CP Violation at the LHC, Boston

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CP Violation at the LHC, Boston

  1. 1. Probing SUSY CP Violation in Stop Decays at the LHC The University of Manchester Frank Deppisch frank.deppisch@manchester.ac.uk University of Manchester in collaboration with Olaf Kittel (Granada U.) arXiv:0905.3088 [hep-ph] SUSY09, Boston, 7 June 2009
  2. 2. CP Violation CP violation in quark sector 2/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  3. 3. CP Violation CP violation in quark sector CP violation in neutrino sector? 3/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  4. 4. CP Violation CP violation in quark sector CP violation in neutrino sector? Baryon Asymmetry of the Universe  B = n B / n  = 6.1 0.3⋅10−10 −0.2 → New mechanism of CP Violation required 4/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  5. 5. CP Violation CP violation in quark sector CP violation in neutrino sector? Baryon Asymmetry of the Universe  B = n B / n  = 6.1 0.3⋅10−10 −0.2 → New mechanism of CP Violation required Supersymmetry Possible new CP phases in SUSY and SUSY-breaking Gaugino mass terms → φM1 , φM3 Higgs mixing term → φµ 3rd generation trilinear scalar coupling terms → φAt,b,τ 5/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  6. 6. Bounds from Electric Dipole Moments Stringent bounds from electron and neutron EDMs ∣d ∣4⋅10−27 e⋅cm e −26 ∣d n∣6⋅10 e⋅cm 6/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  7. 7. Bounds from Electric Dipole Moments Stringent bounds from electron and neutron EDMs ∣d ∣4⋅10−27 e⋅cm e −26 ∣d n∣6⋅10 e⋅cm Generally constrain SUSY phases to be small (or SUSY scale large), e.g. φµ < π/10 7/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  8. 8. Bounds from Electric Dipole Moments Stringent bounds from electron and neutron EDMs ∣d ∣4⋅10−27 e⋅cm e −26 ∣d n∣6⋅10 e⋅cm Generally constrain SUSY phases to be small (or SUSY scale large), e.g. φµ < π/10 … unless cancellations occur between contributions  =1 °  =1 ° 8/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  9. 9. Triple Product Asymmetries CP-even observables at colliders sensitive to phases masses branching ratios cross sections 9/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  10. 10. Triple Product Asymmetries CP-even observables at colliders sensitive to phases masses branching ratios cross sections CP-odd observables are needed to confirm CP Violation 10/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  11. 11. Triple Product Asymmetries CP-even observables at colliders sensitive to phases masses branching ratios cross sections p1 CP-odd observables are needed p3 to confirm CP Violation p2 Momentum triple product Time Reversal T = p1⋅ p 2× p 3  − p2 → T-odd → CPT Invariance → CP-odd − p3 − p1 11/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  12. 12. Triple Product Asymmetries CP-even observables at colliders sensitive to phases masses branching ratios cross sections p1 CP-odd observables are needed p3 to confirm CP Violation p2 Momentum triple product Time Reversal T = p1⋅ p 2× p 3  − p2 → T-odd → CPT Invariance → CP-odd − p3 CP-odd asymmetry − p1 N T 0− N T 0 ∫ sign T ∣M∣ d Lips 2 A= = N T 0 N T 0 ∫∣M∣2 d Lips 12/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  13. 13. Stop Production at the LHC Framework mSUGRA decorated with CP phases at EW scale Benchmark Scenario 13/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  14. 14. Stop Production at the LHC Framework mSUGRA decorated with CP phases at EW scale Benchmark Scenario Stop pair production at Stop boost distribution the LHC Cross section ∗ pp   i  i t t 14/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  15. 15. CP-odd Asymmetries in Stop Decays Stop cascade decay sensitive to φAt, φµ(, φM1) from spin-spin correlations t 1 0 2 L/R l 15/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  16. 16. CP-odd Asymmetries in Stop Decays Stop cascade decay sensitive to φAt, φµ(, φM1) from spin-spin correlations Triple product asymmetries not t 1 Lorentz-invariant 0 2 L/R l 16/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  17. 17. CP-odd Asymmetries in Stop Decays Stop cascade decay sensitive to φAt, φµ(, φM1) from spin-spin correlations Triple product asymmetries not t 1 Lorentz-invariant 0 2 L/R l Asymmetry reduction with stop boost Effect of stop boost on asymmetry 1 ∞ d A = ∫0 lab A d  t  d  t 17/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  18. 18. mSUGRA Parameters left-h. slepton,  1  2 t , 2   L l t   l right-h. slepton, 1  2 t , 2   R l t   l ∣A0∣=500 GeV , tan =5  A =3 /4  , =0 t Minimally required luminosity at the LHC to observe 1σ effect Based only on theoretical significance (statistical fluctuation of signal) S ≈∣A∣  L 18/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  19. 19. CP Phase Sensitivity Asymmetry in the lab frame [%]  1  2 t , 2   R l t   l Min. luminosity required at LHC m0 =70 GeV , m1 /2 =270 GeV ∣A0∣=500 GeV , tan =5 Asymmetry largely independent of φM1 in mSUGRA Large asymmetries possible for small φAt and φµ 19/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  20. 20. Conclusion CP Violation in Stop decays at the LHC Via 2nd Lightest Neutralino Top-Neutralino Spin-Spin Correlations Sensitive to CP phases φAt and φµ in mSUGRA 20/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  21. 21. Conclusion CP Violation in Stop decays at the LHC Via 2nd Lightest Neutralino Top-Neutralino Spin-Spin Correlations Sensitive to CP phases φAt and φµ in mSUGRA Triple Product Asymmetries CP-odd observables → Signal of CP Violation Alternative Sensitivity than EDMs Detectable at LHC 21/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009
  22. 22. Conclusion CP Violation in Stop decays at the LHC Via 2nd Lightest Neutralino Top-Neutralino Spin-Spin Correlations Sensitive to CP phases φAt and φµ in mSUGRA Triple Product Asymmetries CP-odd observables → Signal of CP Violation Alternative Sensitivity than EDMs Detectable at LHC Motivation for experimental analysis Reconstruction Efficiencies Epsilon Product of Four Momenta 22/22 Frank Deppisch SUSY CP Violation in Stop Decays at LHC 7/6/2009

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