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Electroweak Physics at the EIC 1. WEAK NC PARITY VIOLATION AND NEW PHYSICS

Electroweak Physics at the EIC 1. WEAK NC PARITY VIOLATION AND NEW PHYSICS i) APV vs Pol Electron Scattering (A RL ) ii) QWEAK(ep), Moller(ee), DIS(eN  eX) , … 2. Preliminary EIC requirements

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Electroweak Physics at the EIC 1. WEAK NC PARITY VIOLATION AND NEW PHYSICS

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  1. Electroweak Physics at the EIC 1. WEAK NC PARITY VIOLATION AND NEW PHYSICS i) APV vs Pol Electron Scattering (ARL) ii) QWEAK(ep), Moller(ee), DIS(eNeX), … 2. Preliminary EIC requirements For Competitive ARL Program ~100fb-1 (K. Kumar et al.; R. Holt) eg 1034cm-2s-1x107s William J. Marciano Oct 21, 2009

  2. BNL LDRD FY2010 (Funded)Electroweak Physics with an Electron-Ion ColliderDeshpande, Kumar, Marciano, Vogelsang STUDY GOALS • DIS & Nuclear Structure Functions (,Z,W) (Beyond HERA) L(HERA)=1031cm-2s-1  >1033cm-2s-1 • ARL,sin2W(Q2), Radiative Corrections, “New Physics” requires roughly 100fb-1(1034cm-2s-1) • Lepton Flavor Violation: eg epX requires roughly one inverse attobarn=1000fb-1! To be competitive with BR(eX)~10-10 Rates & Backgrounds Need Thorough Study

  3. SOME ISSUES What are the Machine and Detector Requirements? “New Physics Effects” (Z’, Leptoquarks, SUSY, S&T, LFV…) sin2W(Q2) Running Weak Mixing Angle Inclusion of Electroweak Radiative Corrections (Important?) High Precision & Polarization(0.5%?, 0.25%?) Nucleon vs Nuclear Asymmetries (EMC Effect, CSV?) Proton & Deuteron Polarization (Spin Content-Peff?) Various Issues That Need Thorough Study

  4. 1) PV Weak Neutral Currents(Past, Present and Future) • The SU(2)LxU(1)Y Weinberg-Salam Model: weak neutral current coupling g/cosWZf(T3f-2Qfsin2W -T3f5)f T3f=1/2, Qf=electric charge A New Form of Parity Violation! -Z Interference  Parity Violation Everywhere! Depends on sin2W

  5. Atomic Parity Violation (APV) • QW(Z,N) =Z(1-4sin2W)-N Weak Charge W=Weak Mixing Angle QW(p)=1-4sin2W0.08 QW(209Bi83) = -43 -332sin2W =-126 Bi Much Larger but Complicated Atomic Physics Originally APV not seen in Bi  SM Ruled Out? (Later seen: Tl, Bi, Cs…) QW(133Cs55)=-23-220sin2W =-73.16(34) Recent(2008) Atomic Theory Improvement

  6. 1978 SLAC Polarized DIS eD Asymmetry (Prescott, Hughes…) e+De+X -Z Interference ARL= R-L/R+L2x10-4Q2GeV-2(1-2.5sin2W) ~10-4Expected Exp. Gave ARLexp=1.5x10-4sin2W=0.21(2) Confirmed SU(2)LxU(1)Y SM! ±10% Determination of sin2W Precision!

  7. Seemed to agree with GUTS (SU(5), SO(10)…) sin2W=3/8 at unification =mX2x1014GeV sin2W(mZ)MS=3/8[1-109/18ln(mX/mZ)+…] 0.21! (Great Desert?) But later, minimal SU(5) ruled out by proton decay exps (pe+)>1033yr mX>5x1015GeV SUSY GUT UnificationmX1016GeV p1035yr For mSUSY(TeV) sin2W(mZ)MS=0.232 (Good Current Agreement!)

  8. 1980s - Age of EW Precision sin2W needed better than 1% determination Renormalization Prescription Required EW Radiative Corrections Computed Finite and Calculable: DIS N, ve, APV (A. Sirlin &WJM) mZ, mW, Z, ALR,AFB Define Renormalized Weak Mixing Angle:sin2WR sin20W=1-(m0W/m0Z)2=(e0/g0)2 Natural Bare Relation sin2W1-(mW/mZ)2 On Shell Definition, Popular in1980s Induces large (mt/mW)2 corrections Now Largely Abandoned sin2W()MSe2()MS/g2()MS Good for GUT running No Large RC Induced Theoretically Nice/ But Unphysical

  9. sin2Wlep =Z coupling at the Z pole very popular at LEP = sin2W(mZ)MS+0.00028 (best feature) sin2W(Q2) = Physical Running Angle Continuous Incorporates Z mixing loops: quarks, leptons, W Precision measurements at the Z Pole (e+e-Zff) Best Determinations sin2W(mZ)MS = 0.23070(26) ALR(1-4sin2W) (SLAC) sin2W(mZ)MS = 0.23193(29) AFB(bb) (CERN) (3 sigma difference!) World Average: sin2W(mZ)MS=0.23125(16) IS IT CORRECT?

  10. -1=137.035999, G=1.16637x10-5Gev-2,mZ=91.1875GeV + mW=80.398(25)GeVsin2W(mZ)MS = 0.23104(15) Implications: 114GeV<mHiggs<150GeV. New Physics Constraints From: mW, sin2W, ,& G S=ND/6 (ND=# of heavy new doublets, eg 4th generationND=4) mW*= Kaluza-Klein Mass (Extra Dimensions) GG(1+0.0085S+O(1)(mW/mW*)2+…) sin2W(mZ)MS S ND&mW* Average 0.23125(16) +0.11(11) 2(2), mW*3TeV ALR 0.23070(26) -0.18(15) (SUSY) AFB(bb) 0.23193(29) +0.46(17) 9(3)! Heavy Higgs, mW*~1-2TeV Very Different Interpretations. We failed to nail sin2W(mZ)MS!

  11. What about low energy measurements? • DIS  Scattering: R(NX)/(NX) Loop Effects  mt heavy! (Currently 173GeV) Early sin2W(mZ)MS=0.233SUSY GUTS NuTeV sin2W(mZ)MS=0.236(2) High? Nuclear-Charge Symmetry Violation? Radiative Corrections? Other?

  12. Atomic Parity Violation Strikes Back 1990 QW(Cs)exp=-71.04(1.38)(0.88) C. Wieman et al. Electroweak RCQW(Cs)SM=PV(-23-220PV(0)sin2W(mZ)MS) =-73.19(3) 1999 QW(Cs)exp=-72.06(28)(34) Better Atomic Th. 2008 QW(Cs)exp=-72.69(28)(39)sin2W(mZ)MS=0.2290(22) 2009 QW(Cs)exp=-73.16(28)(20)sin2W(mZ)MS=0.2312(16)! 0.5%  Major Constraint On “New Physics” QW(Cs)=QW(Cs)SM(1+0.011S-0.9(mZ/mZ)2+…) eg S=0.00.4 mZ>1.2TeV, leptoquarks, Anapole Moment …

  13. Radiative Corrections to APV (eN Interaction) QW(Z,N)= PV(-N+Z(1-4PVsin2W(mZ)MS) PV=1-/2(1/s2+4(1-4s2)(ln(mZ/M)2+3/2)+….)0.99 PV(0)=1-/2s2((9-8s2)/8s2+(9/4-4s2)(1-4s2)(ln(mZ/M)2+3/2) -2/3(T3fQf-2s2Qf2)ln(mZ/mf)2+…)1.003 s2sin2W(mZ)MS=0.23125, M=Hadronic Mass Scale Radiative Corrections to APV small & insensitive to hadronic unc. Same Corrections Apply to elastic eN scattering as Q20, Ee<<mN

  14. E158 at SLAC Pol eeee Moller)Ee50GeV on fixed target, Q2=0.02GeV2 ALR(ee)=-131(14)(10)x10-9  (1-4sin2W) EW Radiative Corrections -50%! (Czarnecki &WJM) Measured to 12% sin2W to 0.6% sin2W(mZ)MS=0.2329(13) slightly high Best Low Q2 Determination of sin2W APV(Cs) & E158 sin2W(Q2) running ALR(ee)exp=ALR(ee)SM(1+0.24T-0.33S+7(mZ/mZ)2…) Constrains “New Physics” eq mZ>0.6TeV, H--,S, Anapole Moment, …

  15. Goals of Future Experiments • High Precision: sin2W0.00025 or better • Low Q2 Sensitivity to “New Physics” mZ’ >1TeV, S<0.1-0.2, SUSY Loops, Extra Dim., Compositeness….

  16. Future Efforts QWEAK exp at JLAB being prepared Will measure forward ALR(epep)  (1-4sin2W)=QW(p) E=1.1GeV, Q20.03GeV2, Pol=0.801%ARL(ep)3x10-7 small ARL requires long running Goal sin2W(mZ)MS=0.0008 via 4% measurement of ALR Will be best low energy measurement of sin2W ALR(ep)exp=ALR(ep)SM(1+4(mZ/mZ)2+…) eg mz~0.9TeV Sensitivity (Not as good as APV) • The Gorchtein - Horowitz Problem (PRL) Z box diagrams: O(2Ee/mp) 6% of QW(p)! RC Estimate needs to be checked Proposed Qweak Theory Uncertainty < 2%? JLAB Flagship Experiment

  17. Future Efforts: Polarized Moller at JLAB After 12GeV Upgrade ALR(eeee) to 2.5% sin2W(mZ)MS=0.00025! Comparable to Z pole studies! ALR(ee)exp=ALR(ee)SM(1+7(mZ/mZ)2+…) Explores mZ1.5TeV Better than APV, S0.08 etc. Future JLAB Flagship Experiment (difficult!) Complementary to LHC Discoveries

  18. Comparison of QW(p) & QW(Cs) • HPV=G/2[(C1uuu+C1ddd)e5e+ (C2uu5u+C2dd5d)ee+…] QW(p)=2(2C1u+C1d) QW(Cs)=2(188C1u+211C1d) What about the C2q?

  19. What About C2u and C2d? • Renormalized at low Q2 by Strong Interactions Measure in Deep-Inelastic Scattering (DIS), eD & ep ARL(eDeX)2x10-4GeV-2Q2[(C1u-C1d/2)+f(y)(C2u-C2d/2)] f(y)=[1-(1-y)2]/[1+(1-y)2] Standard Model: C1u= (1-8sin2W/3)/2  0.20 C1d=-(1-4/sin2W/3)/2 -0.32 C2u= (1-4sin2W)/2 0.04 C2d =-(1-4sin2W)/2-0.04 C2q sensitive to RC & “New Physics” eg Z (SO(10)) Measure ARL to 0.25%? Measure C2q to 1-2%? Theory (loops)?

  20. JLAB 6 GeV DIS eDeX On the books JLAB 12 GeV DIS eD Proposed (Likely) Goals: Measure C2qs, “New Physics”, Charge Sym. Violation … Effective Luminosity (Fixed Target) 1038cm-2sec-1! What can ep and eD at e-Ion contribute? Asymmetry F.O,M,A2N, AQ2, N1/Q2 (acceptance?) High Q2 Better (but Collider Luminosity?) K. Kumar Talk 100fb-1 Needed Program can be started with lower luminosity Do DIS ep, eD, eN at factor of 10 lower

  21. Single and Double Polarization Asymmetries Polarized e: AeRL=(RR+RL-LR-LL)/(RR+RL+LR+LL)Pe Polarized p: ApRL=(RR+LR-RL-LL)/(RR+LR+RL+LL)Pp Polarized D: Pu=Pd=PD Use to determine quark polarizations Polarized e&p or D AepRRLL= (RR-LL)/(RR+LL)Peff Peff=(Pe+Pp)/(1+PePp) like relativistic velocities addition1 eg Pe=0.85, Pp=0.70 Peff=0.972! uncertainty: Peff/Peff=0.17Pe/Pe+0.08Pp/Pp small If we determine (see above) Pp=0.700.014 Peff=0.9720.0018 Superb! How to best utilize Peff?

  22. Preliminary Comments Use polarized e & polarized p or D at EICARR,LLto 0.25% Systematics? Peff determined to 0.1-0.2% via ApRL & ADRL (possible?) Other? ADRR,LL(1-3.2sin2W) sin2W/sin2W=-0.4ADRR.LL/ADRR.LL 0.25% measurement of ADRR.LLsin2W=0.00023 Sensitive to “New Physics” eg S=0.05 Summary: Measure DIS RR, RL, LR, LL Determine: Pquarks, Peff. sin2W precisely

  23. LDRD ARL GOALS Elucidate Physics Case Examine Machine and Detector Requirements For 0.1% sin2W Determination Include Full EW Radiative Corrections to DIS Is 100fb-1 Sufficient? Doable? Utility of Proton (Deuteron) Polarization? Precision sin2W Stage 1 e-Ion Goals? Study Pol. Quark dist. & Nuclear Effects (EMC, CSV) Important Secondary EIC Goal? Expands Proposal?

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