Probing Supersymmetry with Neutral Current Scattering Experiments

1. Probing Supersymmetry with Neutral Current Scattering Experiments Shufang Su • U. of Arizona

2. Sub-Z precision measurements - • neutral current scattering • heavy quark physics • CP violation, EDM • Rare K-decay, CKM unitarity • muon g-2 • lepton flavor violation … • polarized ee scattering(SLAC E158) • polarized ep scattering(JLab Qweak) • neutrino-nucleus scattering(NuTeV) A. Kurylov, M. Ramsey-Musolf, SS

3. Outline - • motivation • parity-violating electron scattering experiments • radiative corrections to weak charge QW • analysis of SUSY contributions to QW • MSSM contributions • RPV analysis • distinguish various new physics / SUSY • NuTeV experiment • MSSM contributions • RPV analysis • conclusion

4. Motivation - size of loop effects from new physics: (/)(M/Mnew)2 • high precision low energy experiment available - muon g-2: M=m , new  2x10-9, exp < 10-9 • -decay, -decay: M=mW , new  10-3, exp  10-3 • parity-violating electron scattering: M=mW , new  10-3, • 1/Qe,pW10more sensitive to new physics • need exp  10-2 “easier” experiment • indirect+direct: complementary information • consistency test of theory at loop level Qe,pW 1-4 sin2W  0.1 • probe new physics off the Z-resonance - sensitive to new physics not mix with Z

5. -  sin2W  0.0007 at Q2=0.03 (GeV)2 Test of sin2Wrunning - • sin2W(0) - sin2W(mZ2) = +0.007 • QCsw: agree Q2=0 • NuTeV: +3 Q2=20 (GeV)2 • parity-violating electron • scattering (PVES) • ee Moller scattering (SLAC) QeW • ep elastic scattering (J-lab)QpW - • clean environment: Hydrogen target • theoretically clean: small hadronic uncertainties • tree level  0.1 sensitive to new physics

6. Develop consistency checks for theories of new physics using the low energy precision measurements Goal - • minimal Supersymmetric extension of SM (MSSM) SUSY: most promising candidate for new physics • solution to Hierarchy problem • gauge coupling unification • provide a natural electroweak symmetry breaking • dark matter candidate ? (PVES) • with R-parity : loop corrections • without R-parity: tree-level contribution • low-energy precision measurements • PVES: weak charge QeW , QpW , ( QCsW ) - NuTeV: R() -

7. A N+-N- N++N- ALR  QfW V weak charge QfW = 2gfV = 2 If3 -4Qfs2 ep Qweak exp QpWee Moller exp QeW Qe,pW tree1-4s2 -(1-4s2) Qe,pWloop0.0721 -0.0449 exp precision 4% 8%  sin2W0.0007 0.0009 SM running 10  8  Weak charge QW - geA = Ie3 QCsW : sin2W = 0.0021NuTeV: sin2W = 0.0016

8. correction to muon life time General structure of radiative corrections to QfW - Including radiative corrections: QfW =  (2If3 - 4  Qf s2) + f ,: universal, f: depend on fermion species  = 1+SM+SUSY,  = 1+SM+SUSY, f= fSM+fSUSY 

9. correction to , G and mZs2 Radiative contributions - QfW =  (2If3 - 4  Qf s2) + f  f

10.       mqLR2 mlR2, mlL2, mqR2, mlLR2 mqL2, MSSM particle contents - Spin differ by 1/2 SM particle superpartner mass parameter , tan=vu/vd M3 M2 M1

11. One loop SUSY contributions to PVES - • gauge boson • self-energies • external leg corrections • vertex corrections • box diagrams

12. ~ ~ 50 GeV < mq, ml, M1,2,  < 1000 GeV 1.4 < tan < 60 Numerical analysis - • Model-independent analysis • MSSM parameter range: random scan • hard to impose bounds on certain MSSM parameter • show the possible range of MSSM corrections • impose exp search limit on SUSY particles • impose S-T 95% CL constraints • impose g-2 constraints (2nd slepton LR mixing)

13. Correction to weak charge - QfW =  (2Tf3 - 4Qf  s2) + f • QeW andQpW correlated dominant :  (<0)  negative shift in sin2W  (QpW)SUSY / (QpW)SM < 4%,  (QeW)SUSY / (QeW)SM < 8%

14. Dominant contributions - QfW =  (2Tf3 - 4Qf  s2) + f • non-universal corrections • vertex + wavefunction : cancel • box diagrams numerically suppressed •  contribution suppressed by (1-4 s2) • dominant contribution from   (<0)negative shift in sin2W

15.  L = - 1 R-parity - • General MSSM, including B,L-violating operators ijk ’ijk • dangerous  introduce proton decay • R-parity SM particle: even superparticle: odd • stable LSP as dark matter candidate • RPV: only look at L-violating operator

16. RPV 95% CL MSSM loop R-parity violating (RPV) - • RPV operators contribute to Qe,pWat tree level • Exp constraints •  decay: |Vud| = -0.00145  0.0007 • APV(Cs):  QWCs = -0.0040  0.0066 • Re/:  Re/ = -0.0042  0.0033 • G:  G = 0.00025  0.00188 QpW No SUSY dark matter I) Obtain 95% CL allowed region in RPV coefficients II) Evaluate  QWe andQWp G

17.  QpW  QeW  QCsW small sizable • MSSM: • extra Z’: • leptoquark: • RPV SUSY • SUSY correction to heavy nuclei QW •  QW (Z,N)=(2Z+N)  QuW +(2N+Z)  QdW •  QuW >0 •  QdW <0 Correlation between QpW and QeW - •  QW(Z,N) / QW(Z,N) < 0.2 % for Cs • Distinguish new physics

18. Additional PV electron scattering ideas Linear Collider e-e- DIS-Parity, JLab DIS-Parity, SLAC JLab Moller (ee) - Czarnecki, Marciano， Erler et al. N deep inelastic sin2W APV e+e- LEP, SLD SLAC E158 (ee) JLab Q-Weak (ep) (GeV)

19. (N  X) (N  l-(+)X) - R()  (-) MSSM R=-0.0033  0.0015 R=-0.0019  0.0026 - wrong-sign contribution! Davidson et. al., JHEP 02, 037, 2002 NuTeV experiment - NC CC

20. NC CC R-parity violating (RPV) - - • RPV operators contribute to R() at tree level • either wrong sign or too small • hard to explain NuTeV deviation

21. Conclusion - • Parity-violating ee and ep scattering • could be used to test SM and probe new physics • MSSM contribution to QeW andQpW is 8% and 4%  1 expneed higher exp precision to constrain SUSY • correlation between QeW andQpW • distinguish various new physics • distinguish various SUSY scenario whether dark matter is SUSY particle ? • SUSY contribution to NuTeV result • MSSM with R-parity: wrong sign /small • negative gluino contribution: • size constrained by other considerations • hard to explain NuTeV in RPV • SUSY is not responsible for the NuTeV deviation • other new physics ? • hadronic effects ?