Yingchuan Li Weak Mixing Angle and EIC INT Workshop on Pertubative and Non-Pertubative Aspects of QCD at Collider Energies Sep. 17th 2010

22 BNL LDRD Electroweak Physics with an Electron-Ion Collider Deshpande, Kumar, Marciano, Vogelsang STUDY GOALS DIS & Nuclear Structure Functions ( ,Z,W) (Beyond HERA) A RL, sin 2  W (Q 2 ), Radiative Corrections, “New Physics” Lepton Flavor Violation: eg ep  X

Outline 3 Summary. Why is EW precision physics important? The past, present, and future (EIC) of

4 Standard Model 4 SM of particle physics  EW sector: still not sure about how EW symmetry breaking happens  Strong sector: right and complete, hard to solve; Higgs mechanism

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

66 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! See talk by Del Duca on Wed.

777 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 !

8888 EW precision tests: three best measured Z boson mass: Muon life time Fine structure constant: Electron anomalous magnetic moment Fermi constant: LEP

99999 The hunt for Correct? Prediction within SM Z-pole experiment measurements: 3 sigma difference!

10 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?

11 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!

12 Other evidence of Low energy measurements probe 4-fermion interactions:

13 Other evidence of : neutrino scattering Neutrino-nucleon DIS: Neutrino-lepton elastic scattering:  CHARM II:  probe  Paschos-Wolfenstein ratio  NuTeV: Rad. Corr.? Nuclear charge symmetry breaking?  probe

14 Other evidence of : Atomic PV Weak charge:  SM:  2009: Consistent with Z pole measurement!  1990:  1999:  2008:

15 Other evidence of : Moller scattering E158 at SLAC:  Meaure to 12%, extract to 0.6% Establish the running of mixing angle (together with APV) to 6 sigma.  Pol. Electron (E=50 GeV) on fixed target:

16

17 Future effort to nail Goal: 0.1% accuracy Polarized ep & eD collider; QWEAK exp. At JLAB: ep ep; Polarized Moller at JLAB: ee ee; Polarized eD (fixed target) DIS at JLAB (6 & 12 GeV);

18 Future effort: QWEAK & Moller Moller at JLAB:  Measure to 2.5%, extract to 0.1%  Polarized electron beam:  Electron on fixed target after 12 GeV upgrade; QWEAK at JLAB:  Electron (E=1.1 GeV) on fixed target:  Meaure to 4%, extract to 0.3%

19 Plot taken from proposal for JLAB Moller scattering

20 Future effort: eD DIS eD(p) collision DIS:  High luminosity:  Larger asymmetry at higher Q-square;  Lower luminosity ( );  Both electron and deuteron (proton) are polarized; eD (fixed target) DIS:  Advantage: extract

21 E-Ion collider: double asymmetry Both e & p (D) polarized: Polarized p or D: Polarized e:  Effective polarization: Smaller! Larger!

22 Summary The EIC may add new twist to it! Another future measurement of with 0.1% precision is demanded. The most precise (0.1%) measurement at Z pole of still has 3 sigma difference. Precision tests are very important in revealing the physics behind EW symmetry breaking among other things. Thank you !!!