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Randall- Sundrum Gravitons and Black Holes at the LHC

Randall- Sundrum Gravitons and Black Holes at the LHC. Kevin Black Harvard University For the ATLAS and CMS Collaborations. Outline. TeV Scale Gravity Gravitons Black Holes Summary. Landsberg. State of the Standard Model. Effective model which describes data well

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Randall- Sundrum Gravitons and Black Holes at the LHC

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  1. Randall- Sundrum Gravitons and Black Holesat the LHC Kevin Black Harvard University For the ATLAS and CMS Collaborations

  2. Outline • TeV Scale Gravity • Gravitons • Black Holes • Summary Landsberg

  3. State of the Standard Model • Effective model which describes data well • Accommodates but does not explain • Fermion masses • CP-Violation • Well known fine-tuning, hierarchy, triviality problems mH2 ~ ~ MPl2 LEP EWWG – Winter 2007

  4. Why Gravity at the LHC • View Standard Model as effective theory as a low energy approximation • New theory takes over at energy scale comparable to the Higgs mass L ~ 1 TeV • SUSY, Technicolor, Little Higgs, .. • Perhaps there is no other scale , GUT scale is ~ TeV • Gravity made strong by extra dimensions where gravity propagates

  5. SM fields on one of two 4-dimensional brane in a 5-D space time Graviton can propagate in the bulk Kaluza-Klein States on the order of TeV Main parameters: Mass of Graviton Curvature parameter ( c = k/Mpl) Signatures in dilepton, diboson, dijet final states Randall – Sundrum Model wk = MPl e-kr q l l q

  6. Current Direct Limits PRL 100, 091802 (2008) CDF Conference note 9160 Mass limits from 300 – 900 GeV depending on coupling

  7. Two reconstructed muons One |h| < 2.1 One with PT > 24 GeV Use angular distribution to discriminate spin Main background SM Drell-Yan Dimuon Signature See Dilepton Talk Later this session c = 0.01 c = 0.02 c = 0.05 c = 0.10 10fb-1 100 fb-1 300 fb-1

  8. Branching ratio twice as large as dilepton Z’ doesn’t decay into diphotons Backgrounds Direct Diphoton Production Photon + Jet Dijets (photon misidentification) Drell-Yan (missing tracks) Two isolated photons with ET > 150 GeV Isolated both by calorimeter and tracker Diphotons

  9. Two jets |h| < 1 Fit invariant mass (leading 2 jets) Compare observed/predicted Including Systematics Jet Energy Scale Jet Resolution Trigger Prescales Radiation Dijets See Dijets talk later this session…

  10. Dimopolous, Landsberg Black holes could form if two colliding partons have impact parameter smaller than RS Partonic Cross-Section given by geometry, total cross-section convoluted with PDFS Decay by Hawking Radiation Demographic Decay Spherically Symmetric Black Holes b < Rs(E)  BH forms E/2 s = p RS2 b E/2

  11. Black Holes – Generator Studies • CATFISH • Collider grAviTational FIeld Simulator for black Holes Comput.Phys.Commun.177:506-517,2007

  12. Parameters Plank Scale 2 TeV Black Holes 4 – 10 TeV Signature high sphericity high ΣpT high multiplicity Backgrounds tt, W/Z + jets, Diboson, multijets Selection MBH(reco) > 2 TeV Multiplicity > 4 Sphericity < 0.28 Black Hole – CMS I

  13. Black Hole – CMS II

  14. ATLAS Black Holes • Event Selection • Electron or muon with |h| < 2.5, pT > 50 GeV • Two approaches (almost identical results) • |SpT| > 2.5 TeV (jets + leptons) • At least 4 jets and lepton pT > 200 GeV A n=2,m = 5-14 TeV B n=4,m = 5-14 TeV C n=2,m = 8-14 TeV D n=7,m = 8-14 TeV A B C D

  15. ATLAS Black Holes 2 • Reconstruct the visible mass of the black hole from all objects and MET • Very dramatic signature + large signal cross-sections

  16. ATLAS Black Holes 3 • Investigated Event Shapes • Do give separation with background • Very different for different parameters

  17. ATLAS Black Holes 4 • Discovery potential • S/B > 5 • S > 10 • Discovery possible ranging from • Few pb for 5 TeV • ~1 fb for 9 TeV

  18. Summary • Signatures from Gravitons and Black Holes would be dramatic compelling signatures • RS Gravitons should be observable ~5 TeV range and quickly observable for ~1 TeV masses • Black holes could be seen to very high masses (8-9 TeV) with a few to ~ 30 fb-1 of data (depending on parameters) • For older results go to ATLAS and CMS exotics pages • New ATLAS results expected to be made public ~few months…

  19. Backup

  20. Graviton Signatures at the LHC q g g g • Gravitons couple to momentum tensor (contribute to most SM processes) • Monojets • Single Vector Boson production • Dilepton/Dijet/Diboson production • As resonance • As non-resonant modification to SM cross-section q g G G q q V V G q G q q q V l l V q q

  21. Backup Dimuon I Signal Cross-Sections Drell-Yan Backgrounds – others on ~ 10 to 40 times smaller

  22. Dimuon Backup II

  23. Dimuon Backup III

  24. Dimuon backup 4 • Systematics Theory • QCD and EW Scale – 13-17% • PDF – 7% • Systematics Experiment • Misalignment • Pileup - negligible • Background Shape – 10-15% shift in signficance • Trigger –negligible (normalizations float in fit) • Magnetic Field – negligable

  25. Dimuon Backup 5 C = 0.01 C= 0.1 Solid line – ideal Dotted – long term alignment Dashed – “first alignment”

  26. Diphoton Backup I Diphoton production Dijet Drell-Yan Photon + Jet

  27. Diphoton Backup II

  28. Diphoton Backup III

  29. Diphoton Backup 4 Hard Process Scale PDF Uncertainties

  30. Dijet Backup

  31. Sezen Sekmen SUSY 07

  32. Sezen Sekmen SUSY 07

  33. CMS Black Hole Backup PDF Uncertainties : Uncertainty on Signficance ~ 12% Sphericity

  34. Black Hole Backup CMS TDR -2006

  35. As a function of black hole threshold Atlas Black Hole backup

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