Summary of Muon Working Group

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1 Summary of Muon orking Group Report on B. Lee Roberts, EDM and roberts/ Department of Physics Boston University B. Lee Roberts, NP02, Kyoto, September 2002 p.1/25

2 Summary Conclusions of the orking Group e believe that exciting opportunities exist for muon physics at JKJ, and that there is substantial discovery potential in the program of muon physics which we propose. B. Lee Roberts, NP02, Kyoto, September 2002 p.2/25

3 The Program of Muon Physics: Muon EDM to Limit for experiment to 0.05 ppm. cm. from 170 kev to to branching level of PRISM facility. kev. using the B. Lee Roberts, NP02, Kyoto, September 2002 p.3/25

4 Machine Requirements These experiments (except for ) need harmonic operation of the 50 GeV synchrotron, with single bunch fast extraction, as proposed for the PRISM facility. B. Lee Roberts, NP02, Kyoto, September 2002 p.4/25

5 ' # & & # " # ( # Magnetic Moments, -Factors, etc.! "!%$ (1) - magnetic moment; is the spin.!!%$ - gyromagnetic ratio Dirac Equation Predicts In nature radiative corrections make µ Dirac g = 2 + α π µ Kusch and Foley, Schwinger, B. Lee Roberts, NP02, Kyoto, September 2002 p.5/25.

6 ) UT C E A RE PDRF QPB==? ******************* ******************* ******************* ,,,,,,,,,,,,,,,,,,,,,, / /../ /.. /,,,,,,,,,,,,,,,,,,,,,, ;: 9 ;: 9 >= C ;: 9 >= C FE EDB? V ;: 9 >= C <? µ JO X NM JGIH LKH B. Lee Roberts, NP02, Kyoto, September 2002 p.6/25 Theory for Muon + + µ µ S >= X CAB? 8 µ 7 8 µ µ. / µ AB = =>@? < X X AB? µ µ µ ν µ µ µ AF = = P X

7 from Dispersion Theory X X X X X X X X [ Z Y m g $ $ $ $ ` p o n $ # r (3) τ ν τ e+ π + π e µ π 0 π -class Use of -decays Isospin, CVC, no currents, only isovector current. \ c # `ba ^@_ &]\ dfe (2) jlk ih ^@_ u st p r q ^@o r q B. Lee Roberts, NP02, Kyoto, September 2002 p.7/25

8 New Physics Contribution? substructure? µ m 2 a µ = µ 2 Λ Λ _ > 5 Gev anomalous gauge boson coupling? µ ν µ µ Triple Gauge Vertex g = 2? boson substructure? B. Lee Roberts, NP02, Kyoto, September 2002 p.8/25

9 v t _ v t _ t v _ { z x x y d v t _ ~} } y Supersymmetry ν χ χ + µ µ 0 χ µ µ µ µ & \ is sensitive to SUSY with large toy model with equal and large w : (4) & \ o w (5) o w B. Lee Roberts, NP02, Kyoto, September 2002 p.9/25

10 The Experimental Technique ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ Š Š Š Š Š Š Š Š Š Ideal Orbit Kicker Modules π + + µ p = 3.1 GeV/c Pions µ ν Inflector Injection Orbit Storage Ring Target Protons from AGS = 77 mm ~ = 10 mrad β ~ B dl = 0.1 Tm ~ β B. Lee Roberts, NP02, Kyoto, September 2002 p.10/25

11 !! # Œ! Ž! { ' Ž ~ # # Spin Precession! {!% &\ & \! { { Ž m \ and &]\ B. Lee Roberts, NP02, Kyoto, September 2002 p.11/25

12 Ž & Vector relationship for, (not to scale) ω a ω B ω η β x B The EDM causes the spin to precess out of the plane! B. Lee Roberts, NP02, Kyoto, September 2002 p.12/25

13 The Storage Ring Magnet B. Lee Roberts, NP02, Kyoto, September 2002 p.13/25

14 The Average Field is: y [cm] ppm field contours 1998 (1999) y [cm] ppm field contours x [cm] x [cm] In 1999 Quadrupole in 2000 ppm of ppm of. Perfect for NuMass!, B. Lee Roberts, NP02, Kyoto, September 2002 p.14/25

15 Measurements of (9.4 ppm) CERN (10 ppm) CERN µ (13 ppm) E821 (97) µ + (5 ppm) E821 (98) µ + (1.3 ppm) (0.7 ppm) E821 (99) E821 (00) µ + µ + µ + Theory (DH98) a µ B. Lee Roberts, NP02, Kyoto, September 2002 p.15/25

16 Measurements of 220 Brookhaven Muon g-2 Data Standard Model Prediction BNL 00 orld Average BNL a µ BNL 98 DH DEHZ ee 160 B. Lee Roberts, NP02, Kyoto, September 2002 p.15/25

17 Measurements of 220 Brookhaven Muon g-2 Data Standard Model Prediction BNL 00 orld Average a µ 180 BNL 99 DEHZ τ 180 BNL 98 DH DEHZ ee 160 B. Lee Roberts, NP02, Kyoto, September 2002 p.15/25

18 hat if SUSY were true and we knew the Masses? Then the SUSY contribution to would become part of the new standard model. B. Lee Roberts, NP02, Kyoto, September 2002 p.16/25

19 v t _ hat if SUSY were true and we knew the Masses? Then the SUSY contribution to would become part of the new standard model. The measurement of would provide one of the cleanest measurements of. B. Lee Roberts, NP02, Kyoto, September 2002 p.16/25

20 If the difference with theory means non-sm physics: There should be an electric dipole moment ( a new -violation) produced by this same non-standard model physics. If it s SUSY, the EDM comes from the part of the amplitude producing discrepancy. Model predictions vary between cm. and -factory results show the need to go to flavor conserving process where SM -violation is very small to see new physics. B. Lee Roberts, NP02, Kyoto, September 2002 p.17/25

21 { y š y y y EDM Limits Particle Present EDM Limit Standard Model (e-cm) Value (e-cm) n d { (CERN) (E821) New Estimated Dedicated Experiment B. Lee Roberts, NP02, Kyoto, September 2002 p.18/25

22 &! If we could turn off e.g. with a radial field, the spin would rise monotonically with time. v E E µ + µ + θ µ + 2θ B B 0 (a) 1 Time [arb.] 2 B. Lee Roberts, NP02, Kyoto, September 2002 p.19/25

23 The Muon Neutrino Mass Experiment Use storage ring as a spectrometer, inject pions, and measure the forward muons. Using several tricks, one should be able to reduce the direct limit from 170 kev, to kev. ith emulsions as have been pioneered here in Japan, maybe to 1 kev. B. Lee Roberts, NP02, Kyoto, September 2002 p.20/25

24 { Summary At JKJ one could improve on. by about B. Lee Roberts, NP02, Kyoto, September 2002 p.21/25

25 { Summary At JKJ one could improve on. by about A sensitive search for a muon EDM cm with a substantial chance for success for finding one is possible. B. Lee Roberts, NP02, Kyoto, September 2002 p.21/25

26 { Summary At JKJ one could improve on. by about A sensitive search for a muon EDM cm with a substantial chance for success for finding one is possible. The direct limit on the muon neutrino mass can be improved by a factor of 20 to 100. B. Lee Roberts, NP02, Kyoto, September 2002 p.21/25

27 { œ # Summary At JKJ one could improve on. by about A sensitive search for a muon EDM cm with a substantial chance for success for finding one is possible. The direct limit on the muon neutrino mass can be improved by a factor of 20 to 100. The large harmonic, and single bunch fast extraction are very important to reach these new goals. B. Lee Roberts, NP02, Kyoto, September 2002 p.21/25

28 Conclusions Frontier physics with muons can be done using the unique facility which is being built in Japan. B. Lee Roberts, NP02, Kyoto, September 2002 p.22/25

29 Conclusions Frontier physics with muons can be done using the unique facility which is being built in Japan. There is substantial discovery potential which addresses the fundamental questions in the field. B. Lee Roberts, NP02, Kyoto, September 2002 p.22/25

30 Conclusions Frontier physics with muons can be done using the unique facility which is being built in Japan. There is substantial discovery potential which addresses the fundamental questions in the field. Come join us to do it! B. Lee Roberts, NP02, Kyoto, September 2002 p.22/25

31 Experimental Technique for Ÿž B. Lee Roberts, NP02, Kyoto, September 2002 p.23/25

32 The Endpoint Region after Cuts Distance difference between π and highest energy µ counts (mm) B. Lee Roberts, NP02, Kyoto, September 2002 p.24/25

33 v v u_ s u # Time Spectrum, GeV ppm 4 Billion Positrons with E> 2 GeV Number of Positrons/149ns µs µs µs µs µs µs µs µs Time µs µs B. Lee Roberts, NP02, Kyoto, September 2002 p.25/25

(Lifetime and) Dipole Moments

Precision Measurements with the Muon: (Lifetime and) Dipole Moments B.L. Roberts Department of Physics Boston University roberts @bu.edu http://physics.bu.edu/roberts.html B. Lee Roberts, APPEAL07, CAST,