ATLAS Physics Potential III

Borut KersevanJozef Stefan Inst.Univ. of Ljubljana

ATLAS Physics Potential:• Standard Model• Higgs & Susy• BSM: Susy and Exotics

On behalf of the ATLAS collaboration

2

Supersymmetry – Extra particles To stabilise the higgs mass NEED: A scalar partner for every fermion

squark, slepton, (stop, sbottom, selectron, smuon, sneutrino, etc) A fermion partner for ever boson:

gluino, photino, wino, zino, higgsino

(mix to form 4 neutralinos) Inexact symmetry

– broken somehow

3

Two main SUSY scenarios: (RPV/RPC) RP-Conserving RP-Violating

R-Parity: Conservation/Violation

(L.S.P. = “lightest SUSY particle”)

How stable is thelightest SUSYparticle (L.S.P.) ?

Largemissingenergy?

Event can bereconstructedfully?

Sparticleproduction

RPC Stable Yes Usually not Only in pairs

RPV Unstable(decays to leptons or jets)

No Yes Either singly,or in pairs

R=+1 for Standard Model particles R= -1 for SUSY particlessLBR 2)(3)1(

4

What do events look like?

(Baryon number violating)

RPV RPV

(Lepton number violating)

RPC RPC

5

R-Parity Violation RPV

Easier than RPC? The L.S.P. decays!

No missing energy, so reconstruct full event! Case 1: Decays into leptons:

Multi-lepton signature Case 2: Decays into jets:

Multi-jet signature Case 3: Long lifetime:

looks like RPC scenario Sparticles may be produced singly!

L.S.P. = lightest SUSY particle

6

Case 1: Lepton number violating RPV

λ’ijk couples a slepton to two quarks

Can have resonant sneutrino production Cross section can place lower bound on λ’ijk Expect to observe (within 3 years) either

900 GeV sneutrino if λ’211>0.05 350 GeV sneutrino if λ’211>0.01 (present limit: )

GeV) 100/( 60.0 ~211'

RdM

λ’ijk =0.09

Reconstructed neutralino mass peak in mjjμ invariant mass distribution

7

Case 2: Baryon number violating RPV

Each L.S.P. decays to three quarks (u,d,s) forming three jets (jjj)

Require 2 leptons and at least 8 jets: (j+jjj)+(j+ll+jjj)

Look for L.S.P. / chargino peak in mjjj / m jjjll plane

msquark L = 638 ± 5 ±12 GeV

mneutralino 2 = 212 ± 0.3 ± 4 GeV

mslepton R = 155 ± 3 ± 3 GeV

mneutralino 1 = 117 ± 3 ± 3 GeV

8

R-Parity Conservation RPC

L.S.P. stable and weakly interacting, and so “goes missing” Missing energy signature Usually incomplete event reconstruction Need to rely on long decay chains and

kinematic variables (endpoints and distributions)

Sparticles are only produced in pairs Double the trouble Missing information in BOTH halves of

event! More general techniques available!

L.S.P. = lightest SUSY particle

Half an event

9

So the main SUSY signatures are: Lots of jets Lots of leptons Lots of missing energy (RPC) ATLAS Trigger: ETmiss > 70 GeV, 1 jet>80 GeV

(or 4 lower energy jets). Gives 20Hz @ low luminosity.

RPC often seems a better option since it implies:- No proton decay- SUSY particles produced in pairs and decay to stable Lightest SUSY Particle (LSP), usually 0

1 which is stable, neutral and weakly interacting so escapes detector => large missing energy.- WMAP results indicate cold dark matter. LSP is good candidate for cold dark matter

10

SUSY and mSUGRA (1) MSSM Lagrangian depends on 105

parameters (!!) Need to make some assumption to reduce

the degree of freedom mSUGRA depends on 5 (+1) parameters

M0, M1/2, A0, tan(β), sgn(μ), mtop Assuming R parity conservation =>

escaping LSP => large ETMISS and scalar

particles produced in pairs Event cannot be fully reconstructed SUSY is a bgd to itself

Various regions in the par. space Coannihilation, Focus Point, Funnel,

Bulk region

(Ellis et al., Phys. B565 (2003) 176)

M0 (GeV) M1/2(GeV) A0 tanβ sgn(μ) mtop (GeV)

Coannihilation 70 350 0 10 + 175

Focus point 3550 300 0 10 + 175

11

One would like to break SUSY dynamically. Not possible just with MSSM; must communicate breaking in hidden sector via some interactions...Many LHC studies use mSUGRA model. Has simplest gravity mediated breaking with just 4 parameters:- Common scalar mass m0 at GUT scale;- Common gaugino mass m1/2 at GUT scale;- Common trilinear coupling parameter A0;- Common ratio tan(β) of Higgs VEV’s at weak scale. Also sign sgn(µ)=1 of Higgs mass

Must solve RGEs’ to connect GUT and weak scale masses

SUSY and mSUGRA (2)

12

Inclusive Searches: mSUGRA Reach

Discovery Assuming luminosity 1033 cm2 s-1

1300 GeV => “1 week” 1800 GeV => “1 month” 2200 Gev => “1 year”

Backgrounds: Real missing energy from SM processes with

hard neutrino (tt, W+jets, Z+jets) Fake missing energy from detector Jet energy resolution (expecially non-gaussian

tails) critical

(Fast parametric detector response)

13

SUSY Production at LHC: summary

(stau Coannihilation point)

Heavy strongly interacting sparticles (gluinos and squarks) produced in initial interaction Long decay chains and large mass differences between SUSY states; many high PT objects

are observed (lepton, jets, b-jets) If R-Parity is conserved cascade decays to stable undetected LSP (lightest SUSY particle;

neutralino in mSUGRA); large ETmiss signatures

If the model is GMSB, LSP is gravitino. Additional signatures from NLSP (next-to-lightest SUSY particle) decays; for example photons from and leptons from

If R-parity is not conserved LSP decays to 3-leptons, 2leptons+1jet, 3 jets; ETmiss signature is

lost

lqql

g~ q~ l~~

~p p

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Squark/gluon mass scale

(GeV)effM

even

ts

Signal

S.M. BackgroundPeak of Meff distribution correlates well with SUSY scale “as defined above” for mSUGRA and GMSB models. (Tovey)

What you measure:

The Missing Transverse Energy Variable Can only apply momentum conservation in

the plane transverse to the beam. Measure apparent imbalance in final state

using calorimetry (+ muons) 'ETmiss'.

SUSY selection: high-pT jets, large ETmiss and (possibly) isolated leptons.

ETmiss gives excellent discrimination against most SM processes.

Remaining background from events with neutrinos – W/Z + jets, tt, bb.

QCD: from in bb and cc events. Also huge event rate means rare effects due to imperfections in detector can be significant.

Typical SUSY cuts: NJets >= 4 pT(j1) > 100GeV, pT(j4) > 50GeV ETmiss > 100GeV Transverse Sphericity ST > 0.2 0 leptons

ATLAS preliminary(ATLFAST)

Reconstructing ETmiss ETmiss calculated from vector sum over calorimeter cells plus contribution

from muons corrected for energy loss in calorimeter. Noise cells removed with topological clustering algorithm. Cells calibrated with H1 style weights (low energy density cells up-weighted

to compensate for invisible processes in hadronic showers).

ATLAS preliminary

Resolution scales with square root of scalar sum ET :

(ETmiss) ~ 0.5 √ETsum

17

Importance of detailed detector understanding

GEANT simulation already shows events with large missing energy Jets falling in “crack” region Calorimeter punch-through

Vital to remove these in missing energy tails

Large effort in physics commissioning

Lesson from the TevatronEt(miss)

Dealing With Backgrounds In addition to jet and ETmiss cuts,

apply additional cuts to reduce certain backgrounds number of isolated

leptons Meff = ETmiss + ∑pT

jets

Ability to reliably estimate backgrounds is vital to demonstrate excess in signal region.

Systematics from Monte Carlo likely to be large, so try to estimate from data wherever possible particularly important with early data.

Meff (GeV)

1 lepton

W/Z + jets Significantly reduce Z → and W

backgrounds with 1 lepton requirement and mT(l, ETmiss) > mW cut at expense of statistics.

Background now dominated by tops.

ATLAS

Preliminary

(Zll)

Estimate Z → in 0 leptons case by using Z → ll data, replacing lepton pT with ETmiss.

Can use same channel to obtain estimate for W → l.

Meff (GeV)

0 leptons

Top Background(1) For tt → bblqq, can reduce background with transverse mass cut. Then tt → bbllqq becomes the dominant background in the 1 lepton channel.

To obtain estimate: select semi-leptonic top events from a mass window around the top mass (mt = 140 – 200GeV).

Subtract combinatorial background using sideband (mt = 200 – 260GeV).

Top

Mas

s (G

eV)

ATLASPreliminary

T1

sideband

signal

Missing ET (GeV)

Get estimate for semi-leptonic top ETmiss distribution.

ATLASPreliminary

EstimateSUSY selection

21

T2 + SU3

NNobsobs(w SUSY) = 503 (w SUSY) = 503 22 22 NNestestimationimation (w/o SUSY) = 7 (w/o SUSY) = 7 35 35

InIn high M high Missing Eissing ETT region region ( (>500GeV)>500GeV)

Clear excesss (13)!the method proved to be the method proved to be validvalid

Estimating the top bkg from ‘real data’ looks promising...

EstimateSUSY selection (top)SUSY selection (total)

Estimating the precision with1 year statistics at low lumi. (10fbEstimating the precision with1 year statistics at low lumi. (10fb-1-1) ) [ [ using high Pt validation sample (top Pt>500GeV) ]using high Pt validation sample (top Pt>500GeV) ]

Missing ET (GeV)

ATLAS preliminary

Top Background(2)

QCD (1) Two main sources:

fake ETmiss (gaps in acceptance, dead/hot cells, non-gaussian tails etc.)

real ETmiss (neutrinos from b/c quark decays)

Hard to estimate with Monte Carlo depends on details of detector

response need large statistics to get into tails

1 lepton requirement minimises contribution may be best until detector is well

understood (real/fake?) Can reduce contribution by cutting on

correlations in between the leading jets and ETmiss, jets pointing at poorly instrumented regions of the detector etc...

Pythia dijets

SUSY SU3

QCD (2) To obtain estimate : Step 1: Measure jet smearing function

from data Select events: ETmiss > 60

GeV, (ETmiss, jet) < 0.1 Estimate pT of jet closest to

ETmiss as pT

true-est = pTjet + ETmiss

ATLAS preliminary

MET

jets

fluctuatingjet

QCD est (stat errors only) SUSY

ATLAS preliminary

Step 2: Smear low ETmiss multijet

events with measured smearing function.

Technique does not work in low ETmiss region (gaussian jet response), but gives good agreement in tails (SUSY signal region!)

22pb-1

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SUSY Cut Optimization

m(m() ) (~0.4m(~0.4m1/21/2) ) is heavieris heavier,, thusthus optimal missing E optimal missing ETT becomesbecomes higher higher (less sensitive to M (less sensitive to M00))

Similarly tunes for,Similarly tunes for,● the best the best 11stst jet energy jet energy cutcut● the best the best 22ndnd jet energy jet energy cut cut ● the best the best 44thth jet energy jet energy cutcutalso carried out also carried out simultaneously simultaneously Achieve the optimal SUSY Achieve the optimal SUSY cut for each grid pointcut for each grid point

[Z axis] Best Missing E[Z axis] Best Missing ET T Cut (GeV)Cut (GeV)

m1/2 (GeV)

m 0 (Ge

V)

Scan through the mSUGRA parameter grid (mScan through the mSUGRA parameter grid (m1/21/2, m, m00 plane) plane)Optimize the SUSY cut to maximize the signal significanceOptimize the SUSY cut to maximize the signal significanceFixed parameters: tanb = 10, A=0, Fixed parameters: tanb = 10, A=0, >0>0

ATLAS preliminary

25

Discovery Potential Fast simulation resultSignal : Isawig/Jimmy

5-5- discovery potential on m discovery potential on m00-m-m1/21/2 plane plane

100pb-1

m1/2

400

800

1200

m01500500

1fb-1

m1/2

400

800

1200

1500500 m0

0-lepton x1-lepton +

BackgBackgrround is ound is re-examinedre-examined by Matrix Element calc by Matrix Element calc (ALPGEN)(ALPGEN)

0-lepton mode : More statistics is available0-lepton mode : More statistics is available 1-lepton mode : smaller 1-lepton mode : smaller systematic systematic uncertaintyuncertainty

m(g)~1m(g)~1.1.1TeVTeVm(q)~1m(q)~1.1.1TeVTeV

~~ m(g)~0.8TeVm(g)~0.8TeV

m(q)~1.5TeVm(q)~1.5TeV

~~

m(g)~1.6TeVm(g)~1.6TeVm(q)~1.5TeVm(q)~1.5TeV~

~m(g)~1TeVm(g)~1TeVm(q)~1.6TeVm(q)~1.6TeV~

~

tan=10,>0 tan=10,>0

0-lepton x1-lepton +

MMSUSYSUSY<1.1TeV at L=100pb<1.1TeV at L=100pb-1-1

MMSUSYSUSY<1.5TeV at L=1fb<1.5TeV at L=1fb-1-1

The discovery potential for the early dataThe discovery potential for the early data

ATLAS preliminary

ATLAS preliminary

26

Kinematic edges: l+l- edge

EXAMPLE: l+l- edge

The l+l- invariant mass from the decay chain (right) has a kinematic endpoint.

For 100 fb-1, edge measured at 109.10±0.13(stat) GeV

Dominant systematic error on lepton energy scale also ~0.1%

Maximum dilepton invariant mass is related to sparticle masses

27

Plenty of other kinematic endpoints! RPC

Sequential

Branched

28

Edge

pos

ition

s

29

Mass reconstruction: a typical decay chain

llq edge1% error(100 fb-1)

lq edge1% error(100 fb1)

ll edge llq threshold

The invariant mass of each combination has a minimum or a maximum which provides one constraint on the masses of l q

~~ ~~

ATLAS Fast simulation, LHCC Point 5ATLAS TDR ATLAS TDR ATLAS TDR ATLAS TDR

lqql

g~ q~ l~~

~p p

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Dilepton EdgePolesello et al., 1997

Clear signature, easy to trigger: starting point of many mass reconstruction analyses.

Can perform SM & SUSY background subtraction using OF distribution

e+e- + +- - e+- - +e-

Position of edge (LHC Point 5) measured with precision ~ 0.5% (30 fb-1).

~~~

l ll

e+e- + +- e+e- + +- - e+- - +e-

30 fb-1

atlfast

5 fb-1

FULL SIM

Physics TDR

ATLAS ATLASPoint 5

Modified Point 5 (tan() = 6)

Mll (GeV) Mll (GeV)SUSY backgSM backg

31

Model-independent masses Combine measurements from edges of different jet/lepton combinations to

obtain ‘model-independent’ mass measurements. LSP mass uncertainty large, all other masses strongly correlated with it. A

future Linear Collider measurement of mass would improve the precision on all masses.

Sparticle Expected precision (100 fb-1) qL 3% 0

2 6% lR 9% 0

1 12%

~

~

~

~

lR

qL

~~

~ ~

masses (GeV) LHCC5 SPS1am( 122 96

m(lR) 157 143

m( 233 177

m(qL) 687-690 537-543

~~

~

~ATLAS

32

Mass peaks The 4-momentum of the can be

reconstructed from the approximate relation

p(= ( 1-m(m(ll) ) pll

valid when m(ll) near the edge. The can be combined with b-jetsto reconstruct the gluino and sbottom mass peaks from g→bb→bb

~

~

CMS 1 fb-1

m(q= (536 ± 10) GeV

CMS 10 fb-1

m(g= (500 ± 7) GeV

m(g)-m(b2) = (70.6 ± 2.6) GeVm(g)-m(b1) = (103.3 ± 1.8) GeVm(g)-0.99m(= (500.0 ± 6.4) GeV

SPS1a, 300 fb-1, stat. errors only:

ATLAS SPS1a300 fb-1

ATLAS SPS1a300 fb-1

m(bb) (GeV)

m(bb)-m(b) (GeV)

~~~

~~

~ ~

33

Other mass measurements

Right squark

ATLAS 30 fb-1

ATLAS 30 fb-1

2 hard jets and lots of ETmiss.

Reconstruct with

Also works for sleptons.m(qR)-m(= (424.2 ± 10.9) GeV

qR 01q

Two body decay of 02 to

higgs and 01.

Reconstruct higgs mass (2 b-jets) and combine with hard jet.

Get additional mass constraint.

qL q → hq →01bbq

Tau decay dominates neutralino BR at large tan.No sharp edge because of n, but end-point canstill be measured.

~ ~ ~

~

MT2 (GeV) M(bbq) (GeV) M() (GeV)

ATLAS Point 5 100 fb-1

34

From masses to model parametersFrom a given set of measurements one scans the parameter space and finds the points compatible with data. These points are fed to relic density calculators to get constraints on relic density.

ATLAS measurements

Parameter Expected precision (300 fb-1) m0 2% m1/2 0.6% tan() 9% A0 16%

Micromegas 1.1 (Belanger et al.)+ ISASUGRA 7.69

h2

300 fb-1

ATLAS

h2 = 0.1921 0.0053 log10(p/pb) = -8.170.04

35

Full simulation studies

• Goals: test software for data reconstruction and analysis, computing grid production. Study detector-related systematic. Validate fast simulation results.• 10M events produced in 2005.• Five mSUGRA models studied. Focus on cosmologically interesting regions.

Focus Point

Coannihilation

Bulk

LEP excluded No EWSB

SU1

SU2

SU3

36

Full simulation results – SU3

(e+e-) + β2(η) (μ+μ-) – β(η) (e+μ-)

ATLAS Preliminary4.37 fb-1

ATLAS Preliminary4.20 fb-1

ATLAS Preliminary4.20 fb-1

Larger of M(llq)

Smaller of M(llq)

Edge at 99.8 ± 1.2 GeV

lqql

g~ q~ l~~ ~p p

Already with a few fb-1 of data several edges are visible.All results preliminary.

272 GeV

501 GeV

37

Coannihilation (SU1)

ATLAS PreliminaryFull Sim. 20 fb-1

ll edge

ATLAS PreliminaryFull Sim. 20 fb-1

qR edge

ATLAS PreliminaryFull Sim. 20 fb-1

ql(min) edgeql(max) edge

qll edge qll threshold

~

38

Focus-Point (SU2)

SUSY Scalars heavy (3 TeV) - only fermions (gluino, chargino, neutralino) accessible to LHC

Fast discovery, kinematical edges require larger statistics.

ATLAS PreliminaryFull Simulation 6.9 fb-1

ATLAS PreliminaryFast Sim. 300 fb-1

Mll (GeV) Mll (GeV)

01

03 ll

01

02 ll

SU2 SUSY production is: (direct) (4.5 pb)Do not pass cuts to reject SM(little jets & ET

miss) gg →+jets (0.5 pb)Can be separated efficiently from SM

2.6 excess

~~

39

SUSY Summary

SUSY is a very good candidate for early discovery at the LHC If TeV scale SUSY exists, ATLAS and CMS should find it The large variety of signals available in SUSY challenges the performance

of the detectors in all sectors of the collider SUSY discovery is possible in other models which I have not covered here:

Gauge Mediated Supersymmetry Breaking (GMSB) Anomaly Mediated Supersymmetry Breaking (AMSB) R-Parity Violation

Currently great effort in Data Challenges to understand different mSUGRA model points, and to test reconstruction software

Work going on not to miss any new physics signatures at the LHC!

40

Mapping out the new world

Some measurements make high demands on: Statistics (=> time) Understanding of detector Clever experimental technique

LHC Measurement SUSY Extra Dimensions

Masses Breaking mechanism Geometry & scale

Spins Distinguish from ED Distinguish from SUSY

Mixings,Lifetimes

Gauge unification?Dark matter candidate?

41

SUSY spin measurementsNeutralino spin from angles in decay chains

l+~

θq q

_

l-~

Slepton spin from angles in Drell-Yan production

The defining property of supersymmetry Distinguish from

e.g. similar-looking Universal Extra Dimensions

Difficult to measure @ LHC No polarised

beams Missing energy Inderminate initial

state from pp collision

Nevertheless, we have some very good chances…

42

Dark matter relic density consistency?

Use LHC measurements to “predict” relic density of observed LSPs

Caveats: Cant tell about lifetimes beyond

detector Studies done so far in optimistic

case (light sparticles)

To remove mSUGRA assumption need extra constraints:

1. All neutralino masses Use as inputs to gaugino &

higgsino content of LSP2. Lightest stau mass

Is stau-coannihilation important?

3. Heavy Higgs boson mass Is Higgs co-annihilation

important? More work is in progress

Probably not all achievable at LHC ILC would help lots (if in reach)

mSUGRA

assumed

43

R-hadrons

Motivated by e.g. “split SUSY” Heavy scalars Gluino decay through heavy

virtual squark very suppressed

R-parity conserved Gluinos long-lived

Lots of interesting nuclear physics in interactions Charge flipping, mass

degeneracy, … Importance here is that signal is

very different from standard SUSY

44

R-hadrons in detectors Signatures:

1. High energy tracks (charged hadrons)

2. High ionisation in tracker (slow, charged)

3. Characteristic energy deposition in calorimeters

4. Large time-of-flight (muon chambers)

5. Charge may flip Trigger:

1. Calorimeter: etsum or etmiss2. Time-of-flight in muon system

– Overall high selection efficiency Reach up to mass of 1.8 TeV at

30 fb-1

GEANT simulation of pair of R-hadrons

(gluino pair production)

45

RS Gravitons & heavy bosons

Discovery Find mass peak

Characterisation Measure spin

1.5 TeV Randall-Sundrum graviton -» e+e-

Randall -Sudrum graviton spin

pp

θ

gravitone

e

Graviton is spin-2

Angular distributions

46

Exotic WW scattering The ultimate test of electroweak symmetry breaking

Not unitary above ~1 TeV if no new physics

Reconstruct hadronic + leptonic W pair

Require forward jets Veto jets in central regionsignal

BG BG

Most difficult case: continuum signal

5- significance with 30 fb-1 in most difficult case

47

Spectacular states : micro Black Holes

Large EDs Micro black hole decaying via

Hawking radiation Photons + Jets + …

We will certainly know something funny is happening Large multiplicities Large ET Large missing ET Highly spherical

compared to BGs Theory uncertainty limits

interpretation Geometrical information difficult

to disentangle

sphericity

48

Black hole interpretation?

Slide from Lester

49

Micro Black Holes

σ ~ πRS2 ~ O(100)pb

LHC Black Hole Factory BH lifetime ~ 10-27 – 10-25 seconds! Decays with equal probability to all particles via Hawking Radiation Follows almost black body spectrum

Parton

PartonHarris, Palmer, Parker, Richardson, Sabetfakhri, Webber[JHEP05 (2005) 053]

6.1 TeV MBH

J. Tanaka , “Search for Black Holes”, 24/05/03 Athens

)1/(1

141

nBHBH

H Mn

RnT

2

2cGMR BH

s

MBH = √S

Rs

Formation

Decay

50

Micro Black HolesDistinguishingfeatures High Multiplicity High ΣET High Sphericity High Missing PT Democratic Decay

If Mpl ~ O(1 TeV) Black Hole Production possible at LHC

Sensitivity Dominated byTheoretical uncertainty

51

Extra DimensionsNot a new idea (1920’s)

Kaluza and Klein tried to unify Electro-magnetism and General Relativity

Undergoing a RevivalAccess to Extra Dimensions can be restrictedCan Solve Hierarchy problem

Mpl is only an effective scaleNew fundamental scale Mf

Essential for String TheoryCan be compactified

Bulk

Brane

52

Large Extra DimensionsADD Extra Dimensions are flat Only accessible to Gravity SM particles restricted to 4D Brane Could be as large as 0.1mm

Generates Tower of KK gravitons Coupling proportional to 1/Mpl Mass splitting ~ 1/R Observe a continuum of graviton states

Flat

4D

spa

ce

Extra Dimension

22

222

nx PP

mPE

Extra dimensional momentum looks like a mass

53

Large Extra DimensionsDi-photon/leptonKabachenko, Miagkov, Zenin[ATL-PHYS-2001-012] virtual graviton exchange Tower of KK gravitons Measure invariant mass of

photon/lepton pair Min invariant mass cut

extends reach

Enhancement of di-photon

Sensitivity @ 100fb-1 5σ for Mf 6.3-7.9 TeV

SM

Mf = 4.7 TeV

Mf (GeV)

Signal

5σ discovery bounds

100fb-1

10fb-1

54

Warped Extra DimensionsRandall Sundrum (type I)

Randall, Sundrum [PRL 83 (1999) 3370]

Brane metric scales as function of bulk position

Solves Hierarchy problem using warp factor

Small extra space dimensions Well separated graviton mass

spectrum

222 dydxdxeds vuuv

ky

Graviton Mass Spectrum eeG*µµ

Bulk (y)

TeV

Plank

hep-ph/0205106plMkCharacterized by

55

Warped Extra Dimensions

ATLAS is able to explore the entire allowed region

10fb-1

100fb-1

hep-ph/0205106

Allowed Region

56

Warped Extra DimensionsG*e+e-

Allanach, Odagiri,Palmer,Parker Sabetfakhri,Webber[JHEP09(2000)019][JHEP12(2002) 039] Graviton

Produced in kk spectrum

Looked for 1st KK mode Studied models with

narrow resonance

Sensitivity @ 100fb-1 5σ up to MG 2.08TeV

σ.B

(fb)

57

Universal Extra Dimensionsσ for KK pair production

vs mass of KK modeBeauchemin, Azuelos

[ATL-PHYS-PUB-2005-03]

SM particles propagate in Extra Dimensions can move in small Extra

dimensions Often embedded in large

Extra DimensionsKK parity

similar effect to R-Parity conserved at Tree level KK particles always in pairs no virtual KK particles

KK parity conservation means limits on UED are

much weaker

100 events @ 100fb-1

58

UED: KK quark/gluon di-jetBeauchemin, Azuelos [ATL-PHYS-PUB-2005-03]

Direct KK mode production only

Measure excess of dijets with large missing ET

Assume all KK modes decay to gravitons (invisible)

Sensitivity @ 100 fb-1 5σ up to 2.7 TeV

Significance vs KK particle

mass

ET miss (GeV)

Signal

BGCut

200 600 1000 1400

59

UED: KK gluons Heavy quarksg* bb/ttMarch, Ros, Salvachua [ATL-PHYS-PUB-2006-002]

Only produce hadronic decays Tag Heavy quark decays Excess of di-jetsb-quark decays difficult to detect t-quark channel provides clearest signal

Mg* 1TeV

Sensitivity @ 100fb-1

5σ Mg* up to 3.3TeV

Significance vs g* mass

60

Exotics Summary

5σ discoveries with 100fb-1

ADD fundamental Mpl up to 7-8 TeV RS graviton up to 2.08 TeV UED KK particles up to ~3 TeV If Micro Black Holes are produced we will know!

A lot of topics not covered (Z’ for one..) but the ATLAS activities are copious indeed...

Whatever else might be out there remains to be seen...