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Search for Solar Axions: the CAST experiment at CERN

Search for Solar Axions: the CAST experiment at CERN. Aisha Hunte for the CAST Collaboration June 2004, CERN. ( ). Axions. α. The STRONG CP PROBLEM. Possible CP-violating term in QCD lagrangian:.

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Search for Solar Axions: the CAST experiment at CERN

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  1. Search for Solar Axions:the CAST experiment at CERN Aisha Hunte for the CAST Collaboration June 2004, CERN

  2. ( ) Axions α The STRONG CP PROBLEM Possible CP-violating term in QCD lagrangian: Experimental consecuence: prediction of electric dipole moment for the neutron: (A = 0.04 – 2.0) BUT experiment says... So, Peccei-Quinn (1977) propose an elegant solution to this problem. q not anymore a constant, but a field  the axion a(x). CERN, 29th June 2004

  3. a  qq transitions • a – p0 mixing • axion mass > 0 • Dark matter candidate! axion – gluon vertex Axions α The STRONG CP PROBLEM: Peccei-Quinn solution • New U(1) symmetry introduced in the SM: • Peccei Quinn symmetry of scale fa • The AXION appears as theNambu-Goldstoneboson of the spontaneous breaking of the PQ symmetry q absorbed in the definition of a PQ Symmetry: Peccei & Quinn: CP invariance of the strong interactions expected in QCD, for a non vanishing scalar field that gives mass to a fermion through a Yukawa coupling. CERN, 29th June 2004

  4. Axions α pseudoscalar neutral practically stable phenomenology driven by the breaking scale fa and the specific axion model Couples to photon L = g(E•B)a Primakoff (1951) [] PRIMAKOFF EFFECT Any scalar or pseudoscalar particles: axion-like particles CERN, 29th June 2004

  5. Axions α PRIMAKOFF EFFECT Stellar interior  the Sun!! Solar Axions Flux at the Earth [K.van Bibber et al.,1989] CERN, 29th June 2004

  6. Transverse magnetic field (B) X-ray detector X-ray L Axions α Signal: X-rays while tracking (magnet pointing to the Sun) over background Sensitive for m < 10-2 eV Lazarus et al., Brookhaven Tokyo Helioscope:B~4T, L~2m CERN, 29th June 2004

  7. Axions CAST Sensitivity plot Phase II and up (?) Filling the magnet bores with 3He the photon acquires an effective mass: mγ> 0 and by changing the gas pressure we are sensitive to different masses up to ~ 1 eV To Start in 2005 CERN, 29th June 2004

  8. CERN Axion Solar Telescope Sunset Photon detectors Sunrise Photon detectors Sunrise axions Sunset axions Decomissioned LHC test magnet Rotating platform 3 X-ray detectors X-ray Focusing Device CERN, 29th June 2004

  9. CAST is here: LEP Point 8 (former DELPHI point) Building 2875 CERN, 29th June 2004

  10. L= 10 m B=9 T 100 times better  conversion efficiency than any other !! Magnet,platform,cryogenics CAST Experimental area SR8 4He flexible line Magnet Feed Box CERN, 29th June 2004

  11. SEPTEMBER’03 Magnet,platform,cryogenics Looking at the sunrise… MARCH’03 Twice a year (September&March) we can film the Sun through the window CERN, 29th June 2004

  12. On the coming sesion: The X-Ray Telescope & X-Ray Detectors • X-Ray Telescope (Focusing Device) • Detectors • CCD • TPC • Micromegas • Big value of B •L • Low background rate detectorsX-Ray Telescope!!! CERN, 29th June 2004

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