Searches for axions with the International AXion Observatory IAXO Igor G Irastorza Universidad de Zaragoza What next LNF: Perspectives of fundamental physics at the Frascati Laboratory LNF, Frascati, Italy – November 11 th, 2014

Outline Axion motivation: Axion motivation: –Strong CP problem –Axions as CDM –Solar axions Previous helioscopes & CAST Previous helioscopes & CAST IAXO Conceptual Design IAXO Conceptual Design –Magnet –Optics –Detectors IAXO physics potential IAXO physics potential Status of project. Next steps Status of project. Next steps Conclusions Conclusions LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 2 IAXO Letter of Intent: CERN-SPSC signatures / 38 institutions IAXO Conceptual Design: JINST 9 (2014) T05002 (arXiv: ) IAXO Letter of Intent: CERN-SPSC signatures / 38 institutions IAXO Conceptual Design: JINST 9 (2014) T05002 (arXiv: )

Why axions? Strong CP problem: why strong interactions seem not to violate CP? – –CP violating term in QCD is not forbidden. But neutron electric dipole moment not observed Natural answer if Peccei-Quinn mechanism exists – –New U(1) global symmetry  spontaneously broken – –Proposed in 1977 LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza3 PRIMAKOFF EFFECT As a result, new pseudoscalar, neutral and very light particle is predicted, the axion (Weinberg, Wilczek) It couples to the photon in every model

Beyond axions Diverse theory motivation Diverse theory motivation –Higher scale symm. breaking –String theory –DM / DE candidates –Astrophysical hints Generic Axion-like particles (ALPs) parameter space  Generic Axion-like particles (ALPs) parameter space  LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 4 AXIONS Minicharged particles Chamaleons Hidden photons / paraphotons WISPs (Weakly interacting Sub-eV Particle) ALPS

Axions as Dark Matter? Axions are produced in the early Universe by a number of processes: Axions are produced in the early Universe by a number of processes: –Axion realignment –Decay of axion strings –Decay of axion walls 5 NON-RELATIVISTIC (COLD) AXIONS RELATIVISTIC (HOT) AXIONS Axion masses ma > ~0.9 eV gives densities too much in excess to be compatible with latest CMB data Axion masses ma > ~0.9 eV gives densities too much in excess to be compatible with latest CMB data Hannestad et al, JCAP 08 (2010) 001 (arXiv: ) Axion mass giving the right CDM density? Depends on cosmological assumptions: Axion mass giving the right CDM density? Depends on cosmological assumptions: “classical window” ~ – eV “classical window” ~ – eV “anthropic window” ~ much lower masses possible “anthropic window” ~ much lower masses possible Higher masses  subdominant CDM / non-standard scenarios Higher masses  subdominant CDM / non-standard scenarios – Thermal production LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza

Axion motivation in a nutshell Most compelling solution to the Strong CP problem of the SM Axion-like particles (ALPs) predicted by many extensions of the SM (e.g. string theory) Axions, like WIMPs, may solve the DM problem for free. (i.e. not ad hoc solution to DM) Astrophysical hints for axion/ALPs? Astrophysical hints for axion/ALPs? –Transparency of the Universe to UHE gammas –White dwarfs anomalous cooling  point to few meV axions Relevant axion/ALP parameter space at reach of current and near-future experiments Still too little experimental effort devoted to axions when compared e.g. to WIMPs… (not justified…) LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 6

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 7 Detecting axions Relic Axions Relic Axions –Axions that are part of galactic dark matter halo:  Axion Haloscopes Solar Axions Solar Axions –Emitted by the solar core.  Crystal detectors  Axion Helioscopes Axions in the lab Axions in the lab  “Light shinning through wall” experiments  Vacuum birrefringence experiments ADMX in US CERN  IAXO DESY CERN

Solar Axions Solar axions produced by photon-to- axion conversion of the solar plasma photons in the solar core Solar axions produced by photon-to- axion conversion of the solar plasma photons in the solar core LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 8 axions  Solar axion flux [van Bibber PRD 39 (89)] [CAST JCAP 04(2007)010] Solar physics + Primakoff effect Only one unknown parameter g a  Solar physics + Primakoff effect Only one unknown parameter g a 

LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza9 axions Transverse magnetic field (B) X ray detector AXION PHOTON CONVERSION L COHERENCE 1 Axion helioscope [Sikivie, PRL 51 (83)] Axion helioscope [Sikivie, PRL 51 (83)] Axion Helioscope principle

Axion Helioscopes Previous helioscopes: Previous helioscopes: –First implementation at Brookhaven (just few hours of data) [Lazarus et at. PRL 69 (92)] –TOKYO Helioscope (SUMICO): 2.3 m long 4 T magnet Presently running: Presently running: –CERN Axion Solar Telescope (CAST) LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 10

CAST CERN LHC test magnet Decommissioned LHC test magnet (L=10m, B=9 T) Moving platform ±8°V ±40°H (to allow up to 50 days / year of alignment) 4 magnet bores to look for X rays 3 X rays detector prototypes being used. X ray Focusing System to increase signal/noise ratio. X-ray focussing optics 2 low background Micromegas 1 low background Micromegas LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 11

CAST at work LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 12 Movie credit: Cenk Yildiz

Axion CDM postinflation Mixed-Axion CDM Axion HDM Axion/ALP parameter space WISPy CDM JCAP06(2012)013 WISPy CDM JCAP06(2012)013

Sensitivity goal: >4 orders of magnitude improvement in signal- to-noise ratio wrt CAST. (>1 order of magnitude in sensitivity of g a  ) IAXO – Concept No technological challenge (build on CAST experience) – New dedicated superconducting magnet, built for IAXO (improve >300 B 2 L 2 A f.o.m wrt CAST) – Extensive (cost-effective) use x-ray focalization over ~m 2 area. – Low background detectors (lower 1-2 order of magnitude CAST levels) Enhanced axion helioscope: JCAP 1106:013,2011 LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 14

IAXO – Conceptual Design Large toroidal 8-coil magnet L = ~20 m 8 bores: 600 mm diameter each 8 x-ray optics + 8 detection systems Rotating platform with services LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 15

IAXO magnet TOROIDAL CONFIGURATION specifically built for axion physics TOROIDAL CONFIGURATION specifically built for axion physics Each conversion bore (between coils) 600 mm diameter Each conversion bore (between coils) 600 mm diameter Cryostat Cold mass Bores go through cryostat Magnetic length 20 m Total cryostat length 25 m

IAXO magnet IAXO magnet concept presented in: IEEE Trans. Appl. Supercond. 23 (ASC 2012) Adv. Cryo. Eng. (CEC/ICMC 2013) IEEE Trans. Appl. Supercond. (MT 23) IAXO magnet concept presented in: IEEE Trans. Appl. Supercond. 23 (ASC 2012) Adv. Cryo. Eng. (CEC/ICMC 2013) IEEE Trans. Appl. Supercond. (MT 23) LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 17

IAXO x-ray optics Focal length ABRIXAS spare telescope, in use in one of the 4 bores of CAST (pioneer use of x- ray optics in axion research) X-rays are focused by means of grazing angle reflection (usually 2) Many techniques developed in the x-ray astronomy field. But usually costly due to exquisite imaging requirements LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 18

IAXO x-ray optics Each bore equipped with an x-ray optics Exquisite imaging not required BUT need cost-effective way to build 8 (+1 spare) optics of 600 mm diameter each LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 19

IAXO x-ray optics Technique of choice for IAXO: optics made of slumped glass substrates coated to enhance reflectivity in the energy regions for axions Same technique successfully used in NuSTAR mission, recently launched The specialized tooling to shape the substrates and assemble the optics is now available Hardware can be easily configured to make optics with a variety of designs and sizes Key institutions in NuSTAR optics: LLNL, U. Columbia, DTU Denmark. All in IAXO ! NuSTAR optics assembly machine NuSTAR telescope ~400 mm Ø LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 20

IAXO x-ray optics IAXO optics conceptual design AC Jakobsen et al, Proc. SPIE 8861 (2013) LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 21

IAXO low background detectors 8 detector systems Small gas chamber with Micromegas readouts for low-background x-ray detection Shielding LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 22

IAXO low background detectors Small Micromegas-TPC chambers: Shielding Radiopure components Offline discrimination Goal background level for IAXO: – c keV -1 cm -2 s -1 Already demonstrated: ~8×10 -7 c keV -1 cm -2 s -1 (in CAST 2014 result) c keV -1 cm -2 s -1 (underground at LSC) Active program of development. Clear roadmap for improvement. History of background improvement of Micromegas detectors at CAST Nominal values at CAST IAXO goals See arXiv: LNF, Italy, Nov201423

IAXO low background detectors Optics+detector pathfinder system in CAST IAXO optics+detector joint system Newly designed MM detector (following IAXO CDR) New x-ray optics fabricated following technique proposed for IAXO (but much smaller, adapted to CAST bore) First time low background + focusing in the same system Very important operative experience for IAXO Installed & commissioned successfully in CAST last september. Now taking data LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 24 X-ray optics specifically built for axions Low background Micromegas 8.5 cm Calibration photons (source 14 m away) focused onto the Micromegas

IAXO sensitivity prospects Astrophysical hints for ALPs IAXO in the high mass end, and future phases of ADMX in the low mass end will explore large part of the QCD axion model region in the next decade. Much larger QCD axion region explored LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 25

Additional IAXO physics cases LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 26 Possible additional technologies to push E thresholds down: GridPix TES Low-noise CCDs Possible additional technologies to push E thresholds down: GridPix TES Low-noise CCDs Detection of “BCA”-produced solar axions (with relevant g ae values) More specific WISPs models at the low energy frontier of particle physics: – Paraphotons / hidden photons – Chamaleons – Non-standard scenarios of axion production Microwave LSW setup Use of microwave cavities or dish antennas, DM axion searches IAXO as “generic axion/ALP facility”

IAXO-DM configurations? ADMX leader halosocope at m a ~1-10  eV. Big motivation to explore higher masses. Many new ideas being put forward. R&D needed. Common point: large magnets needed. Various possible arrangements in IAXO. Profit the huge magnetic volume available: 1.Single large cavity tuned to low masses 2.Thin long cavities tuned to mid-high masses. Possibility for directionality. Add several coherently? 3.Dish antenna focusing photons to the center. Not tuned. Broadband search. Competitive at higher masses? LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 27 B0B0 Haloscope concept: DM axions convert into MW photons inside cavity resonant to m a Haloscope concept: DM axions convert into MW photons inside cavity resonant to m a PRD85 (2012) Directional effect: JCAP 1210 (2012) 022 PRD85 (2012) Directional effect: JCAP 1210 (2012) 022 Long thin cavities in dipole magnets JCAP 1304 (2013) 016 Directional effect: arXiv: JCAP 1304 (2013) 016 Directional effect: arXiv: Large spherical mirror

Additional IAXO physics cases direct detection or relic axions/ALPs Promising as further pathways for IAXO beyond the helioscope baseline First indications that IAXO could improve or complement current limits at various axion/ALP mass ranges… Caution: preliminary studies still going on. Important know-how to be consolidated. Precise implementation in IAXO under study. sensitivity prospects to be considered tentative LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 28 See J. Redondo, talk at Patras2014, CERN

IAXO timeline LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 29 ~18 months -> TDR + preparatory activities ~3.5 years construction ~2.5 years integration + commissioning

IAXO costs LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 30 Laboratory engineering, maintenance & operation and physics exploitation not included

IAXO status of project LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza : First studies concluded (JCAP 1106:013,2011) 2013: Conceptual Design finished (arXiv: ). – Most activity carried out up to now ancillary to other group’s projects (e.g. CAST) August 2013: Letter of Intent submitted to the CERN SPSC – LoI: [CERN-SPSC ] – Presentation in the open session in October 2013: January 2014: Positive recommendations from SPSC. 2014: Transition phase: In order to continue with TDR & preparatory activities, formal endorsement & resources needed. – Some IAXO preparatory activity already going on as part of CAST near term program. – Preparation of a MoU to carry out TDR work.

CERN SPSC recommendations This was endorsed by the Research Board in March2014 Minutes of the 206th CERN Research Board held on March2014: LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 32 SPSC Draft minutes [Jan 2014] The Committee recognises the physics motivation of an International Axion Observatory as described in the Letter of Intent SPSC-I-242, and considers that the proposed setup makes appropriate use of state-of-the-art technologies i.e. magnets, x-ray optics and low-background detectors. The Committee encourages the collaboration to take the next steps towards a Technical Design Report. The Committee recommends that, in the process of preparing the TDR, the possibility to extend the physics reach with additional detectors compared to the baseline goal should be investigated. The collaboration should be further strengthened. Considering the required funding, the SPSC recommends that the R&D for the TDR should be pursuit within an MOU involving all interested parties. SPSC Draft minutes [Jan 2014] The Committee recognises the physics motivation of an International Axion Observatory as described in the Letter of Intent SPSC-I-242, and considers that the proposed setup makes appropriate use of state-of-the-art technologies i.e. magnets, x-ray optics and low-background detectors. The Committee encourages the collaboration to take the next steps towards a Technical Design Report. The Committee recommends that, in the process of preparing the TDR, the possibility to extend the physics reach with additional detectors compared to the baseline goal should be investigated. The collaboration should be further strengthened. Considering the required funding, the SPSC recommends that the R&D for the TDR should be pursuit within an MOU involving all interested parties.

Next steps Start works towards a Technical Design Report. As part of such: – Construction of a demostration coil IAXO-T0 – Construction of a prototype x-ray optics IAXO-X0 – Construction of a prototype low background detector setup IAXO-D0 – Complete pathfinder project detector+optic at CAST – Feasibility studies for “IAXO-DM” options. TDR completion is a ~2-4 MEUR effort. Memorandum of Understanding in preparation among interested parties. Site studies Search for new interested partners (in view of construction phase – magnet is the issue) LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 33 IAXO-T0

Conclusions LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 34 Increasing interest for axions: – Physics case, theory, cosmology, astrophysics Increasing experimental effort – CAST at CERN Field in a transition: from small experiments to Big Science? IAXO proposal is timely, ambitious, large impact in the axion landscape & discovery potential IAXO as a generic multi-experiment “axion facility” First steps after the positive recommendation from CERN SPSC. New partners welcome. Good opportunity for institutions like LNF? What next? Search for axions!

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 35 Backup slides…

InGrid Detectors Micromegas built on top of a CMOS ASIC Bump bond pads of the ASIC are used as charge collection pads Mesh made of thin aluminum foil One hole per readout pixel → well aligned → each primary electron can be seen as one hit on a pixel Cosmic ray track 2 X-ray photons of a 55 Fe source

Background Suppression Knowledge of individual primary electrons gives detailed information on signal shape Different event shape variables can be used to distinguish background events (tracks) from signal events (photons) First likelihood ratio-based analysis reached a background suppression of 120 Threshold of detector is dominated by transmission of entrance window Good energy resolution with pixel counting eliminating contribution of gas amplification pixels per track length Efficiency vs. background rejection Detailed desciption in: C. Krieger, J. Kaminski and K. Desch, InGrid-based X-ray detector for low background searches, NIM A729 (2013) 905–909 Spectrum of a 55 Fe source

Latest CAST results: preliminary LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 38 All 3 He data ( ) in progress. All 3 He data ( ) in progress. Masses up to 1.15 eV Masses up to 1.15 eV Final He3 result paper in preparation Final He3 result paper in preparation 2012  New data with He-4 with improved sensitivity 2012  New data with He-4 with improved sensitivity

IAXO in ASPERA  Latest draft of the ASPERA roadmap 2011 LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 39 European Astroparticle Roadmap

AXION theory motivation Axion: introduced to solve the strong CP problem Axion: introduced to solve the strong CP problem LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 40 In QCD, nothing prevents from adding a term like that to the lagrangian: ( ) In fact, two known facts may induce such kind of term: - The structure of the QCD vacuum (U(1) A problem) - EW quark mixing 2 contributions of very different origin…

AXION theory motivation Axion: introduced to solve the strong CP problem Axion: introduced to solve the strong CP problem LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 41 In particular, this term would predict an electric dipole moment for the neutron of a magnitude: (A = 0.04 – 2.0) This term is CP violating. But strong interactions are not observed to violate CP

AXION theory motivation But experiment says… But experiment says… LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 42 So, Why so small? High fine-tunning of two different contributions required Peccei-Quinn (1977) propose an elegant solution to this problem.  not anymore a constant, but a field  the axion a(x). Fine-tunning reached naturally, dinamically.

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 43 AXION models  PQ scale –Original axions: f a –Original axions: f a ~ electroweak scale  too strong couplings, ruled out by experiment – f a –Otherwise: f a >> electroweak scale  PQ charges of SM fermions (or additional ones) – –KSVZ axions: only new exotic quarks carry PQ (“hadronic axions”) – –DFSZ axions: SM fermions do carry PQ charge. Therefore, direct axion-fermion couplings are model-dependent. Other basic axion properties are more model-independent

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 44 AXION phenomenology Axion-gluon vertex present in every axion model Axion-gluon vertex present in every axion model And therefore… Axion-nucleon coupling Axion-nucleon coupling Axion-pion mixing Axion-pion mixing Axion gets a mass through its mixing with the pion Axion gets a mass through its mixing with the pion axion – gluon vertex  Mass very small, but not zero.  Mass is related to the PQ scale

TAE2013, Benasque, Spain, Sep 2013 Igor G. Irastorza / Universidad de Zaragoza 45 AXION phenomenology Axion-photon coupling present in every model. 2 contributions: Axion-photon coupling present in every model. 2 contributions: –Through axion-pion mixing. –Through fermion loops, for fermions with both a PQ charge and electric charge (therefore, model-dependent). This is probably the most relevant of axion properties. Most axion detection strategies are based on the axion-photon coupling

TAE2013, Benasque, Spain, Sep 2013 Igor G. Irastorza / Universidad de Zaragoza 46 AXION phenomenology Axion-photon conversion in the presence of an electromagnetic field (Primakoff effect) Axion-photon conversion in the presence of an electromagnetic field (Primakoff effect) This can be This can be an artificial magnetic field an artificial magnetic field The Coulomb field of the plasma in the core of a star The Coulomb field of the plasma in the core of a star The periodic E field of a crystalline structure The periodic E field of a crystalline structure … …

AXION as Dark Matter? 47 non baryonic Dark Matter ~26.8 % Visible < 1% “Dark energy” ~68.3% Baryonic < 5% Galactic scale Cosmological scale Can not be baryonic Can not be baryonic Can not be relativistic (CDM) Can not be relativistic (CDM) Can not be standard (neutrinos) Can not be standard (neutrinos) Need to go beyond the SM  Need to go beyond the SM  WIMPs AXIONS SUSY PQWW LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 48 LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 48 AXION Cosmology Axions are produced in the early Universe by a number of processes: Axions are produced in the early Universe by a number of processes: –Axion realignment –Decay of axion strings –Decay of axion walls –Thermal production NON-RELATIVISTIC (COLD) AXIONS RELATIVISTIC (HOT) AXIONS

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 49 LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 49 AXION Cosmology Axion realignment: Axion realignment: a V a V When T > T QCD is arbitrary is arbitrary When T ~ T QCD  0  0 As the Universe cools down below T QCD, space is filled with low energy axion field fluctuations. Their density depends on the initial value of (“misalignment angle”)

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 50 LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 50 Axion Cosmology The CDM axion relic density is uncertain as it depends on several factors: The CDM axion relic density is uncertain as it depends on several factors: Inflation before PQ transition CASE 1 Inflation before PQ transition CASE 1 –“initial misaligment angle” 0 varies spatially  Averaged. –Contributions from axion strings and domain walls must be computed  difficult (see Sikivie astro-ph/ ) Late-inflation scenario (inflation after PQ transition) CASE 2 Late-inflation scenario (inflation after PQ transition) CASE 2 –The “initial misaligment angle” 0 unique for all visible universe. –Strings and walls wiped out by inflation. Not contributing. And in any case difficult to compute their contribution. Very approximately: Very approximately: CASE 2 CASE 1 Sikivie astro-ph/

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 51 LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 51 Axion Cosmology Which value for f a (and therefore mass) gives the right amount of axion density? Which value for f a (and therefore mass) gives the right amount of axion density? –Late-inflation: Wide range of mass possible if initial misalignment “tuned” –Late-inflation: Mass determined but calculation uncertain. In general… In general… –Range of axion masses of – eV are of interest for the axion to be the (main component of the) CDM. J. Hamann et al. arXiv:

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 52 LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 52 Axion Cosmology Relativistic axions (HDM) are created by thermal production: Relativistic axions (HDM) are created by thermal production: –At high T, axions are in creation-annihilation equilibrium with the rest of particles (thermal population of axions, satisfying Boltzmann equation). –When the Universe cools down below T D, the axion freeze-out temperature, the thermal population decouples and its density red-shifts till today. In order to have substantial relativistic axion density, the axion mass must be close to 1 eV. (ma >1.02 eV gives densities too much in excess to be compatible with latest CMB data) In order to have substantial relativistic axion density, the axion mass must be close to 1 eV. (ma >1.02 eV gives densities too much in excess to be compatible with latest CMB data) Hannestad et al, JCAP 0804 (2008) 019 [ (astro-ph)]

Axion DM after BICEP2 Quite an impact… (a few preprints) Quite an impact… (a few preprints) –Marsh et al. arXiv: –L. Visinelli, P. Gondolo arXiv: –Choi el al.arXiv: –Chun. arXiv: –E. Di Valentino et al. Mena. arXiv: among others… In summary: if “high inflation scale” interpretation of BICEP2 results is right… “classical window” (high mass) scenario is favored. LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 53

From Wantz 2010 From Wantz 2010 LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 54

Axions in Astrophysics TAE2013, Benasque, Spain, Sep 2013 Igor G. Irastorza / Universidad de Zaragoza 55, like the Sun, by Primakoff conversion of the plasma photons. Axions are produced at the core of stars, like the Sun, by Primakoff conversion of the plasma photons. –Axions drain energy from stars and may alter their lifetime. Limits are derived to the axion properties –Solar Age: g a  ~< 3 x GeV -1 –Helioseismology: g a  ~< GeV -1 –Neutrino flux: g a  ~< 7 x GeV -1 [arXiV ] –Helium burning lifetime: g a  ~< GeV -1 –SN 1987A a   may produce gamma lines in the emission from certain places (i.e. galactic center). Axion decay a   may produce gamma lines in the emission from certain places (i.e. galactic center). –But axion decay constant is normally very long (>> Universe life) See Raffelt astro-ph/ and references therein

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 56 Buffer gas to go to higher masses Extending the coherence to higher axion masses... Coherence condition (qL << 1) is recovered for a narrow mass range around m  N e : number of electrons/cm 3  : gas density (g/cm 3 )

The cooling of white dwarfts Luminosity function (WD’s per unit magnitude) altered by axion cooling Luminosity function (WD’s per unit magnitude) altered by axion cooling Claim of detection of new cooling mechanism (Isern 2008) Claim of detection of new cooling mechanism (Isern 2008) Axion-electron coupling of ~1x (  axion masses of 2-5 meV or larger) fits data. Axion-electron coupling of ~1x (  axion masses of 2-5 meV or larger) fits data. LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 57 (Isern et al. 2008,2010) DFSZ axion (cos  =1)

The cooling of white dwarfs meV masses seem out of reach of even for an improved axion helioscope… BUT meV masses seem out of reach of even for an improved axion helioscope… BUT Axion-electron coupling provides extra axion emission from the Sun… Axion-electron coupling provides extra axion emission from the Sun… Extra emission concentrated at lower energies (~1 keV) Extra emission concentrated at lower energies (~1 keV) Such axion could produce a detectable signal in IAXO Such axion could produce a detectable signal in IAXO LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 58

Factor ~20 better in g a  (~ in signal strength!!) Factor ~20 better in g a  (~ in signal strength!!) LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 59 IAXO sensitivity prospects

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 60 Micromegas CAST Since new Micromegas detectors replaced the multiwire TPC in the sunset side. – –Better shielding At sunrise side. The Micromegas detector substantially upgraded: – –microbulk, shielding, monitoring, frontal calibration, flow controller, In overall  increasingly better backgrounds & sensitivity Sunset Micromegas Sunrise Micromegas

Axions in Astrophysics LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 61, like the Sun, by Primakoff conversion of the plasma photons. Axions are produced at the core of stars, like the Sun, by Primakoff conversion of the plasma photons. –Axions drain energy from stars and may alter their lifetime. Limits are derived to the axion properties –Solar Age: g a  ~< 3 x GeV -1 –Helioseismology: g a  ~< GeV -1 –Neutrino flux: g a  ~< 7 x GeV -1 [arXiV ] –Helium burning lifetime: g a  ~< GeV -1 –SN 1987A a   may produce gamma lines in the emission from certain places (i.e. galactic center). Axion decay a   may produce gamma lines in the emission from certain places (i.e. galactic center). –But axion decay constant is normally very long (>> Universe life) See Raffelt astro-ph/ and references therein

ALP astrophysical “hints” Observation of gamma-rays from distant sources Observation of gamma-rays from distant sources [MAGIC arXiv: , HESS, Nature 440 (2006) 1018] Observation of UHE cosmic rays from distant sources Observation of UHE cosmic rays from distant sources AGN luminosity relations [Burrage et al. PRL 102 (2009)] AGN luminosity relations [Burrage et al. PRL 102 (2009)] Correlations in quasar polarization observed at Gpc distances. Probably local effect: axion-photon mixing in the galactic magnetic field. [Payez et al arXiv: ] White-dwarf luminosity function: favors axion coupled to electrons [Isern et al 2008 ApJ 682] LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 62

IAXO in astroparticle roadmaps LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 63 ASPERA/APPEC Roadmap acknowledges axion physics, CAST, and recommends progress towards IAXO. ASPERA/APPEC Roadmap acknowledges axion physics, CAST, and recommends progress towards IAXO. Important community input in the European Strategy for Particle Physics Important community input in the European Strategy for Particle Physics Presence in the Briefing Book of the ESPP, which reflects also APPEC roadmap recommendations. Presence in the Briefing Book of the ESPP, which reflects also APPEC roadmap recommendations. ESPP recomends CERN to follow APPEC recomendatons. ESPP recomends CERN to follow APPEC recomendatons. Important effort in relation with US roadmapping (Snowmass, and P5 process). Snowmass reports speak very favourably of axion physics and IAXO. Important effort in relation with US roadmapping (Snowmass, and P5 process). Snowmass reports speak very favourably of axion physics and IAXO. C. Spiering, ESPP Krakow

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 64 Detecting DM axions: “haloscopes” Resonant cavities (Sikivie,1983) Resonant cavities (Sikivie,1983) –Primakoff conversion inside a “tunable” resonant cavity –Energy of photon = m a c 2 +O(  2 ) B0B0 Axion DM field Non-relativistic Frequency  axion mass Axion DM field Non-relativistic Frequency  axion mass Primakoff conversion of DM axions into microwave photons inside cavity If cavity tuned to the axion frequency, conversion is “boosted” by resonant factor (Q quality factor) If cavity tuned to the axion frequency, conversion is “boosted” by resonant factor (Q quality factor) Cavity dimensions smaller than de Broglie wavelength of axions

Haloscopes - AMDX Leading experiment: U. Washington Leading experiment: U. Washington –Many years of R&D –high Q cavity (1 m x 60 cm Ø) –8 T superconducting solenoid –Low noise receivers based on SQUIDs –Sensitivity to few  eV proven –New program ADMX-HF to go to higher frequencies LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 65

LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 66 ? ? ? ?

Axion DM detection – new ideas Recent papers proposing new detection schemes. Very active field! Recent papers proposing new detection schemes. Very active field! –Precession of nuclear spins (CASPERs): PRD 84, (2011) and arXiv: –Long thin cavities in dipole fields: PRD85 (2012) –Directional effect in long thin cavities: JCAP 1210 (2012) 022 –Dish antenna: JCAP 1304 (2013) 016 –Directional effect in dish antenna: arXiv: –LC circuit in B field: PRL 112, (2014) –Active resonators: arXiv: –Cavitiy with wires: arXiv: (also old Sikivie paper) LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 67

Detecting DM axions with IAXO? All ideas have in common: big magnets needed All ideas have in common: big magnets needed LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 68 JCAP 1304 (2013) 016 Directional effect: arXiv: JCAP 1304 (2013) 016 Directional effect: arXiv: PRD85 (2012) Directional effect: JCAP 1210 (2012) 022 PRD85 (2012) Directional effect: JCAP 1210 (2012) 022 Long thin cavities in dipole magnets Large spherical mirror

IAXO-DM configurations? Prospects under study. Very motivated (encouraged by CERN SPSC) Prospects under study. Very motivated (encouraged by CERN SPSC) Needed new know-how (cavities, low noise microwave detectors…) Needed new know-how (cavities, low noise microwave detectors…) Various possible arrangements in IAXO. Profit the huge magnetic volume available: Various possible arrangements in IAXO. Profit the huge magnetic volume available: 1.Single large cavity tuned to low masses 2.Thin long cavities tuned to mid-high masses. Possibility for directionality. Add several coherently? 3.Dish antenna focusing photons to the center. Not tuned. Broadband search. Competitive at higher masses? LNF, Italy, Nov2014Igor G. Irastorza / Universidad de Zaragoza 69

IAXO LoI authorlist LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza signatures 38 institutions 90 signatures 38 institutions

Expertise Needed know-how well covered: Axion theory & phenomenolgy Axion Cosmology & Astrophysics Axion detection phenomenology X-ray detectors Low background techniques X-ray optics Superconducting magnets and technology Needed know-how well covered: Axion theory & phenomenolgy Axion Cosmology & Astrophysics Axion detection phenomenology X-ray detectors Low background techniques X-ray optics Superconducting magnets and technology

Axion parameter space White Dwarfs Astrophysical hints for ALPs CDM “classical window” Vaxuum mis. + defects mixed CDM Axions as HDM CDM “anthropic window” WISPy CDM JCAP06(2012)013 WISPy CDM JCAP06(2012)013 LNF, Italy, Nov2014 Igor G. Irastorza / Universidad de Zaragoza 72