1. LFV and LUV at CLEO Lepton-Flavor Violation: –Probe non-SM physics and/or SM extensions –Here, report on Upsilon(1S)   Complements other studies MEG (   e  ) @PSI Many searches for    Lepton UniVersality: –“Sometimes a lepton is just a lepton” (Freud [sic]) –If not, then something interesting!

2. LFV in the charged sector d t b 1 2 3 Generation Quarks Leptons   e c u s e   Energy Quark mixing (CKM) Neutrino Oscillations Mixing in the charged Lepton sector?

3. Lepton Flavor Violation Sakharov Conditions for Matter- Universe: –Baryon Number Violation (B [L=lepton no.]) –C-parity (CP-parity) Violation –Universe non-thermal for some time B, L “accidental symmetries”, but B-L good QN

4. LFV summary:  decay 1940 1950 1960 1970 1980 1990 2000 2010 10 -1 10 -2 10 -3 10 -4 10 -5 10 -6 10 -7 10 -6 10 -9 10 -10 10 -11 10 -12 10 -13 10 -14 10 -15  → e   → eA  → eee SUSY SU(5) BR(   e  ) = 10 -13   A  eA = 10 -15  BR(     ) = 10 -8 SUSY SU(5) BR(   e  ) = 10 -13   A  eA = 10 -15  BR(     ) = 10 -8 Current Limits: BR(  +  e +  ) < 1.2 x 10 -11 (MEGA) 1)  Ti → eTi < 7 x 10 -13 (SINDRUM II) 2) Current Limits: BR(  +  e +  ) < 1.2 x 10 -11 (MEGA) 1)  Ti → eTi < 7 x 10 -13 (SINDRUM II) 2) 1) hep-ex/9905013 2) A. van der Schaaf, priv. comm. BR Year “Supersymmetric parameterspace accessible by LHC” (Ritt, MEGs)

5. Upsilon Decays access a different kinematic regime!

6. Or add interactions at new scale Datta et al (PRD60, 014011, 1999: Y   l<0.01; J/p   l<6x10 -7

7. CLEO search The detector: CLEO was the first “CLEO-type” detector 10 GeV energy regime; Good resolution!

8. Experimental Search Search for Y   ;   e Off-resonance samples used for control & comparison. Primary search variables are scaled momenta of two charged tracks. Extended maximum likelihood used to evaluate event-by-event consistency with LFV

9. Signal parametrized as f(scaled electron,scaled muon momentum)

10. Known backgrounds saturate observables

11. No signal observed over background  set limits

12. Lepton Universality Here, “LUV”   (nS)  l + l - universal (if no BSM). LUV NOT statement that  (nS)  l + l - =  (mS)  l + l -. In case of Upsilon: –Y   easiest 2 Back-to-Back tracks Direct Continuum Subtraction –Y  ee coupling extracted through total Upsilon width Bhabha subtraction otherwise BIG –Here, discuss measurement of Y   + comparison with Y   and Y  ee –Very similar to Y   : straightforward ON-OFF –To minimize systematics, use consistent muon ID for both dilepton modes

13. Dielectronic widths (PRL96, 092003, 2006) NOTE: Precision measurements – typically 2%!

14. Measure tau pair xsct w/ many modes: “Expected ratio”=0.82 (phase space)

15. Compare on-off resonance yields:

16. MC to derive efficiency

17. RESULTS (relative)

18. Internal consistency

19. Absolute BF (+ratio just presented)

20. Conclusions Standard Model once again triumphs. –Although differences in dileptonic widths, resonance-to- resonance, are interesting… No indication of departures from SM, but keep looking… No more Upsilon resonance data  Resonance program for J/psi underway.

22. LFV in the SM vs. SUSY (m  eg) SM SUSY probes slepton mixing matrix ≈ 10 -12 LFV in the SM is immeasurable small SUSY models predicts BR(  → e  ) just below the current experimental limit of 1.2 x 10 -11 Decay  → e  is free of “SM background” (no hadronic corrections) LFV in the SM is immeasurable small SUSY models predicts BR(  → e  ) just below the current experimental limit of 1.2 x 10 -11 Decay  → e  is free of “SM background” (no hadronic corrections) The discovery of  → e  would by physics beyond the SM