Exploring Supersymmetry without Bias: MSSM Analysis at ATLAS

1. Signatures of Supersymmetry Without Prejudice Berger, Conley, Cotta, Gainer, JLH, Le, Rizzo arXiv:0812.0980, 0903.4409, in progress J. Hewett, HEP2010

2. Supersymmetry at the LHC SUSY discovery generally ‘easy’ at LHC ~ q Cut: ETmiss > 300 GeV

4. LHC Supersymmetry Discovery Reach mSUGRA - Model where gravity mediates SUSY breaking – 5 free parameters at high energies Squark and Gluino mass reach is 2.5-3.0 TeV @ 300 fb-1 at 14 TeV

5. Reconstructionof Sparticle Masses at LHC Squarks and Gluinos have complicated decay chains Mainanalysistool: dileptonedge in02 01l+ l- Proportional to Sparticle mass differences Introduces strong mass correlations

6. ATLAS SUSY Analyses with a Large Model Set • We are running our ~70k MSSM models through the ATLAS • SUSY analysis suite, essentially designed for mSUGRA , to • explore its sensitivity to this far broader class of SUSY models • We first need to verify that we can approximately reproduce • the ATLAS results for their benchmark mSUGRA models with • our analysis techniques • By necessity there are some differences between the two • analyses…. • This is extremely CPU intensive!

7. ATLAS has already made use of some of these models!

8. ATLAS FEATURE SuSpect generates spectra with SUSY-HIT# for decays NLO cross section for ~85 processes using PROSPINO** & CTEQ6.6M PYTHIA for fragmentation & hadronization PGS4-ATLAS for fast detector sim ISASUGRA generates spectrum & sparticle decays NLO cross section using PROSPINO & CTEQ6M Herwig for fragmentation & hadronization GEANT4 for full detector sim ** version w/ negative K-factor errors corrected # version w/o negative QCD corrections & with 1st & 2nd generation fermion masses included as well as explicit small m chargino decays

9. The ATLAS SUSY analyses: • 2,3,4-jet +MET • 1l, ≥4-jet +MET • SSDL  • OSDL • Trileptons + (0,1)-j +MET •  +≥ 4j +MET • ≥4j w/ ≥ 2btags + MET • Stable particle search

10. 4-jet +MET - Benchmark Points ATLAS Feature We do a good job at reproducing the mSUGRAbenchmark points in this channel !

11. Sample Feature Model Results

12. 1l+4j+MET – Benchmark Points ATLAS Feature

13. Single Lepton Analysis: Sample Feature Models

14. b-jet analysis – Benchmark Points ATLAS Feature

15. b-jet analysis Sample Feature Models

16. Some Results From the First 20k Models @ 14 TeV & 1fb-1 • ‘Remove’ some possibly difficult models which may • require some specialized analyses (note PYSTOP issues) • Determine how many models are visible or not in each • analysis @ the 5 level allowing for a 20% systematic un- • certainty in the ATLAS generated SM backgrounds • The results are still HIGHLY PRELIMINARY!!!

17. Some Results From the First 20k Models * *  ID & reconstruction in PGS is a bit too optimistic & needs to be reaccessed

18. Some Results From the First 20k Models

19. Sample Difficult Models

20. Some Dark Matter Candidates • The observational constraints are no match for the creativity of theorists • Masses and interaction strengths span many, many orders of magnitude, but not all candidates are equally motivated • Weakly Interacting Massive Particle (WIMP) SUSY HEPAP/AAAC DMSAG Subpanel (2007)

21. Assume a new (heavy) particle  is initially in thermal equilibrium: cc↔ f f (2) Universe cools: cc f f (3) cs “freeze out”: ccf f (1) (2) (3) → / ← / → / ← The WIMP ‘Miracle’ Zeldovich et al. (1960s)

22. The amount of dark matter left over is inversely proportional to the annihilation cross section: WDM ~ <sAv>-1 HEPAP LHC/ILC Subpanel (2006) [band width from k = 0.5 – 2, S and P wave] A ~ 2/ m2 Remarkable “coincidence”: DM ~ 0.1 for m ~ 100 GeV – 1 TeV! particle physics independently predicts particles with about the right density to be dark matter !

23.   photons, positrons , anti-protons…. ‘in the sky’ right now may be seen by FERMI & other experiments N N (elastic) scattering may be detected on earth in deep underground experiments If  is really a WIMP it may be directly produced at the LHC ! Of course,  does not come by itself in any new physics model & there is usually a significant accompanying edifice of other interesting particles & interactions with many other observational predictions So this general picture can be tested in many ways….

24. Predictions for Relic Density WMAP

25. Correlation Between Dark Matter Density & the LSP-nLSP Mass Splitting Small mass differences can lead to rapid co-annihilations reducing the dark matter density….

26. Direct Detection Expectations Spin Dependent Spin Independent Predictions span orders of magnitude… Far smaller than mSUGRA expectations

27. Distinguishing Dark Matter Models Barger etal Flat Priors

28. What fraction of the space is covered as, e.g., CDMS/XENON improve their search reaches?? The parameter space ‘coverage’ improves rather slowly…

29. Cosmic Ray Positron/Electron Flux • χ2 fit to 7 highest energy PAMELA data points • Vary boost for best fit (take Boost ≤ 2000) Positron Spectrum Boost Factor Preliminary!

30. Annihilation Cross Section Channels flat

31. Fermi/LAT Photon Measurements Constraints from Dwarf Galaxies

32. Do the Model Points Cluster in the 19-Dimensional Parameter Space? • New data mining procedure based on Gaussian • potentials • Full Model Set before constraints is random – no • clustering M. Weinstein

33. Clustering of Models (12000 Points) Gainer, JLH, Rizzo, Weinstein, in progress

34. Summary • Studied the pMSSM, without GUT & SUSY breaking assumptions, subject to experimental constraints • We have found a wide variety of model properties not found in mSUGRA/CMSSM • Colored sparticles can be very light • NLSP can be basically any sparticle • NLSP-LSP mass difference can be very small • Wider variety of SUSY predictions for Dark Matter & Collider Signatures than previously thought • Things to keep in mind for LHC analyses • MSSM  mSUGRA: a more general analysis is required • Stable charged particle searches are very important • Many models can lead to soft particles + MET • Mono-jet search is important

35. This new decade promises to be exciting, full of discoveries with a revolution in humanity’s exploration of the fundamental nature of the Universe! CDMS

36. 133- 183 133- 243 >243 GeV <133 GeV Models with Large SI Direct Detection Cross Sections wrt CDMSII

37. 100 700