Optical Search for QED vacuum magnetic birefringence, Axion & photon Regeneration Last Results from the OSQAR “Light Shining Through a Wall” Experiment P. Pugnat Laser-based Particle/Astroparticle Physics Experiments at CERN To test QED & probe the Low Energy Frontier…

► 29 Members from 12 Institutes (CERN, Cz, Fr & Po) 2 CERN, Geneva, Switzerland G. Deferne, P. Pugnat (spokesperson, now at LNCMI-CNRS), A. Siemko Charles University, Faculty of Mathematics & Physics, Prague, Czech Republic M. Finger Jr., M. Finger, M. Slunecka Czech Technical University, Faculty of Mechanical Engineering, Prague J. Hošek, M. Kràl, K. Macuchova, M. Virius, J. Zicha ISI, ASCR, Brno, Czech Republic A. Srnka IMEP/LAHC - INPG, Grenoble, France L. Duvillaret, G. Vitrant, J.M. Duchamp IN, CNRS – UJF & INPG, BP 166, Grenoble, France R. Ballou Johannes Gutenberg University of Mainz, Germany M. Schott, C. Weinsheimer LASIM, UCB Lyon1 & CNRS, Villeurbanne, France M. Durand (now at NIST, Gaithersburg), J. Morville LIPhy, UJF & CNRS, Saint-Martin d'Hères, France R. Jost, S. Kassi, D. Romanini Technical Uuniversity of Liberec, Czech Republic M. Šulc, Š. Kunc, R.Puliček, F.Švec Warsaw University, Physics Department, Poland A. Hryczuk, K. A. Meissner (co-spokesperson)

Outline Introduction Overview of the OSQAR Experiments –VMB & Photon Regeneration (PR) –Short & Long Term Perspectives Some Highlights from Collaborating Institutes PR Experiment at CERN – Last results & Ongoing Progress Summary & Perspectives The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics3

To measure for the 1 st time the QED Vacuum Magnetic Birefringence (Heisenberg & Euler, Weisskopf, 1936) i.e. the vacuum magnetic “anomaly” of the refraction index “ n-1” ~ in 9.5 T To explore the Physics at the Low Energy Frontier (sub-eV) –Axion & Axion Like Particles i.e. solution to the strong CP problem (Weinberg, Wilczek, 1978) & Non-SUSY Dark Matter candidates (Abbott & Sikivie; Preskill, Wise & Wilczek, 1983) –Paraphotons (Georgi, Glashow & Ginsparg, 1983), Milli-charged Fermions –Chameleons (Khoury & Weltman, 2003) –The Unknown … “Exploring a new territory with a precision instrument is the key to discovery”, Prof. S.C.C. Ting A New Way of doing Particle Physics based on Laser beam(s) Spin-offs in the domain of the metrology of electric & magnetic fields Scientific Motivations in a Nutshell The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics4 xxxx Delbrück scattering

Interest of Axions The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics5 Axion Physics –axions are theoretically necessary - the only known solution of the “strong CP-problem“ –without axions the neutron dipole electric moment is unnaturally small –axions couple to gluons (solving the strong CP-problem) and to photons (basis of OSQAR experiment) “Massive” Axions i.e. O( MeV) excluded after extensive search in nuclear transition, particle decays ( )  “Invisible” axion models in the range eV, i.e. No longer a HEP problem… “Small can also be beautiful”

Principles of the Experiments The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics LN 2 cooled CCD Use of 2 LHC cryo-dipoles (double apertures, 9 T over 2 x 14.3 m) 6 ► In one aperture of dipole-1, measurement of the Vacuum Magnetic Birefringence & Dichroïsm ► In the 2 nd aperture of dipole-1 & one aperture of dipole-2, Photon Regeneration Experiment x a  9.5 T x  ~ 53 m

The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics Experiments - Expected results - Short & “Long” Term Perspectives PVLAS, PRL 96 (2006) CAST ALPs 2010 Expectation for 2014/15 OSQAR-PR From C. Hagmann, K. van Bibber, L.J. Rosenberg, Physics Lett. B, vol.592, 2004 Photon Regeneration Experiment - Preliminary Phase to test PVLAS results; 1 dipole with/without gas (done) * - Phase-1 : 2 dipoles, CW laser beam, extra & intra cavity to improve BFRT/GammeV results ( ) and ALPs ( ) - Phase-2 : 2 dipoles, CW laser beam & High Finesse FP cavity ( ) - Phase-3 : more than 2 dipoles to be competitive with CAST (long term) “n-1 Experiment” i.e. VMB & Linear Dichroism * * - Phase-1 & 2 : Measurements of QED prediction in O(  2 ) & O(  3 ) respectively within 1 dipole (started, long term…) * P. Pugnat, et al. Phys. Rev. D 78, (2008) * * P. Pugnat, et al. Czech Journal of Physics, Vol.55 (2005), A389; Czech Journal of Physics, Vol.56 (2006), C193; Axion Search 7

Few Highligths

New Theoretical Development The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics9 Provide a single source of explanation for axion couplings and neutrino masses…

Spin-off : a New Start-up has been created by Prof. L. Duvillaret Partners Awards 10 staffs at present ► Strong motivations to apply the know-how for precise magneto- optic measurements The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics10 Dynamic range 70 dB Bandwidth 18 GHz * L. Duvillaret et al., J. Opt. Soc. Am. B 19, p (2002) (Addressed in CERN-SPSC )

Highlights from the Czech Teams Funding awarded for Axion Detection by Laser-based Experiments from Czech Science Foundation (March 2011 – December 2013) Participants and main responsibilities –Technical University of Liberec, Department of Physics, Qualification of optical elements of FP cavities for VMB measurement –Czech Technical University in Prague, Department of Precision Mechanics and Optics, production and measurement of high finesse FP cavity –Charles University in Prague, Faculty of Mathematics and Physics, Department of Low Temperature Physics, provides a new CCD for the Photon Regeneration Experiment + R&D for new detectors Examples of contributions –Ring Imaging Cherenkov Detector –HESS Mirror Telescopes ( High Energy Stereoscopic System for the investigation of cosmic  rays in the 100 GeV range) The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics11

Photon Regeneration – LSW Principle Exclusion limit forg A  B (T)B -1 Magnetic Length (m)L -1 Optical power (W)P -1/4 Detector efficiency  -1/4 Detection threshold (  /s) dN  /dt 1/4 Time integration  t -1/8 The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics12 P. Sikivie, PRL 51 (1983) K. van Bibber et al. PRL 59 (1987) 759

The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics Photon Regeneration ► Operation since 2010 with 2 aligned 9T LHC dipoles A B C A B C D E F D E F B1 E1 53 m 13 “An invisible light shining through a wall” K. van Bibber et al. PRL 59 (1987) 759

2013 LSW Run - Experimental The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics14 LN2 cooled CCD - ISA/Jobin Yvon model T64000 CCD chip, EEV 1024 × 256 square pixels of 26  m, 26.6 x 6.7 mm Measured (QE + Gain) = 33.7 ± 0.7 % at nm 15 W CW Verdi laser from Coherent at the entrance of the first LHC dipole

2013 LSW Run – Experimental The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics15 Total time integration - Scalar search: 80 hours - Pseudo-scalar search: 80 hours Time of exposition 2700 s ► Periodic check during data taking of the beam alignement with the CCD Attenuator Powermeter Filter 1 Filter 2 lens input window Laser 1st Anticryostat Shutter 2st Anticryostat CCD chip ► Careful check of the sensitivity of the CCD

The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics16

The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics17 Preliminary 2013 run

Perspectives The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics Run (Aug-Sept) with state-of-the-art CCD 2015 Run Operation with the 20 m long Fabry-Perot cavity under development & test QE = 95 % at nm Darkcurrent < ° C / Readout noise: 2.5 e-

Longer Term Perspective The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics19 With LHC Dipoles, i.e. Experiment of ~150 m long,… Phys. Rev. Lett. 98, (2007)

As intermediate step… The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics20 A laser cavity extended up to 5 m inside the magnet aperture was already built with an intra-cavity CW power larger than few 100 W ►Ongoing study using a mirror with a larger radius to extend the cavity up to 20 m… arXiv: v1

Summary ► OSQAR-PR is now entering in the virgin territory for LSW type experiment The OSQAR CERN For Low Energy Laser-based Particle/Astroparticle Physics21 KSVZ DFSZ A gap of opportunities for the unknown...

22 ► See the poster session Thursday