Slide 1

CAST FRC-D 2012-31 CAST FRC - 9th Meeting

Chaired by Sergio Bertolucci (CERN)

CAST status report and perspectives Konstantin Zioutas, for the CAST collaboration

CERN

25th October 2012 (bld. 60/5-012)1

http://cdsweb.cern.ch/record/1484230 ; http://indico.cern.ch/conferenceDisplay.py?confId=210202 2 Evaluation Axions Dark matter?. . . . . . . . . . . . . . . . . .

Paraphotons Hidden sector Chameleons Dark energy?? with CAST in the forefront!Solarthe only movable telescope @ 1.8K33

. s CHs / sCcccccc

~10% Lsolar axions: 0.02 eV.

With the presence of a buffer gas it can be restored for a narrow mass range:

Coherence condition: qL < ,

with

Physics Program & main results9

Proposal approved by CERN (13th April 2000)Commissioning(2002) CAST Phase I: vacuum operation (2003 - 2004) completed CAST Phase II: (20052011)4He run, (20052006) completed 0.02 eV < ma < 0.39 eV3He run (2007-2011) completed ongoing analysis (0.39eV new paraphoton limit, beyond schedule CAST byproduct2323Request for running in 2013 - 20142424TOTAL: 9 months of data taking25Expected sensitivity with the setup proposed in vacuum conditions 9 calendar months assuming 75% data taking efficiency. Two assumptions for the Micromegas background: 1.510-6(black line) and 810-7counts keV-1cm-2s-1 (red line)

Physics motivation: Axions & ALPs

~2002Optimistic perspective: 26Physics motivation: the sub keV range a first for a helioscope like CAST new territoryA WISP discovery would have a tremendous impact on our understanding of fundamental physics, astrophysics and may shed light upon the mysteries of DM and DE.Fundmental physics at low energies the quest for axions & other new light particlesC. Spiering, European Astroparticle Physics: Status and Vision , European Strategy Preparatory Group, Krakow, September 2012,http://indico.cern.ch/conferenceDisplay.py?confId=182232

Solar ChameleonsChameleons are Dark Energy candidates to explain the acceleration of the UniverseChameleon mass depends on the energy density of its environmentChameleon particles can be created by the Primakoff effect in a strong magnetic field. This can happen in the tachocline of 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 experiments.CAST new physics 2012-2014: Chameleonsaxion helioscope = chameleon helioscope @ LE!!Sub-keV detector threshold+vacuumSolar Paraphotons: Hidden Sector particles (Theoretically motivated)

kinetic mixing with thermal photons: oscillations

NO magnetic field! NO cold bores neededExpected photons from Solar Chameleons Converted in CAST magnet2728Solar Chameleons with CASTThe Sun dashed line is derived from the maximum allowed solar chameleon luminosity (=0.1Lsolar). The CAST line reflects the maximum sensitivity expected to be reached with CAST assuming 2cts/100min while being sensitive to the whole solar chameleon spectrum (=3.13108). The corresponding solar chameleon luminosity CAST could detect is about 410-4Lsolar, with the associated chameleon-to-photon conversion probability being Pch = 3.910-17. This plot shows also other only experimentally derived limits, which exclude a chameleon matter coupling of m>109.

29Detectors: Upgraded MMs & new InGrid & new XRT

Nominal values during data taking periodsShielded Micromegas(bulk and microbulk technology)Special shielding conditions in Canfranc Underground LabUnshielded Micromegas (classic technology)New Sunset MicromegasIn CASTThorough tests in Canfranc Underground LaboratoryPerformance of new Sunset detectors with upgraded shielding + muon vetoNew design for sunrise Micromegas aiming for background ~810-7 s-1keV-1cm-2

30Upgrades: ULB Micromegas

ULB background:

1st half of 2013reduction of the noise of visible TES -> DCR down to 0.1 mHzstart production of keV-TES2nd half of 2013laboratory tests of keV-TESbeam tests at CAST (subject to acquisition of Ministry funds)41Upgrades: TES

Voltage pulses corresponding to the absorption of one or more ~0.8 eV photons7th June, quench of magnet during first ramp of year.