ATRAP Probing Fundamental Physics with Antimatter Stefan Ulmer (BASE) RIKEN Fundamental Symmetries Laboratory for the AD-Collaborations Representing the AD Community currently: 6 collaborations – 60 Research institutes/universities – 350 researchers ATRAP K. Blaum, Y. Matsuda, C. Ospelkaus, W. Quint, J. Walz, Y. Yamazaki Investigating the properties of antimatter with AMO methods (traps and lasers) Outline Introduction: physics motivation and goals Methods: techniques applied by the AD collaborations Results: major achievements of recent years Outlook: physics perspective in the ELENA era ATRAP Problem: Big Bang Scenario and Consequences 1. A cosmic microwave background should exist as a fire-ball remnant of the Big Bang 1. 1965 Penzias and Wilson observed CMWB with a black body spectrum of 2.73(1)K, by far too intense to be of stellar origin. 2. Understandable Big Bang nucleosynthesis scenario describes exactly the observed light element abundances as found in «cold» stellar nebulae. 3. Using the models which describe 1. and 2.: Prediction Observation Baryon/Photon Ratio 10-18 Baryon/Photon Ratio 10-9 Baryon/Antibaryon Ratio 1 Baryon/Antibaryon Ratio 0.0001 ATRAP Following the current Standard Model of the Universe our predictions of baryon to photon ratio are wrong by about 9 orders of magnitude while our baryon/antibaryon ratio is wrong by about four orders of magnitude. Summary WE HAVE A PROBLEM mechanism which created the obvious baryon/antibaryon asymmetry in the universe is not understood One strategy: Compare the fundamental ATRAP properties of matter / antimatter conjugates with ultra high precision Strategy Energy Resolution • Use simple well-understood systems -> provides < ψ∗|∆푉|ψ >= ∆퐸 high sensitivity with respect to potential deviations and new physics. Kostelecky et al. • 푯 흍 = 푯ퟎ + 푽풆풙풐풕풊풄 흍 Absolute energy resolution (normalized 훾휇퐷 − 푚 − 푎 훾휇 − 푏 훾 훾휇 휓 = 0 to m-scale) might be a more 휇 휇 휇 5 appropriate measure to characterize 휟푬풆풙풐풕풊풄 = 흍ȁ푽풆풙풐풕풊풄ȁ흍 the sensitivity of an experiment with respect to CPT violation. • Single particle measurements in Penning traps give high energy resolution. matter sector Relative Energy SME Figure precision resolutio of merit proton lifetime (direct) >1.67 e34 y n −18 −9 KaonLorentz ~10 ~10 ~ 10-18 proton m 30 p.p.t. ∆푚 eV pViolating-pത ~10−11 ~10−18 ~ 10-26 proton magn. moment 3.3 p.p.b. In the matter sector, q/m eV ATRAP measurements with incredible p-pത g- ~10−6 ~10−12 ~ 10-21 hydrogen 1S/2S 0.004 p.p.t. factor eV precision have been hydrogen GSHFS 0.7 p.p.t. demonstrated SME has no predictive power / missing link from EFT to particle physics Example: the BASE trap - a special place • A vacuum of 5e-19 mbars • best characterized vacuum on earth, • comparable to pressures in the interstellar medium • Antiproton storage times of several 10 years. • Not more than 3000 atoms in a vacuum volume of 0.5l • Order 100 to 1000 trapped antiprotons • A local inversion of the baryon asymmetry BASE ANTIMATTER INVERSION local volume 0.00013 m3 Baryons in local trap volume 1.65*10-7 Antibaryon in local trap volume 100 8 Antibaryon/Baryon Ratio 5.9*10 ATRAP Ratio Inversion 3.8*1012 With this instrument: Investigate properties of antimatter very precisely CPT tests based on particle/antiparticle comparisons R.S. Van Dyck et al., Phys. Rev. Lett. 59, 26 (1987). Recent B. Schwingenheuer, et al., Phys. Rev. Lett. 74, 4376 (1995). Past CERN H. Dehmelt et al., Phys. Rev. Lett. 83, 4694 (1999). G. W. Bennett et al., Phys. Rev. D 73, 072003 (2006). Planned M. Hori et al., Nature 475, 485 (2011). ALICE G. Gabriesle et al., PRL 82, 3199(1999). J. DiSciacca et al., PRL 110, 130801 (2013). S. Ulmer et al., Nature 524, 196-200 (2015). ALICE Collaboration, Nature Physics 11, 811–814 (2015). M. Hori et al., Science 354, 610 (2016). H. Nagahama et al., Nat. Comm. 8, 14084 (2017). M. Ahmadi et al., Nature 541, 506 (2017). M. Ahmadi et al., Nature 586, doi:10.1038/s41586-018-0017 (2018). CERN AD antihydrogen 1S/2S antihydrogen 1S-2S antihydrogen GSHFS ATRAP Momentum in the AD community antimatter sector 2013 antiproton lifetime > 0.3 y antiproton m 120 p.p.t. matter sector antiproton m. moment 0.002 antihydrogen 1S/2S - proton lifetime (direct) >1.67 e34 y antihydrogen GSHFS - proton m 30 p.p.t. proton magn. moment 3.3 p.p.b. hydrogen 1S/2S 0.004 p.p.t. antimatter sector 2019 hydrogen GSHFS 0.7 p.p.t. antiproton lifetime > 10.6 y antiproton m 70 p.p.t. antiproton m. moment 1.5 p.p.b. ATRAP • Recent rapid progress towards a antihydrogen 1S/2S 2 p.p.t. better understanding of antimatter. antihydrogen GSHFS 350 p.p.m. Antiprotons – CERN 5.3 MeV antiprotons 25 GeV/c protons 3.5 GeV/c antiprotons -> Degrader -> 1keV Within a production/deceleration -> Electron cooling -> 0.1 eV cycle of 120s + 300s of preparation ATRAP -> Resistive cooling -> 0.000 3 eV time we bridge 14 orders of -> Feedback cooling -> 0.000 09 eV magnitude Most of these methods were pioneered and first demonstrated by the TRAP collaboration (Gabrielse et al.) Pioneering Highlights Production of 11(2) relativistic antihydrogen atoms at LEAR (PS210) in 1995. G. Baur et al., Phys. Lett. B 368 (1996) 251 W. Oelert (Juelich) Comparison of the proton to antiproton charge to mass ratio at fractional precision of 90 p.p.t. G. Gabrielse et al., Phys. Rev. Lett. 82 (1999) 3198 ATRAP Together with the discovery of antiprotonic helium by T. Yamazaki / R. Hayano / Iwasaki et al. ... Convinced CERN to start the AD program. The AD/ELENA-facility Six collaborations, pioneering work by Gabrielse, Oelert, Hayano, Hangst, Charlton et al. 40 m BASE, ATRAP, Fundamental properties of the antiproton ALPHA, ATRAP, Spectroscopy of 1S-2S in antihydrogen ASACUSA, ALPHA Spectroscopy of GS-HFS in ELENA - 100 keV antihydrogen ASACUSA AD - 5.3 MeV Antiprotonic helium spectroscopy ALPHA, AEgIS, GBAR ATRAP Test free fall/equivalence principle with antihydrogen M. Hori, J. Walz, Prog. Part. Nucl. Phys. 72, 206-253 (2013). Antihydrogen • Idea: Investigate the electro-magnetic spectrum of antihydrogen • Problem: antihydrogen does not exist -> needs to be synthesized First Demonstration: M. Amoretti, Nature 419 (2002) 456, ATHENA collaboration • Problem: ...and trapped...being the difficult part because 퐸 electric force: 퐹Ԧ = 푞 ∙ 훻휙 = 1000퐾 푡표 100000퐾 푘퐵 typical trap depth ATRAP magnetic force: 퐹Ԧ = 휇 ∙ 훻퐵 퐸 푒 = 0.1퐾 푡표 0.5퐾 푘퐵 • Alternative: Produce antihydrogen by antiproton/positronium interaction Antihydrogen Physics • Electronic Structure of Antihydrogen • GSHFS of Antihydrogen Measured by G. Gabrielse (Harvard) and Holger Mueller (Berkeley) Measured by BASE / ASACUSA 2 2 2 2 1 푚푒 16 휋 푚푒푐 훼 2 퐸푛푙푚 = 푅∞(− 2 + 푓푛푙푚 훼, , 푥푥푥 + 3 2 푟푝 ) 푛 푚푝 3푛 ℎ ATRAP 2 1 2 훼 Tests / Measurements of 푚푒푐 2 ℎ푐 • Properties of the positron 3 2 2 16 푚푝 푚푒 휇푒 휇푝 푚푒 훼 푐 • Antimatter interactions 휈퐺 = 3 푚푝 + 푚푒 푚푝 휇퐵 휇푁 ℎ • QED tests with antimatter × (1 + ∆ + ∆ + ∆ ) ATRAP • Antiprotons charge radius 푄퐸퐷 퐻퐴퐷 푆푇 Rather insensitive to the properties of the antiproton Sensitive to antiproton substucture antihydrogen milestone – trapping (2010) • After almost 10 years of R’n’D • plasma compression • evaporative plasma-cooling • autoresonance excitation HBAR simulation left bias right bias no bias PBAR simulations ATRAP At that time, about 0.7 hbar atoms per mixing cycle antihydrogen milestone – spectroscopy • since 2010 -> trapping rate increased by a factor of 20 • But how can experimentalists perform optical spectroscopy in 20 to 100 particles? Single-sided constrain: 200 p.p.t. • 2016/2017 -> trapping rate further increased • Improved detector code & more time 훎ퟏ퐒ퟐ퐒 = ퟐ ퟒퟔퟔ ퟎퟔퟏ ퟏퟎퟑ ퟎퟖퟎ. ퟑ (ퟎ. ퟔ) 퐤퐇퐳 ATRAP • Additional headroom – laser cooling / laser waist / 0- field measurements etc… ALPHA collaboration, Nature 541, 506 (2017) ASACUSA CUSP – Beam of Antihydrogen • Apparatus • Signal on antihydrogen detector • Basic idea is to conduct a Rabi type measurement of antihydrogen GSHFS production polarized beam very successful measurements on hydrogen beam demonstrated in SMI group (Widmann ATRAP et al.) 흂푯푭푺 = ퟏ, ퟒퟐퟎ, ퟒퟎퟓ, ퟕퟒퟖ. ퟒ ퟑ. ퟒ 푯풛 (ퟐ. ퟕ 풑. 풑. 풃. ) M. Diermaier et al., Nat. Commun., 8 (2017) ARTN 15749 . Penning trap Low Noise B Amp C R L radial confinement: Amp Amp FFT B B0 zˆ p p p 2 2 axial confinement: (,) z V02 c z Resonator 2 FFT currents: 1 fA -95 Axially excited, trapped antiprotons -100 -105 Modified Cyclotron Axial Motion V k -110 Motion z V -115 0 -120 Signal (dBm) Vk Magnetron Motion -125 -130 645300 645400 645500 645600 645700 Frequency (Hz) Axial z 680kHz Magnetron 8kHz ()z Modified Cyclotron 28,9MHz ATRAP Invariance-Relation Cyclotron Frequency Cyclotron frequency relates measurable quantity to 2 2 2 1 q ion B fundamental properties of cz c 2 m ion trapped charged particle Measurements in Penning traps Cyclotron Motion Larmor Precession g: mag. Moment in units of B nuclear magneton e e c B L gB m 2m L simple p p difficult 휈푐,푝ҧ 푒푝ҧ/푚푝ҧ = S. Ulmer, A. Mooser et al. PRL 106, S. Ulmer et al. PRL 107, 103002 (2011) 휈푐,푝 푒푝/푚푝 253001 (2011) ATRAP Determinations of the q/m ratio and g-factor reduce to measurements of frequency ratios -> in principle very simple experiments –> full control, (almost) no theoretical corrections required. the BASE trap RT PT CT AT • Lifetime measurement HV Electrodes Degrader Spin flip coil Electron gun Pinbase trapping of antiprotons for Reservoir Trap: Stores a cloud of antiprotons, suspends single antiprotons for measurements. > 400 days Trap is “power failure save”. antiproton lifetime limit 2 Precision Trap: Homogeneous field for frequency measurements, B2 < 0.5 mT / mm t1/2 > 10.2 a ATRAP Cooling Trap: Fast cooling of the cyclotron motion, 1/g < 4 s Sellner, S.