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(Anti)Proton Mass and Magnetic Moment

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(Anti)Proton Mass and Magnetic Moment FFK Conference 2019, Tihany, Hungary Precision measurements of the (anti)proton mass and magnetic moment Wolfgang Quint GSI Darmstadt and University of Heidelberg on behalf of the BASE collaboration spokesperson: Stefan Ulmer 2019 / 06 / 12 BASE – Collaboration • Mainz: Measurement of the magnetic moment of the proton, implementation of new technologies. • CERN Antiproton Decelerator: Measurement of the magnetic moment of the antiproton and proton/antiproton q/m ratio • Hannover/PTB: Laser cooling project, new technologies Institutes: RIKEN, MPI-K, CERN, University of Mainz, Tokyo University, GSI Darmstadt, University of Hannover, PTB Braunschweig C. Smorra et al., EPJ-Special Topics, The BASE Experiment, (2015) WE HAVE A PROBLEM mechanism which created the obvious baryon/antibaryon asymmetry in the Universe is not understood One strategy: Compare the fundamental properties of matter / antimatter conjugates with ultra-high precision 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 Limits on Exotic Physics • Experiments test the Standard Model for exotic interactions 0 ! " #$%&'( ! Dirac equation CPT-odd modifications )*$%&'( !+#$%&'( +! V. A. Kostelecky, N. Russell, → + + 0801.0287v10 (2017). • Boson field exclusively coupling to antimatter Δ , Single particles in Penning traps test the SM at an energy resolution of 10 -24 to 10 -26 GeV sensitive: comparisons of particle/antiparticle magnetic moments in traps 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 -> Resistive cooling -> 0.000 3 eV time we bridge 14 orders of -> Feedback cooling -> 0.000 09 eV magnitude The BASE Apparatus at CERN RT: Reservoir trap RT PT CT AT PT: Precision trap CT: Cooling trap AT: Analysis trap HV Electrodes 7 Degrader Spin flip coil Electron gun Pinbase Main Tool: Penning Trap r B r radial confinement: = ˆ B B0 z Invariance-Relation ρ2 Φρ =2 − axial confinement: ( ,z ) Vc0 2 z 2 2 2 2 ν= ν+ + ν − + ν r c z B Vk V Modified Cyclotron Motion Axial Motion 0 Cyclotron Frequency V ν k z 1 q ν ν = ion B + c π 2 m ion Magnetron Motion ν − Φ(z ) ν = Axial z 680 kHz Magnetron ν − = 8 kHz Modified Cyclotron ν + = 28,9 MHz Proton/Antiproton Charge-to-Mass Comparison S. Ulmer et al., Nature 524 , 196 (2015) Measurements in Penning traps Cyclotron Motion Larmor Precession r g: magnetic moment in units of B nuclear magneton ω = e e c B ω = g B hω m L 2m L simple p p difficult ,-,./ 0./1./ S. Ulmer, A. Mooser et al. PRL 106, S. Ulmer, A. Mooser et al. PRL 107, 253001 (2011) 103002 (2011) ,-,. 0.1. 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. Frequency Measurements • Measurement of tiny image currents induced in trap electrodes -95 Low Noise Axially excited, trapped antiprotons Amp -100 -105 C R L -110 p p p Amp Amp FFT -115 -120 Signal Signal (dBm) Resonator FFT -125 -130 645300 645400 645500 645600 645700 currents: 1 fA Frequency (Hz) • In thermal equilibrium: – Particles short noise in parallel – Appear as a dip in detector spectrum – Width of the dip -> number of particles 2 1 R q ∆ν = ⋅ N 2π m D H. Nagahama et al., Rev. Sci. Instrum. 87, 113305 (2016) Measurement configuration Extract antiprotons and H - ions, compare cyclotron frequencies Park Precision Park Reservoir electrode trap electrode trap Measure , & ,J K,- antiproton H- ion 34,56 9:1;56 =12? 9:1;56 2 x 34,78 9:1;78 =12? 9:1;78 Measure ,& ,J K,- I A BC BD E5FG,78 =H 8 91 " 2 " ; Comparison of H-/antiproton cyclotron frequencies: 7 5 5 5 5 5 One frequency ratio per 4 minutes with ~ 6 ppb uncertainty Rtheo = 1.001 089 218 754 2(2) G. Gabriesle et al., PRL 82 , 3199 (1999). 12 Proton to Antiproton Q/M: Physics 9U1V;W6 "1 1 69 R 10 SZI 9U1V;W • In agreement with CPT conservation • Exceeds the energy resolution of 6521 frequency ratios previous result by a factor of 4. S. Ulmer, et al., Nature 524 , 196 (2015) • Constrain of the gravitational anomaly for antiprotons: 10 sidereal day 20 8 L-,. L-,./ I -9 39EN 1; O1P L-,. 6 - 1)/10 0 theo 4 /R Our 69 ppt result sets exp (R 2 a new upper limit of -20 (a.u.) Output Lock-In 0 ST 0 4 8 12 16 20 24 10000 100000 EN 1 Q 8.7 R 10 Time (h) Time (s) • Set limit of sidereal (diurnal) variations in • Conclusion: proton/antiproton charge-to-mass ratios Matter and Antimatter clocks run at the same frequency to < 0.72 ppb/day hω L Spin up Very very Continuous Stern hard work Gerlach Effect [./ ]./ 0./1./ , Spin down ^ [\ 2 0.1. ,- Straight- Image Current foward Measurements r B 14 Larmor Frequency – extremely hard Measurement based on continuous Stern-Gerlach effect . Energy of magnetic dipole in _` 9a. b =; magnetic field Frequency Measurement I Leading order magnetic field I d Spin is detected and analyzed via = =H " =I 9c ; correction 2 an axial frequency measurement This term adds a spin dependent quadratic axial potential -> Axial frequency becomes a function of the spin state a.=I =I Δ3e f g. .3 3 - Very difficult for the proton/antiproton system. I =Ie 0.3 i1 - Most extreme magnetic conditions ever applied to single particle. S. Ulmer, et al. PRL 106, 253001 (2011) j,e170 lc Single Penning trap method is limited to the ppm level Next Step: The Double Penning-Trap Method 0.6 0.5 0.4 0.3 0.2 0.1 spin probability flip spin 0.0 -0.1 -0.003 0.000 0.003 0.006 0.009 0.012 ν ν L/ c 0.6 0.5 0.4 0.3 0.2 0.1 0.0 spin flip probability probability flip spin -0.1 -0.002 0.000 0.002 0.004 0.006 0.008 0.010 0.012 ν /ν L c 1.) measure cyclotron , Initialize the spin state 4 2.) drive spin transition at ,mn particle transport analyze the spin state 0.4 0.4 0.4 0.4 0.2 spin up spin up 0.2 0.2 spin up 0.2 spin up (Hz) (Hz) (Hz) (Hz) z,0 z,0 z,0 z,0 ν ν ν ν 0.0 0.0 0.0 0.0 no spin-flip in PT spin flipped in PT -0.2 -0.2 -0.2 -0.2 spin down axial - frequency axial axial - frequency axial axial - frequency axial spin down spin down - frequency axial spin down -0.4 -0.4 -0.4 -0.4 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 2 4 6 8 10 12 measurement measurement measurement measurement measures spin flip probability as a function of the drive frequency in the homogeneous magnetic field of the precision trap The holy -grail : single antiproton spin flips C. Smorra et al., Phys. Lett. B 769, 1 (2017) • First non-destructive observation of single antiproton spin quantum transitions. The Magnetic Moment of the Antiproton 3000-fold improvement in g factor difference G. Schneider et al. , Science 358 , 1081 (2017) op ]./ ]. [\ q. rsq tur vuu wq 9tq; yH q . 2 2 2 op6 q. rsq tur vuu x 9uq; q C. Smorra et al. , Nature 550 , 371 (2017) 18 The Antiproton Magnetic Moment A milestone measurement in antimatter physics Mainz effort started BASE approved ASACUSA 1E-3 exotic atoms ATRAP ) BASE pbar +g single Penning traps p 1E-6 { > 3000 )/(g pbar -g BASE multi-Penning traps p 1E-9 { reached proton limit (BASE Mainz) 2(g principal limit of current method 1E-12 1985 1990 1995 2000 2005 2010 2015 2020 CERN COURIER, 3 / 2018. C. Smorra et al., Nature 550 , 371 (2017). year BASE achievements since 2011 Observation of spin flips with Most precise proton Precise CPT test with baryons: Most precise antiproton comparison of cyclotron frequencies a single trapped proton g-factor measurment g-factor measurment S. Ulmer, et al., Nature 524, 196 (2015) H. Nagahama, et al., Nature Comms. 8, 14084 (2017) C. Smorra et al. , Nature 550 , 371 (2017) S. Ulmer, et al., PRL 106, 253001 (2011) A. Mooser, et al., PRL 110, (2013) 9U1V; 1 " W6 1 69 R 10 SZI Application of the double 9U1V;W Penning-trap technique g/2 = 2.792 846 5 (23) g/2 = 2.792 847 350 (9) Rexp,c = 1.001 089 218 755 (64) (26) A. Mooser et al. , Nature 509 , 596 (2014). To be improved by another First direct high precision factor of 10 to 100 Sixfold improvement compared to measurement of the proton previous measurement magnetic moment.
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