Lisa Randall Harvard UniversityLisa Randall, Harvard University

Ente ing Ne E aEnte ing Ne E aEntering New EraEntering New Era

M h ll LHC hM h ll LHC hMany challenges as LHC approachesMany challenges as LHC approachesCritical questions:Critical questions:

Are we optimizing existing searches?Are we optimizing existing searches?Are we doing all the searches possible?Are we doing all the searches possible?

M d lM d lModelsModelsLowerLower--Scale: Supersymmetry, Little HiggsScale: Supersymmetry, Little HiggsHigherHigher--Scale: Strongly Interacting theories, Extra Scale: Strongly Interacting theories, Extra dddimensionsdimensions

Focus today on extra dimensions Focus today on extra dimensions Bon s Wa to lea n abo t q ant m g a itBon s Wa to lea n abo t q ant m g a itBonus: Way to learn about quantum gravity Bonus: Way to learn about quantum gravity and strongly interacting physicsand strongly interacting physics

OUTLINE OF TALKSOUTLINE OF TALKSOUTLINE OF TALKSOUTLINE OF TALKS

Lecture 1: Introduction to RS1Lecture 1: Introduction to RS1MotivationMotivationOriginal ModelOriginal ModelOriginal ModelOriginal ModelKK signatures of original modelKK signatures of original model

Lecture 1Lecture 1--2 Bulk RS2 Bulk RSKK Signatures when bulk gauge bosons, fermionsKK Signatures when bulk gauge bosons, fermions

Lecture 2Lecture 2Black Holes from Extra DimensionsBlack Holes from Extra DimensionsBlack Holes from Extra DimensionsBlack Holes from Extra Dimensions

Lecture 3Lecture 3Flavor from Warped Extra DimensionsFlavor from Warped Extra Dimensions

M ti ti f N Di iM ti ti f N Di iMotivations for New DimensionsMotivations for New Dimensions

String theory: extra dimensions essential String theory: extra dimensions essential Lower energies: Extra dimensions can Lower energies: Extra dimensions can ggilluminate connections among observable illuminate connections among observable phenomena in new ways phenomena in new ways General Relativity works for any number General Relativity works for any number of dimensionsof dimensionsPlus:Plus:Bonus: Even shed light on purely fourBonus: Even shed light on purely four--g p yg p ydimensional physicsdimensional physics

A New View of Weak Scale PhysicsA New View of Weak Scale PhysicsA New View of Weak Scale PhysicsA New View of Weak Scale Physics

Many new results in physics in last ten yearsMany new results in physics in last ten yearsy p y yy p y ySome of the most exciting involve extra Some of the most exciting involve extra dimensions of spacedimensions of spaceIntriguing possibilities for our universe: bothIntriguing possibilities for our universe: bothIntriguing possibilities for our universe: both Intriguing possibilities for our universe: both theoretical and experimentaltheoretical and experimentalWarped geometry plays a central role in string Warped geometry plays a central role in string p g y p y gp g y p y gtheory todaytheory todayWarped geometry has particularly interesting Warped geometry has particularly interesting signatures: resonances!signatures: resonances!signatures: resonances!signatures: resonances!Critical to explore theoretical possibilities and Critical to explore theoretical possibilities and experimental consequencesexperimental consequences

What’s Ne ? B anesWhat’s Ne ? B anesWhat’s New? BranesWhat’s New? Branes

Branes:Branes:

Distinguish Distinguish dimensions along dimensions along gga brane from a brane from those those perpendicular to itperpendicular to it

Important Important Ph l i l/M d lPh l i l/M d l B ildiB ildiPhenomenological/ModelPhenomenological/Model--Building Building

ImplicationsImplicationspp1)1) Don’t need curled up dimensions to get Don’t need curled up dimensions to get

small extra dimensionsmall extra dimension1)1) Can be bounded by branesCan be bounded by branes

Before Branes,Before Branes,C l dC l d Di i l W tDi i l W tCurledCurled--up Dimension only Way to up Dimension only Way to

Hide DimensionHide Dimension

Idea is that something small is invisible

Here the small thing is a dimension of space

Entire universe is curled up!

Dimensions you observe depend Dimensions you observe depend iion size:on size:

Two dimensions for a small bugTwo dimensions for a small bugTwo dimensions for a small bugTwo dimensions for a small bug

rc

One dimension for a bigger One dimension for a bigger ( l ti t ll d( l ti t ll d di i )di i )(relative to rolled(relative to rolled--up dimension) up dimension)

bugbuggg

rc

Bo nded b B anesBo nded b B anesBounded by BranesBounded by Branes

rc

Important Important Ph l i l/M d lPh l i l/M d l B ildiB ildiPhenomenological/ModelPhenomenological/Model--Building Building

ImplicationsImplicationspp1)1) Don’t need curled up dimensions to get small Don’t need curled up dimensions to get small

extra dimensionextra dimension1)1) Can be bounded by branesCan be bounded by branes

2)2) Not all matter travels in bulk; BRANEWORLDNot all matter travels in bulk; BRANEWORLD1)1) Not necessarily KK mode of electron, photonNot necessarily KK mode of electron, photon2)2) Extra Dimensions can be much bigger than thoughtExtra Dimensions can be much bigger than thought

Particles can be stuck on a braneParticles can be stuck on a braneLik W t d l t “ hLik W t d l t “ hLike Water droplets on “shower Like Water droplets on “shower

brane”brane”LowerLower--dimensional dimensional surface in highersurface in higher--dimensional spacedimensional spacedimensional spacedimensional spaceShower curtains trap Shower curtains trap things (waterthings (waterthings (water things (water droplets) on lowerdroplets) on lower--dimensional surfaces. dimensional surfaces. Similarly, particles can Similarly, particles can be confined to a be confined to a threethree--dimensionaldimensionalthreethree dimensional dimensional brane brane

B ane o ldB ane o ldBraneworldBraneworldHigherHigher--dimensional world in which particles and dimensional world in which particles and

tt t k btt t k bmatter are stuck on a branematter are stuck on a brane

Drawn as 2D

Really 3D

And really

i fi itinfinite

The boundary brane might house matter, particles; or could be brane inside bulk

Important Important Ph l i l/M d lPh l i l/M d l B ildiB ildiPhenomenological/ModelPhenomenological/Model--Building Building

ImplicationsImplicationspp1)1) Don’t need curled up dimensions to get small Don’t need curled up dimensions to get small

extra dimensionextra dimension1)1) Can be bounded by branesCan be bounded by branes1)1) Can be bounded by branesCan be bounded by branes

2)2) Not all matter travels in bulk; BRANEWORLDNot all matter travels in bulk; BRANEWORLD;;1)1) Not necessarily KK mode of electron, photonNot necessarily KK mode of electron, photon2)2) Extra Dimensions can be much bigger than thoughtExtra Dimensions can be much bigger than thought

3)3) Warping permits even infinite dimensionWarping permits even infinite dimension1)1) Gravity gets localizedGravity gets localizedy gy g

With branes, we’ve found warped geometryWith branes, we’ve found warped geometrysolutions that provide:solutions that provide:solutions that provide:solutions that provide:

New way to hide dimensionsNew way to hide dimensionsN t f l i th iN t f l i th iNew concept of our place in the universeNew concept of our place in the universeNew way to explain weakness of gravityNew way to explain weakness of gravity

Connection to Ph sicsConnection to Ph sicsConnection to PhysicsConnection to Physics

Hi h P blHi h P blHierarchy Problem:Hierarchy Problem:

Why is gravity so weak compared Why is gravity so weak compared to the other elementary forces?to the other elementary forces?

Might not seem weak but magnet can take on the entireMight not seem weak but magnet can take on the entiremagnet can take on the entire Earth-magnet can take on the entire Earth-

Hi h P blHi h P blHierarchy ProblemHierarchy ProblemNeed “fine-tuning” to get very differentmasses

Key issue in particle physics today

One that will be resolved at LHC

“Fine“Fine--tuning” is unlikely:tuning” is unlikely:FineFine tuning is unlikely:tuning is unlikely:

Barnett Newman: Broken Obelisk

RS1 “Multiverse:”RS1 “Multiverse:” With Raman Sundrum

Warped Spacetime Geometry Warped Spacetime Geometry Sundrum

•Two branes•Two branes

•Gravity will be concentrated on GravitybraneGravitybrane

•But we live on a second brane:

•The Weakbrane/TeV Brane•The Weakbrane/TeV Brane

Natural for gravity to be weak!Natural for gravity to be weak!Natural for gravity to be weak!Natural for gravity to be weak!

Small probability for Small probability for graviton to be near graviton to be near the Weakbranethe WeakbraneIf we live anywhere If we live anywhere b h G i bb h G i bbut the Gravitybrane, but the Gravitybrane, gravity will seem gravity will seem weakweakweakweakNatural consequence Natural consequence of warped geometryof warped geometryof warped geometryof warped geometry

R li A Fifth Di iR li A Fifth Di iRescaling Across Fifth DimensionRescaling Across Fifth Dimension

m_->e-kr m

Important for phenomenology: weak scaleweak scale physics

Higgs mass escaledHiggs mass escaledHiggs mass rescaledHiggs mass rescaled

Kinetic term has 2 powers of warp factorKinetic term has 2 powers of warp factorMass term has 4Mass term has 4Result is mass rescaledResult is mass rescaledIn fact warp factor is like conformal factorIn fact warp factor is like conformal factorIn fact warp factor is like conformal factorIn fact warp factor is like conformal factor

So if modes localized near TeV braneSo if modes localized near TeV braneSo…if modes localized near TeV braneSo…if modes localized near TeV braneExpect TeV massExpect TeV massT t t b t f KK d !T t t b t f KK d !Turns out to be true for KK modes!Turns out to be true for KK modes!

How to test?How to test?How to test?How to test?

Search for new particles!Search for new particles!Everything near weak brane should have TeV massEverything near weak brane should have TeV massKaluzaKaluza--Klein (KK)Klein (KK) particlesparticlesCarry momentum in extra dimensionsCarry momentum in extra dimensionsLooks like mass in 4 dimensionsLooks like mass in 4 dimensionsConnection to mass andConnection to mass and weakness of gravity weakness of gravity g yg yrelative to other known forcesrelative to other known forces tells us tells us LHC will have the right energy to search for LHC will have the right energy to search for consequences of this theoryconsequences of this theory

Experimental Signal: Experimental Signal: p gp gTeVTeV--scale Graviton Resonances!scale Graviton Resonances!

Protons collideProtons collideProduce a KaluzaProduce a Kaluza--

LHC CollisionProduce a KaluzaProduce a KaluzaKlein particleKlein particleWhich DecaysWhich Decays l tproton Which DecaysWhich DecaysDefinite mass Definite mass spectrum andspectrum and

electron

spectrum and spectrum and “spin”“spin”--22

positron

proton

How to find KK masses and How to find KK masses and interactionsinteractions

Solve equations of motionSolve equations of motionBessel function solutionsBessel function solutionsBessel function solutionsBessel function solutionsImpose two boundary conditions at branesImpose two boundary conditions at branesO i t li bi tiO i t li bi tiOne gives correct linear combinationOne gives correct linear combinationSecond gives quantization conditionSecond gives quantization condition

Wa ef nction Eq ationWa ef nction Eq ationWavefunction EquationWavefunction Equation

Change a iablesChange a iablesChange variablesChange variables

Volcano potential: ‘q nt m‘quantum mechanics’ potential

Find sol tionFind sol tionFind solutionFind solution

Impose Bo nda ConditionsImpose Bo nda ConditionsImpose Boundary ConditionsImpose Boundary Conditions

KK modesKK modesKK modesKK modes

Find modes at every mass scaleFind modes at every mass scaleHowever essentially linearly quantized inHowever essentially linearly quantized inHowever essentially linearly quantized in However essentially linearly quantized in multiples of kemultiples of ke--krkr

cc within mass range of within mass range of order m (cutoff)order m (cutoff)order m (cutoff)order m (cutoff)That is (m/k) modes in our vicinityThat is (m/k) modes in our vicinityT th l k t l i t ti tT th l k t l i t ti tTo us theory looks strongly interacting at To us theory looks strongly interacting at TeVTeV(not true for full 5d theory)(not true for full 5d theory)

TeV scale KK modes1000 TeV modes1000 TeV

mode1012 TeV Mode

Obse able KK modesObse able KK modesObservable KK modesObservable KK modes

In RS1, KK spectrum very distinctiveIn RS1, KK spectrum very distinctiveTeV, 2 TeV, 3 TEV (rough) spectrumTeV, 2 TeV, 3 TEV (rough) spectrum, , ( g ) p, , ( g ) p

TeV scale modes localized on weak braneTeV scale modes localized on weak branee sca e odes oca ed o ea b a ee sca e odes oca ed o ea b a eHave “warped” gravitational interactionHave “warped” gravitational interactionSo 1/TeV scale graviton interaction withSo 1/TeV scale graviton interaction withSo 1/TeV scale graviton interaction with So 1/TeV scale graviton interaction with Standard Model particles (not 1/MStandard Model particles (not 1/MPlPl))Much stronger than gravitational!Much stronger than gravitational!Much stronger than gravitational!Much stronger than gravitational!

Experimental Signal: Can search for Experimental Signal: Can search for p gp gextra dimensions!extra dimensions!

Protons collideProtons collideProduce a KaluzaProduce a Kaluza--

LHC CollisionProduce a KaluzaProduce a KaluzaKlein particleKlein particleWhich DecaysWhich Decays l tproton Which DecaysWhich DecaysDefinite mass Definite mass spectrum andspectrum and

electron

spectrum and spectrum and “spin”“spin”--22

positron

proton

If you produce a KK mode of the gravitionIf you produce a KK mode of the gravitionNot just missing energy!Not just missing energy!Mode decays inside detectorMode decays inside detector just like most other heavyjust like most other heavyMode decays inside detectorMode decays inside detector——just like most other heavy just like most other heavy particles we hope to discoverparticles we hope to discoverMeans we can reconstruct mass, spin (we hope!)Means we can reconstruct mass, spin (we hope!)Would be first genuine signature of quantum gravity Would be first genuine signature of quantum gravity Graviton itself too weakly interacting to detect directlyGraviton itself too weakly interacting to detect directlyNot true for its KK modes!Not true for its KK modes!Not true for its KK modes!Not true for its KK modes!

Search for Resonances

H. Davoudiasl, J. Hewett, T. Rizzo

Reach fo G a iton KK ModesReach fo G a iton KK ModesReach for Graviton KK ModesReach for Graviton KK Modes

Davoudiasl, Hewett, Rizzo

graviton has spin 2graviton has spin 2M=1.5 TeV 100fb-1

A l di ib iAngular distributions

RS1 gives clean TeVRS1 gives clean TeV--KKKK--graviton signalgraviton signalOne of first things LHC could findOne of first things LHC could findSS 2 d d f d f d2 d d f d f dSpinSpin--2 and gap in spectrum definite indication of warped 2 and gap in spectrum definite indication of warped extraextra--dimensional geometrydimensional geometryCould also exist strongly interacting TeVCould also exist strongly interacting TeV--scale physics to scale physics to g y gg y g p yp ycomplement this measurementcomplement this measurementEven low scale quantum gravity or light string states Even low scale quantum gravity or light string states could appear (we’ll return to this)could appear (we’ll return to this)could appear (we ll return to this)could appear (we ll return to this)But not the only implementation of RS1But not the only implementation of RS1mechanismmechanismWh t d thi i l b t h t t i ?Wh t d thi i l b t h t t i ?What does this imply about search strategies?What does this imply about search strategies?

Variations on RS1: Infinite extra Variations on RS1: Infinite extra dimensiondimension

I fi it di iInfinite dimenison

weakbraneweakbrane

Missing Ene g SignalMissing Ene g SignalMissing Energy SignalMissing Energy Signal

Looks like 6 large dimensionsLooks like 6 large dimensionsIn this case KK mode decays to lighter KKIn this case KK mode decays to lighter KKIn this case KK mode decays to lighter KK In this case KK mode decays to lighter KK modesmodesKK energy goes to missing energyKK energy goes to missing energyKK energy goes to missing energyKK energy goes to missing energy

Variations of RS1:Variations of RS1:Variations of RS1:Variations of RS1:matter in bulk or on brane??matter in bulk or on brane??

Two key features that make bulk matter Two key features that make bulk matter possiblepossiblepp

Size of fifth dimension extremely small (only Size of fifth dimension extremely small (only about 30 times fundamental scaleabout 30 times fundamental scale——exponential hierarchy)exponential hierarchy)

Means coupling won’t be too diluted/weakMeans coupling won’t be too diluted/weak

You only need Higgs on the Weakbrane to You only need Higgs on the Weakbrane to address the hierarchyaddress the hierarchy

Problem only for the Higgs scalar: gauge boson Problem only for the Higgs scalar: gauge boson and fermion masses are protectedand fermion masses are protected

Merits of bulk fermions and gauge Merits of bulk fermions and gauge g gg gfieldsfields

5D5D cutcut--off is Planck scaleoff is Planck scaleAllows for unification!Allows for unification!Allows for unification!Allows for unification!

Also interesting modelAlso interesting model--building:building:f f lf f lFermion masses from wavefunction overlap Fermion masses from wavefunction overlap

with Higgs field (on Weakbrane)with Higgs field (on Weakbrane)

W ’ll th t b lk i hW ’ll th t b lk i hWe’ll see that bulk scenarios have We’ll see that bulk scenarios have distinctive signaturesdistinctive signatures

Modes at All Ene giesModes at All Ene giesModes at All EnergiesModes at All Energies

TeV scale KK modes1000 TeV modes1000 TeV

mode1012 TeV Mode

B lk UnificationB lk UnificationBulk UnificationBulk UnificationNet contribution from all modesNet contribution from all modesGivesGives logarithmiclogarithmic runningrunningGives Gives logarithmic logarithmic running running From TeV scale to Planck scaleFrom TeV scale to Planck scaleLESSON 2: very natural to have unificationLESSON 2: very natural to have unification

GravityGravityGravityGravityCouplingCoupling

strengthstrength

CouplingCoupling

strengthstrength

Gravity Gravity energyenergyGravity Gravity energyenergy

energyenergyenergyenergy

strengthstrengthstrengthstrength

Fermion masses from Fermion masses from wavefunctionswavefunctions

Might expect nontrivial profilesMight expect nontrivial profilesMasses depend on overlap with HiggsMasses depend on overlap with HiggsMasses depend on overlap with HiggsMasses depend on overlap with HiggsExpect light fermions localized near Expect light fermions localized near Planck/Gravity branePlanck/Gravity branePlanck/Gravity branePlanck/Gravity braneTop near Weakbrane since it’s heavyTop near Weakbrane since it’s heavy

tRuL,dL tRL L

Fla o hie a chiesFla o hie a chiesFlavor hierarchiesFlavor hierarchiesz~ez~ekrφ

dd f ( /k /2) ff ( /k /2) fddzzf=(M/k+1/2) ff=(M/k+1/2) ff~zf~zν

f~e f~e krφ(M/k+1/2)

M/k=M/k=νν<<--1/2 : light quarks1/2 : light quarksM/k=M/k=νν<< 1/2 : light quarks1/2 : light quarksνν>>--1/2: top quark1/2: top quark

B lk RSB lk RSBulk RSBulk RS

Variation of RS1: fermions and gauge Variation of RS1: fermions and gauge bosons in bulkbosons in bulkHierarchy just like beforeHierarchy just like beforeBut flavor unification possibilitiesBut flavor unification possibilitiesBut flavor, unification possibilitiesBut flavor, unification possibilities

However: Important Differences in However: Important Differences in Ph l f BPh l f BPhenomenology from BranePhenomenology from Brane--

Localized MatterLocalized MatterRicher SpectrumRicher SpectrumKK modes of KK modes of

Weak bosonsWeak bosonsWeak bosonsWeak bosonsGluons Gluons FermionsFermionsAs well as gravitonsAs well as gravitons

But lower Production Cross Section for GravitonBut lower Production Cross Section for GravitonBut…lower Production Cross Section for GravitonBut…lower Production Cross Section for GravitonPlus decays primarily into topsPlus decays primarily into tops

Changes search strategies dramaticallyChanges search strategies dramatically

Gl on Gl on KK WFsGl on Gl on KK WFsGluon, Gluon KK WFsGluon, Gluon KK WFs

PlanckPlanck brane

Kk Gluon wavefunction

graviton

TeV brane

Gluon KK wavefunciton

Richer Spectrum…Richer Spectrum…But Lower Production Cross SectionBut Lower Production Cross SectionBut Lower Production Cross SectionBut Lower Production Cross Section

for the Gravitonfor the GravitonLi ht k l li d fLi ht k l li d fLight quarks are localized away from Light quarks are localized away from HiggsHiggs

Hence away from TeV braneHence away from TeV braneNo DrellNo Drell--Yan production from quarksYan production from quarks

Gluons are spread throughout the bulkGluons are spread throughout the bulkHence coupling to graviton Hence coupling to graviton

is volume suppressedis volume suppressed

G a iton Inte actionsG a iton Inte actionsGraviton InteractionsGraviton Interactions

Volume suppressedO(1) 1/ k¼r ; or 0O(1), 1/ k¼rc; or 0

G a iton inte actionsG a iton inte actionsGraviton interactionsGraviton interactions

Feat es of inte actionsFeat es of inte actionsFeatures of interactionsFeatures of interactions

The suppression by MThe suppression by M44L is a factor of 1/N L is a factor of 1/N from the dual gauge theory perspectivefrom the dual gauge theory perspectiveg g y p pg g y p p1/1/μμTeVTeV is local cutoffis local cutoff1/kr1/kr because gluon has flat wavebecause gluon has flat wave1/kr1/krcc because gluon has flat wave because gluon has flat wave function: volume factorfunction: volume factorF i b h iF i b h iFermion behaviorFermion behavior

KK G a iton P od ctionKK G a iton P od ctionw/Liam Fitzpatrick,Jared

KK Graviton ProductionKK Graviton ProductionKaplan, Liantao Wang

Final State? Dominant Decay to Final State? Dominant Decay to yyrightright--handed topshanded tops

More narrownarrow

Determining top jets: delta R: Determining top jets: delta R: g p jg p jAngle between decay productsAngle between decay products

Angular dependence: spin Angular dependence: spin g p pg p pdetermination determination

Graviton: some reachGraviton: some reachOther Bulk Modes?Other Bulk Modes?

Gl on Gl on KK WFsGl on Gl on KK WFsGluon, Gluon KK WFsGluon, Gluon KK WFs

PlanckPlanck brane

Kk Gluon wavefunction

graviton

TeV brane

Gluon KK wavefunciton

Gl on KK Mode!Gl on KK Mode!Gluon KK Mode!Gluon KK Mode!

Gluon KK mode coupling to light quarks is Gluon KK mode coupling to light quarks is much bigger than gravitonmuch bigger than graviton

Gluon KK mode wave function peaked at TeV Gluon KK mode wave function peaked at TeV branebraneB t l ti l fl t i b lkB t l ti l fl t i b lkBut relatively flat in bulk;But relatively flat in bulk;Only square root volumeOnly square root volume

Al t l KK d li ht bAl t l KK d li ht bAlso expect gluon KK mode lighter by Also expect gluon KK mode lighter by factor 1.5factor 1.5Fi ll 1/MFi ll 1/MFinally no 1/MFinally no 1/MMuch larger reach for gluon KK modeMuch larger reach for gluon KK mode

Understand from dual point of view in terms of gluon KK mixing-vector meson dominance

Note only gluon production from quarks.

At tree level, gluon coupling vanishes.

Gluon wave function

KK Gluon fermion interactionKK Gluon fermion interaction(relative to g(relative to gss))

D i t t j t b k dD i t t j t b k d

w/Ben Lillie, Liantao Wang

Dominates over top jet backgroundDominates over top jet background

However, signal doesn’t dominate However, signal doesn’t dominate , g, gover jet backgroundover jet background

Top dete mination dR?Top dete mination dR?Top determination: dR?Top determination: dR?

Clea lClea lClearly…Clearly…

Efficient top jet identification required, Efficient top jet identification required, especially for heavier KK gluonsespecially for heavier KK gluonsp y gp y gCould be:Could be:

Top jet mass measurementTop jet mass measurementTop jet mass measurementTop jet mass measurementDetailed substructure of jets: eg hard leptonDetailed substructure of jets: eg hard lepton

Beyond our studyBeyond our studyBeyond our studyBeyond our studyBut can determine accuracy with which But can determine accuracy with which determination is requireddetermination is required

Conclude require at most 10% fake Conclude require at most 10% fake qqraterate

Spin Dete minationSpin Dete minationSpin DeterminationSpin Determination

Forward region significance enhanced with pt cut

For light masses, can determine For light masses, can determine g ,g ,model structure: tmodel structure: tRR

Angle between lepton and top momentum axis

S mmaS mmaSummarySummary

Weak scale physics should be testable at LHCWeak scale physics should be testable at LHCIncluding RS1, whatever the implementationIncluding RS1, whatever the implementationg , pg , pBest signature: spinBest signature: spin--2 resonance and mass gap2 resonance and mass gapIn bulk, gluon KK mode will be importantIn bulk, gluon KK mode will be importantbu , g uo ode be po ta tbu , g uo ode be po ta tDecays into tops criticalDecays into tops criticalChallenge is to maximize energy reachChallenge is to maximize energy reachChallenge is to maximize energy reachChallenge is to maximize energy reachBut hope for pinning this downBut hope for pinning this down

To be doneTo be doneTo be doneTo be done

Think about jet characteristicsThink about jet characteristicsDetailed substructureDetailed substructureDetailed substructureDetailed substructure

Push Push bb tagging to limittagging to limitExplore hard leptonsExplore hard leptonsExplore hard leptonsExplore hard leptons

Concl deConcl deConcludeConclude

If RS1 solves the hierarchy problem, we If RS1 solves the hierarchy problem, we should be able to tellshould be able to tellClean KK graviton signal if SM on braneClean KK graviton signal if SM on braneFarFar reaching KK gluon signal if SM in bulkreaching KK gluon signal if SM in bulkFarFar--reaching KK gluon signal if SM in bulkreaching KK gluon signal if SM in bulkSupplemented by graviton KK signal if Supplemented by graviton KK signal if

ffi i tl l lffi i tl l lsufficiently low scalessufficiently low scalesBut challenges: top quark ID foremost!But challenges: top quark ID foremost!