CP Violation at the LHC, Boston
Transcript of CP Violation at the LHC, Boston
Probing SUSY CP ViolationProbing SUSY CP Violationin Stop Decays at the LHCin Stop Decays at the LHC
The
Uni
vers
ity
of M
anch
este
r
Frank [email protected]
University of Manchester
in collaboration with Olaf Kittel (Granada U.)
arXiv:0905.3088 [hep-ph]
SUSY09, Boston, 7 June 2009
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC22/22/22
CP ViolationCP Violation
CP violation in quark sector
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC33/22/22
CP ViolationCP Violation
CP violation in quark sectorCP violation in neutrino sector?
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC44/22/22
CP ViolationCP Violation
CP violation in quark sectorCP violation in neutrino sector?Baryon Asymmetry of the Universe
→ New mechanism of CP Violation required
B = nB/n = 6.1−0.20.3⋅10−10
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC55/22/22
CP ViolationCP Violation
CP violation in quark sectorCP violation in neutrino sector?Baryon Asymmetry of the Universe
→ New mechanism of CP Violation requiredSupersymmetry 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
B = nB/n = 6.1−0.20.3⋅10−10
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC66/22/22
Bounds from Electric Dipole MomentsBounds from Electric Dipole MomentsStringent bounds from electron and neutron EDMs ∣d e∣4⋅10−27e⋅cm
∣d n∣6⋅10−26e⋅cm
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC77/22/22
Bounds from Electric Dipole MomentsBounds from Electric Dipole MomentsStringent bounds from electron and neutron EDMs
Generally constrain SUSY phases to be small (or SUSY scale large), e.g. φµ < π/10
∣d e∣4⋅10−27e⋅cm∣d n∣6⋅10−26e⋅cm
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC88/22/22
Bounds from Electric Dipole MomentsBounds from Electric Dipole MomentsStringent bounds from electron and neutron EDMs
Generally constrain SUSY phases to be small (or SUSY scale large), e.g. φµ < π/10
… unless cancellations occur between contributions
∣d e∣4⋅10−27e⋅cm∣d n∣6⋅10−26e⋅cm
=1°=1°
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC99/22/22
Triple Product AsymmetriesTriple Product Asymmetries
CP-even observables at colliders sensitive to phasesmassesbranching ratioscross sections
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC1010/22/22
Triple Product AsymmetriesTriple Product Asymmetries
CP-even observables at colliders sensitive to phasesmassesbranching ratioscross sections
CP-odd observables are needed to confirm CP Violation
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC1111/22/22
Triple Product AsymmetriesTriple Product Asymmetries
CP-even observables at colliders sensitive to phasesmassesbranching ratioscross sections
CP-odd observables are needed to confirm CP Violation
Momentum triple product
→ T-odd → CPT Invariance → CP-odd
p1p3
p2
T= p1⋅ p2× p3
− p1
− p3
− p2
Time Reversal
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC1212/22/22
Triple Product AsymmetriesTriple Product Asymmetries
CP-even observables at colliders sensitive to phasesmassesbranching ratioscross sections
CP-odd observables are needed to confirm CP Violation
Momentum triple product
→ T-odd → CPT Invariance → CP-odd
CP-odd asymmetry
p1p3
p2
A=N T0−N T0
N T0N T0=∫ sign T ∣M∣2d Lips
∫∣M∣2d Lips
T= p1⋅ p2× p3
− p1
− p3
− p2
Time Reversal
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC1313/22/22
Stop Production at the LHCStop Production at the LHC
FrameworkmSUGRA decorated with CP phases at EW scale
Benchmark Scenario
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC1414/22/22
Stop Production at the LHCStop Production at the LHC
FrameworkmSUGRA decorated with CP phases at EW scale
Benchmark Scenario
Stop pair production at the LHCppt i t i
∗
Stop boost distributionCross section
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC1515/22/22
CP-odd Asymmetries in Stop DecaysCP-odd Asymmetries in Stop DecaysStop cascade decay sensitive to φAt, φµ(, φM1) from spin-spin correlations
20 l L /R
t 1
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC1616/22/22
CP-odd Asymmetries in Stop DecaysCP-odd Asymmetries in Stop DecaysStop cascade decay sensitive to φAt, φµ(, φM1) from spin-spin correlations
Triple product asymmetries not Lorentz-invariant
20 l L /R
t 1
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC1717/22/22
CP-odd Asymmetries in Stop DecaysCP-odd Asymmetries in Stop DecaysStop cascade decay sensitive to φAt, φµ(, φM1) from spin-spin correlations
Triple product asymmetries not Lorentz-invariant Asymmetry reduction with stop boost
Effect of stop boost on asymmetry
20 l L /R
Alab= 1∫0
∞ d d t
Ad t
t 1
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC1818/22/22
mSUGRA ParametersmSUGRA Parameters
Minimally required luminosity at the LHC to observe 1σ effectBased only on theoretical significance (statistical fluctuation of signal) S≈∣A∣ L
right-h. slepton, t1 2 t , 2l R lleft-h. slepton, t 1 2 t , 2l L l
∣A0∣=500 GeV , tan =5At=3 /4 ,=0
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CP Phase SensitivityCP Phase Sensitivity
Asymmetry largely independent of φM1 in mSUGRALarge asymmetries possible for small φAt and φµ
Asymmetry in the lab frame [%]
m0=70 GeV , m1 /2=270 GeV∣A0∣=500 GeV , tan=5
Min. luminosity required at LHCt 1 2 t , 2l R l
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC2020/22/22
ConclusionConclusion
CP Violation in Stop decays at the LHCVia 2nd Lightest NeutralinoTop-Neutralino Spin-Spin CorrelationsSensitive to CP phases φAt and φµ in mSUGRA
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC2121/22/22
ConclusionConclusion
CP Violation in Stop decays at the LHCVia 2nd Lightest NeutralinoTop-Neutralino Spin-Spin CorrelationsSensitive to CP phases φAt and φµ in mSUGRA
Triple Product AsymmetriesCP-odd observables → Signal of CP ViolationAlternative Sensitivity than EDMsDetectable at LHC
7/6/2009Frank Deppisch SUSY CP Violation in Stop Decays at LHC2222/22/22
ConclusionConclusion
CP Violation in Stop decays at the LHCVia 2nd Lightest NeutralinoTop-Neutralino Spin-Spin CorrelationsSensitive to CP phases φAt and φµ in mSUGRA
Triple Product AsymmetriesCP-odd observables → Signal of CP ViolationAlternative Sensitivity than EDMsDetectable at LHC
Motivation for experimental analysisReconstruction EfficienciesEpsilon Product of Four Momenta