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

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

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

7. muon (g-2) storage ring Muon lifetime t  = 64.4  s (g-2) period t a = 4.37  s Cyclotron period t C = 149 ns

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

9. Storage Ring Cross Section Field in ppm

10. 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.

11. Bill Marciano presentation to P5 Committee

19. A (g-2)  Experiment to ± 0.25 ppm Precision –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

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

21. E969 New Baseline – 0.25 ppm total error Systematic error goals: –for  a : 0.1 ppm –for  p : 0.1 ppm Statistical error goal: –for  a : 0.2 ppm Total Error Goal: –a  : 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

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

23. 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

24. Systematic uncertainty (ppm)1998199920002001E969 Goal Magnetic field –  p 0.50.40.240.170.1 Anomalous precession –  a 0.80.30.310.210.1 Statistical uncertainty (ppm)4.91.30.620.660.2 Total Uncertainty (ppm)5.01.30.730.720.25 Summary of goals

25. 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.