Reconstruction of Reconstruction of Fundamental SUSY Fundamental SUSY Parameters at Parameters at LHC and LC LHC and LC Rémi Lafaye - CERN/ATLAS on leave from LAPP-IN2P3 On behalf of the SFitter and Fittino authors: P. Bechtle, K. Desch, R. L, T. Plehn, P. Wienemann and D. Zerwas and the members of the SPA project
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Reconstruction of Fundamental SUSY Parameters at LHC and LC Rémi Lafaye - CERN/ATLAS on leave from LAPP-IN2P3 On behalf of the SFitter and Fittino authors:
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Reconstruction of Reconstruction of Fundamental SUSY Fundamental SUSY
Parameters at Parameters at LHC and LC LHC and LC
Rémi Lafaye - CERN/ATLAS on leave from LAPP-IN2P3
On behalf of the SFitter and Fittino authors: P. Bechtle, K. Desch, R. L, T. Plehn, P. Wienemann and D. Zerwas
and the members of the SPA project
8/17/2004 R. Lafaye 2
OutlineOutline
Reconstruction of Fundamental SUSY Parameters at LHC and LC
1. The SPA project2. SPS1a uncertainties at LHC and LC3. Top-down approach: SPS1a mSUGRA scenario4. Bottom-up approach: SPS1a pMSSM fit5. Back to GUT scale
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1. The SPA Project1. The SPA Project
SPA: Supersymmetry Parameter Analysis
The SPA project is a joint study of theorists and experimentalists working on LHC and LC phenomenology
SPA Tasks: High-precision determination of the SUSY Lagrange parameters at
the electroweak scale Extrapolation to high scale to reconstruct the fundamental
parameters and the mechanism for SUSY breaking Need to match expected experimental accuracy with theoretical
predictions Extend the set of observables Coherent LHC/LC analysis
Starting point: LHC/LC study group report [G. Weiglein et al.]
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1. SPA Conventions1. SPA Conventions
SUSY particle masses = pole masses Use DR scheme and scale MSUSY = 1 TeV Except for Higgs mixing matrix:
On-shell and scale = light Higgs mass Standard Model input:
Summary of accelerators SUSY capabilities: LHC: gluino, squarks, neutralinos and sleptons masses and
couplings LC: charginos, heavy Higgs and slepton mass high precision
measurements enough information to check mSUGRA assumptions without
assuming a given SUSY breaking scenario
Generic MSSM has 105 (too many) free parameters.Make some assumptions: All phases = 0 No mixing between generations No mixing within first 2 generations
pMSSM 24 parameters
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4. pMSSM Fit Results4. pMSSM Fit Results
Mass measurements only
Include theoretical uncertainties
500 GeV-LC gives high precision in the slepton sector
Only LHC can scan the squark sector apart for stop right
[SFitter]
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4. pMSSM Fit Results4. pMSSM Fit Results
500 GeV-LC gives high precision on crucial parameters LHC necessary for any determination of M3 and squark sector
[SFitter]
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4. pMSSM Scan Plots4. pMSSM Scan Plots
We use a 24 parameter fit, some are easy to fit:
LC: no heavy squarks
no 2 dependencyLHC: low 2 dependency
[SFitter]
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4. pMSSM Scan Plots4. pMSSM Scan Plots
Others need additional observables:
Mirror solution and low 2 dependency Smooth but very low 2 dependency
120 independent fits - smeared observables Experimental errors only except for mh Start values: from tree-level formulae Use mass and cross section measurements mt included in the fit
MEAN VALUE ~ 0.0 and RMS ~ 1.0 Uncertainties correctly estimated