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 Accommodates but does not explain Fermion masses CP-Violation Well known fine-tuning, hierarchy, triviality problems LEP EWWG – Winter 2007  m H 2 ~~ M Pl 2

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  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

Randall – Sundrum Model 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/M pl ) Signatures in dilepton, diboson, dijet final states  wk = M Pl e -kr  q q l l

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

Dimuon Signature Two reconstructed muons One |  | < 2.1 One with P T > 24 GeV Use angular distribution to discriminate spin Main background SM Drell-Yan c = 0.01 c = 0.02 c = 0.05 c = fb fb fb -1 See Dilepton Talk Later this session

Diphotons 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 E T > 150 GeV Isolated both by calorimeter and tracker

Dijets Two jets |  Fit invariant mass (leading 2 jets) Compare observed/predicted Including Systematics Jet Energy Scale Jet Resolution Trigger Prescales Radiation See Dijets talk later this session…

Black Holes Dimopolous, Landsberg Black holes could form if two colliding partons have impact parameter smaller than R S Partonic Cross-Section given by geometry, total cross-section convoluted with PDFS Decay by Hawking Radiation Demographic Decay Spherically Symmetric E/2 b b < R s (E)  BH forms  R S 2

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

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

Black Hole – CMS II

ATLAS Black Holes Event Selection Electron or muon with |  |  p T > 50 GeV Two approaches (almost identical results) |  p T | > 2.5 TeV (jets + leptons) At least 4 jets and lepton p T > 200 GeV A n=2,m = 5-14 TeV C n=2,m = 8-14 TeV B n=4,m = 5-14 TeV D n=7,m = 8-14 TeV ABCDABCD

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

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

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

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…

Backup

Graviton Signatures at the LHC 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 q g g g G g G q q G V q q G V q q l l q q V V

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

Dimuon Backup II

Dimuon Backup III

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

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

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

Diphoton Backup II

Diphoton Backup III

Diphoton Backup 4 Hard Process Scale PDF Uncertainties

Dijet Backup

Sezen Sekmen SUSY 07

Sezen Sekmen SUSY 07

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

Black Hole Backup CMS TDR -2006

Atlas Black Hole backup As a function of black hole threshold