptionbreaks due toelectron-positron pairproduction on the Ex-tragalacticBackground Light (EBL)

  24. Hintsforaxionor ALP effects in propagationofTeVphotonsthroughuniverse? • TeVphotonsofdistantActiveGa-lactic Nuclei (AGN) shouldfeatureabsorptionbreaks due toelectron-positron pairproduction on the Ex-tragalacticBackground Light (EBL) • Not thecase: (e.g. Horns, Meyer `12) • 50 spectra (HESS, MAGIC, Veritas), assumption: minimal EBL; absorptionruled out bymorethan 4 sigma

  25. Hintsforaxionor ALP effects in propagationofTeVphotonsthroughuniverse? • TeVphotonsofdistantActiveGa-lactic Nuclei (AGN) shouldfeatureabsorptionbreaks due toelectron-positron pairproduction on the Ex-tragalacticBackground Light (EBL) • Not thecase: (e.g. Horns, Meyer `12) • 50 spectra (HESS, MAGIC, Veritas), assumption: minimal EBL; absorptionruled out bymorethan 4 sigma • Possibleexplanation: Photon <-> ALP conversion in astrophysicalmagneticfields(Roncadelli et al.,Sanchez-Conde et al.)

  26. Hintsforaxionor ALP effects in propagationofTeVphotonsthroughuniverse? • TeVphotonsofdistantActiveGa-lactic Nuclei (AGN) shouldfeatureabsorptionbreaks due toelectron-positron pairproduction on the Ex-tragalacticBackground Light (EBL) • Not thecase: (e.g. Horns, Meyer `12) • 50 spectra (HESS, MAGIC, Veritas), assumption: minimal EBL; absorptionruled out bymorethan 4 sigma • Possibleexplanation: Photon <-> ALP conversion in astrophysicalmagneticfields(Roncadelli et al.,Sanchez-Conde et al.) • Hastobe an ALP: too light for a QCD axionwith such a decaycon-stant

  27. Hintforaxion/ALP-production in whitedwarfs? • Non-standard energie-lossmechanism in whitedwarfs, cf. Isern et al. • Compatiblewithaxionor ALP production in electron-bremsstrahlung

  28. Can weexplainthesehintswithin IIB axiverse? • Anomaloustransparencyofuniverseandanomalousenergylossofwhitedwarfscouldbeexplainedby • Model wherevisiblesectorbuildfromintersectingbranes in geometricregime • Yieldsrequiredvaluesfor • ALP masscouldbegeneratedbysingle Kähler potential instanton, e.g. requires • Astrophyicalhintscompatiblewith intermediate string-scalescenario

  29. Laboratory probesofaxionand ALPs with intermediate scaledecayconstant?

  30. Search for solar axionsand ALPs • Sun strong sourceofaxionsand ALPs • Helioscopesearchesforaxions/ALPs and HPs

  31. Search for solar axionsand ALPs • Sun strong sourceofaxionsand ALPs • Helioscopesearchesforaxions/ALPs and HPs • CAST … CERN Axion Solar Telescope

  32. Search for solar axionsand ALPs • Sun strong sourceofaxionsand ALPs • Helioscopesearchesforaxions/ALPs and HPs • CAST … CERN Axion Solar Telescope • IAXO … International Axion Observatory (underinvestigation)

  33. Search for solar axionsand ALPs

  34. Search for ALPs via light-shining-through-walls • ALPs can pass walls • Light-shining-through-walls experiments: (here ALPS (@DESY)):

  35. Search for ALPs via light-shining-through-walls • ALPS: • HERA dipole (8.4 m, 5 T) • Primary laser: enhanced LIGO laser (1064 nm, 35 W) • Frequencydoubled: 523 nm • 300-fold power build-up in cavity

  36. Search for ALPs via light-shining-through-walls • ALPS: • HERA dipole (8.4 m, 5 T) • Primary laser: enhanced LIGO laser (1064 nm, 35 W) • Frequencydoubled: 523 nm • 300-fold power build-up in cavity

  37. Search for ALPs via light-shining-through-walls • ALPS: • HERA dipole (8.4 m, 5 T) • Primary laser: enhanced LIGO laser (1064 nm, 35 W) • Frequencydoubled: 523 nm • 300-fold power build-up in cavity • ALPS-II plans (2016+): • 12 + 12 HERA dipoles • Increased power build-up (~5000) • Cavity also on regenerationpart

  38. Search for ALPs via light-shining-through-walls • ALPS: • HERA dipole (8.4 m, 5 T) • Primary laser: enhanced LIGO laser (1064 nm, 35 W) • Frequencydoubled: 523 nm • 300-fold power build-up in cavity • ALPS-II plans (2016+): • 12 + 12 HERA dipoles • Increased power build-up (~5000) • Cavity also on regenerationpart • Similarplans also atFermilab (REAPR)

  39. Summary andconclusions • String phenomenologyholdsthepromiseof an axiverse – the QCD axion plus a (possibly large) numberoffurtherultralightaxion-like par-ticles, possiblypopulatingeachdecadeofmass down tothe Hubble scale • Promisefulfilled in LARGE Volume Scenario of IIB stringcompactifi-cations • Models thatexhibit a QCD axionwith an intermediate-scaledecayconstantand additional evenlighteraxion-likeparticleshavingthe same decayconstantandcouplingtothephotoncanexplainastrophysicalanomaliesandbetested in thenextgenerationofhelioscopesand light-shining-through-walls experiments • Cosmologyof LVS axiverse still tobeinvestigated in detail

  40. Backup: Hidden photons

  41. Backup: Hidden photons

  42. Backup: More probesofultralightaxionsand ALPs cf. Arvanitaki, Dimopoulos, Dubovsky, Kaloper, March-Russell `09

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