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g-2: Past and Future

g-2: Past and Future. G. Bunce for the g-2 Collaboration Spin2006, Kyoto. Phys. Rev. D73, 072003 (2006) Final report of the E821 muon anomalous magnetic moment measurement at BNL

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g-2: Past and Future

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  1. g-2: Past and Future G. Bunce for the g-2 Collaboration Spin2006, Kyoto

  2. Phys. Rev. D73, 072003 (2006) Final report of the E821 muon anomalous magnetic moment measurement at BNL G.W. Bennett, B. Bousquet, H.N. Brown, G. Bunce, R.M.Carey, P. Cushman, G.T. Danby, P.T. Debevec, M. Deile, H. Deng, W. Deninger, S.K. Dhawan, V.P. Druzhinin, L. Duong, E. Efstathiadis, F.J.M. Farley, G.V. Fedotovich, S. Giron, F.E. Gray, D. Grigoriev, M. Grosse-Perdekamp, A. Grossman, M.F. Hare, D.W. Hertzog, X. Huang, V.W. Hughes, M. Iwasaki, K. Jungmann, D. Kawall, M. Kawamura, B.I Khazin, J. Kindem, F. Krienen, I. Kronkvist, A. Lam, R. Larsen, Y.Y. Lee, I. Logoshenko, R. McNabb, W. Meng, J. Mi, J.P. Miller, Y. Mizumachi, W.M. Morse, D. Nikas, C.J.G. Onderwater, Y. Orlov, C.S. Ozben, J.M. Paley, Q. Peng, C.C. Polly, J. Pretz, R. Prigl, G. zu Putlitz, T. Qian, S.I. Redin, O. Rind, B.L.Roberts, N. Ryskulov, S. Seykh, Y.K. Semertzidis, P. Shagin, Yu. M. Shatunov, E.P. Sichtermann, E. Solodov, M. Sossong, A. Steinmetz, L.R. Sulak, C. Timmermans, A. Trofimov, D. Urner, P. von Walter, D. Warburton, D. Winn, A. Yamamoto, and D. Zimmermann

  3. Magnetic moments, g-factors

  4. We measure the difference frequency between the spin and momentum precession With an electric quadrupole field for vertical focusing 0

  5. Experimental Technique Central orbit Kicker Modules R=711.2cm d=9cm Electric Quadrupoles Protons Pions Inflector (from AGS) p=3.1GeV/c Target (1.45T) Injection orbit • Muon polarization • Muon storage ring • injection & kicking • focus by Electric Quadrupoles • 24 electron calorimeters Storage ring (from Q. Peng)

  6. Muon lifetime tm = 64.4 ms (g-2) period ta = 4.37 ms Cyclotron period tC = 149 ns muon (g-2) storage ring

  7. We count high-energy electrons as a function of time.

  8. Storage Ring Cross Section Field in ppm

  9. E821 achieved 0.5 ppm and the e+e- based theory is also at the 0.6 ppm level. Both can be improved. All E821 results were obtained with a “blind” analysis.

  10. Bill Marciano presentation to P5 Committee

  11. A (g-2)m Experiment to ± 0.25 ppmPrecision –BNL E969 Collaboration R.M. Carey, I. Logashenko, K.R. Lynch J.P. Miller B.L. Roberts-Boston University; G. Bunce W. Meng, W. Morse, P. Pile, Y.K. Semertzidis -Brookhaven; D. Grigoriev B.I. Khazin S.I. Redin Yuri M. Shatunov, E. Solodov – Budker Institute; F.E. Gray B. Lauss E.P. Sichtermann – UC Berkeley and LBL; Y. Orlov – Cornell University; J. Crnkovic ,P. Debevec D.W. Hertzog, P. Kammel S. Knaack, R. McNabb – University of Illinois UC; K.L. Giovanetti – James Madison University; K.P. Jungmann C.J.G. Onderwater – KVI Groningen; T.P. Gorringe, W. Korsch – U. Kentucky, P. Cushman – Minnesota; Y. Arimoto, Y. Kuno, A. Sato, K. Yamada – Osaka University; S. Dhawan, F.J.M. Farley – Yale University

  12. world average E821 achieved 0.54 ppm and is statistics dominated. All E821 results were obtained with a “blind” analysis.

  13. E969 New Baseline – 0.25 ppm total error • Systematic error goals: • for wa: 0.1 ppm • for wp: 0.1 ppm • Statistical error goal: • for wa: 0.2 ppm • Total Error Goal: • am: 0.25 ppm Beam with 4x quadrupoles: factor 2-3 Injection magnet opened: factor 2 in stored muons Field measurement improvements Segmented calorimeters for pileup

  14. Open the superconducting injector magnet. Length = 1.7 m; Central field = 1.45T Open end prototype, built and tested →X2 Increase in Beam

  15. New segmented detectors of tungsten / scintillating- fiber ribbons to deal with pile-up • prototype under construction • bases will be gated. • new custom electronics and DAQ

  16. Summary of goals

  17. Summary • Historically (g-2) has placed a major hurdle in the path of new theories beyond the standard model. • The (g-2) result must fit with other evidence into a consistent picture of new physics. • We hope that this measurement will be pursued to even greater precision in the future, either at BNL or at the Japan Hadron Facility. I would like to thank Lee Roberts and Bill Marciano for the use of many slides.

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