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Muon (g-2) to 0.20 ppm

Muon (g-2) to 0.20 ppm. P969. B. Lee Roberts Representing the new g-2 collaboration: Boston, BNL, BINP, Cornell, Illinois, James Madison, Kentucky , KVI-Groningen, LBL&UC-Berkeley , Minnesota, Yale. roberts@bu.edu http://physics.bu.edu/roberts.html.

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Muon (g-2) to 0.20 ppm

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  1. Muon (g-2) to 0.20 ppm P969 B. Lee Roberts Representing the new g-2 collaboration: Boston, BNL, BINP, Cornell, Illinois, James Madison, Kentucky, KVI-Groningen, LBL&UC-Berkeley, Minnesota, Yale roberts@bu.edu http://physics.bu.edu/roberts.html B. Lee Roberts, BNL PAC9 September 2004

  2. This is a new collaboration built on the foundation of E821 • Core of our expertise from E821 remains • New institutes have joined and we are actively recruiting additional collaborators • Our precision storage ring remains the centerpiece of the experiment B. Lee Roberts, BNL PAC9 September 2004

  3. Standard Model Value for (g-2)from virtual radiative processes B. Lee Roberts, BNL PAC9 September 2004

  4. Ongoing worldwide effort to improve knowledge of … • Lowest order hadronic contribution • Hadronic light-by-light B. Lee Roberts, BNL PAC9 September 2004

  5. 1st-order hadronic from e+e- annihilation and t decay B. Lee Roberts, BNL PAC9 September 2004

  6. Update: August 2004 (ICHEP) • Precise e+e-and t data are incompatible ... especially at energies above the r • New KLOE data using radiative return support the CMD2 e+e- data • Isospin correction issues for the t data remain unresolved B. Lee Roberts, BNL PAC9 September 2004

  7. Pion Formfactor 45 45 CMD-2 KLOE 40 35 30 25 20 15 • Comparison with CMD-2 in the Energy Range 0.37 <sp<0.93 GeV2 10 (375.6  0.8stat  4.9syst+theo) 10-10 KLOE 1.3% Error (378.6  2.7stat  2.3syst+theo) 10-10 0.9% Error 5 CMD2 0 • At large values of sp (>mr2) KLOE is consistent with CMD and therefore • They confirm the deviation from t-data! • . sp [GeV2] 0.4 0.5 0.6 0.7 0.8 0.9 KLOE, CMD2 Data on R(s) 2pcontribution to amhadr • KLOE has evaluated theDispersions Integral for the 2-Pion-Channel in the Energy Range0.35 <sp<0.95 GeV2 ampp = (388.7  0.8stat  3.5syst  3.5theo) 10-10 Courtesy of G. Venanzone B. Lee Roberts, BNL PAC9 September 2004

  8. A. Höcker at ICHEP04 B. Lee Roberts, BNL PAC9 September 2004

  9. aμ is sensitive to a wide range of new physics • muon substructure • anomalous couplings • SUSY (with large tanβ ) • many other things (extra dimensions, etc.) B. Lee Roberts, BNL PAC9 September 2004

  10. Where we came from: B. Lee Roberts, BNL PAC9 September 2004

  11. Today with e+e- based theory: All E821 results were obtained with a “blind” analysis. B. Lee Roberts, BNL PAC9 September 2004

  12. Discrepancy with e+e- based theory • What might this mean? • New physics or a fluctuation? • Consider a SUSY example B. Lee Roberts, BNL PAC9 September 2004

  13. In CMSSM, am can be combined with b sg, cosmological relic density Wh2, and LEP Higgs searches to constrain c mass Excluded by direct searches Allowed 2s band am(exp)– am(e+e- thy) Preferred Excluded for neutral dark matter Courtesy K.Olivebased on Ellis, Olive, Santoso, Spanos B. Lee Roberts, BNL PAC9 September 2004

  14. The CMSSM plot with error on Dam of 4.6 x 10-10(assuming better theory and a new BNL g-2 experiment) Dam=24(4.6) x 10-10 (discrepancy at 6 s) Dam = 0 (4.6) x 10-10 Current Discrepancy Standard Model B. Lee Roberts, BNL PAC9 September 2004

  15. Discrepancy with e+e- based theory • What might this mean? • New physics or a fluctuation? • Consider a SUSY example • Either way, the muon (g-2) provides a wonderful test of the standard model B. Lee Roberts, BNL PAC9 September 2004

  16. With a discrepancy like this… • You’ve got to keep working • Either you confirm the discrepancy or • You show it’s not there… • But you can’t ignore it! • The stakes are just too high. • That’s why we’re here today. B. Lee Roberts, BNL PAC9 September 2004

  17. The experimental concept remains the same: B. Lee Roberts, BNL PAC9 September 2004

  18. And so does the ring B. Lee Roberts, BNL PAC9 September 2004

  19. Strategy of the improved experiment • More muons – E821 was statistics limited sstat = 0.46 ppm, ssyst = 0.3 ppm • Backward-decay, higher-transmission beamline • New, open-end inflector • Upgrade detectors, electronics, DAQ • Improve knowledge of magnetic field B • Improve calibration, field monitoring and measurement • Reduce systematic errors on ωa • Improve the electronics and detectors • New parallel “integration” method of analysis B. Lee Roberts, BNL PAC9 September 2004

  20. Near side Far side Pedestal vs. Time E821: Forward decay beam Pions @ 3.115 GeV/c Decay muons @ 3.094 GeV/c B. Lee Roberts, BNL PAC9 September 2004

  21. Expect for both sides P969: Backward decay beam Pions @ 5.32 GeV/c Decay muons @ 3.094 GeV/c No hadron-induced prompt flash Approximately the same muon flux is realized B. Lee Roberts, BNL PAC9 September 2004

  22. Muon capture and transmission in decay section will double by doubling quads E821 lattice Lattice doubled B. Lee Roberts, BNL PAC9 September 2004

  23. Improved transmission into the ring Inflectoraperture Inflector Storage ring aperture E821 Closed End P969 Proposed Open End B. Lee Roberts, BNL PAC9 September 2004

  24. Systematic Error Evolution • Field improvements will involve better trolley calibrations, better tracking of the field with time, temperature stability of room, improvements in the hardware • Precession improvements will involve new scraping scheme, lower thresholds, more complete digitization periods, better energy calibration B. Lee Roberts, BNL PAC9 September 2004

  25. B. Lee Roberts, BNL PAC9 September 2004

  26. E821: Precession Measurement B. Lee Roberts, BNL PAC9 September 2004

  27. T Method Q Method E969: Precession Measurement • Expect 5 x more rate • Segment calorimeters • 500 MHz waveform digitization • Greatly increased data volume for DAQ • Introduce parallel “Q” method of data collection and analysis • Integrate energy flow vs. time B. Lee Roberts, BNL PAC9 September 2004

  28. Fast, dense and segmented W-SciFi calorimeters • 20-fold segmentation • 0.7 cm X0 • 14%/Sqrt(E) B. Lee Roberts, BNL PAC9 September 2004

  29. Schedule • FY 2005 • R&D as funding permits • FY 2006-2007 • Construction • FY 2008 • Fall, pulse on demand, debugging • Spring, 3 week engineering run • FY 2009 • 2100 hours data collection (26 weeks @ 80 hr/wk) B. Lee Roberts, BNL PAC9 September 2004

  30. Conclusions:With a 2.7 σ discrepancy … • We can and must press ahead to the systematic limit of the technique • The considerable investment to date at BNL can be further extended by modest upgrades • We expect: 0.54 ppm → 0.2 ppm (projected) • In parallel, the theory effort continues and will improve to perhaps 0.3 ppm • Muon (g-2) continues to address the most fundamental questions in our field B. Lee Roberts, BNL PAC9 September 2004

  31. B. Lee Roberts, BNL PAC9 September 2004

  32. Systematic errors on ωa (ppm) Σ* = 0.11 B. Lee Roberts, BNL PAC9 September 2004

  33. Goal for ωpsystematic errors E969 (i) (I) (II) (III) (iv) *higher multipoles, trolley voltage and temperature response, kicker eddy currents, and time-varying stray fields. B. Lee Roberts, BNL PAC9 September 2004

  34. a(had) from hadronic decay? • Must assume CVC, no second-class currents, make the appropriate isospin breaking corrections. decay has no isoscalar piece, while e+e- does Let’s look at the branching ratio and Fπ from the two data sets: B. Lee Roberts, BNL PAC9 September 2004

  35. Tests of CVC (A. Höcker – ICHEP04) B. Lee Roberts, BNL PAC9 September 2004

  36. Comparison with e+e- theory (from ICHEP04) (from F. Teubert’s summary talk.) B. Lee Roberts, BNL PAC9 September 2004

  37. F. Teubert, ICHEP04 – E-W plenary summary talk B. Lee Roberts, BNL PAC9 September 2004

  38. (I) (II) (III) (IV) * higher multipoles, trolley voltage and temperature response, kicker eddy currents, and time-varying stray fields. Field Uncertainties - History

  39. (III) (II) (I) (IV) * higher multipoles, trolley voltage and temperature response, kicker eddy currents, and time-varying stray fields. Source of Uncertainty 1998 1999 2000 2001 Absolute Calibration 0.05 0.05 0.05 0.05 2001 Calibration of Trolley 0.3 0.20 0.15 0.09 Trolley Measurements of B0 0.1 0.10 0.10 0.05 Interpolation with the fixed probes 0.3 0.15 0.10 0.07 Inflector fringe field 0.2 0.20 - - uncertainty from muon distribution 0.1 0.12 0.03 0.03 Other* 0.15 0.10 0.10 Total 0.5 0.4 0.24 0.17 Field Shimming B. Lee Roberts, BNL PAC9 September 2004

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