1 CAST achievements and perspectives K. Zioutas University of Patras & CERN Naxos, 8/5/2014 Abstract: CAST is a 3rd generation axion helioscope and its outcome since 2000 along with the ongoing activities will be presented. Recently, CAST became the first chameleon helioscope searching for such dark energy constituents. For the future, CAST has the potential to become an antenna for axion relics. The use of a home made highest sensitive force sensor from solid state physics might transform CAST to a powerfull chameleon helioscope, being sensitive also to the chameleon coupling to matter. If time allows, further implications in astroparticle physics will be mentioned.

2 The CAST collaboration

3 4 fundamental questions (+ gravity) after the HIGGS discovery: ? What is dark matter? ? What is dark energy? Matter - Antimatter asymmetry ? What is the origin of the ‘strong CP-problem’? nEDM → 0 why nEDM → 0 Now: DM ≈ DE >> chance coincidence? Physics motivation:  New physics! 3

4 SPS accelerator Geneva Airport LHC accelerator CERN main site CAST

 B X  virtual α CAST 5 Decommissioned prototype LHC dipole magnet: B=9 T, L=9.26 m

SUN  SUN  the convenient lab for new physics!? Note: Allowed emission of exotica < 10% L solar !! + gravitational self-trapping of massive ~axions/WISPs  (yield ~10 -7 )   accumulation over 4.5 Gyears … … without visible ageing effects ! L.DiLella, K.Z., Astropart. Phys. (2003) 6

CERN Axion Solar Telescope: QCD Axions or other exotica Detection => Inverse Primakoff effect: Axion / CH interacting coherently with a magnetic field (~B 2 ) convert to a photon Signal: excess of X-rays during sun tracking Differential axion flux on Earth Pierre Sikivie 1983 => Production: Primakoff effect => Thermal photons interacting with solar nuclei / B  Axions & CHs 7

= CAST = a difficult experiment: - 1.8K - superconducting (  quenches ! ) - moving / alignment - Cryo Fluid Dynamics of buffer gas  tracking - low background X-ray detectors  the only(!?) telescope at 1.8K 8

Shielded Micromegas (bulk and microbulk technology) Shielding upgrade Unshielded Micromegas (classic technology) Canfranc, underground laboratory Micromegas evolution University of Zaragoza T. VafeiadisRencontres de Moriond EW 2014 Transparent windows => nanotechnology 9

  Spare # from german space program... not in the original proposal!  unique   ID potential + signal and noise improvement  CAST fulfilled original proposal from 1999  CAST fulfilled original proposal from 1999 CAST X-ray telescope 10

Background Tracking Signal simulation ~ 8x10 -5 cts keV -1 cm -2 s -1 Spot position well determined Full sensitivity of telescope exploited Counts in the spot compatible with background level Background rate 1-7keV: X-ray Telescope / CCD CAST Status & Perspectives, Theopisti Dafni (UNIZAR), Moriond2010 Solar axions! paraphotons, chameleons? 11

12 CAST alignment with Sun, Moon, …

? 13 => This is CAST => CDM Since Fritz Zwicky (1933) Q: What is “dunkle Materie” made of? >> Beyond original CAST proposal >>

14 CMB years ~400/cm 3 ? C ν B 1 sec ~50/cm 3 ? $ ? CaB – sec $ ~10 12 cm 3 (m axion c 2 ≈ meV) ? Cosmic relics $ $ Joerg Jaeckel

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Preliminary Analysis of data with SDDPRELIMINARY First data from final configuration – Shielding and Cooling Background 6 hrs each night (field ON) Solar tracking data ~ 100 mins each morning Tracking (red) and background (blue) rates 400 – 1500 eV – Typically < 4∙10 -5 Hz (per 76 eV bin) 16 Solar Chameleon spectrum

First look at sub keV in CAST 17 >> End 2013 The “first” solar chameleon helioscope βγβγ β matter + β matter + β γ

A novel self-made force sensor >> ! >> towards nominal sensitivity! RadPres sensor >> Dark Energy >> ~Chameleons => β matter KWISP βγβγ G. Cantatore M. Karuza 18

Radiation pressure from solar Chameleons? - - A nano-membrane reflects solar chameleons  radiation pressure & shift of membrane - - Membrane motion can be detected within a Fabry-Perot (FP) interferometer shifted membrane probe beam profile motionless membrane Radiationpressure FP cavity mirror 19 17/12/2013 (1mm)x(1mm), 50nm thick Si 3 N 4 membrane mounted on a 200 µm Si substrate FP cavity mirror A novel interdisciplinary concept in dark U. Trieste, U. Rijeka, … !work in progress! -10 L CH ≥ L ʘ

New perspective: CAST as a tracking haloscope for relics Helioscope (axion/chameleon/paraphoton) Haloscope (*) for (streaming) axions/ALPS/paraphotons m ≳ eV/c 2 ( λ ≲ 1 cm ) Single photon detection! ⇒ recover existing detectors!? ⇒ search in progress CAST plusses: large B, moveable, T~1.8K ⇒ m ≲ eV/c 2 ? ⇒ cavity? … ADMX ? The “Dish Antenna” concept (arXiv: , arXiv: arXiv: arXiv: /12/ D. Hoffmann (TU-Darmstadt), A. Lindner (DESY), K.Z.

Needed: +=> wide band detectors + expertise => from astrophysics - => - Photoconductor detectors => ~ μm [MPE] => W /#/10h <= 100x? 100 dishes? =>=> => W => subcritical for aDM ( ≈ W) - - Kinetic Induction Detectors (KIDs) [MPI-Bonn] ~10 5 # ADCs binning with Fourier analysis READOUT!? => => a quasi Q=10 5 & no scan ~ GHz >>aDM - - work in progress => more DM => directional, streams, caustics, … =>=> => (Planetary) gravitational Lensing => ~10 4 x flux? ~.01c (Sun) & ~.001c (Jupiter) 21

haloscope New perspective: CAST as a tracking haloscope for relics + … CAST: past + pioneering future!? The “Dish Antenna” concept / DESY Streaming DM (axions/ALPS/paraphotons/..) + 17/12/ If so … Feasibility study:  MPE (Garching) … μm sensors  MPI (Bonn) … mm sensors =>  Grav. Lensing => ~10 4 higher flux? ~.01c (Sun) & ~.001c (Jupiter)

23 in all experimental DM => important challenge: ~ ~10 2 eV Y. Semertzidis eV << = one solution G. Cantatore

24 CAST: has a “good” name since =>>> to replace? => ~100M€ >> 2019 A reference axion experiment >> next #

17/12/ astrophysical ( solar ) signatures ! CAST inspiring for … …overlooked?! => #) => Solar mysteries suggest (out)streaming DM #) - Simulation - GAIA in orbit (Febr ) >> galactic streams? => streaming DM !! #) #) The 11-years solar cycle as the manifestation of the dark Universe, K.Z., M. Tsagri, Y.K. Semertzidis, T. Papaevangelou, D.H.H. Hoffmann, V. Anastassopoulos, Mod. Phys. Lett. A (2014) in press (arXiv: )arXiv: GAIA calibration + CAST + DM search

2013 CERN Zaragoza Patras /12/

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29 => Conclusion =>

30 => Conclusion => … we insist

31 => Conclusion => … we insist CAST has a future !!

Solar Chameleons P. Brax, K. Zioutas, Phys. Rev. D82 (2010) arXiv: [astro-ph.SR] Detection prospects for solar and terrestrial chameleons P. Brax, A. Lindner, K. Zioutas, Phys. Rev. D85 (2012) arXiv: [hep-ph]arXiv: Detection of radiation pressure from solar chameleons O.K. Baker, A. Lindner, Y.K. Semertzidis, A. Upadhye, K. Zioutas arXiv: [astro-ph.IM]arXiv: A chameleon helioscope, K. Baker, A. Lindner, A. Upadhye, K. Zioutas arXiv: [astro-ph.SR]arXiv: Gravitational lensing by the Sun of non-relativistic penetrating particles D.H.H. Hoffmann, J. Jacoby, K. Zioutas, Astropart. Phys. 20 (2003) 73 DOI: /S (03) /S (03) Flux Enhancement of Slow-moving Particles by Sun or Jupiter: Can they be Detected on Earth? B.R. Patla, R.J. Nemiroff, D.H.H. Hoffmann, K. Zioutas, ApJ. 780 (2014) The 11-years solar cycle as the manifestation of the dark Universe K. Zioutas, M. Tsagri, Y.K. Semertzidis, T. Papaevangelou, D.H.H. Hoffmann, V. Anastassopoulos >> special issue of Mod. Phys. Lett. A (2014) "Indirect Dark Matter Searches“ Searching for WISPy Cold Dark Matter with a Dish Antenna, D. Horns, J. Jaeckel, A. Lindner, A. Lobanov, J. Redondo, A. Ringwald, JCAP 1304 (2013) 016, DOI: / /2013/04/ / /2013/04/016 CAST opens a new window into dark energy and dark matter after 11 years of operation and continuous renewal. D. Hoffmann, K. Zioutas, PH – NEWSLETTER (Dec. 2013) 32 First results from the CERN Axion Solar Telescope (CAST) - CAST Collaboration (Zioutas, K. et al.) Phys. Rev. Lett. 94 (2005) hep-ex/ An Improved limit on the axion-photon coupling from the CAST experiment - CAST Collaboration (Andriamonje, S. et al.) JCAP 0704 (2007) 010 hep-ex/ Search for 14.4-keV solar axions emitted in the M1-transition of Fe-57 nuclei with CAST - CAST Collaboration (Andriamonje, S. et al.) JCAP 0912 (2009) 002 arXiv: [hep-ex] SLAC-PUB Search for solar axion emission from 7 Li and D(p, γ ) 3 He nuclear decays with the CAST γ -ray calorimeter - CAST Collaboration (Andriamonje, S. et al.) JCAP 1003 (2010) 032 arXiv: [hep-ex] FERMILAB-PUB Probing eV-scale axions with CAST - CAST Collaboration (Arik, E. et al.) JCAP 0902 (2009) 008 arXiv: [hep-ex] CAST search for sub-eV mass solar axions with 3He buffer gas - CAST Collaboration (Aune, S. et al.) Phys. Rev. Lett. 107 (2011) arXiv: [hep-ex] CAST solar axion search with 3 He buffer gas: Closing the hot dark matter gap - CAST Collaboration (M. Arik, et al.) Phys. Rev. Lett. 112 (2014) arXiv: [hep-ex]arXiv:

33 P R E L I M I N A R Y Chameleons : exclusion plot

InGrid Detector Detector for Q4 was developed starting from Micromegas detectors. InGrid based on Timepix Drift distance 3 cm Gas mixture Ar:iC 4 H :2.3 Entrance window 2 µm aluminized Mylar foil. 34

35 Radiation pressure from solar Chameleons A thin micromembrane having a suitable density absorbs momentum from a flux of chameleons coming from the sun and reflecting off it: the resulting radiation pressure causes a collettive motion (shift) of the membrane (arXiv: ) Membrane motion can be detected with high sensitivity by exploiting the multiplication factor afforded by the finesse (resonator Q in practice) of a Fabry-Perot (FP) interferometer During operation the FP is kept at resonance with a probe laser beam by means of a feedback loop: the control signal of this loop contains the information on membrane motion and hence on chameleon properties

Optical cavity … with a movable end mirror (membrane). 6nN=1W P circ Mass m & Frequency ω Μ nm, ~50ngram (r 1,t 1 ) ~7mm (r 2,t 2 ) ~2-3 mm -10 L CH ≥ L ʘ >> first test soon ! 36

21/7/2012 Maximum sensor area: 1 mm 2 & Typical thickness: nm Material: amorphous Si 3 Ni 4 or single-crystal Si Resonance frequency: 1 kHz - 1 MHz Force sensitivity at RT: N/Hz 1/2 (on resonance) & N/Hz 1/2 (at dc) Force sensitivity at resonance frequency, at 300 mK: N/Hz 1/2 (on resonance) & N/Hz 1/2 (at dc) Note: N/m 2 ► mbar ► 0.1 μW/cm 2, OR + 10 μW/cm 2 ► N/m 2 = N/mm 2 + (10 4 s) 1/2 =100x improved sensitivity: ► N/mm 2 /3hours(DC) ► 100nW/cm 2 ►10 -5 L max-solar-CH Potential improvements: ++ x10 (#sensors) + x100 (focusing mirror(s)) + x100 (resonance) ► N/mm 2 / 3hours RT) ► 1 pW/cm 2 ► L RT 37

CAST Detectors - active and planned Micromegas (active) and new generation MM (commissioning) - few keV range Low-threshold detectors SDD (active) - > 400 eV range InGrid (commissioning) eV and above BaRBE (commissioning) - eV range Detectors for expanding sensitivity KWISP Radiation Pressure force sensor (prototype) dish antenna tracking haloscope (feas. study phase) 38