Highlights from the Race to New Physics at the LHC

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Highlights from the Race to New Physics at the LHC

Scott Thomas

Rutgers University

April 6, 2012

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LHC has Opened up a Vast Landscape of Un-Explored Territory

Many Opportunities to Explore this New Territory Not Static - Discovery Potential Continually Evolving

Strategy:

Wide Spectrum of Searches – Mow down Un-Cut Territory Adapt Searches to Exploit Rapidly Changing Discovery Potential

( Search First for What can be Discovered First – Match the Search to the Discovery Potential )

Search for New Physics: Higgs + SUSY + …

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Simplified Model Topologies

CMS Highlights

New Physics Searches

Di-Jet Regge Resonances, Multi-Jets, Di-Photon + MET, OS Di-lepton, Multi-Lepton, Multi-Lepton + Kinematics

Higgs -> Multi-Leptons (Higgs -> Di-Photon, Higgs -> WW -> l n l n )

Consistent On-Shell Effective Theory

Coming Highlights for 2012

Outline:

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Underlying Theoretical Framework

Models Simulations Signatures

Experimental Signature Search

Generally No Single Definitive Prediction (SUSY) Just Hope that Some States (Super-Partners ) are Kinematically Accessible Make (Prioritized) List of Signatures and Do the Experimental Searches …

SUSYExperimental Searches

Decoupling Limits

Search for New Physics: Theory <-> Experiment

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Experiment - Signatures Most Important Metric

Production and Decay Topologies -> Final States -> Signatures

Relatively Narrow Intermediate States

Parameterized by

Mass Spectrum, Spins + Quantum Numbers (or Decay Distributions) (More later … )

Organize Mapping Theory <-> Experiment

G / m << 1

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(Dube, Glatzer, Somalwar, Sood, ST)

Factorized Mapping - Simplified Topologies

# Topologies # Decays in Each Topology

Acceptance for Topology t in Final State f Final State

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# Topologies # Decays in Each Topology

Acceptance for Topology t in Final State f Final State

• Production s’s Factor Out of Problem • Cascade Br’s Factor Out of Problem• Acceptances Factor Out of Problem At = At(mi) Only Multiple Topologies + Multiple Channels Easily Combined • Good for Arbitrary Relations Among st,Brat,mit (No Assumptions) Can Add More Topologies Later (Incoherent) (Since Don’t Simulate Combinations of Topologies)• Report s.Br and s.Br.A(mi) or A(mi) for Each Topology

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CDF Tri-Lepton Search Parameterization Becoming Standard for CMS + ATLAS Searches - Benchmarks Very Useful for Theory-Level Studies … (More later)

Production and Decay Topologies

Simulation

Experimental Signature Search

• Production s’s Factor Out of Problem • Cascade Br’s Factor Out of Problem• Acceptances Factor Out of Problem At = At(mi) Only Multiple Topologies + Multiple Channels Easily Combined • Good for Arbitrary Relations Among st,Brat,mit (No Assumptions) Can Add More Topologies Later (Incoherent) (Since Don’t Simulate Combinations of Topologies)• Report s.Br and s.Br.A(mi) or A(mi) for Each Topology

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Search for New Physics: Experiment

Objectelectron

photon jet

b-jet

muontau

Searching for Extremely Rare Processes (Approaching part per 1015 level )

Control of “Fake” Objects Crucial !! (An example later)

Reconstructed Physics Objects

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Signature Space - Physics Objects

MET , …

Leptons , taus , Photons , …

Jets , b-jets

Searches are Built Around SM (+fake) Backgrounds –

Design Searches Away from “Origin” of Signature Space Along Some Axis or Axes

s (fb) 7 TeV

W 100,000,000 Z 30,000,000tt 150,000

WW 40,000WZ 17,000ZZ 6,500

H inclusive 17,900

ttW 150ttZ 100WWW 60

ttWW 2

ww (400 GeV ) 10gg (1 TeV) 10

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Signature Space - Physics Objects

MET , …


Jets , b-jets

s (fb) 7 TeV

W 100,000,000 Z 30,000,000tt 150,000

WW 40,000WZ 17,000ZZ 6,500

H inclusive 17,900

ttW 150ttZ 100WWW 60

ttWW 2

ww (400 GeV ) 10gg (1 TeV) 10

Searches are Built Around SM (+fake) Backgrounds –

Design Searches Away from “Origin” of Signature Space Along Some Axis or Axes

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Search for New Physics

Highlights: CMS – Rutgers

Di-Jet Regge Resonances Multi-Jet Resonances Di-Photon + MET Multi-Lepton Multi-Lepton + Kinematics Higgs -> Di-photon

Multi-Jets (CDF) Di-Jet Extinction Boosted top-top-jet …

Highlights: CMS

Higgs -> WW -> l n l n OS Di-Lepton … Phenomenology:

COSET Higgs -> Multi-Leptons Higgs -> WW -> l n l n Kinematic Reconstruction Testing Higgs Mechanism New Physics with Higgs …

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Search for New Physics

Highlights: CMS – Rutgers

Di-Jet Regge Resonances Multi-Jet Resonances Di-Photon + MET Multi-Lepton Multi-Lepton + Kinematics Higgs -> Di-photon

Multi-Jets (CDF) Di-Jet Extinction Boosted top-top-jet …

Spare Experimental Realities: Triggers, Cuts, Data Analysis, Characterize Backgrounds, Fake Rates, Data Driven Closure Tests, …

Highlights: CMS

Higgs -> WW -> l n l n OS Di-Lepton … Phenomenology:

COSET Higgs -> Multi-Leptons Higgs -> WW -> l n l n Kinematic Reconstruction Testing Higgs Mechanism New Physics with Higgs …

High pT: s(pp jj) Largest – First Place to Look for New Physics String Scale a0

-1 = ms2 Could be O(TeV)

SU(3)

SU(2)

Quark

W-Boson

Gluon Quarks, Gluons = Open String Modes on D-Branes

Open String Regge Excitations - Any D-Brane Realization String Theory - Observable for ms = O(TeV) - Significant Modification of QCD

Open String Di-Jet Regge Resonances

Tower of Excitations for Gluon, All Quarks, … g* , q*

mn

2 = n ms2 n = 1,2,3,… Equally Space in m2

Degenerate (up to small finite corrections) Regge Excitation Spins J = 0,…,n

Previous Work:

Cullen, Perlestein, Peskin e+e- Collider Anchordoqui, Goldberg, Lust Di-Jets Interesting SignatureNawata, Stieberger, Taylor (Only some channels, Color Averaged Only, Estimate of Incoherent Widths, No Interference Effects, ... )

String-String Scattering

= n or nnn

Veneziano Form Factor

Crossing Symmetry: x <-> y s-Channel Resonances in Many Color and Flavor Channels ms = O(TeV) - Significant Modification of Di-Jets

Regge Level Spin

Open String Di-Jet Regge Resonances (Kilic, ST)

QCD 2 -> 2 Scattering Amplitudes with Veneziano Form Factor

All Spin and Most Color Channels …


Singular on s-channel Regge poles - Improve Scattering Amplitudes for Leading Re-scattering Effects - Finite Width of Resonances

Modified Optical Theorem:

Includes Effects of Coherence Quantum Interference Among Regge Resonances of Different Spin and Intereference with Continuum

2 = =

2Res2

Res1


Direct Probe of String Theory

Constructive Interference

Destructive Interference

1st Resonance BIG –

Many Quark and Gluon Color and Flavor Channels, Multiple Spins – Add (In)Coherently

mn2 Spacing

Gn Grow Rapidly with n

7 Tev Parton Level

Incorporate Improved Veneziano Amplitudes into Veneziano Monte Carlo (VMC) (Reduces to Pythia 2->2 Scattering for ms -> large)


ms > 2.4 TeV (3 pb-1)

(Eventually - Contact Interaction)

Open String Di-Jet Regge Resonances (Kilic, ST, Harris, …, CMS)

ms > 4.0 TeV (1 fb-1)

(Eventually - Contact Interaction)

Open String Di-Jet Regge Resonances (Kilic, ST, Harris, …, CMS)

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SUSY Topologies Produce Super-Partners in Pairs or Possibly Resonantly if R-Sym Violation

SM Particles Emitted in Cascade Decays of Super-Partners

R-Symmetry Conserved Violated

Lightest Stable Un-Stable Super-Partner

Generic Non-Degenerate Spectrum - High pT Isolated Objects:

Jets, b-Jets, Electrons, Muons, Taus, Z-Bosons, Photons, MET, Top Quarks + Lightest Super-Partner(s) SUSY Great Signature Generator

Detect Passage Through Detector

Lepton

Jets

Jets

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The Scale of Super-Symmetry Breaking

Possible Decay to Goldstino (component of gravitino) Provides a Natural Classification of Inclusive Signatures

SM Particle

Goldstino

Lightest SM Super-Partner Meta-Stable

• Prompt Decay < O(100) TeV

• Decay Within Detector O(100) TeV • Effectively Stable in > O(100) TeV Detector

Finite Gap Emitted SM Particle - High pT

Blunt Inclusive Analyses that Capture Final Decays to Goldstino are Robust … (No Softening from Compressed Spectrum)

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SUSY Inclusive Signature Classification (RPC)

Run II Workshop: hep-ph/0008070

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SUSY Inclusive Signature Classification (RPC)

Run II Workshop: hep-ph/0008070

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LHC SUSY Production

Irreducible Super-Partner Pair Production

Rapidly Beyond Tevatron in Relatively Low Background Final States

Strong Production > O(pb-1) (2010 – 2011 ½ -> )

Weak Production > O(fb-1) (2011 ½ – 2012 -> )

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Di-Photon + Jets + MET Signature

Bino

Goldstino

Photon

Gluino, Squarks

Jets

(Gershtein, ST, Zhao, Park, … , CMS)

Neutralino -> Photon + Goldstino (Prompt) with Strong Production

Necessarily Extra Jet(s) - Reduces Background - …

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Bino

Goldstino

Photon

Gluino, Squarks

Jets


Significant SM BackgroundNear Origin of Di-photon + MET Space

Neutralino -> Photon + Goldstino (Prompt) with Strong Production


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Gluino, Squarks

Bino

Goldstino

Photon

Jets


Neutralino -> Photon + Goldstino (prompt) with Strong Production


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Opposite Sign Di-Leptons + Jets + MET Signature

Wino

Lepton

Gluino

Jets

Squarks

Bino

Jets

SleptonLepton

Neutralino -> Neutralino + Di-Lepton with Strong Production

Top-Top Irreducible Background Significant ! (t -> Wb -> l n b)

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(Park, Lath, ST)

Average MET Distribution = Average pT(ll) Distribution

In-Situ Data Driven MET Characterization

Dominant Background is Self-Calibrating !

MET or pT(ll) (GeV)

Blue METGreen Vector Sum ll

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Wino

Lepton

Gluino

Jets

Squarks

Bino

Jets

SleptonLepton



(CMS)

HT = S |pT | Jets

Relatively Low Backgrounds (WZ + Di-Leptons + fakes)

Tri-Leptons + MET Signature Chargino -> Neutralino + Lepton Neutralino -> Neutralino + Di-Lepton

Tevatron – Narrowly Focussed on Classic Tri-Lepton Signature (Flavor + Charge + MET)

LHC – Considerably Expanded Scope + Intrinsic Sensitivity …

Wino

Lepton Bino

SleptonLepton

Backgrounds Closely Correlate with Type of Di-Lepton Pairs within Set of Multi-leptons

Multi-Lepton Signatures (Somalwar, Gray, Zhao, Park, ST)

Classify All Multi-Leptons Channels: Defines a Multi-Channel Hierarchy of Backgrounds

Multi-Lepton Signatures (Somalwar, Gray, Zhao, Park, ST)

Multi-Lepton Signatures


(Somalwar, Gray, Zhao, Park, ST)

Use Classification Along with NDY > 0 On/Off Z to Make Hierarchical Ordering of Multi-Lepton Channels According to Background Events -> Channels Lowest to Highest Background Exclusively

Maximizes Sensitivity (Given Signal may Overlap with Low Background Channels)

Exclusive Combination of All Channels



(Somalwar, Gray, Zhao, Park, ST)

(CMS)

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Multi-Lepton Signatures (Somalwar, Gray, Lath, ST, Walker, Arora, Panwalker, Contreras-Campana, … CMS)157 Exclusive Channels ->

ST Analysis 4.7 fb-1

ST = S |pT | All Objects

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Multi-Lepton Signatures (Somalwar, Gray, Lath, ST, Walker, Arora, Panwalker, Contreras-Campana, … CMS)157 Exclusive Channels ->

MET + HT Analysis 4.7 fb-1

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Wino

Goldstino

Lepton

Gluino

Jets

Squarks

Bino

SleptonR

Lepton

Jets

mq = 0.8 mg , mlR = 0.3 mC , mN = 0.5 mC

Slepton Co-NLSP - Prompt Decay to Goldstino with Strong Production

Leptonic RPV and No-MET Hadronic RPVTopologies also …

(Somalwar, Gray, Lath, ST, Walker, Arora, Panwalker, Contreras-Campana, … CMS)

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The Variables Object pT’ , MET, HT, ST, meff, …

Very Blunt Instruments

Useful Far Out Along Axes in the Signature Space where SM Backgrounds are Low

Low “Temperature” Regions of Signature + Phase Space

Searches are Effectively Thermal in these Low “Temperature” Regions

Kinematic Correlations are Required for More Refined Measurements Closer to the Origin of Signature Space (Less Inclusive)

Signal Might be Buried There Under SM Background Low ST, MET, … , Top, Bottom, or Tau Enriched

MET , …


Jets , b-jets

High pT: s(pp Multi-jets) Large

Multi-Jet Signature

jet

jet jetjet

jetjet

Purely Hadronic Final States Very Difficult – Prodigious QCD Background … Axis Un-explored Great Discovery Potential to Strong New Physics

QCD Fills Up Phase Space

Standard Techniques Fail

(Lath, Halkiadakis, Essig, ST)

Boosted Tri-Jet Resonance

Focus on Resolved Individual Jets Rather Than Giant Merged Jets

mje

t-jet

-jet

pT,jet-jet-jet

Cut

Accept

Combinatoric Confusion

Boosted Resonance

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Multi-Jet Signature

QCD Fills Up Phase Space

Approximately Scale Invariant

j j j

j j j

pp QQ

SUSY – Hadronic RPV

(Lath, Halkiadakis, Essig, ST)

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Multi-Jet Signature



j j j

j j j

pp QQ


(Lath, Halkiadakis, Seitz, Dugan, Hidas, ST, … , CMS)

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Multi-Jet Signature



j j j

j j j

pp QQ



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Multi-Jet Signature




CDF Search First Observation of Boosted Tops pt>300 GeV (Tri-Jet Resonance) Excess !

5 fb-1 Results Soon

Extended Other Searches tt+jet Leptons …

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Cascade Decay Correlations

S-matrix = f( mijk…2 ) (Unpolarized,

T- Invariant Spins Unobserved)f( mijk…

2 ) = f( mij2 )

Probability Distribution in Generalized Dalitz Space mij2

i,j = All Pairs

True of Sub-processes Also

Exploit (Sub-Process) Correlations in Searches

3-Point Interaction

Amplitude (Almost) Uniquely Determined by Lorentz Invariance up to Momentum Dependent Form Factor

f(p12,p2

2,p32)

J = ½, ½, 0

J = ½, ½, 1

……

Near Mass Shell

Form Factor Nearly Constant G/m << 1

Cascade Decay Correlations

Consistent On-Shell Effective Theory for Cascade Decay Correlations (COSET)

Develop Effective Field Theory - Calculate Cascade Decay Correlations

Systematic Expansion in G/m , m/M

Provides Framework to Consider Wide Range Standard Model + New Physics Processes Correlations in Generalized Multi-Dimensional Dalitz Spaces of Invariants

Leading Order in COSET Expansion: Sequential Two Body Cascade Decays Invariant Mass Distributions in Generalized Dalitz Space Spin 0, ½ (SUSY) No Arbitrary Couplings

(Graesser, ST Shelton, Park)

COSET – Sequential Two-Body Cascade Decay Correlations

½

0½

½ ½

0

0½

½

0

0½

½

Triangle Hump Half-Cusp

Chiral Insertion

Chiral Structure Unique - Independent of Majorana/Weyl, Dirac, PseudoDirac, …

(1 / G

)( d

G /

dx)

(1 / G

)( d

G /

dx)

(1 / G

)( d

G /

dx)

x x x

Only Possibilities for Adjacent Branch Correlations with J=0, ½ (Almost) Complete List of Correlations - Three Sequential Decays J <= 1


x = mll / mllmax

Discerning SUSY - Cascade Decay Correlations

(Template) Search for Correlations in Data

Limited Set of Possible Adjacent Branch Correlations : J=0, ½ Adjacent Di-Lepton Distributions – All Possible SUSY Spectra

SUSY Distinctive Patterns


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Wino

Lepton

Gluino

Jets

Squarks

Bino

Jets

SleptonLepton



(CMS)

Low “Temperature”Region of Phase Space

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Wino

Lepton

Gluino

Jets

Squarks

Bino

Jets

SleptonLepton



(CMS)


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Wino

Lepton

Gluino

Jets

Squarks

Bino

Jets

SleptonLepton



(CMS)


OS Di-Lepton Edge

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Wino

Lepton

Gluino

Jets

Squarks

Bino

Jets

SleptonLepton



(CMS)


Triangle, Hump, Half Cusp …

Next To Nearest OnShell Mass Extraction Technique (NNOMET)

Correlations Uniquely Determined by Masses and Spins - COSET (SUSY) Three Sequential Cascade Decays

Jets+ Leptons+MET

Includes Combinatoric “Non-Confusion” for Lepton1,2

Distribution In 3D Dalitz Space Uniquely Determined in Terms of 4 Mass Parameters 4 Sparticle Masses in Cascade Decay Tree

m2jl

d G

/ d

mjl

m2jl

Does Not Use Measurent of MET

m2ll

m2jl

(Park,ST )

Next To Nearest OnShell Mass Extraction Technique (NNOMET) LM1 Benchmark TDR Cuts 14 TeV , 100 pb-1

Red – SUSY Decay Sequence Blue – SUSY “Combinatoric” Decay Sequence Green – Top Background

Likelihood Entropy Kinematic Mass Parameters

(S+S)/B = 1/3

O(50) SUSY Events

Form an Ensemble of All Jets pT > 60 GeV + 2 Leptons Multiple Entries per Event

B (GeV)

A (

GeV)

Deploy at Discovery Level …

(Park,ST )

Multi-Lepton Signatures Sensitive to Extremely Rare Processes

Un-anticipated Background – “fake” lepton

Largest Source: Z -> l l g* -> l l l (l) (Others)

(Somalwar, Gray, Lath, ST, Walker, Arora, Panwalker, Contreras-Campana, … CMS; Kilic, Park)

Asymmetric Internal Conversion g* -> e(e) , m(m)

Compare External Conversion in Material g* -> e(e)

Standard MC’s Don’t Capture IR Singular Region of Phase Space

Developed Special Purpose AIC MC

First Observed in Multi-Dimensional Dalitz Distribution O(few) Events

First Observation of Z -> lll(l), llll

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Multi-Lepton Signature + Kinematics Build Searches Around Backgrounds

Tri-Leptons – Dominant Irreducible Background = WZ


mll (GeV)

mT

l’MET

(Ge

V)

5 fb-1 WZ

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Multi-Lepton Signature + Kinematics Build Searches Around Backgrounds

Tri-Leptons – Dominant Irreducible Background = WZ


mll (GeV)

mT

l’MET

(Ge

V)

Wino

Lepton Bino

SleptonLepton

Kinematic Sub-Division of Appropriate Channels

Further Enhances Sensitivity

5 fb-1 WZ + Wino-Slepton-Bino

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All Blunt “Thermal” Searches Can be Improved With Refined Kinematics …

But Generally Become Less Inclusive …

Price of Digging Towards Origin in Signature Space

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Multi-Lepton Signals of Higgs (Craig, Gray, Park, Kilic, Somalar, ST)

Higgs Final States Will Eventually Contaminate Multi-lepton Search …

Turn Around – Multi-Leptons as Search for Higgs

Decay:

h -> ZZ -> l l t t -> l l l t h -> WW -> l n l n h -> t t -> t l

Production:

Wh -> l n h Zh -> t t h -> t l h tth -> WbWb h ->b l n b l n h

Signal Spread Out over Many Channels Minimal Significance in Any Given Channel

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Multi-Lepton Signals of Higgs (Craig, Gray, Park, Kilic, Somalar, ST)

Higgs Final States Will Eventually Contaminate Multi-lepton Search …

Turn Around – Multi-Leptons as Search for Higgs (No Kinematic Optimization)

Decay:

h -> ZZ -> l l t t -> l l l t h -> WW -> l n l n h -> t t -> t l

Production:

Wh -> l n h Zh -> t t h -> t l h tth -> WbWb h ->b l n b l n h

Estimated s / sSM Limit 5 fb-1

Calculated A(mh) for 11 SimpleTopologies Exclusive Combination - (extrapolation)

Illustrates Power of Multi-Channel Multi-Lepton Search

Signal Spread Out over Many Channels Minimal Significance in Any Given Channel

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Inclusive Blunt “Thermal” Analyses have Mowed Down a Lot of Territory

More Refined Analyses Have Begun to Dig Down Towards the Origin of Signature Space (Kinematic Refinements + Other Reconstruction Techniques)

Many Signatures Well Probed – Some Low Scale SUSY Breaking Scenarios , … , Many more , …

Lot’s of Uncut Territory to Explore Particularly O(few) 100 GeV scale !! *

2012 Will be the Year of Discovery at the LHC Expect First Definite Results for the EWSB Sector … *

The Search for New Physics

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No Definitive Discovery to Report Quite Yet

The Race is Still On

So Stayed Tuned …

Highlights from the Race to New Physics at the LHC

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