Wolfgang Quint (w.quint@gsi.de)

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Penning trap measurement of the magnetic moment of the antiproton. Wolfgang Quint (w.quint@gsi.de). GSI Darmstadt, Germany. Villars Meeting, Sept. 25, 2004. m p : magnetic moment g p : g-factor s: spin m N : nuclear magneton. B. g-Factor of the antiproton. - PowerPoint PPT Presentation

Text of Wolfgang Quint (w.quint@gsi.de)

  • Wolfgang Quint (w.quint@gsi.de)GSI Darmstadt, GermanyPenning trap measurement of themagnetic moment of the antiproton

    Villars Meeting, Sept. 25, 2004

  • g-Factor of the antiprotonproton: gp = 22.792847337(29)*accuracy: 10-8antiproton: gpbar = 22.800(8)* accuracy: 10-3*Particle Data Group

  • Larmor precessionfrequency:g-Factor of the antiprotonB: magnetic field in Penning trap

  • Geonium: Single electron in a Penning trapanomaly transition(2 , )(1 , )(0 , )(nc , )(1 , )(0 , )(nc , )Electron(nc: cyclotron quantum number)(Dehmelt, Van Dyck)

  • Single antiproton in a Penning trapProton(expected accuracy)

  • Electronic detection of a single antiprotonc2-2 z2+2

  • Cyclotron resonance of a single antiprotonmeasured at LEAR,1993(G. Gabrielse,D. Phillips,W. Quint)

  • Larmor precession fre-quency of bound electron:BG-Factor of the bound electron in H-like ions new value for the electron mass

  • Quantum jumps of a single hydrogen-like ion Axial frequency depends on spin direction due to continuous Stern-Gerlach effect

  • spin has magneticmoment magnetic bottle:B(z) = B0 + B2z2magnetic energy:Emagn(z) = B0 B2z2attractive orrepulsive forceaxial frequency =f (spin directionContinuous Stern-Gerlach effect

  • precisiontrapanalysistrap Principle: Excitation of spin-flip in precision trap (homogeneous magnetic field) Detection of spin-flip in analysis trap (inhomogeneous magnetic field for spin-flip detection)Double-Trap Technique for g-Factor Measurements

  • experiment: g(12C5+) = 2.001 041 596(1) (4) theory: g(12C5+) = 2.001 041 591(7)

    statisitical error: dg/g = 210-9 total error: dg/g = 210-9 (limited by the knowledge of me)T. Beier et al., PRL 88, 011603 (2002)V. Yerokhin et al., PRL 89, 143001 (2002) Measurement of the g-factor of the bound electron with an accuracy of 7 x 10-10G-Factor of bound electronin highly charged ions

  • Parameters of g-factor experiments

    Electron(Van Dyck/Dehmelt)C5+(Mainz/ GSI)O7+(Mainz/ GSI)Antiproton(proposed)Magnetic moment gmB/2gmB/2gmB/2gmN/2

    g-Factorg = 2.00...g = 2.00...g = 2.00...g = 5.58Magnetic bottle0.15 mT/mm210 mT/mm210 mT/mm2230 mT/mm2

    Dnz due tospinflip1.3 Hz0.7 Hz0.46 Hz0.25 Hz

  • Improvement of accuracy in gpbar by six orders of magnitudeConclusions Important test of CPT invariance for baryons Measurement of the magnetic moment of the bound electron with an accuracy of 7 x 10-10. This experimental technique can be employed for the measurement of the magnetic moment of the antiproton.