Introduction MSSM scan LHC Study Summary SUSY LHC signatures without prejudice John Conley Physics Institute University of Bonn Searching for New Physics at the LHC, GGI, 22 October 2009 John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Supersymmetry Motivation Outline Introduction 1 Supersymmetry Motivation MSSM scan 2 Parameters Constraints Features of viable models LHC Study 3 Procedure Benchmarks Preliminary results Summary and outlook 4 John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Supersymmetry Motivation Outline Introduction 1 Supersymmetry Motivation MSSM scan 2 Parameters Constraints Features of viable models LHC Study 3 Procedure Benchmarks Preliminary results Summary and outlook 4 John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Supersymmetry Motivation SUSY must be broken Exact SUSY means every particle has a partner with exactly the same properties (except spin). Most if not all of these partners would have been discovered by now if they exist. Therefore, if SUSY exists, it is broken and sparticles are heavy. A lot of freedom Unbroken SUSY is economical–no new parameters! Most general SUSY-breaking introduces 105 new parameters. Theoretical considerations and/or experimental constraints can reduce this number. John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Supersymmetry Motivation Outline Introduction 1 Supersymmetry Motivation MSSM scan 2 Parameters Constraints Features of viable models LHC Study 3 Procedure Benchmarks Preliminary results Summary and outlook 4 John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Supersymmetry Motivation Handling MSSM parameter space In an ideal world, we could examine signatures of 105-dimensional space in detail. This is impractical. Top-down approaches One can adopt a constraining theoretical assumption (usually on high-scale parameters). This is often a specific SUSY-breaking model. Pros: highly constraining ( � 5 params.), theoretically motivated. Cons: Many different possible scenarios, correlations in spectrum/observables. John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Supersymmetry Motivation Handling MSSM parameter space In an ideal world, we could examine signatures of 105-dimensional space in detail. This is impractical. Bottom-up approaches One can instead restrict the low-energy parameter space to a phenomenologically viable subset. Assumptions are typically made to automatically satisfy flavor and CP-violation observables, in particular. Pros: no reliance on unproven theoretical assumptions, physically motivated. Cons: Parameter space is still large unless some additional assumptions are made. John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Supersymmetry Motivation The breadth of the MSSM Because of practical limitations, we may not have explored all interesting regions of the MSSM. The above approaches have been limited to certain corners of parameter space, and we have only seen a subset of signatures. We would like, though, to be ready for anything at the LHC and beyond. John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Supersymmetry Motivation Our goal Is it feasible to study MSSM parameter space in full generality? Our goal is to take a step towards that. We: Use a bottom-up approach, taking the minimum set of phenomenologically motivated assumptions; Randomly scan the broadest possible range of parameter space; Check each point against all experimental constraints; And investigate the properties and signatures of the remaining models. Berger, Gainer, Hewett, and Rizzo; JHEP 0902:023,2009 John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Outline Introduction 1 Supersymmetry Motivation MSSM scan 2 Parameters Constraints Features of viable models LHC Study 3 Procedure Benchmarks Preliminary results Summary and outlook 4 John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Outline Introduction 1 Supersymmetry Motivation MSSM scan 2 Parameters Constraints Features of viable models LHC Study 3 Procedure Benchmarks Preliminary results Summary and outlook 4 John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Phenomological assumptions CP-conserving minimal flavor violation degenerate 1 st & 2 nd gen. sfermions neglect 1 st and 2 nd generation Yukawas These assumptions are motivated by observation. John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Scanning the MSSM parameter space After applying our assumptions We’re left with 19 real, weak-scale parameters (pMSSM). We scan 10 7 points. 100 GeV ≤ m ˜ f ≤ 1 TeV 50 GeV ≤ | M 1 , 2 , µ | ≤ 1 TeV 100 GeV ≤ M 3 ≤ 1 TeV | A b , t ,τ | ≤ 1 TeV 1 ≤ tan β ≤ 50 43 . 5 GeV ≤ m A ≤ 1 TeV John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Outline Introduction 1 Supersymmetry Motivation MSSM scan 2 Parameters Constraints Features of viable models LHC Study 3 Procedure Benchmarks Preliminary results Summary and outlook 4 John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Enforcing theoretical and experimental constraints Theoretical constraints No tachyons, no charge- or color-breaking minima, consistent EWSB LSP is lightest neutralino and thermal relic Experimental constraints Precision electroweak and flavor measurements Relic density < WMAP value Dark matter direct detection LEP and Tevatron sparticle and Higgs searches Required the use of fast detector simulation John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Tevatron multijet plus missing energy constraint To be model-independent required a full Monte Carlo study. 600 Squark Mass (GeV) ∼ LEP2 χ ± 500 ~ ± LEP2 l DØ II 400 DØ IA UA1 UA2 CDF IB no mSUGRA 300 solution DØ IB 200 DØ, L=2.1 fb -1 tan β =3, A =0, µ <0 0 100 LEP 0 0 100 200 300 400 500 600 Gluino Mass (GeV) Outside MSUGRA, constraints can be weaker! John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Tevatron stable chargino search 10 -1 -1 DØ 1.1 fb (c) DØ 1.1 fb (b) 10 Observed Cross Section Limit Observed Cross Section Limit ) [pb] Expected Cross Section Limit ) [pb] Expected Cross Section Limit NLO Cross Section Prediction 1 NLO Cross Section Prediction 1 NLO Cross Section Uncertainty NLO Cross Section Uncertainty 1 1 - - χ χ + 1 + 1 χ χ -1 10 -1 10 → → p p (p (p -2 10 -2 10 σ σ -3 -3 10 10 50 100 150 200 250 300 50 100 150 200 250 300 Charged Gaugino Mass [GeV] Charged Higgsino Mass [GeV] We have many charginos nearly degenerate with the LSP , so this is an important constraint. We interpolate between Wino and Higgsino bounds for arbitrary charginos. John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Survival rates Only 0 . 68 % , or 68,422 survive all constraints. John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Outline Introduction 1 Supersymmetry Motivation MSSM scan 2 Parameters Constraints Features of viable models LHC Study 3 Procedure Benchmarks Preliminary results Summary and outlook 4 John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features NLSP identity The NLSP can be anyone! 100000 10000 number of models 1000 100 10 1 e , b u g d u t d R R R L e, L nLSP John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Squark masses 2500 u L u R 2000 d L d R number of models 1500 1000 500 0 0 200 400 600 800 1000 m [GeV] q Squarks can be light They can evade Tevatron constraints because of cascade decays, soft jets, or small cross sections. John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Parameters Constraints Features Gluino mass Gluino can be very light! LSP mass vs. gluino mass m LSP (GeV) m g (GeV) John Conley SUSY LHC signatures without prejudice
Introduction MSSM scan LHC Study Summary Procedure Benchmarks Preliminary results Outline Introduction 1 Supersymmetry Motivation MSSM scan 2 Parameters Constraints Features of viable models LHC Study 3 Procedure Benchmarks Preliminary results Summary and outlook 4 John Conley SUSY LHC signatures without prejudice
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