SUSY Strong Production Searches @ ATLAS Christopher Young 18th - - PowerPoint PPT Presentation

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SUSY Strong Production Searches @ ATLAS

Christopher Young

18th March 2012

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Christopher Young

Contents

◮ Very brief introduction ◮ The suite of ATLAS searches for Strongly Produced SUSY ◮ 0-lepton meff search (≥ 2 − 6 jets) (ATLAS-CONF-2012-033) ◮ 0-lepton high jet multiplicity search (≥ 6 − 9 jets) (ATLAS-CONF-2012-037) ◮ 1-lepton search (≥ 3 − 4 jets) (hard and soft leptons) (ATLAS-CONF-2012-041) - NEW this week! ◮ Conclusions

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SUSY Strong Production Searches @ ATLAS

Christopher Young

Introduction

◮ SUSY strong production is characterised by the pair and associated production

• f squarks (˜

q) and gluinos (˜ g). ◮ These can then decay either directly to the LSP (usually assumed to be the lightest neutralino) or through a series of intermediate SUSY particles.

• ˜

q ˜ g ˜ χ0

1

q ¯ q

• ˜

q ˜ χ0

1

q

• ˜

q ˜ χ+

1

˜ g ˜ χ0

1

W + q ¯ q ◮ In the R-Parity conserving models considered the lightest neutralino is assumed to be (collider) stable so passes through the detector undetected. ◮ Signatures therefore involve jets, missing transverse energy (E miss

T

) and possibly leptons (inc. τs) from cascade decays (and, additionally, possibly photons). ◮ Searches for R-Parity violating SUSY, long lived charged particles and specific searches for gauginos and 3rd generation squarks are covered in separate talks.

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Introduction II

◮ Here I am presenting three ATLAS analyses with the full 2011 dataset which have sensitivity to these models of interest;

• 1. 0-lepton meff (≥ 2 − 6 jets) (ATLAS-CONF-2012-033)
• 2. 0-lepton high multiplicity (≥ 6 − 9 jets) (ATLAS-CONF-2012-037)
• 3. 1-lepton (≥ 3 − 4 jets) (ATLAS-CONF-2012-041) - NEW this week!

◮ There are many other ATLAS analyses also sensitive to these models that are still in the process of being updated to the full dataset:

◮ Di-photon + E miss T

(1.07fb−1) arXiv:1111.4116

◮ Di-lepton + jets + E miss T

(1.04fb−1) arXiv:1110.6189

◮ ≥ 1τ + jets + E miss T

(2.05fb−1) ATLAS-CONF-2012-005

◮ ≥ 2τs + E miss T

(2.05fb−1) ATLAS-CONF-2012-002

◮ 2 Same Sign leptons + jets + E miss T

(2.05fb−1) ATLAS-CONF-2012-004

◮ ≥4 leptons + E miss T

(2.05fb−1) ATLAS-CONF-2012-001 ◮ For a full list and more information please see; https://twiki.cern.ch/twiki/bin/view/AtlasPublic/SupersymmetryPublicResults

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≥ 1τ and ≥ 2τ Analysis Results

◮ τ leptons can often be found in the cascade decays. (eg. ˜ τ NLSP) ◮ Dedicated searches have looked at the ≥ 1τ and ≥ 2τ final states. ◮ No significant excess was observed and limits were set in a GMSB model. ◮ Below are the signal regions before the final cuts for the ≥ 1τ (upper) and ≥ 2τ (lower) analyses and the two exclusion limits.

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l ~ Theory excl.

)

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R

e ~ LEP 95% CL ( OPAL 95% CL 95% CL limit:

s

CL )

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• bs. limit
• exp. limit

)

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• bs. limit
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• exp. limit

=1

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>0, C µ =3,

5

=250 TeV, N

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GMSB: M

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=7 TeV s

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0-lepton meff Analysis

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0-lepton meff Analysis

◮ Update of previous published result (arXiv:1109.6572) with re-optimised signal region definitions (including extension to ≥5 and ≥6 jets), improved background determination and increased integrated luminosity. ◮ Veto events with electons (pT > 20 GeV |η| < 2.47) or muons (pT > 10 GeV |η| < 2.4). ◮ The data is split into different streams by inclusive multiplicity ranging from ≥ 2 to ≥ 6 jets. ◮ This is designed to maintain good sensitivity to a large range of models from those with directly decaying squarks giving ≥ 2 jets in the final state to longer decay chains with many jets in the final state. ◮ The discriminating variable meff(incl.) is defined as the scalar sum of the E miss

T

and all the jets in the event with pT > 40 GeV. ◮ Multi-jet processes with no/low real E miss

T

are reduced to a very small level through cuts on the minimum azimuthal angle between jets and the E miss

T

and

• n the ratio of E miss

T

/meff(NJ)1 ◮ A second 2-jet stream is defined with a tighter cut on E miss

T

/meff(NJ) designed to enhance sensitivity to models with smaller sparticle mass splittings. ◮ In total 11 signal regions are defined.

1When forming this ratio meff is computed from the leading N jets in the N jet stream.

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0-lepton meff Analysis: Signal Region Cuts

Requirement Channel A A’ B C D E E miss

T

[GeV] > 160 pT(j1) [GeV] > 130 pT(j2) [GeV] > 60 pT(j3) [GeV] > – – 60 60 60 60 pT(j4) [GeV] > – – – 60 60 60 pT(j5) [GeV] > – – – – 40 40 pT(j6) [GeV] > – – – – – 40 ∆φ(ji, E miss

T

) > 0.4 (i = {1, 2, (3)}) 0.4 (i = {1, 2, 3}), 0.2 (pT > 40 GeV jets) E miss

T

/meff(Nj) > 0.3 (2j) 0.4 (2j) 0.25 (3j) 0.25 (4j) 0.2 (5j) 0.15 (6j) meff(incl.) [GeV] > 1900/1400/– –/1200/– 1900/–/– 1500/1200/900 1500/–/– 1400/1200/900

Cuts used to define each of the channels in the analysis. SRs are defined by the last cut on meff (incl.). The E miss

T

/meff cut in any N jet channel uses a value of meff constructed from only the leading N jets. However, the final meff (incl.) selection uses all jets with pT > 40 GeV. The three meff (incl.) selections listed in the final row denote the ‘tight’, ‘medium’ and ‘loose’ selections respectively. Not all channels possess all three SRs.

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0-lepton meff Analysis: Background Estimation

◮ To evaluate the Standard Model background in the signal regions, Control Regions (CR) are formed enriched in the different primary background processes; W → lν +jets, Z → νν +jets, t¯ t and jet miss-measurement in multi-jet events. CR SR Background CR process CR selection CR1a Z(→ νν)+jets γ+jets Isolated photon CR1b Z(→ νν)+jets Z(→ ℓℓ)+jets |m(ℓ, ℓ) − m(Z)| < 25 GeV CR2 Multi-jets Multi-jets Reversed ∆φ(ji, E miss

T

) cut CR3 W (→ ℓν)+jets W (→ ℓν)+jets 30 GeV < mT (ℓ, E miss

T

) < 100 GeV, b-veto CR4 t¯ t and single-t t¯ t → bbqq′ℓν 30 GeV < mT (ℓ, E miss

T

) < 100 GeV, b-tag ◮ Signal region style cuts are applied treating leptons as jets in W and t¯ t CRs and adding the photon or Z pT to the E miss

T

in the Z CRs. ◮ Good agreement in the shape of the meff distribution is seen in these Control Regions.

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0-lepton meff Analysis: Background Estimation

◮ Having defined a set of control regions for each signal region in similar kinematic regimes transfer factors are then defined; N(SR, est, proc) = N(CR, obs, proc) × (TransferFactor) (1) = N(CR, obs, proc) × N(SR, raw, proc) N(CR, raw, proc)

• ◮ N(SR, est, proc) is the Signal Region background estimate for the process

◮ N(CR, obs, proc) is the observed number of data events in the Control Region for the process ◮ N(SR, raw, proc) and N(CR, raw, proc) are raw, un-normalised estimates of the contributions from the process to the Signal and Control Regions respectively. ◮ For the vector boson and t¯ t backgrounds these transfer factors are taken from Monte-Carlo. ◮ For the Multi-jet background a data driven technique based on smearing low E miss

T

events by the detector resolution is employed. ◮ By using these ratios several of the systematics partially cancel. ◮ A global fit for the normalisation of each background from the 5 control regions is simulataneously performed separately for each signal region.

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Christopher Young

0-lepton meff Analysis: Background Estimation

◮ As an example here I show the 5 Control Regions (before final meff cuts) for the 3 jet stream.

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0-lepton meff Analysis: Results

◮ The results of the global fit, the oberserved number of data events and degree

• f statistical agreement for the first 6 Signal Regions. The numbers in brackets

denote the background prediction before the fit is performed.

Process Signal Region SRC loose SRE loose SRA medium SRAp medium SRC medium SRE medium t¯ t+SingleTop 74 ± 13 (75) 66 ± 26 (64) 7 ± 5 (5.1) 11 ± 3.4 (10) 12 ± 4.5 (10) 17 ± 5.8 (13) Z/γ+jets 70 ± 22 (61) 22 ± 6.4 (13) 31 ± 9.9 (34) 64 ± 20 (69) 17 ± 5.9 (16) 8 ± 2.9 (4.4) W +jets 62 ± 9.3 (61) 23 ± 11 (23) 19 ± 4.5 (21) 26 ± 4.6 (30) 8.1 ± 2.9 (11) 5.9 ± 3 (4.7) QCD jets 0.39 ± 0.4 (0.16) 3.7 ± 1.9 (3.8) 0.14 ± 0.24 (0.13) 0 ± 0.13 (0.38) 0.024 ± 0.034 (0.013)0.8 ± 0.53 (0.64) Di-Bosons 7.9 ± 4 (7.9) 4.2 ± 2 (4.2) 7.3 ± 3.7 (7.5) 15 ± 7.4 (16) 1.7 ± 0.87 (1.7) 2.7 ± 1.3 (2.7) Total 214 ± 24.9 ± 13 119 ± 32.6 ± 11.664.8 ± 10.2 ± 6.92115 ± 19 ± 9.69 38.6 ± 6.68 ± 4.77 34 ± 4.47 ± 5.57 Data 210 148 59 85 36 25 local p0 (Gaus. σ) 0.55(-0.14) 0.21(0.8) 0.65(-0.4) 0.9(-1.3) 0.6(-0.26) 0.85(-1)

◮ Good agreement within the uncertainties is seen between the predicted and

• bserved numbers of events.

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0-lepton meff Analysis: Results

◮ The results of the global fit, the oberserved number of data events and degree

• f statistical agreement for the final 5 Signal Regions. The numbers in brackets

denote the background prediction before the fit is performed.

Process Signal Region SRA tight SRB tight SRC tight SRD tight SRE tight t¯ t+SingleTop0.22 ± 0.35 (0.046) 0.21 ± 0.33 (0.066) 1.8 ± 1.6 (0.96) 2 ± 1.7 (0.92) 3.9 ± 4 (2.6) Z/γ+jets 2.9 ± 1.5 (3.1) 2.5 ± 1.4 (1.6) 2.1 ± 1.1 (4.4) 0.95 ± 0.58 (2.7) 3.2 ± 1.4 (1.8) W +jets 2.1 ± 0.99 (1.9) 0.97 ± 0.6 (0.84) 1.2 ± 1.2 (2.7) 1.7 ± 1.5 (2.5) 2.3 ± 1.7 (1.5) QCD jets 0 ± 0.0024 (0.002) 0 ± 0.0034 (0.0032) 0 ± 0.0058 (0.0023)0 ± 0.0072 (0.021) 0.22 ± 0.25 (0.24) Di-Bosons 1.7 ± 0.95 (2) 1.7 ± 0.95 (1.9) 0.49 ± 0.26 (0.51) 2.2 ± 1.2 (2.2) 2.5 ± 1.3 (2.5) Total 7 ± 0.999 ± 2.26 5.39 ± 0.951 ± 2.01 5.68 ± 1.79 ± 1.51 6.84 ± 1.7 ± 2.1 12.1 ± 4.59 ± 3.04 Data 1 1 14 9 13 local p0 (Gaus. σ) 0.98(-2.1) 0.95(-1.7) 0.018(2.1) 0.29(0.55) 0.45(0.13)

◮ Good agreement within the uncertainties is seen between the predicted and

• bserved numbers of events.

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0-lepton meff Analysis: Results

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0-lepton meff Analysis: Results

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0-lepton meff Analysis: Results

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0-lepton meff Analysis: Limits

◮ Having not observed any significant excess limits are set on a simplified model consisting of first and second generation squarks, a gluino octet and a massless LSP and in the MSUGRA/CMSSM plane with tan β = 10 ; A0 = 0 ; µ > 0 ◮ For each point in the planes the signal region with the best expected exclusion is used to evaluate whether the point is excluded or not.

gluino mass [GeV]

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squark mass [GeV]

600 800 1000 1200 1400 1600 1800 2000

= 100 fb

SUSY

σ = 10 fb

SUSY

σ = 1 fb

SUSY

σ

) = 0 GeV

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• bserved 95% C.L. limit

s

CL median expected limit

s

CL σ 1 ± Expected limit ATLAS EPS 2011

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>0 µ = 0, = 10, A β MSUGRA/CMSSM: tan

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Combined

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s

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s

CL ATLAS EPS 2011 LSP τ ∼ LEP Chargino No EWSB

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0-lepton High Multiplicity Analysis

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0-lepton High Multiplicity Analysis

◮ Analysis targeting longer decay chains of SUSY particles resulting in final states with very large jet multiplicity and lower E miss

T

. ◮ Update of previous 1.34fb−1 analysis (arXiv: 1110.2299) with increased number of signal regions and increased luminosity. ◮ Updated procedures and more detailed study allowed removal of the ∆R(jet,jet) cut present in the previous version. ◮ Large increase in signal acceptance. ◮ Object definitions, event cleaning and lepton veto the same as 0-lepton meff analysis. ◮ 6 signal regions defined. Signal region 7j55 8j55 9j55 6j80 7j80 8j80 Isolated Leptons (e, µ) =0 Jet pT > 55 GeV > 80 GeV Jet |η| < 2.8 Number of jets ≥ 7 ≥ 8 ≥ 9 ≥ 6 ≥ 7 ≥ 8 E miss

T

/√HT > 4 GeV1/2

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0-lepton High Multiplicity Analysis: Backgrounds

◮ Due to the softer E miss

T

requirements and lack of ∆φ(ji, E miss

T

) cuts, jet miss-measurement is a primary background in this search. ◮ The cuts are designed to allow a robust estimation of this background. ◮ The E miss

T

/√HT distribution is observed to be stable under changes in nJet. ◮ This is due to the jet resolution dependence of the ATLAS detector. ◮ Shape is taken from lower multiplicity (after subtracting other backgrounds) and normalised at low E miss

T

/√HT. ◮ Primary systematics are; closure at lower multiplicity/lower E miss

T

/√HT, the varying amounts of heavy flavour jets at different nJet and the subtraction of the other backgrounds in forming the template.

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0-lepton High Multiplicity Analysis: Backgrounds

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0.6 0.8 1 1.2 1.4

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SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton High Multiplicity Analysis: Backgrounds

◮ t¯ t, W +jets and Z+jets backgrounds follow a similar approach to the 0-lepton meff analysis. ◮ Valiation regions are formed requiring muons. ◮ Control regions are defined applying SR cuts and treating the muon as a jet (for W and t¯ t) or adding them to the E miss

T

(for Z). ◮ Transfer functions are used when adequate CR statistics are present, otherwise Monte-Carlo estimations are used. ◮ Monte-Carlo is validated at high multiplicity by looking at jet multiplicity distributions with reduced jet pT cuts.

2 4 6 8 10 12

Number of events

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

• 1

L dt ~ 4.7 fb

∫

> 45 GeV jets

T

p Top validation region ATLAS Preliminary

= 7 TeV) s Data 2011 ( Total SM prediction ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ) τ τ , µ µ (ee, → Alpgen Z =240

1/2

m =2960, m SUSY

Number of jets

2 4 6 8 10 12

DATA / Prediction 0.5 1 1.5 2

2 4 6 8 10 12

Number of events

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

• 1

L dt ~ 4.7 fb

∫

> 55 GeV jets

T

p Top control region ATLAS Preliminary

= 7 TeV) s Data 2011 ( Total SM prediction ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ) τ τ , µ µ (ee, → Alpgen Z =240

1/2

m =2960, m SUSY

Number of jets

2 4 6 8 10 12

DATA / Prediction 0.5 1 1.5 2

1 2 3 4 5 6 7 8 9 10

Number of events

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

7

10

• 1

L dt ~ 4.7 fb

∫

> 55 GeV jets

T

p W validation region ATLAS Preliminary

= 7 TeV) s Data 2011 ( Total SM prediction ν µ → Alpgen W ql,ll → t Alpgen t ) τ τ , µ µ (ee, → Alpgen Z ν ) τ (e, → Alpgen W =240

1/2

m =2960, m SUSY

Number of jets

1 2 3 4 5 6 7 8 9 10

DATA / Prediction 0.5 1 1.5 2

22 / 48

SLIDE 23

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton High Multiplicity Analysis: Results

◮ No significant excess is observed in any of the six signal regions. Signal region 7j55 8j55 9j55 6j80 7j80 8j80 Multi-jets 91±20 10±3 1.2±0.4 67±12 5.4±1.7 0.42±0.16 t¯ t → qℓ, ℓℓ 55±18 5.7±6.0 0.70±0.72 24±13 2.8±1.8 0.38±0.40 W + jets 18±11 0.81±0.72 0+0.13 13±10 0.34±0.21 0+0.06 Z + jets 2.7±1.6 0.05±0.19 0+0.12 2.7±2.9 0.10±0.17 0+0.13 Total Standard Model 167±34 17±7 1.9±0.8 107±21 8.6±2.5 0.80±0.45 Data 154 22 3 106 15 1 pSM 0.64 0.27 0.28 0.52 0.07 0.43

23 / 48

SLIDE 24

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton High Multiplicity Analysis: Results

2 4 6 8 10 12 14 16

1/2

Number of events / 2 GeV

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

• 1

L dt ~ 4.7 fb

∫

> 55 GeV

T

7 jets p ≥ ATLAS Preliminary

= 7 TeV) s Data 2011 ( Background prediction qq) → t Multi-jets (inc. t ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ν ν → Alpgen Z τ τ → Alpgen Z =240

1/2

m =2960, m SUSY

]

1/2

[GeV

T

H /

miss T

E

2 4 6 8 10 12 14 16

DATA / Prediction

0.5 1 1.5 2

2 4 6 8 10 12 14 16

1/2

Number of events / 2 GeV

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

• 1

L dt ~ 4.7 fb

∫

> 80 GeV

T

6 jets p ≥ ATLAS Preliminary

= 7 TeV) s Data 2011 ( Background prediction qq) → t Multi-jets (inc. t ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ν ν → Alpgen Z τ τ → Alpgen Z =240

1/2

m =2960, m SUSY

]

1/2

[GeV

T

H /

miss T

E

2 4 6 8 10 12 14 16

DATA / Prediction

0.5 1 1.5 2

24 / 48

SLIDE 25

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton High Multiplicity Analysis: Results

2 4 6 8 10 12 14 16

1/2

Number of events / 2 GeV

• 2

10

• 1

10 1 10

2

10

3

10

4

10

5

10

• 1

L dt ~ 4.7 fb

∫

> 55 GeV

T

8 jets p ≥ ATLAS Preliminary

= 7 TeV) s Data 2011 ( Background prediction qq) → t Multi-jets (inc. t ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ν ν → Alpgen Z τ τ → Alpgen Z =240

1/2

m =2960, m SUSY

]

1/2

[GeV

T

H /

miss T

E

2 4 6 8 10 12 14 16

DATA / Prediction

0.5 1 1.5 2

2 4 6 8 10 12 14 16

1/2

Number of events / 2 GeV

• 2

10

• 1

10 1 10

2

10

3

10

4

10

5

10

• 1

L dt ~ 4.7 fb

∫

> 80 GeV

T

7 jets p ≥ ATLAS Preliminary

= 7 TeV) s Data 2011 ( Background prediction qq) → t Multi-jets (inc. t ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ν ν → Alpgen Z τ τ → Alpgen Z =240

1/2

m =2960, m SUSY

]

1/2

[GeV

T

H /

miss T

E

2 4 6 8 10 12 14 16

DATA / Prediction

0.5 1 1.5 2

25 / 48

SLIDE 26

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton High Multiplicity Analysis: Results

2 4 6 8 10 12 14 16

1/2

Number of events / 2 GeV

• 2

10

• 1

10 1 10

2

10

3

10

4

10

5

10

• 1

L dt ~ 4.7 fb

∫

> 55 GeV

T

9 jets p ≥ ATLAS Preliminary

= 7 TeV) s Data 2011 ( Background prediction qq) → t Multi-jets (inc. t ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ν ν → Alpgen Z τ τ → Alpgen Z =240

1/2

m =2960, m SUSY

]

1/2

[GeV

T

H /

miss T

E

2 4 6 8 10 12 14 16

DATA / Prediction

0.5 1 1.5 2

2 4 6 8 10 12 14 16

1/2

Number of events / 2 GeV

• 2

10

• 1

10 1 10

2

10

3

10

4

10

5

10

• 1

L dt ~ 4.7 fb

∫

> 80 GeV

T

8 jets p ≥ ATLAS Preliminary

= 7 TeV) s Data 2011 ( Background prediction qq) → t Multi-jets (inc. t ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ν ν → Alpgen Z τ τ → Alpgen Z =240

1/2

m =2960, m SUSY

]

1/2

[GeV

T

H /

miss T

E

2 4 6 8 10 12 14 16

DATA / Prediction

0.5 1 1.5 2

26 / 48

SLIDE 27

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton High Multiplicity Analysis: Results

27 / 48

SLIDE 28

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton High Multiplicity Analysis: Limits

◮ Having observed no significant excess we set limits. ◮ Limits are set in a simplified model with a gluino octet which decays to a t¯ t pair and ˜ χ0

1, and in the MSUGRA/CMSSM plane with tan β = 10 ; A0 = 0 ; µ > 0. [GeV]

g ~

m

500 600 700 800 900 1000

[GeV]

1

χ ∼

m

100 200 300 400 500 600

0.26 0.14 0.09 0.06 0.04 0.03 0.03 0.02 0.02 0.02 0.02 0.55 0.16 0.1 0.07 0.05 0.04 0.03 0.02 0.02 0.02 0.02 0.4 0.14 0.1 0.06 0.05 0.03 0.03 0.02 0.02 0.02 0.27 0.13 0.09 0.06 0.04 0.03 0.03 0.02 0.02 0.23 0.12 0.08 0.05 0.04 0.03 0.03 0.02 0.23 0.11 0.08 0.06 0.04 0.03 0.03 0.21 0.12 0.07 0.05 0.04 0.03 0.23 0.12 0.08 0.05 0.04 0.24 0.13 0.08 0.06 0.22 0.12 0.08 0.19 0.13 0.24

Cross section excluded at 95% C.L. [pb]

• 3

10

• 2

10

• 1

10 forbidden

1

χ ∼ t t → g ~ 1

χ ∼ t t → g ~ production, g ~

• g

~

• 1

= 4.7 fb

int

L combined

miss T

Multi-jets plus E Preliminary ATLAS combined

miss T

Multi-jets plus E

95% C.L. limit

s

• bs. CL

95% C.L. limit

s

• exp. CL

σ 1 ±

• exp. limit
• 1

SS Dilepton, 2.0 fb

• 1

1-lepton plus bjet, 2.0 fb

[GeV] m

500 1000 1500 2000 2500 3000 3500

[GeV]

1/2

m

150 200 250 300 350 400 450 500 550

(600) g ~ ( 8 ) g ~ (600) q ~ ( 1 ) q ~ ( 1 4 ) q ~

1 ±

χ ∼ LEP 2 Theoretically excluded

>0 µ = 0, = 10, A β MSUGRA/CMSSM: tan

• 1

= 4.7 fb

int

L combined

miss T

Multi-jets plus E Preliminary ATLAS combined

miss T

Multi-jets plus E

95% C.L. limit

s

• bs. CL

95% C.L. limit

s

• exp. CL

σ 1 ±

• exp. limit
• 1

, 1.0 fb

miss T

2,3,4 jets plus E ≥

• 1

, 1.3 fb

miss T

MultiJets plus E

• 1

SS Dilepton, 2.0 fb

28 / 48

SLIDE 29

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis

29 / 48

SLIDE 30

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis

◮ Update of the 1fb−1 analysis (arXiv:1109.6606) ◮ A new signal region has been defined with a soft lepton and using a E miss

T

trigger, designed to increase sensitivity to SUSY decay spectra involving small mass differences. ◮ Also, for the first time in ATLAS SUSY searches a procedure of performing a simultaneous fit across the shape of the signal distribution. ◮ Finally, some of the background uncertainties are constrained by fitting to the shape of the jet multiplicity in the background control regions. ◮ These updates have resulted in a large increase in the power of this search channel.

30 / 48

SLIDE 31

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis: Lepton Definition

◮ In this analysis two kinds of signal region are considered; “hard” and “soft” lepton. ◮ Hard electrons: These are required to pass tighter identification requirements than those vetoed in the 0-lepton analyses, have survived the overlap removal, pass isolation criteria, not fall in unrespondent areas of the calorimeter and have pT> 25 GeV, |η| < 2.47. ◮ Soft electrons: These have to pass the above criteria, not lie in the calorimeter transition region (1.37 < |η| < 1.52) and have 7 < pT < 25 GeV. ◮ Hard muons: These are to pass the identification criteria employed in the 0-lepton analysis, pass overlap removal, and in addition pass isolation criteria. They are required to have pT > 20 GeV, |η| < 2.4. ◮ Soft muons: These are required to pass the above criteria but have 6 < pT < 20 GeV. ◮ The two criteria of leptons are therefore orthogonal allowing for channels to be combined in the future. ◮ Events with additional leptons are vetoed. ◮ Jets and E miss

T

are defined as in the 0-lepton analyses.

31 / 48

SLIDE 32

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis: Signal Regions

◮ Three different signal regions are defined for this analysis (although note that a shape fit is performed in the final discriminating variable for exclusion).

3-jet 4-jet soft-lepton Trigger Single electron or muon (+jet) Missing ET Nlep == 1 == 1 == 1 pℓ

T (GeV)

> 25 (20) > 25 (20) [7,25] ([6,20]) pℓ2

T (GeV)

< 10 < 10 < 7 (6) Njet ≥ 3 ≥ 4 ≥ 2 pjet

T (GeV)

> 100, 25, 25 > 80, 80, 80, 80 > 130,25 pjet 4

T

(GeV) < 80 — — E miss

T

(GeV) > 250 > 250 > 250 MT (GeV) > 100 > 100 > 100 E miss

T

/Meff > 0.3 > 0.2 > 0.3 Minc

eff (GeV)

> 1200 > 800 — The pT selections for leptons are given for electrons (muons). The transverse mass (MT) of the lepton (ℓ) and Pmiss

T

is defined as MT =

• 2pℓ

TE miss T

(1 − cos(∆φ( ℓ, Pmiss

T

))) The inclusive effective mass (Minc

eff ) is the scalar sum of the pT of the lepton, the jets and E miss T

: Minc

eff = pℓ T +

• i=1

pT,i + E miss

T

where the index i runs over all jets with pT> 25 GeV, |η| < 2.5 in the event.

32 / 48

SLIDE 33

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis: Backgrounds

◮ The main backgrounds to this search are;

• 1. semi and fully leptonic t¯

t

• 2. W (→ lν)+jets

◮ Control regions are formed for each of these backgrounds as defined below;

3- and 4-jet 3- and 4-jet soft-lepton soft-lepton W control t¯ t control W control t¯ t control Njet ≥ 3 ≥ 3 Same as signal region pjet

T (GeV)

> 80, 25, 25 > 80, 25, 25 Same as signal region Njet (b-tagged) ≥ 1 ≥ 1 E miss

T

(GeV) [30,120] [30,120] [180,250] [180,250] MT (GeV) [40,80] [40,80] [40,80] [40,80] Minc

eff (GeV)

> 400 > 400 — —

[GeV]

inc eff

m 200 400 600 800 1000 1200 1400 1600 1800 Data / SM 1 2 Events / 50 GeV

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

7

10

• 1

L dt = 4.7 fb

∫

ATLAS Preliminary W+jets Control Region

combined µ e and cut

inc eff

>80,25,25 GeV, before m

T

3 jets p =7 TeV) s Data 2011 ( Standard Model multijets (data estimate) W+jets Z+jets t t single top Dibosons =300 1/2 =820 m MSUGRA m

[GeV]

inc eff

m 200 400 600 800 1000 1200 1400 1600 Data / SM 1 2 Events / 50 GeV

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

7

10

• 1

L dt = 4.7 fb

∫

ATLAS Preliminary Top Control Region

combined µ e and cut

inc eff

>80,25,25 GeV, before m

T

3 jets p =7 TeV) s Data 2011 ( Standard Model multijets (data estimate) W+jets Z+jets t t single top Dibosons =300 1/2 =820 m MSUGRA m

>25 GeV jets

T

number of p 2 4 6 8 10 Data / SM 1 2 Events

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

7

10

8

10

• 1

L dt = 4.7 fb

∫

ATLAS Preliminary W+jets Control Region

combined µ e and >400 GeV

inc eff

>80,25,25 GeV, m

T

3 jets p =7 TeV) s Data 2011 ( Standard Model multijets (data estimate) W+jets Z+jets t t single top Dibosons =300 1/2 =820 m MSUGRA m

33 / 48

SLIDE 34

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis: Background Fit

◮ A fit to the control region data is performed based on the profile likelihood method. ◮ There are 4 inputs to the fit:

• 1. The observed number of events in each jet multiplicity bin of the W and

t¯ t Control Regions.

• 2. The Transfer Factors that relate the number of observed events for each

process in the different control and signal regions. When testing a signal model the signal contamination is also included.

• 3. The fake lepton background (see CONF for details on the data-driven

method used to find this).

• 4. The Monte-Carlo estimations of the other small backgrounds.

◮ Uncertainties are treated as nuissance parameters in this fit and correlations of these nuissance parameters between bins is taken into account. ◮ It should be noted that the number of input measurements is sufficient for the fit to be over-constrained such that uncertainties can be reduced by the fit. ◮ Most notably the dependence on the matching scale parameter, kTfac is greatly reduced (by ∼a factor of 2) by using the data to constrain the fit. (some uncertainties, most notably JES, are not constrained)

34 / 48

SLIDE 35

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis: Fit Validation

◮ The background fit is validated in an intermediate region of parameter space between the control and signal regions.

[GeV]

miss T

E 40 80 120 160 200 240 280 320 360 [GeV]

T

m 20 40 60 80 100 120 140 160 180 Signal Region High m W+j W+j Control Region Validation Region

no b−jet no b−jet

top top

1 b−jet 1 b−jet ≥ ≥

Multijet Control Region

T

(a) Graphical Representation of regions.

inc eff

m [GeV] 400 600 800 1000 1200 1400 1600 Events / 200 GeV

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

7

10

8

10 ATLAS Preliminary

• 1

Ldt = 4.7 fb

∫

=7 TeV) s Data 2011 ( Standard Model multijets (data estimate) W+jets & Z+jets t t single top & diboson

(b) W Validation region

inc eff

m [GeV] 400 600 800 1000 1200 1400 1600 Events / 200 GeV 1 10

2

10

3

10

4

10

5

10

6

10

7

10

8

10 ATLAS Preliminary

• 1

Ldt = 4.7 fb

∫

=7 TeV) s Data 2011 ( Standard Model multijets (data estimate) W+jets & Z+jets t t single top & diboson

(c) High mT Validation region

inc eff

m [GeV] 400 600 800 1000 1200 1400 1600 Events / 200 GeV

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

7

10

8

10 ATLAS Preliminary

• 1

Ldt = 4.7 fb

∫

=7 TeV) s Data 2011 ( Standard Model multijets (data estimate) W+jets & Z+jets t t single top & diboson

(d) Top Validation region

35 / 48

SLIDE 36

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis: Results

◮ When the fit is extended to the signal region (including the observed data) and a signal strength parameter is included the results are found to be consistent with the Standard Model.

3-jet 4-jet soft lepton Observed events 3 6 26 Fitted bkg events 5.7 ± 4.0 8.3 ± 3.1 32 ± 11 Fitted top events 2.0 ± 1.5 5.3 ± 2.1 8.6 ± 3.4 Fitted W/Z+jets events 2.9 ± 2.1 2.0 ± 0.7 15 ± 7 Fitted other bkg events 0.5 ± 0.7 0.9 ± 0.8 0.62 ± 0.24 Fitted multijet events 0.3 ± 0.4 0.17 ± 0.30 8 ± 4 MC exp. SM events 5.6 7.9 32 MC exp. top events 1.9 5.0 8.6 MC exp. W/Z+jets events 3.1 2.0 15 MC exp. other bkg events 0.3 0.7 0.62 Data-driven multijet events 0.3 0.17 8 Results of the fit in the signal regions. Nominal expectations from simulation (MC), normalized to theoretical cross-sections, are given for comparison. The errors shown are the statistical plus systematic uncertainties; there is a strong negative correlation between the uncertainties for the fitted t¯ t versus W /Z+jets events.

36 / 48

SLIDE 37

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis: Signal Regions

[GeV]

inc eff

m 400 600 800 1000 1200 1400 1600 Data / SM 1 2 Events / 200 GeV

• 1

10 1 10

2

10

3

10

4

10

• 1

L dt = 4.7 fb

∫

ATLAS Preliminary 3-Jet Analysis

combined µ e and cut

inc eff

3-Jet Signal Region before m

=7 TeV) s Data 2011 ( Standard Model multijets (data estimate) W+jets Z+jets t t single top Dibosons =300

1/2

=820 m MSUGRA m [GeV]

inc eff

m 400 600 800 1000 1200 1400 1600 Data / SM 1 2 Events / 200 GeV

• 1

10 1 10

2

10

3

10

4

10

• 1

L dt = 4.7 fb

∫

ATLAS Preliminary 4-Jet Analysis

combined µ e and cut

inc eff

4-Jet Signal Region before m

=7 TeV) s Data 2011 ( Standard Model multijets (data estimate) W+jets Z+jets t t single top Dibosons =300

1/2

=820 m MSUGRA m Events / 0.1 20 40 60

• 1

L dt = 4.7 fb

∫

ATLAS Preliminary Combined Soft Lepton

Soft Lepton Signal Region cut

eff

/ m

miss T

before E =7 TeV) s Data 2011 ( Standard Model multijets (data estimate) W+jets Z+jets t t single top Dibosons Simplified model =345

LSP

=425 m

g ~

m eff

/ m

miss T

E 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Data / SM 1 2

37 / 48

SLIDE 38

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis: Limits

◮ When setting limits the meff shape of the signal in the signal region is used, along with the CR contamination, for the fit. ◮ Limits are set in the MSUGRA/CMSSM plane and in a simplified model defined by the pair production of gluinos followed by the decay; ˜ g → q¯ q

′ ˜

χ±

1 → q¯

q

′W ± ˜

χ0

1, where the

chargino mass is fixed half way between that of the gluino and the neutralino.

[GeV] m 500 1000 1500 2000 2500 3000 3500 [GeV]

1/2

m 200 300 400 500 600 700

( 6 G e V ) q ~ ( 1 G e V ) q ~ ( 1 4 G e V ) q ~ (600 GeV) g ~ ( 1 G e V ) g ~ (1400 GeV) g ~

>0 µ = 0, = 10, A β MSUGRA/CMSSM: tan =7 TeV s ,

• 1

= 4.7 fb

int

L 3- and 4-jet analyses

ATLAS

95% CL

S

Observed CL

S

Expected CL σ 1 ±

S

Expected CL

• 1

= 1.04 fb

int

1-lepton, L

1 ±

χ ∼ LEP2 Stau LSP Theoretically excluded

Preliminary

[GeV]

gluino

m 300 400 500 600 700 800 900 1000 1100 [GeV]

LSP

m 200 400 600 800 1000 Cross Section Excluded at 95% CL [pb]

• 3

10

• 2

10

• 1

10 1 10

2

10

1-Step Decay, x=1/2

1

χ ∼

1

χ ∼ qqqqWW → g ~ g ~ 3- and 4-jet analyses =7 TeV s ,

• 1

= 4.7 fb

int

L Observed 95% CL Expected σ 1 ± Expected

ATLAS Preliminary

[GeV]

gluino

m 300 400 500 600 700 800 900 1000 1100 [GeV]

LSP

m 200 400 600 800 1000 Cross Section Excluded at 95% CL [pb]

• 3

10

• 2

10

• 1

10 1 10

2

10

1-Step Decay, x=1/2

1

χ ∼

1

χ ∼ qqqqWW → g ~ g ~ soft-lepton =7 TeV s ,

• 1

= 4.7 fb

int

L Observed 95% CL Expected σ 1 ± Expected

ATLAS Preliminary

38 / 48

SLIDE 39

SUSY Strong Production Searches @ ATLAS

Christopher Young

Conclusions

◮ Three analyses have been presented. ◮ All use 4.7fb−1 of 7 TeV data. ◮ No excess above the Standard Model expectation was observed. ◮ Limits were set in MSUGRA/CMSSM and some simplified models. ◮ Searches designed to be generic → should cover many other models. ◮ Other analyses are in the process

• f being updated to the full dataset.

◮ We look forward to 8 TeV running this year. ◮ Are there any questions?

[GeV] m

500 1000 1500 2000 2500 3000 3500

[GeV]

1/2

m

100 200 300 400 500 600 700

( 6 ) g ~ (1000) g ~ ( 1 4 ) g ~ (600) q ~ ( 1 ) q ~ ( 1 4 ) q ~

1 ±

χ ∼ LEP 2 Stau LSP Theoretically excluded

95% C.L. limits

s

CL >0 µ = 0, = 10, A β MSUGRA/CMSSM: tan

• 1

= 4.7 fb

int

L

Preliminary ATLAS

Observed Expected Observed Expected Observed Expected 2-6 jets ≥ 0-lepton, 6-9 jets ≥ 0-lepton, 3,4 jets ≥ 1-lepton,

ATLAS-CONF-2012-033 ATLAS-CONF-2012-037 ATLAS-CONF-2012-041

39 / 48

SLIDE 40

SUSY Strong Production Searches @ ATLAS

Christopher Young

Back-Up Slides

40 / 48

SLIDE 41

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton meff Analysis: Objects

◮ Jets: Candidates are reconstructed using the anti-kt jet clustering algorithm with a distance parameter of 0.4. These are calibrated using pT and η-dependent calibration factors based on Monte Carlo corrections validated with extensive test-beam and collision-data studies. Only jet candidates with pT > 20 GeV are retained. ◮ Electrons: Candidates are required to have pT> 20 GeV, to have |η| < 2.47, and to pass electron shower shape and track selection criteria. ◮ Muons: Candidates are required to have pT > 10 GeV and |η| < 2.4. ◮ Overlap removal: Jets within ∆R < 0.2 of an electron candidate are removed. Following this any lepton within ∆R < 0.4 of a jet are removed. ◮ Lepton Veto: If any electron or muon candidate is left after overlap removal the event is vetoed. ◮ Missing Transverse Energy (E miss

T

): The calculation of the E miss

T

uses muon candidates before overlap removal and calorimeter clusters with |η| < 4.5 that are calibrated to physics objects that they are associated with. Clusters that are not associated with high pT physics objects are also included uncalibrated. ◮ Event Cleaning: A series of cuts are also applied to reduce the non-collision and detector noise backgrounds to a very low level.

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SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton meff Analysis: Background Estimation

◮ The 5 Control Regions and Signal Region (before final meff cuts) for the 2 jet stream.

500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

4

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson multijet SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR2 SRA

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

4

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR3 SRA

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR4 SRA

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 1 10

2

10

3

10

4

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets + jets (Alpgen) γ V + jets (Alpgen) γ Preliminary ATLAS CR1a SRA

meffincl 500 1000 1500 2000 2500 3000 DATA / MC 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR1b SRA

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

4

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t Z+jets W+jets Diboson multijet SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS SRA

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5

42 / 48

SLIDE 43

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton meff Analysis: Background Estimation

◮ The 5 Control Regions and Signal Region (before final meff cuts) for the 2 jet “prime” stream.

500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson multijet SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR2 SRA’

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

4

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR3 SRA’

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR4 SRA’

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 1 10

2

10

3

10

4

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets + jets (Alpgen) γ V + jets (Alpgen) γ Preliminary ATLAS CR1a SRA’

meffincl 500 1000 1500 2000 2500 3000 DATA / MC 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR1b SRA’

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

4

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t Z+jets W+jets Diboson multijet SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS SRA’

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5

43 / 48

SLIDE 44

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton meff Analysis: Background Estimation

◮ The 5 Control Regions and Signal Region (before final meff cuts) for the 4 jet stream.

500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson multijet SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR2 SRC

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR3 SRC

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR4 SRC

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets + jets (Alpgen) γ V + jets (Alpgen) γ Preliminary ATLAS CR1a SRC

meffincl 500 1000 1500 2000 2500 3000 DATA / MC 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR1b SRC

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

3

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t Z+jets W+jets Diboson multijet SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS SRC

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5

44 / 48

SLIDE 45

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton meff Analysis: Background Estimation

◮ The 5 Control Regions and Signal Region (before final meff cuts) for the 5 jet stream.

500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson multijet SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR2 SRD

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR3 SRD

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR4 SRD

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets + jets (Alpgen) γ V + jets (Alpgen) γ Preliminary ATLAS CR1a SRD

meffincl 500 1000 1500 2000 2500 3000 DATA / MC 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR1b SRD

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t Z+jets W+jets Diboson multijet SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS SRD

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5

45 / 48

SLIDE 46

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton meff Analysis: Background Estimation

◮ The 5 Control Regions and Signal Region (before final meff cuts) for the 6 jet stream.

500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson multijet SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR2 SRE

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR3 SRE

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR4 SRE

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 1 10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets + jets (Alpgen) γ V + jets (Alpgen) γ Preliminary ATLAS CR1a SRE

meffincl 500 1000 1500 2000 2500 3000 DATA / MC 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t W+jets Z+jets Diboson SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS CR1b SRE

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5 500 1000 1500 2000 2500 3000 Entries / 100 GeV 1 10

2

10

• 1

L dt = 4.7 fb

∫

= 7 TeV) s Data 2011 ( SM Total and single top t t Z+jets W+jets Diboson multijet SM+SU(500,570,0,10) SM+SU(2500,270,0,10) Preliminary ATLAS SRE

(incl.) [GeV]

eff

m 500 1000 1500 2000 2500 3000 DATA / SM 0.5 1 1.5 2 2.5

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SLIDE 47

SUSY Strong Production Searches @ ATLAS

Christopher Young

0-lepton High Multiplicity Analysis: t¯ t Control and Validation Plots

2 4 6 8 10 12

Number of events

• 1

10 1 10

2

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5

10

6

10

• 1

L dt ~ 4.7 fb

∫

> 45 GeV jets

T

p Top validation region ATLAS Preliminary

= 7 TeV) s Data 2011 ( Total SM prediction ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ) τ τ , µ µ (ee, → Alpgen Z =240

1/2

m =2960, m SUSY

Number of jets 2 4 6 8 10 12

DATA / Prediction 0.5 1 1.5 2

2 4 6 8 10 12

Number of events

• 1

10 1 10

2

10

3

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5

10

6

10

• 1

L dt ~ 4.7 fb

∫

> 55 GeV jets

T

p Top validation region ATLAS Preliminary

= 7 TeV) s Data 2011 ( Total SM prediction ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ) τ τ , µ µ (ee, → Alpgen Z =240

1/2

m =2960, m SUSY

Number of jets 2 4 6 8 10 12

DATA / Prediction 0.5 1 1.5 2

2 4 6 8 10 12

Number of events

• 1

10 1 10

2

10

3

10

4

10

5

10

6

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• 1

L dt ~ 4.7 fb

∫

> 80 GeV jets

T

p Top validation region ATLAS Preliminary

= 7 TeV) s Data 2011 ( Total SM prediction ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ) τ τ , µ µ (ee, → Alpgen Z =240

1/2

m =2960, m SUSY

Number of jets 2 4 6 8 10 12

DATA / Prediction 0.5 1 1.5 2

2 4 6 8 10 12

Number of events

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

• 1

L dt ~ 4.7 fb

∫

> 45 GeV jets

T

p Top control region ATLAS Preliminary

= 7 TeV) s Data 2011 ( Total SM prediction ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ) τ τ , µ µ (ee, → Alpgen Z =240

1/2

m =2960, m SUSY

Number of jets 2 4 6 8 10 12

DATA / Prediction 0.5 1 1.5 2

2 4 6 8 10 12

Number of events

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

• 1

L dt ~ 4.7 fb

∫

> 55 GeV jets

T

p Top control region ATLAS Preliminary

= 7 TeV) s Data 2011 ( Total SM prediction ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ) τ τ , µ µ (ee, → Alpgen Z =240

1/2

m =2960, m SUSY

Number of jets 2 4 6 8 10 12

DATA / Prediction 0.5 1 1.5 2

2 4 6 8 10 12

Number of events

• 1

10 1 10

2

10

3

10

4

10

5

10

6

10

• 1

L dt ~ 4.7 fb

∫

> 80 GeV jets

T

p Top control region ATLAS Preliminary

= 7 TeV) s Data 2011 ( Total SM prediction ql,ll → t Alpgen t ν ) τ , µ (e, → Alpgen W ) τ τ , µ µ (ee, → Alpgen Z =240

1/2

m =2960, m SUSY

Number of jets 2 4 6 8 10 12

DATA / Prediction 0.5 1 1.5 2

47 / 48

SLIDE 48

SUSY Strong Production Searches @ ATLAS

Christopher Young

1-lepton Analysis: Gains due to changes

◮ The plot below shows the ratio of the excluded cross-section from the hard and soft lepton analyses highlighting the gain in the compressed scenario region of the soft lepton analysis.

[GeV]

gluino

m 300 400 500 600 700 800 900 1000 1100 [GeV]

LSP

m 200 400 600 800 1000

Ratio of Cross Sections Excluded at 95% CL (3- and 4-jet analyses / soft-lepton)

• 2

10

• 1

10 1 10

1-Step Decay, x=1/2

1

χ ∼

1

χ ∼ qqqqWW → g ~ g ~ =7 TeV s ,

• 1

= 4.7 fb

int

L Observed 95% CL (soft-lepton) Observed 95% CL (3- and 4-jet analyses)

ATLAS Preliminary

48 / 48