The direct search for solar + other exotica with CAST

K. Zioutas University of Patras, Greece

on behalf the CAST collaboration

Abstract: The working principle and the performance of the CERN Solar Telescope (CAST) will be presented. CAST is sensitive also to other exotica like paraphotons [from the hidden sector] and to chameleons [candidates for the dark energy]. In addition, work is in progress for new windows-of-opportunity, e.g., as to whether CAST can become an antenna with built-in directionality for relic axions. To quantify such a performance for CAST, information about inner solar magnetic fields and the dynamic Sun can help.

13/5/2011 1 The cosmological inventory:

• But, what is dark energy or dark matter ?

M x (r)  r

• A particle relic from GMthetotal Big(r) Bang is strongly implied for DM / DE Vr  - WIMPs ? r - Axions ? ….??..  Beyond Standard Model physics!

2 Roberto Peccei Physics motivation for axions: solve the strong CP problem: why nEDM → 0 spin-parity  0-  ≈ πο, γ (M1) ~ stable!

Axions  cosmology  dark matter

 solve solar problems?!

 The new ~axion fingerprints from solar physics?

3 Sun: A perfectly shielded “radioactive” source of exotica Bsolar essential!

~106 years

~2 sec ν’s Axions E. Georgiopoulou / UoPatras Chameleons

1 km Paraphotons mfp γthermal ... 1cm WISPs -3000km 0km - 4mm + more?

Rsurface | 4 tachocline Solar Axions: SUN  the convenient lab for new physics!?

Note:

Allowed emission of exotica < 10% Lsolar !!

+ 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)

5 a-helioscope 

6 H. Primakoff The Primakoff Effect 1951

axion

g

Behind all present axion work! ×B,Ε 7 CERN Axion Solar Telescope: QCD Axions or other exotica

Pierre Sikivie 1983

Signal: excess of X-rays during alignment over background Production: Primakoff effect Detection Inverse Primakoff: Thermal photons interacting axion interacting coherently with a strong with solar nuclei produce Axions. magnetic field (~B2) converts to a photon

Expected number of Photons: Differential axion flux on Earth da E  4.2keV Ng   Pag  S t dEa a  dEa -17 Paγ  1.710 2  g   aγ   10 1  10 GeV 

CAST Status & Perspectives, Theopisti Dafni (UNIZAR), Moriond2010 9 The CAST experiment Location

CAST

10 Decommissioned prototype LHC dipole magnet. CAST B=9 T, L=9.26 m

α g

gvirtual X B

11 Tracking system precision

Several yearly checks cross-check that the magnet is Sun Filming following the Sun with the required precision • Twice a year (March – September) GRID Measurements Direct optical check. Corrected for optical refraction • Horizontal and Vertical encoders define the magnet orientation • Verify that the dynamic Magnet Pointing precision (~ 1 arcmin) is within • Correlation between H/V encoders has been our aceptance established for a number of points (GRID points)

• Periodically checked with geometer measurements

12 BarBE μM HECHEC XRT CCD

13 X-ray Telescope / CCD

Tracking Background Signal simulation

• Spot position well determined • Full sensitivity of telescope exploited

• Counts in the spot compatible with background level

• Background rate 1-7keV: ~ 8x10-5cts keV-1cm-2s-1

Solar axions! paraphotons, chameleons?

CAST Status & Perspectives, Theopisti Dafni (UNIZAR), Moriond2010 14 CAST phase II – principle of detection ma > 0.02 eV

X ray detector Transverse magnetic field (B) X ray axions A

L

• Extending the coherence to higher axion masses... • Coherence condition (qL << 1) is recovered

for a narrow mass range around mg

3 Ne: number of electrons/cm r: gas density (g/cm3)

15 CAST

CAST 0.01 0.1 m [eV] 1.

… sCAST: 1999  2020

17 How much beyond CAST? CAST (1999)  NGAH (~2020)

ADMX

18 Towards a new relic axion antenna with CAST?

Dielectric waveguide inside the CAST magnet may perform as a new kind of “macroscopic fiber”, being a sensitive detector for relic axions:

 ~ 0.1 - 1 meV rest mass range (experimentally inaccessible)

19 • The fiber output is split in two ports by a, γ’, CH, ... means of an optical switch actuated by a TTL signal. Each port can be instrumented with a photon counter

• In the present configuration one port is coupled to a cooled Photo Multiplier Tube and the other is blocked, allowing on-line monitoring of the instantaneous background

• In future set-ups the second port will also be coupled to a detector, presumably a TES-based sensor, thus doubling the 20 “live” tracking time Solar paraphotons  beyond SM physics

Hidden Sector particles  Theoretically motivated

- kinetic mixing: γ ↔ γ’ oscillations

 NO magnetic field!  NO cold bores needed

 Vacuum path length relevant for oscillations -> upstream in front of the detector

 a good sensitivity requires: 3 ULB MMs & FS pnCCD

 also for chameleons!

M. Davenport, S. Gninenko, S. Troitsky, C. Yeldiz, K. Z. (2011) 21 Paraphoton detection sensitivity  Off-pointing Low energy threshold: MM + CCD!

Ideal XRT / CCD Solar paraphoton flux m=10eV. .

m=0.1eV > 1.0 keV . > 0.3 keV > 0.1 keV …………..

P r e l I m I n a r y ……………

10eV 100eV100eV 1keV 1keV 10keV 10keV

Lowering energy threshold – increases the sensitivity  more flux

M. Davenport, S. Gninenko, S. Troitsky, C. Yeldiz, K. Z. (2011) 22 Solar Chameleons P. Brax, K. Z. PRD (2010)

• Chameleons are DE candidates to explain the acceleration of the Universe • Chameleon particles can be created by the Primakoff effect in a strong magnetic field. This can happen in the Sun. • The chameleons created inside the sun eventually reach earth where they are energetic enough to penetrate the CAST experiment. Like axions, they can then be back-converted to X-ray photons. • In vacuum, CAST observations lead to stronger constraints on the chameleon coupling to photons than previous exp’s. • When gas is present in the CAST pipe, the analogue spectrum of regenerated photons shows characteristic oscillations: ID

 axion helioscope = chameleon helioscope, but @ LE!!

23 Solar Chameleons - CAST P. Brax, A. Lindner, K.Z. (2011)

vacuum 0.1 mbar

1 [keV] 1 [keV]

The analogue spectrum [/hour/keV] of regenerated photons as predicted to be seen by CAST: matter coupling = 106, B=30T in a shell of width 0.1R Regenerated chameleons. solar around the tachocline (~0.7R ). Core magnetic field = 100T solar

1 mbar

 Low energy threshold + vacuum

[keV]

24 Corona … enigma…. 1939  2011  … ? the coronal heating mechanism remains unknown!

…. with ~axions, Chameleons, … WISPs?

B. De Pontieu, et al., Science 331 (2011) 55-58 http://www.sciencemag.org/content/331/6013/55.abstract See also http://www.sciencemag.org/content/suppl/2011/01/05/331.6013.55.DC1/De-Pontieu.SOM.pdf 26 ? CAST solar physics

axion signal  2 ( [Bʘ] + ρ )  (dis)appearance of photons

 γ - deficit / excess

spatiotemporal dependence!! “unexpected”  + Chameleons!

 @ ARs

25 CAST @ the Sun? Note: Bʘ  ignored sofar…

It is remarkable + fascinating that the Sun emits intense X-rays...  mystery S. Tsuneta, AAPPS Bulletin, 19(#3) (2009) 11 http://www.cospa.ntu.edu.tw/aappsbulletin/data/19-3/11Hinode.pdf

Mystery or harbinger of exciting new physics  CAST-like axion signature

27 Expected CAST-like signatures in space: 1996 -

Converted solar axion spectrum 2D simulation 16

8

0

5 10 RHESSI science nugget, Eaxion [keV] H. Hudson, 30.4.2007

Pseudoscalar conversion and X-rays from the sun -4 2 ED Carlson,L-S Tseng, PLB 365 (1996) 193  ma « 10 eV/c

28  2 ...observation IF max≈10-20[meV/c ] ...

… axion conversion @ photosphere  absorption, …, down-comptonization, …

Questions!! Typical analog solar X-ray spectrum solar minimum solar maximum YOHKOH

Eγ ≈ 0.3 - 4 keV

K. Z., M Tsagri, Y Semertzidis, T. Papaevangelou, T. Dafni, V. Anastassopoulos, New J. Phys. 11 (2009) 105020 http://iopscience.iop.org/1367-2630/11/10/105020 29 Klaus Galsgaard Manolis Georgoulis Angelos Vourlidas

THANKS for discussions – teaching!!

Reproduced spectra from directly measured solar X-rays from: a) the main phase of a large flare with T∼20MK [7] (green dashed), b) a flare with RESIK and RHESSI (red dots), c) preflaring periods after having subtracted the main X-ray flare component from the original spectra [7] (purple histogram), d) non-flaring active regions with T≈6MK, i.e. sunspots (blue dots), e) non-flaring quiet Sun, with T≈ 2.7MK, at solar minimum with SPhinX (blue dashed line) [8]; this is also supported by the recent findings that in the Quiet Sun regions stronger magnetic fields occur in deeper layers than in the ARs [2], mplying more down-comptonization and giving rise to a larger slope. The initial broad solar axion spectrum is also shown shadowed (pink dashed line). Two GEANT4 simulated spectra following multiple Compton scattering from a depth of ∼350 km and ∼400 km are also shown for comparison (thin histograms), where the estimated plasma frequency, i.e., also the axion rest mass, is ∼17meV/c2. The uncertainty is a factor of ∼2, since the density changes by factor of ∼4 between the ∼300 km and ∼1000 km depth. Note the strong deviations of the indirectly derived spectra (grey lines) in the past [9] of the non-flaring quiet Sun at solar minimum and that of the active Sun at solar maximum below ∼ 1 keV (SPhinX measurements). The spectra are not to scale.

Z., Vafeiadis, Tsagri, Semertzidis, Papaevangelou, Dafni, Anastassopoulos, 6th Patras workshop, UoZurich, 2010 http://www-library.desy.de/preparch/desy/proc/proc10-03.pdf p. 89 30 E.g.:  ?

• measured - bb ? Residual analog spectrum? • (measured)max – (measured)min

• (measured)quiet – (measured)active

Z., Vafeiadis, Tsagri, Semertzidis, Papaevangelou, Dafni, Anastassopoulos, 6th Patras workshop, UoZurich, 2010 http://www-library.desy.de/preparch/desy/proc/proc10-03.pdf p/89 31 CMB SUN

ΔΤ ≈ ± 200μK

ΔT/T ∼a few×10-5 ΔT/T ∼ 103

New physics! » new physics?! 32 Further reading:

• http://www.physik.hu-berlin.de/gk1504/events/springblockcourse2011/ 4 lectures to PhD candidates

• http://ctp.snu.ac.kr/axion/ ASK2011 / Seoul

• http://iopscience.iop.org/1367-2630/11/10/105020 review article http://www.annualreviews.org/doi/full/10.1146/annurev.nucl.56.080805.140513 review article

• http://axion-wimp.desy.de/ Proceedings PATRAS workshops

33 33 Thanks Sun!!

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