1. K. Kumar, W. Marciano, Y. Li Electroweak physics at EIC - Summary of week 7 INT Workshop on Pertubative and Non-Pertubative Aspects of QCD at Collider Energies Nov. 19th 2010

2. Outline 2 Conclusion Lepton flavor violation at EIC Weak mixing angle at EIC Introduction: symmetry of SM

3. 3 Standard Model: symmetry and symmetry breaking 3 Symmetries breaking:  EW gauge symmetry breaking;  Many accidental global symmetries L, B, B-L, LF…;  QCD and EW gauge symmetries; Symmetries:  Broken discrete symmetries C, P, CP;  Dynamical chiral symmetry breaking;

4. 4 LFV: e-tau conversion (Talks by M. Gonderinger and A. Deshpande)

5. 5 Accidental symmetries of SM violated by irrelevant operators – induced by new physics L, B, B-L, LF… respected by relevant operators in SM - specific quantum numbers of SM fields global symmetries (may or may not be gauged); violated in extension of SM - new fields carrying new quantum numbers Search for BSM by search for violation of these symmetries

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7. 7 Flavor & CP problem for BSM What about the new physics scale?  high enough to suppress flavor and CP violations;  low enough to stabilize the EW breaking scale; Hunted for long time but not found (mostly involving first-two generations). Solution: treat the 3 rd generation differently “More minimal SUSY”, Cohen, Kaplan, Nelson 1996; “Warped Extra Dim.”, Randall, Sundrum 1999; Large FV and CPV associated with 3 rd generation

8. 88 LFV of tau Various processes:  Magnetic moment operator ;  e-tau conversion (e p->tau, X);  tau -> 3 e; Various operators:  4-fermion operators;  tau -> e, gamma;

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11. 11 Theoretical and experimental analysis

12. 12 Weak mixing angle at EIC (Talks by K. Kumar, W. Marciano, and YL)

13. 13 Scenarios of Higgs mechanism Higgsless models; Composite Higgs as a PGB; Fundamental Higgs: hierarchy problem  Georgi-Kaplan model;  Extra Dim;  SUSY;  Technicolor;

14. 14 To ping down the EW symmetry breaking Indirect searchs via precision tests Direct search at high energy collider  KK modes;  SM Higgs;  Low energy tests of neutral current;  SUSY particles;  other exotics; What can EIC do on this?  Z-pole measurements; Major motivation for LHC!

15. 15 EW sector with SM Higgs Three para. (g,g’,v) determine properties of EW gauge bosons  Neutral current:  Masses:  EM coupling:  Charged current: Higgs and top mass enters at loop level !

16. 16 EW precision tests: three best measured Z boson mass: Muon life time Fine structure constant: Electron anomalous magnetic moment Fermi constant: LEP

17. 17 The hunt for Correct? Prediction within SM Z-pole experiment measurements: 3 sigma difference!

18. 18 The implications of World average: Rule out most technicolor models Consistent with LEP bound (MH>114 GeV) Suggestive for SUSY (MH<135 GeV) Satisfied and happy?

19. 19 The implications of CERN result: Suggestive for technicolor models Consistent with LEP bound (MH>114 GeV) SLAC result: Suggestive for SUSY Ruled out by LEP bound (MH>114 GeV) + m W =80.398(25) GeV Very different implication! We failed to nail weak mixing angle!

20. 20 Past and currently planed experiments: Where does EIC stand?

21. 21 Weak mixing at EIC The ugly:  Large uncertainty with the polarized PDFs;  Higher asymmetry at high Q: The good:  Both beam polarized;  Low luminosity ( ) compared to fixed target experiments ; The bad:  Large uncertainty (5%) with the hadron beam polarization;

22. 22 Weak mixing at EIC How to control the systematic error? What is the required luminosity to reach specific statistical error? What are the good asymmetries?

23. 23 Single-spin asymmetries Simplified for e-d: PDF drops out for isosinglet Large x: antiquark contribution negligible, small uncertainty in PDF Large uncertainty (5%) For e-p collider:

24. 24 Effective polarization Take advantage of effective polarization:

25. 25 Double-spin asymmetry Simplified for e-d at kinematic region with y->1:

26. 26 Good asymmetries e-d collider: e-p collider:

27. 27 Preliminary MC simulation results single-spin asymmetry in e-p:

28. 28 Preliminary results on reachable precision e-p collider with polarized electron beam:

29. 29 Past, currently planed, and EIC experiments: Weak mixing probed at wide range of Q at EIC:

30. 30 Summary and outlook Precision tests are very important probe of BSM before and after LHC. Thank you !!! Many things to do  measure over a wide range of Q with statistical error similar to the Z-pole experiments and other planed low-Q experiments (JLab) ;  think about other topics; EIC has good chance to  go beyond HERA on bounds on e-tau conversion;  redo the analysis of signal selection efficiency for e-tau at EIC;  a better understanding of systematic error of PVDIS;