Low Energy Physics : Cold AntiHydrogen. Alessandro Variola, S.Dagoret, F.Zomer, J.Haissinski, M.Urban Seminaire : Mike Charlton

Motivations: Why Cold Antihydrogen ? CPT test & Antimatter Gravity (G) & Antimatter studies & Prospects for low energy physics : cold antihydrogen measurements STAR TREK COLD ? For precision experiments : at least 1 mK (~ eV) !!!

And more : why cold antihydrogen physics ? It is a multidisciplinary field. Challenging technologies. A lot of top level applied physics : So FUN !!! Cold Antihydrogen CPT Symmetry Gravity Cosmology Monte Carlo Cold Plasmas Pbar & e + cloud Traps Neutral trapping Detectors 140K Software Simulations Lasers Cooling Lyman  Spectroscopy Cryogenics UH Vacuum record Other Measurements: Ryd. Const Hbar neutrality BEC (De) Accelerator Physics (RFQD) e + source Magnetic measurements Atomic Physics

Cold Antihydrogen – Two Main Physics Goals Test of CPT Invariance Antimatter gravity Weak Equivalence Principle Assumptions: Locality, Lorentz Invariance, Unitarity, flat-space time Consequences for particles and antiparticles: Equal mass, lifetime Equal and opposite charge and magnetic moment Antihydrogen : Identical energy levels WEP Requires the gravitational acceleration of a falling object to be independent of its composition

CPT

CPT => Everybody wish is that CPT is not violated ! (The standard model is based on this…) BUT : Strange things happen ……

A lot of Theoretical speculations do exist (Kostelecky, Ellis, Mavromatos, Pospelov …) 1) Lorentz Violation – Antimatter give direct measurements (SM Extension) 2) Locality -> string theories may violate CPT 3) Unitarity -> topologically non-trivial fluctuation in space time (Hawking, Ellis, Mavromatos) Theoretical speculations? Let’ see it from a positive point of view => CPTV is an open field: No underlying theory (only the Kostelecky model is proposed as a SM extension SME …) No single gold-plated measurement Each particle sector complimentary Where to look? Highest precisions - Compare matter to antimatter in best measured observables : Lowest absolute energies At low energies, CPTV could be Planck-suppressed e.g. m p 2 /Mplanck ~ x/ GeV. So High Precision needed Why Hbar ? CPT Violations. Different models are proposed based on the rupture of the basic assumptions

Unlikely to be violated ? This is an experimental question ! Many fundamental symmetries in Nature are broken. To attain a resolution close to the Kaon exp we have to go for the Antihydrogen 1S-2S Spectroscopy CPT & CPTV (e/m)

CPT and Lorentz violating theories and experiments General theories Kostelecký et al., “Standard Model Extension”; Ellis, Mavromatos, Quantum Gravity Coleman and Glashow, Huet and Peskin, S. Hawking, Isger et al., Kobayashi and Sanda, Greenberg, Urbanowski, Mocioiu et al. Scarbelli, Belich et al., Chiba et al., Bazeia, Klinkhamer, Yamaguchi, Li and Zhang, Chiba and Ivanova, Datta et al., Takeuchi, Alexanian and Balachandran, Andrianov et al., Casadio and Gruppuso (brane) Neutrino sector Murayama and Yanagida Barenboim, Lykken et al.; Strumia; Gonzalez-Garcia, Schwetz et al.; Barger et al.; Raghavan; Pakvasa and Valle; Ohlsson, Huber; de Gouvea; Mocioiu et al.; Pakvasa Experimental tests M. Hori et al. ASACUSA: anti-protonic helium V. Hughes et al. Muonium hyperfine structure H. Dehmelt et al. electron and positron in penning trap G. Gabrielse et al. proton and antiproton in penning trap M. Romalis et al. 3 He-K magnetometer CPLEAR/KTeV neutral kaon mass difference Belle/Babar: B factories MiniBooNE: neutrino oscillations

G

WEP & antimatter gravity measurements Gravity is one of the less precise measured constants….. and on antimatter it has never been tested !!!! Questions : Did they fall in the same way? Do they fall differently but in the same direction? Do they fall in opposite direction? General Relativity says : they fall in the same way ! But….. - Limits exist on antimatter gravity => no evidence in Eotvos experiment by e + -e - pair creation [Schiff] and no exp.evidence of WEP violation on matter in Eotvos exp., - Chu (Nobel Prize)=> On matter WEP Ok between micro and macro at the level with the “atomic fountain” and Raman Spectroscopy. NO DIRECT MEASUREMENTS EXIST BUT: Again a lot of speculation exist concerning antimatter WEP violation in the context of Quantum Gravity,Non Newtonean Gravity, Supersymmetry…………

Antimatter gravity measurements How to measure anti-gravity and/or WEP violation with antimatter : Shift of the trapped antihydrogen equilibrium position. Same order of magnitude of the trap depth ~ Gravitational energy (~ 1.2 mK) (Gabrielse G. Hyp int. 1988) Low resolution, low energy for trapping but ready when antihydrogen is trapped ________________________________________________________ Spectroscopy=> RedShift with different Gravitational potentials (Charlton et al Phys exp 1994 based on Morrison idea) Must be very accurate. What the best  V? ________________________________________________________ Atomic interferometer : Laser fountain, interferometer (Chu et al.). Precision Coooooooool => Laser cooling but => High power Lyman alpha!!!! CW : Pulsed ok but increase the repetition frequency

H Experiments

ATHENA & ATRAP How a Cold Hbar spectroscopy measurements works : 1 st step : production AD p Production (GeV) Deceleration (MeV) Trapping (keV) Cooling (~ meV) Na-22 e + Production (MeV) Moderation Accumulation (eV) Transfer & cooling (meV) p - and e + in mixing trap interacting – cooling & Antihydrogen formation Detection ~ 10 8 e + ~10 4 p Hbar P - e ATRAP, field ionization ATHENA, annihilation products

How a Cold Hbar spectroscopy measurements works : 2nd step : Confinement, Trapping and cooling Neutral and charged simoultaneously Collaboration. Antihydrogen Light For cooling the faster method is laser cooling: before annihilation needs 300 photons to cool from 100 K to less than 1 K (A neutral trap has a depth of ~ 0.6K/T ). This has to be done in few  sec, so it is important to work on a highly permitted line (Lyman alpha…).

ALPHA. How a Cold Hbar spectroscopy measurements works : 3rd step : Spectroscopy. Shot a ultra-stabilized laser on !! Hbar cloud PM- Lyman alpha Detector 2  spectroscopy

Atomic Fountain S-2S spectroscopy Beams Traps 1S-2S spectroscopy HFS HFS Example: Precision of Spectroscopy,.. (Haensch – Nobel Prize) Chu (nobel prize)

And more (CPT connected) : Hbar Neutrality Based on H 2 molecular beam measurement by Zorn, Hughes et al. Positroninum beam 4  10  8 p atoms SF6 gas 10  21 [Dylla,- King] ? pe  He atom  6  10  8 ( e/m cycl freq: 10  10 ) Limits on |dq/q| Hbar R? 2 body direct 3 body Need calculation e-e- e+e+ p p

Now and future

“In the past 6 years, the creation of antihydrogen has advanced from the totally visionary to the merely very difficult” --- Dan Kleppner, 1992 Summary Antihydrogen Workshop Where we were…..

Where we are…..ATHENA, 2002 The number of produced antihydrogen atoms was essentially limited by the number of antiprotons at disposal $

Where we are ATHENA + ATRAP 1) Hbar production rate (~ 100 Hz at mixing) 2) Hbar formation mechanism (Three body and guiding center atoms privileged) 3) Hbar rate temperature dependence 4) Hbar rate density dependence 5) Hbar production state (High Rydberg) 6) Hbar production velocity (Temperature) 7) Hbar on-off (time driven production via - heating) 8) Hbar formation during Pbar cooling 9) Hbar production symmetry respect Pbar 10) Hbar Driven production (via positronium)

3 T in catching region, 1 T in mixing for larger neutral well depth Outer solenoid Inner solenoid Mirror coils Next Step (near future): ALPHA (new ATHENA) & ATRAP. Trapping neutral and charged simultaneously

…and ASACUSA It measures the absence of signal !!!

After neutral trapping principle has been tested NEXT frontier : For high number trapping & precise exp. => COOLING !!!!!! 1) Sympathetic electron - Pbar cooling 2) Cyclotron mixed electron-Pbar cooling (New) 3) Lyman-  cooling. (Or other lines?...new ideas are welcome…..) 4) Sympathetic Pbar cooling with laser cooled Osmium Atoms (New) 5) Rotating Wall for positron plasmas and collision recombination Far future… (not too much!)

Future possibilities: 2 main Facilities dedicated to low energy pbar physics : CERN GSI

First Production Quantum State Manipulations Stable Trapping Precision Spectroscopy CPT Violation Gravity Attempt for a Possible Antihydrogen Laser Experiment Roadmap Attempt for a Possible Antihydrogen Laser Experiment Roadmap ? Laser induced formation First laser-antiatom interaction e+ temperature measurement 3-body plasma effects Two-step Laser induced formation First bound-to-bound spectroscopy Hbar velocity via Doppler width Resonant velocity selection Non-neutral plasma stability studies Resonant particle transport Trapped particle modes Quadropole vs. multipole effect Steps Along the Way 1s-2s spectroscopy Comparison with hydrogen Resonant ionization Where we are going in the near and far future………..

Fabry Perot cavity for Hbar cooling. ( f doubled for Lyman  ) High rate positron source based on low energy electron accelerator. (Useful also for positronium physics…) High accumulation rate (see P.Perez project….) Hbar Detectors & Electronics. ….and good physicists And what about LAL ? How to partecipate to ALPHA And what about LAL ? How to partecipate to ALPHA

Conclusions : Low Energy Physics is a “moving world” so……….

Hbar Vertex Counts Mixing time (sec)

How to produce and detect Hbar

and ATRAP