The CAST Experiment A search for Solar Axions

The CAST Experiment A search for Solar Axions CAST Jaime Ruz Armendáriz, LFNAE, Zaragoza University On behalf of the CAST Collaboration

The CAST Experiment OUTLINE ± CAST The CAST Experiment • • Motivation Description ± CAST First Phase • • Description Results ± CAST Second Phase • Description • Results ± STATUS Jaime Ruz Armendáriz. HEP 2007, Manchester

The CAST Experiment MOTIVATION CAST QCD predicts the breaking of CP symmetry in strong interactions, but so far this has never been observed by any experiment. CP violation implies then an electric dipole moment for the neutron… Theoretically Experiments find The Strong CP-Problem: Why is so small? Two different contributions here: QCD vacuum and EW quark mixing Jaime Ruz Armendáriz. HEP 2007, Manchester

The CAST Experiment MOTIVATION CAST Axion axion – gluon vertex θ absorbed in the definition of a Pseudo Scalar Goldstone boson resulting from the spontaneously broken symmetry introduced by Peccei-Quinn global chiral symmetry UPQ(1) to enforce strong CP conservation. • Mass (from a-π0 mixing): (Astrophysical Argument, HB) • Coupling to photons: • Mean life time Jaime Ruz Armendáriz. , where for i. e. HEP 2007, Manchester

The CAST Experiment MOTIVATION Jaime Ruz Armendáriz. CAST HEP 2007, Manchester

The CAST Experiment MOTIVATION CAST SOLAR BLACK BODY RADIATION DIFFERENTIAL AXION FLUX AT THE EARTH SURFACE Jaime Ruz Armendáriz. HEP 2007, Manchester

The CAST Experiment DESCRIPTION Jaime Ruz Armendáriz. CAST HEP 2007, Manchester

The CAST Experiment DESCRIPTION TPC CAST aims to reconvert solar axions back into photons μM CCD § DECOMMISSIONED LHC MAGNET. L=9. 26 m B=9 T § 3 X-ray DETECTORS (2003 - …) § 1 X-ray telescope (2003 - …) § 2 x 1. 5 hours/day of exposure time [2003 - 2004] [2005 - 2006] [2007 - … ] Vacuum 4 He 3 He ma < 0. 02 e. V ma < 0. 34 e. V ma < 1. 16 e. V TELESCOPE Jaime Ruz Armendáriz. HEP 2007, Manchester

The CAST Experiment DESCRIPTION CAST Pointer Crosshairs 2. 6 m Camera 5. 0 m MFB Optical Axis Tube Magnet CAST-Magnet is crosscheck visually to be aligned with the Sun Center within 0. 02°! Jaime Ruz Armendáriz. HEP 2007, Manchester

The CAST Experiment CAST First Phase. DESCRIPTION CAST • Vacuum inside the cold bore (magnet region) SIGNAL The photon acquires an effective mass mγ = 0 Excess of X-ray in TRACKING over BACKGROUND (Coherence condition q. L<1 ) Jaime Ruz Armendáriz. HEP 2007, Manchester

The CAST Experiment CAST First Phase. RESULTS 95% Upper Limit CAST 95% Upper Limit Best Fit gagg TPC 95% Upper Limit Best Fit gagg 95% Upper Limit Tracking Background 2003 DATA Jaime Ruz Armendáriz. µM Best Fit gagg 95% Upper Limit Background CCD 2004 DATA HEP 2007, Manchester

The CAST Experiment CAST First Phase. RESULTS Jaime Ruz Armendáriz. CAST HEP 2007, Manchester

CAST First Phase. Description CAST First Phase. RESULTS Jaime Ruz Armendáriz. CAST HEP 2007, Manchester

The CAST Experiment CAST Second Phase. DESCRIPTION CAST • Extending coherence for higher axion masses … FILL MAGNET BORE WITH HELIUM The photon acquires an effective mass mγ > 0 Jaime Ruz Armendáriz. HEP 2007, Manchester

The CAST Experiment CAST Second Phase. DESCRIPTION CAST • Coherence restored for a narrow mass range around mγ mγ can be adjusted by changing the gas pressure [2005 - 2006] [2007 - … ] Jaime Ruz Armendáriz. 4 He 3 He ma < 0. 34 e. V ma < 1. 16 e. V HEP 2007, Manchester

The CAST Experiment CAST Second Phase. RESULTS CAST Preliminary Result 4 He Jaime Ruz Armendáriz. Phase HEP 2007, Manchester

The CAST Experiment STATUS CAST No axions yet, CONTINUE DATA TAKING Jaime Ruz Armendáriz. HEP 2007, Manchester

The CAST Experiment STATUS CAST No axions yet, CONTINUE DATA TAKING Jaime Ruz Armendáriz. HEP 2007, Manchester