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AEGIS A ntimatter E xperiment: G ravity, I nterferometry, S pectroscopy

AEGIS A ntimatter E xperiment: G ravity, I nterferometry, S pectroscopy. C. Canali INFN sez. Genova 11° ICATPP Como, 8 October 2009. The AEGIS Collaboration. LAPP, Annecy, France D. Sillou. UCBL Lyon, France P.Nedelec. Queen’s U Belfast, UK G. Gribakin, H.R.J.Walters. CERN

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AEGIS A ntimatter E xperiment: G ravity, I nterferometry, S pectroscopy

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  1. AEGIS Antimatter Experiment: Gravity, Interferometry, Spectroscopy C. Canali INFN sez. Genova 11° ICATPP Como, 8 October 2009

  2. The AEGIS Collaboration LAPP, Annecy, France D. Sillou UCBL Lyon, France P.Nedelec Queen’s U Belfast, UK G. Gribakin, H.R.J.Walters CERN M. Doser, A. Dudarev, D. Perini (+ support from T. Eisel, F. Haug, T. Niinikoski) INFN Genova, Italy C. Canali,C. Carraro, V. Lagomarsino, G. Manuzio, G. Testera, S. Zavatarelli MPI-K Heidelberg A. Fisher,A. Kellerbauer, U. Warring, C. INFN Firenze, Italy G. Ferrari, M. Prevedelli, G. Tino INFN Milano, Italy I. Boscolo, N. Brambilla,F. Castelli, S. Cialdi, L. Formaro, A. Gervasini, M. Giammarchi, F. Leveraro, A. Vairo Kirchhoff Inst. Of Phys., Heidelberg, Germany M. Oberthaler INR Moscow, Russia A.S. Belov, S. N. Gninenko, V. A. Matveev, A. V. Turbabin ITEP Moscow, Russia W. M. Byakov, S. V. Stepanov, D.S. Zvezhinskij Politecnico Milano, Italy G. Consolati, A. Dupasquier, R. Ferragut, P. Folegati, F. Quasso New York Univ. USA H.H. Stroke Univ. Oslo, Norway O. Rohne, S. Stapnes INFN Pavia-Brescia, Italy G.Bonomi, A. Fontana, A. Rotondi, A. Zenoni IRNE Sofia, Bulgary N. Djurelov Czech Tech. Univ, Prague, Czech Republic V. Petracek, D. Krasnicky, M. Spacek INFN Padova-Trento, Italy R.S. Brusa, D. Fabris, M. Lunardon, S. Mariazzi, S. Moretto, G. Nebbia, S. Pesente, G. Viesti INP Minsk, Belarus G. Drobychev ETH Zurich, Switzerland S.D. Hogan, F. Merkt La. Aime’ Cotton, Orsay, France L. Cabaret, D. Comparat Qatar University I. Y. Al-Qaradawi

  3. AEGIS Antimatter Experiment: Gravity, Interferometry, Spectroscopy • Physical Motivations: why antimatter? • Gravity and antimatter • AEGIS: measuring g on antihydrogen • Overview • Measuring g on H • Conclusions

  4. Gravity: • WEP test • General Relativity test Antimatter system: CPT: - + e e ( q / m ) - + e e Magnetic moment ( g - 2) p p Charge/mass ( q / m ) 0 0 K K Mass difference f - + μ μ ( g - 2) -6 -9 -12 -15 -18 10 10 10 10 10 relative precision [P. B. Schwinberg et al., Phys. Lett. A 81 (1981) 119] [R. S. Van Dyck, Jr. et al., Phys. Rev. Lett. 59 (1987) 26] [G. Gabrielse et al., Phys. Rev. Lett. 82 (1999) 3198] [Y. B. Hsiung, Nucl. Phys. B (PS) 86 (2000) 312] [G. W. Bennett et al., Phys. Rev. Lett. 92 (2004) 161802] • Spectroscopy on antihydrogen

  5. High precision spectroscopy: Gravity measurement: The frequency of the 1S-2S transition in hydrogen has been measured with high precision: f = 2 466 061 413 187 103(46) Hz Charged particles are extremely sensitive to electric fields: we need a neutral system… [M. Niering et al., Phys. Rev. Lett. 84 (2000) 5496] We need neutral (cold) antimatter: Anti-hydrogen!

  6. Matter-matter: matter-antimatter: General relativity is a classical (non quantum) theory! • Tensor → “Newton”, always attractive • Vector → repulsive between like charges • Scalar → always attractive • The non-Newtonian terms could (almost) cancel out if a ≈ band v ≈ s , but would produce a striking effect on antimatter [T. Goldman, M. Nieto Phys. Lett 112B 437-440 (1982)] [ E. Fischbach, C. Talmadge “The search for Non Newtonian Gravity” Springer]

  7. ATHENA first cold H-bar Antiproton discovery Positron discovery PS210 first H-bar ATRAP2 ALPHA AEGIS proposal Dirac equation Fermilab ATRAP 1955 1996 1932 2002 2008 Wow!… so, let’s start the experiment! 1927

  8. AD PS ATHENA first cold H-bar Antiproton discovery Positron discovery PS210 first H-bar AEGIS proposal ATRAP2 ALPHA Dirac equation Fermilab ATRAP 1932 1996 1955 2002 2008 1999 The AD – Antiproton Decelerator Protons Antiprotons

  9. 1999 The AD – Antiproton Decelerator protons 26 GeV/c from PS 3.5 → 0.1 GeV/c 3.5 GeV/c ATRAP AD ring Stochastic & electron cooling ASACUSA ATHENA • Delivered to experimental areas: • 107 antiprotons delivered every ~85 s • 0.1 GeV/c • 200 ns bunches

  10. AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) http://aegis.web.cern.ch aegis atrap 2007: proposal submitted 2008: experiment approved by CERN 2009: start building … asacusa alpha

  11. Antihydrogen production based on: Penning traps B= 1 T H prod. region 100 mK • Confinement in vacuum of • charged partcles: • B-Field → radial confinement • E-Field → axial confinement B=1T Moiré’ deflectometer Stark accelerator AD side p entrance Positronium Production region Positrons from accumulator Positrons trap

  12. Goal: first direct measurement of Earth’s gravitational acceleration g on antimatter • p catching and cooling • positrons accumulation • Antihydrogen production • Beam formation • g measurement time 0s 100s B=1T

  13. p catching and cooling Electron plasma 5kV GOAL: >104 antiprotons @ 100 mK • From AD: • 107 antiprotons delivered every ~85 s • 0.1 GeV/c • 200 ns bunches • 104 antiprotons in trap [athena] • electron cooling of antiprotons • Resistive cooling • Sympathetic cooling with negative ions (?)

  14. H-bar production (Charge exchange Ps + p → H + e) Stark acceleration Ps excitation (Double laser pulse n=1 → n=3 → n=25) Ps production (bound state e+e-) e+ bounch

  15. e+ accumulator & positronium production • Production of positrons from a Surko-type source and accumulator • 22Na radioactive source (40 mC) • 108 e+ every 200 s • e+ slowing down and Ps formation • Ps thermalize within target (eV) • Ground state Ps emitted in vacuum • High Yield (30-50%) • Precise timing (few tens ns)

  16. n = 35 1064 nm, 4 ns 615 nm 205 nm 1670 nm 2 135 mJ Q-switched dye laser n = 3 Nd: Y AG laser PPLN 4 cm n = 2 6 mJ 3 mJ OPG 205 nm Etalon 3 mJ PPLN 2 cm 1650-1710 nm O P A n = 1 positronium excitation • Two laser steps: • nPs = 1 → nPs = 3 • nPs = 3 → nPs = 20 … 40 (tunable) • >106 Rydberg positronium atoms are expected

  17. Antihydrogen state related to initial Ps* state Produced antihydrogen has the same temperature of antiprotons (100 mK): Low energy H! Large cross section ~ a0nPs4 σ = 10-9 cm 2 Antihydrogen production occur via charge exchange process: [C. H. Storry et al., Phys. Rev. Lett. 93 (2004) 263401]

  18. The beam is produced using a stark accelerator: • H is in Rydberg state • Interactions between electric dipole moment and • a non-uniform electric field: • Δv of several 100 m/s within about 1 cm • Electric fields: few 100 V/cm (limited by field ionization) • Already working with Rydberg hydrogen! • [E. Vliegen & F. Merkt, J. Phys. B 39 (2006) L241]

  19. H L h vh How to measure g? • Produce an horizontal antihydrogen beam, velocity few 100 m/s • Horizontal flight path about 1 m • Vertical gravity deflection : 20 microns @ 500m/s • Poor beam collimation: beam size after flight: several cm Gravity measurement with ordinary matter have been performed with a Moirè deflectometer: σ(g)/g = 2×10-4 [M. K. Oberthaler et al., Phys. Rev. A 54 (1996) 3165]

  20. G1 G2 Detector 20 cm 40 cm 40 cm Ls 30 cm (distance antihydrogen source-first grating) Grating distance L 40 cm Grating size: 20 x 20 cm2 Grating period: a=80 μm Grating transparency 30% Detector resolution 10 μm Only classical interactions

  21. x counts Binning (grating period) Vh= 600 m/s Montecarlo results

  22. x Vh= 600 m/s Vh= 400 m/s counts

  23. x Vh= 600 m/s Vh= 400 m/s Vh= 300 m/s counts

  24. x Vh= 600 m/s Vh= 400 m/s Vh= 300 m/s Vh= 250 m/s counts

  25. T: time of flight between the two gratings a: grating period Measurement of g to 1%: • 108 e+ in 200-300 s • • 5x106 Rydberg Ps. • • 105 antiprotons captured and cooled to 100 mK • rate: 103 H / AD cycle • • 105 antihydrogen athoms (2-3 settimane).

  26. Conclusions ( & ambitions): AEGIS will use already well-know techniques together with innovative schemes Members of AEGIS are already working on this… Gravity on antimatter has never been tested AEGIS could perform the first measure of this kind never performed An antihydrogen beam open the way to new experimental possibilities Trapping antihydrogen & spectroscopy, atomic fountain, BEC, High precision g-meas. …

  27. Thanks for your attention http://aegis.web.cern.ch/

  28. The g measurement • Send the antihydrogen beam through the deflectometer: t0 defined within msec • For every antihydrogen measure the vertical position x and the arrival time on the detector • Few tens antihydrogen/cycle; flight time ms; • The large beam velocity spread makes pileup negligible • Reconstruct the flight time T between the 2 gratings • Group together Hbar having T in a proper interval (T1,T2) : make a T2 distribution symmetric • Build the “1 period” arrival position distribution N(x/a) : about 103 detected particles • Use a phase tracking algorithm to find the shift • Find g by fitting the relation N(x) 10 mm resolution Infinite resolution x/a

  29. p catching and cooling • positrons accumulation • Antihydrogen production • Beam formation • g measurement Capture and cooling of antiprotons • From AD: • 107 antiprotons delivered every ~85 s • 0.1 GeV/c • 200 ns bunches • Catching: • Degrader foil • Reflecting and trapping in Penning trap (5kV) • 104 antiprotons in trap [athena] • Cooling: • previously loaded plasma with 107 electrons • electrons quickly cool down by cyclotron radiation • electron cooling of antiprotons • Resistive cooling • Sympathetic cooling with negative ions (?)

  30. positron plasma [C. Regenfus, NIM A501 (2003) 65] antiprotons Recombination experiments: ATHENA & ATRAP Core idea: trapping in the same region and e+ Cylindrical Penning trap

  31. B=1T B=5T Diocotron jump of positrons P-bar catching region P-bar cooling region

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