Searches for electroweak production of supersymmetric particles with the ATLAS detector

Searches for electroweak production of

supersymmetric particles with the ATLAS detector

Carlos Moreno-Martínez (IFAE Barcelona)

CPAN Days XIII

21st March 2022, Huelva (Spain)

CPAN Days

C. Moreno-Martínez

!2

21 March 2022

Searches for EWK sparticles in ATLAS

• Naturalness arguments in the MSSM predict light electroweak sparticles

• Large parameter space opened up with LHC Run 2

• Very challenging compared to strongly produced particles due to their small cross section

• General strategy: design regions enriched with signal events

• Target signatures with jets, missing transverse energy (MET) and other high momentum objects

• Estimate background from data in background enriched regions and validated in regions kinematically similar to signal regions

• Interpret results with simplified SUSY models - this talk: R-Parity Conserving (RPC) scenarios

Signal
 Region

Validation
 Region 2 Validation


Region 1

Control
 Region

Variable 1

Variable 2

(VR2)

10

³

Pair-production cross section in simplified models at 13 TeV

LHC SUSY Cross Section WG

(SR) (VR1)

(CR)

CPAN Days

C. Moreno-Martínez

!3

21 March 2022

EWK 4L analysis

˜^⌥₁

˜^±₁ / ˜⁰2

˜⁰₁

Z/h

˜⁰₁ p Z/h

p

W^⇤

G˜

`

`

W^⇤/Z^⇤

G˜

``

loose

SR0-ZZ

tight

SR0-ZZ

bveto loose

SR0-ZZ

bveto tight

SR0-ZZ

bveto loose

SR0

bveto tight

SR0

breq

SR0

bveto loose

SR1

bveto tight

SR1 breq

SR1

bveto loose

SR2

bveto tight

SR2

breq

SR2 SR5L

1 10 102

Events ^{Data Ztt}_{Total SM Higgs}

Reducible VVV

ZZ Other

ATLAS

4 leptons

= 13 TeV, 139 fb-1

s

loose SR0-ZZ tight SR0-ZZ bveto loose SR0-ZZ bveto tight SR0-ZZ bveto loose SR0 bveto tight SR0 breqSR0 bveto loose SR1 bveto tight SR1 breqSR1 bveto loose SR2 bveto tight SR2 breqSR2 SR5L

−2 0 2

Significance

200 300 400 500 600 700 800

) [GeV]

0

χ1

/ ∼

0

χ2

/ ∼

±

χ1

m(∼ 0

10 20 30 40 50 60 70 80 90 100 ) [%]G~ Z →0 1χ∼B(

ATLAS 13 TeV, 36 fb-1 SUSY)

theory

1 σ Observed Limit (±

exp) 1 σ Expected Limit (±

G~

Z/h

0 → χ1

, ∼

0

χ1

∼

0

χ2

∼

±

χ1

Higgsino ∼

=13 TeV, 139 fb-1

s

All limits at 95% CL

4 leptons

ATLAS

• Final states with 4 or more leptons

•

Sensitivity to higgsino models in the context of General Gauge Mediation (GGM) SUSY breaking

• SRs with at least 4 leptons (e/μ) and no tau req.

•

Four regions: 2 exclusive (b-jet veto) and 2 inclusive (≥0 b)

•

Loose/tight MET cuts for sensitivity to low/high mass

• Main backgrounds: ZZ and ttZ

•

Estimated from MC, normalized to data in dedicated CR

•

Backgrounds from fake/non-prompt leptons estimated from data with fake-factor method

• No significant excess found

•

SRs combined prioritizing the ones with best exclusion

•

Large sensitivity to low masses with large decay BR to Z

JHEP 07 (2021) 167

SRs for RPV models

RPC GGM

CPAN Days

offWZ 0j

CRWZ offWZ

nj

CRWZ offWZ

0j

VRWZ offWZ

nj

VRWZ offWZ

ll

nj-lowm

VRWZ VRttoffWZ offWZ

0j

VRFF offWZ

nj

VRFF offWZ

T

nj-lowp

1 VRFF

10 102

103

104

105

106

107

108

Events

Data Z+jets

Total SM tt

WZ tt+X

ZZ Others

offWZ

CR/VR

=13 TeV, 139 fb-1

s

ATLAS

offWZ 0jCRWZ offWZ njCRWZ offWZ 0jVRWZ offWZ njVRWZ offWZ llnj-lowmVRWZ offWZ tVRt offWZ 0jVRFF offWZ njVRFF offWZ Tnj-lowpVRFF

Pre-fit Post-fit

−2 0 2

Significance

−0.1 0 0.1

DifferenceRelative

WZ_CR_0jets WZ_CR_LowHTWZ_CR_HighHTWZ_VR_nJ0 WZ_VR_LowHTWZ_VR_HighHTfakes_VR top_VR top_VRAl

1 10 102

103

104

105

Events

Data Z+jets

Total SM tt

WZ tt+X

ZZ Others

=13 TeV, 139 fb-1

s

ATLAS

WZ,Wh

CR/VR

Pre-fit Post-fit

0jWZCRWZ TLowHWZCRWZ THighHWZCRWZ 0jWZVRWZ TLowHWZVRWZ THighHWZVRWZ WZ VRFF WZ tVRt incWZ tVRt

−0.2 0 0.2

DifferenceRelative 2−

0 2

Significance

C. Moreno-Martínez

!4

21 March 2022

EWK 3L+MET analysis

• Final states with 3 leptons and missing energy

•

Target chargino/neutralino production through the intermediate 
 W/Z/h* bosons

•

Topologies with same-flavour opposite-sign (SFOS) and 
 different-flavour opposite-sign (DFOS) leptons

• Main backgrounds:

•

WZ events estimated with MC, normalized to data

•

Z+jets with fake/non-prompt leptons fake factor method

• Selection for on-shell WZ and Wh* decays

•

Three signal regions:

•

^SRWZ: one SFOS lepton pair with mll ~mZ

•

^SRWh(SFOS): one SFOS lepton pair with mll ≠ mZ

•

^SRWh(DFOS): one DFOS lepton pair

•

Dedicated CR/VR for WZ events, split in bins of njet and HT

• Selection for off-shell W*Z* decays

•

Events selected with upper cut in max. lepton-pair invariant mass

•

Four signal regions for different event topologies:

•

2 low-MET SRs with njet = 0 (MET < 50 GeV) and njet ≥ 1 (MET < 200 GeV)

•

2 high-MET SRs with njet = 0 (MET > 50 GeV) and njet ≥ 1 (MET >200 GeV)

•

CR/VR defined with on-shell Z and low-MET cut, split in njet

˜^±₁

˜⁰₂ W^(⇤)

Z^(⇤) p

p

˜⁰₁

`

⌫

˜⁰₁

`

`

˜^±₁

˜⁰₂ W

p h p

˜⁰₁

`

⌫

˜⁰₁

``X

On-shell WZ + Wh CR/VR

Off-shell WZ

Eur. Phys. J. C 81 (2021) 1118

CPAN Days

C. Moreno-Martínez

!5

21 March 2022

EWK 3L+MET Results

WZ-1 SR SR^WZ-2

WZ-3 SR SR^WZ-4

WZ-5 SR SR^WZ-6

WZ-7 SR SR^WZ-8

WZ-9 SR SR^WZ-10

WZ-11 SR SR^WZ-12

WZ-13 SR SR^WZ-14

WZ-15 SR SR^WZ-16

WZ-17 SR SR^WZ-18

WZ-19 SR SR^WZ-20

−1

10 1 10 102

103

104

Events

Data tt

Total SM tt+X

WZ Others

ZZ WZ(300,200)

Z+jets WZ(600,100)

=13 TeV, 139 fb-1

s

ATLAS

SRWZ

-1WZ SR -2WZ SR -3WZ SR -4WZ SR -5WZ SR -6WZ SR -7WZ SR -8WZ SR -9WZ SR -10WZ SR -11WZ SR -12WZ SR -13WZ SR -14WZ SR -15WZ SR -16WZ SR -17WZ SR -18WZ SR -19WZ SR -20WZ SR

−2 0 2

Significance

SR1_WhSR2_WhSR3_WhSR4_WhSR5_WhSR6_WhSR7_WhSR8_WhSR9_WhSR10_WhSR11_WhSR12_WhSR13_WhSR14_WhSR15_WhSR16_WhSR17_WhSR18_WhSR19_WhSR_DFOS_0jSR_DFOS_1j

−1

10 1 10 102

103

104

Events

Data Higgs

Total SM Z+jets

WZ Others

t

t Wh(190,60)

Triboson Wh(200,25)

=13 TeV, 139 fb-1

s

ATLAS

SRWh

-1SFOSWh SR -2SFOSWh SR -3SFOSWh SR -4SFOSWh SR -5SFOSWh SR -6SFOSWh SR -7SFOSWh SR -8SFOSWh SR -9SFOSWh SR -10SFOSWh SR -11SFOSWh SR -12SFOSWh SR -13SFOSWh SR -14SFOSWh SR -15SFOSWh SR -16SFOSWh SR -17SFOSWh SR -18SFOSWh SR -19SFOSWh SR -1DFOSWh SR -2DFOSWh SR

−2 0 2

Significance

0jb 0jc 0jd 0je 0jf1 0jf2 0jg1 0jg2 njb njc njd nje njf1 njf2 njg1 njg2 0jb 0jc 0jd 0je 0jf1 0jf2 0jg1 0jg2 nja njb njc njd nje njf njg

1 10 102

103

Events

Data Z+jets W*Z*(200,190)

Total SM tt W*Z*(250,210)

WZ tt+X W*Z*(300,240)

ZZ Others W*Z*(250,170)

=13 TeV, 139 fb-1

s

ATLAS

0jb 0jc 0jd 0je 0jf1 0jf2 0jg1 0jg2 njb njc njd nje njf1 njf2 njg1 njg2 0jb 0jc 0jd 0je 0jf1 0jf2 0jg1 0jg2 nja njb njc njd nje njf njg

−2 0 2

Significance

ET

low offWZ

SR

ET

high offWZ

SR

offWZ

SR

˜^±1

˜⁰2

W^(⇤)

Z^(⇤) p

p

˜⁰1

`

⌫

˜⁰1

`

`

˜^±₁

˜⁰₂ W

p h p

˜⁰₁

`

⌫

˜⁰₁

``X

Eur. Phys. J. C 81 (2021) 1118

• All SRs divided in multiple bins for enhanced sensitivity

•

^{SRWZ and SRWh}(SFOS) divided in MET, mT and njet

•

^SRWh(DFOS) divided in njet

•

^SRoffWZ regions split according to lepton kinematics, focus on compressed scenarios

• No significant excess found over SM prediction

˜^±₁

˜⁰2

W^(⇤)

Z^(⇤) p

p

˜⁰1

`

⌫

˜⁰1

`

`

On-shell WZ

Off-shell WZ

Wh*

• Statistical combination of multiple SRs for sensitivity to a variety of models

•

Results combined also with previous 2L+MET compressed analysis: Phys. Rev. D 101, 052005 (2020)

• Large exclusion in NLSP-LSP mass plane for wino/bino dominated scenarios

•

Excluded NLSP mass up to 640 GeV for massless LSP, and LSP mass up to 240 GeV in off-shell region

• Large sensitivity to models with light higgsinos

•

Less stringent observed limits than expected due to mild excess in SRs, compatible with 2σ uncertainty band

•

Excluded NLSP masses up to 190 GeV for massless LSP

CPAN Days

C. Moreno-Martínez

!6

21 March 2022

EWK 3L+MET Interpretations

100 200 300 400 500 600 700 800 ) [GeV]

2

χ 0

, ∼

1

χ±

m(∼ 0

100 200 300 400 500 600

) [GeV] 1 0 χ ~m(

)

1 0χ

∼( m ) =

2 0χ

∼(

m m^Z

) +

1 0χ

∼( m ) =

2 0χ

∼( m

)

1 0χ

∼( m ) =

2 0χ

∼(

m m^Z

) +

1 0χ

∼( m ) =

2 0χ

∼( m

)

1 0χ

∼( m ) =

2 0χ

∼(

m m^Z

) +

1 0χ

∼( m ) =

2 0χ

∼( m

)

1 0χ

∼( m ) =

2 0χ

∼(

m m^Z

) +

1 0χ

∼( m ) =

2 0χ

∼( m

ATLAS

=13 TeV, 139 fb-1

s

All limits at 95% CL

exp) 1σ Expected Limit (±

theory) 1σ Observed Limit (± Obs. Limit on-shell Obs. Limit off-shell Obs. Limit compressed ATLAS 8 TeV excluded

2) χ 0

)=m(∼

1

χ±

wino/bino(+) m(∼

1

χ 0

∼

1

χ 0

WZ ∼

1→ χ±

∼

2

χ 0

∼

160 180 200 220 240 260 280 300 320 ) [GeV]

2

χ0

/∼

1

χ±

m(∼ 0

20 40 60 80 100 120 140 160 ) [GeV] 1 0 χ∼m(

mh

) + 1 0χ

∼( m ) = 2 0

∼(χ m

exp) 1 σ Expected Limit (±

theory) 1 σ Observed Limit (±

ATLAS 8 TeV excluded

ATLAS

1

χ0

∼

1

χ0

Wh∼

1→ χ±

∼

2

χ0

∼

=13 TeV, 139 fb-1

s

All limits at 95% CL

˜^±₁

˜⁰₂ W^(⇤)

Z^(⇤) p

p

˜⁰₁

`

⌫

˜⁰₁

`

`

˜^±₁

˜⁰₂ W

p h p

˜⁰₁

`

⌫

˜⁰₁

``X

Eur. Phys. J. C 81 (2021) 1118

• Comprehensive search for a number of scenarios

•

Baseline MSSM scenarios with different mass 
 hierarchies between bino, wino and higgsino

•

Gauge-mediated SUSY breaking models

•

SUSY coupled with axion models, axino LSP

• Final states with 2 hadronic boson decays + MET

•

W/Z/h reconstructed with large-R jets

•

Use track sub-jets to identify the topologies 
 Z/h bb (2B2Q) and W/Z qq (4Q)

•

Independent SRs for each category 
 based on boson candidate kinematics

• Main background: Z/W+jets, diboson production

•

Shape estimated from MC, normalization derived in fit to data

CPAN Days

C. Moreno-Martínez

!7

21 March 2022

EWK 0L+MET analysis 2B2Q SRs

4Q SRs

Inclusive SR

Inclusive SR

˜heavy

˜heavy

p p

˜light

W/Z q

q

˜light

Z/h

b b

˜_heavy

˜_heavy p

p

˜_light W/Z

q q

˜_light

W/Z

q q

Phys. Rev. D 104 (2021) 112010

•

Combine all inclusive SRs except for wino-to-bino model - no ZZ/Zh allowed

•

Wino NLSP: excluded masses between 400 and 1050 GeV

•

Higgsino NLSP: excluded wino masses between 450 and 90 GeV

•

Exclusion limits independent of NLSP decay branching ratio and LSP

CPAN Days

C. Moreno-Martínez

!8

21 March 2022

EWK 0L+MET - Results

• No excess observed in the signal regions

• SRs statistically combined for exclusion limits

•

Different combinations depending on targeted model

0 2 4 6 8 10 12

Events

Data Total SM W+jets

Z+jets VV Other

C1N2-WZ, (900,100) GeV C1N2-Wh, (900,100) GeV

) = 50%

G~

→ Z

0

χ1

) = 800 GeV, B(∼

0

χ1

) m(∼ G~ , H~ (

= 13 TeV, 139 fb-1

s

ATLAS SR Post-fit

4Q-WW 4Q-WZ 4Q-ZZ 4Q-VV

2B2Q-WZ 2B2Q-Wh 2B2Q-ZZ 2B2Q-Zh 2B2Q-VZ 2B2Q-Vh

−2 0 2

Significance

400 500 600 700 800 900 1000 1100 1200 ) [GeV]

3

χ0

/∼

2

χ±

m(∼ 0

100 200 300 400 500 600 ) [GeV] 1 0 χ∼m(

exp) 1 σ Expected limit (±

SUSY)

theory

σ 1

± Observed limit (

ATLAS

> 0 = 10, µ tanβ , X=W/Z/h)

0

χ2

∼

0

χ1

∼

±

χ1

: ∼ H~

0, χ3

∼

±

χ2

: ∼ W~ +XX ( H~ H~ W~→ W~

, All limits at 95% CL = 13 TeV, 139 fb-1

s

400 500 600 700 800 900 1000 1100 1200 ) [GeV]

2

χ0

/∼

1

χ±

m(∼ 0

100 200 300 400 500 600 ) [GeV] 1 0 χ∼m(

exp) 1 σ Expected limit (±

SUSY)

theory

σ 1

± Observed limit (

ATLAS

) = 50%

0

χ1

Z∼

0→ χ2

B(∼

0) χ1

: ∼ B~

0, χ2

∼

±

χ1

: ∼ W~ +WW/WZ/Wh ( B~

B~ W~→ W~

, All limits at 95% CL = 13 TeV, 139 fb-1

s

400 500 600 700 800 900 1000 1100 1200 ) [GeV]

2

χ0

m(∼ 0

100 200 300 400 500 600 ) [GeV] 1 0 χ∼/ 1± χ∼m(

exp) 1 σ Expected limit (±

SUSY)

theory

1 σ Observed limit (±

ATLAS

> 0 = 10, µ tanβ , X=W/Z/h)

0

χ1

∼

±

χ1

: ∼ W~

0, χ3

∼

0

χ2

∼

±

χ2

: ∼ H~ +XX ( W~ W~ H→ H~~

, All limits at 95% CL = 13 TeV, 139 fb-1

s

400 500 600 700 800 900 1000 1100 1200 ) [GeV]

2

χ0

m(∼ 0

100 200 300 400 500 600 ) [GeV] 1 0 χ∼m(

exp) 1 σ Expected limit (±

SUSY)

theory

1 σ Observed limit (±

ATLAS

) = 50%

0

χ1

Z∼

0→ χ2

B(∼ , X=W/Z/h)

0

χ1

: ∼ B~

0, χ3

∼

0

χ2

∼

±

χ1

: ∼ H~ +XX ( B~ B~ H~→ H~

, All limits at 95% CL = 13 TeV, 139 fb-1

s

Higgsino LSP

Wino LSP

Bino LSP

Bino LSP

Wino-like NLSP Higgsino NLSP

Interpretation for baseline MSSM models

Inclusive SRs

Inclusive SRs Inclusive SRs

4Q-VV 2B2Q-WZ 2B2Q-Wh

Phys. Rev. D 104 (2021) 112010

CPAN Days

C. Moreno-Martínez

!9

21 March 2022

EWK 0L+MET - Results (II)

• Scenarios with higgsino NLSP only

•

Decays exclusively to Higgs or Z bosons - combine regions without W-bosons

• Excluded GGM scenarios w/ 450 GeV < m(H) < 950 GeV at 100% decay BR to Z boson

• Excluded axino masses depend largely on decay BR

0 2 4 6 8 10 12

Events

Data Total SM W+jets

Z+jets VV Other

C1N2-WZ, (900,100) GeV C1N2-Wh, (900,100) GeV

) = 50%

G~

→ Z

0

χ1

) = 800 GeV, B(∼

0

χ1

) m(∼ G~ , H~ (

= 13 TeV, 139 fb-1

s

ATLAS SR Post-fit

4Q-WW 4Q-WZ 4Q-ZZ 4Q-VV

2B2Q-WZ 2B2Q-Wh 2B2Q-ZZ 2B2Q-Zh 2B2Q-VZ 2B2Q-Vh

−2 0 2

Significance

200 400 600 800 1000 1200 1400 1600 1800 2000 ) [GeV]

0

χ1

m(∼ 0

10 20 30 40 50 60 70 80 90 100 ) [%]G~ Z→0 1χ∼B(

exp) 1 σ Expected limit (±

SUSY)

theory

1 σ Observed limit (±

ATLAS

-1) arXiv:2103.11684 (4L, 139fb Observed 95% CL

-1) arXiv:1806.04030 (multi-b, 36.1fb Observed 95% CL

0) χ2

∼

0

χ1

∼

±

χ1

: ∼ H~ ( G~ or h G~

→Z

0

χ1

, ∼ H~ H~

All limits at 95% CL = 13 TeV, 139 fb-1

s

Interpretation with GGM and axino models

300 400 500 600 700 800 900 1000 1100 1200 ) [GeV]

0

χ1

m(∼ 0

100 200 300 400 500 600 700 800

) [GeV]a~m( ^{) = 100%a}

Z~

0 → χ1

B(∼

) = 75%

a~

→ Z

0

χ1

B(∼

) = 50%

a~

→ Z

0

χ1

B(∼

) = 25%

a~

→ Z

0

χ1

B(∼

Expected limit Observed limit

ATLAS

0) χ2

∼

0

χ1

∼

±

χ1

: ∼ H~ ( a~ or h a~

→Z

0

χ1

, ∼ H~ H~

, All limits at 95% CL = 13 TeV, 139 fb-1

s

Phys. Rev. D 104 (2021) 112010

• Wide search program in ATLAS for chargino/neutralino production

•

Multiple analyses optimized depending on decay chain into the LSP

• Analyses targeting SM-boson-mediated decays provide large exclusion

•

Excluded NLSP masses up to ~1.1 TeV, great improvement in off-shell regime

• Analyses for slepton-mediated decays not discussed in this presentation

•

Large portion of parameter space also excluded, up to NLSP mass of 1.15 TeV

CPAN Days

C. Moreno-Martínez

!10

21 March 2022

Chargino/Neutralino - Status

100 200 300 400 500 600 700 800 900 1000 1100 ) [GeV]

0

χ2

, ∼

±

χ∼1

m(

0 50 100 150 200 250 300 350 400 450 ) [GeV]0 1χ∼m(

Expected limits Observed limits

WW 0l, 2l

arXiv:1908.08215 ATLAS-CONF-2022-006 arXiv:2108.07586

via

−

χ1

∼

+

χ1

∼

WZ 0l, 2l, 3l

arXiv:1806.02293 arXiv:1911.12606 arXiv:2106.01676 arXiv:2108.07586 CERN-EP-2022-014

Wh lbb, 0l

arXiv:1909.09226 arXiv:2108.07586

0 via χ2

∼

±

χ1

∼

All limits at 95% CL Preliminary

ATLAS s=13 TeV, 36.1-139 fb^-1 March 2022

0 ) χ1

∼ ) = m(

0χ2

∼ m(

) + m(

Z )

01

∼χ ) = m(

0χ2

∼ m(

) + m(

h )

01

∼χ ) = m(

0χ2

∼ m(

200 400 600 800 1000 1200

) [GeV]

0

χ2

, ∼

±

χ∼1

m(

0 100 200 300 400 500 600 700 ) [GeV]0 1χ∼m(

Expected limits Observed limits

2l ν∼

L /

~l

arXiv:1509.07152 arXiv:1908.0821

2τ ντ

/ ∼ τ∼L

arXiv:1407.0350 arXiv:1708.07875

via

−

χ1

∼

+

χ1

∼

2l+3l ν∼

L /

~l

arXiv:1509.07152 arXiv:1803.02762

via

0

χ2

∼

±

χ1

∼

2τ ντ

/ ∼ τ∼L

arXiv:1708.07875

via

0

χ2

∼

±

χ1

/∼

−

χ1

∼

+

χ1

∼

All limits at 95% CL Preliminary

ATLAS s=8,13 TeV, 20.3-139 fb^-1 July 2019

0 ) ] χ2

, ∼

±

χ1

) + m( ∼

0

χ1

[ m( ∼ 21 ) = ν∼

L/ / τ∼

lL

m( ~

)

0

χ1

∼ ) = m(

02

∼χ m(

ATL-PHYS-PUB-2021-019

CPAN Days

C. Moreno-Martínez

!11

21 March 2022

Searches for slepton pair production

100 200 300 400 500 600 700 800

m(

_L,R

) [GeV]

0 100 200 300 400 500 600

m (

0 1

) [G eV ]

m( ^L,R

) <m(⁰¹)

ATLAS Preliminary

13 TeV, 139 fb ¹

March 2022

pp _L,⁺_{R L,R}, ⁰₁

8 TeV, 20.3 fb ¹ ∈[e, ] arXiv:1403.5294 Soft 2 ∈[e, ] arXiv:1911.12606

2 ∈[e, ] arXiv:1908.08215

2 , ∈[e, ] CONF-2022-006

2 hadronic = arXiv:1911.06660 LEP Rexcluded

All limits at 95% CL

Observed limits Expected limits

All limits at 95% CL

Observed limits Expected limits

, Δm∼m(W)

• In some scenarios, sleptons are also light enough to be produced at the LHC

• A number of searches in ATLAS target slepton pair production

•

Analyses with multiple e/μ or hadronically decaying τ-leptons

•

Focus on topologies with light sleptons decaying to SM-lepton and neutralino LSP

• Large portion of the parameter space excluded for the lightest slepton

•

Excluded lightest slepton masses up to 700 GeV, compressed region still very challenging

ATL-PHYS-PUB-2021-019

CPAN Days

C. Moreno-Martínez

!12

21 March 2022

Conclusions

• Extensive search program for EWK production of SUSY particles in ATLAS

• No evidence for SUSY found (yet)

• Complex strategies lead to large improvements with respect to previous results

• Enhanced sensitivity to compressed/off-shell scenarios, testing naturalness arguments in the MSSM at high-mass

• Large portion of the phase space excluded with the full LHC Run-2 dataset

• New opportunities with LHC Run-3 to start soon and HL-LHC program

Backup

!13

CPAN Days

C. Moreno-Martínez

!14

21 March 2022

EWK 4L - RPV interpretation

900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 ) [GeV]

0

χ2

/ ∼

±

χ∼1

m(

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 ) [GeV]0 1χ∼m(

SUSY)

theory

1 σ Observed Limit (±

exp) 1 σ Expected Limit (±

≠ 0 λ12k

≠ 0 λi33

) < 10 GeV

0

χ1

∼ ) - m(

0

χ2

/ ∼

±

χ1

m(∼

-ν

+l

→l

0

χ1

, ∼

0

χ1

Z/h ∼

0→ χ∼2 0, χ∼1

±

→W

±

χ1

production, ∼

±

χ1

∼

0

χ2

+ ∼

−1

∼χ

+

χ1

∼

=13 TeV, 139 fb-1

s

All limits at 95% CL 4 leptons

ATLAS

700 800 900 1000 1100 1200 1300 1400 ) [GeV]

νL

/ ∼

±

lL

m(~ 200

400 600 800 1000 1200 1400 1600 1800 ) [GeV]0 1χ∼m(

SUSY)

theory

1 σ Observed Limit (±

exp) 1 σ Expected Limit (±

≠ 0 λ12k

≠ 0 λi33

) < 10 GeV

0

χ1

) - m(∼ νL

/ ∼

±

lL

m(~

-ν

+l

→l

0

χ∼1 0, χ1

ν∼

L→ ν∼

0, χ∼1

l±

±→ lL

production, ~ ν∼L

±

lL

+ ~ νL

∼ νL

+ ∼

−L

~l

+

lL

~

=13 TeV, 139 fb-1

s

All limits at 95% CL 4 leptons

ATLAS

˜^±₁

˜^⌥₁ / ˜⁰2

˜⁰₁

˜⁰₁ p

p

W

`

`

⌫

W/Z/h `

`

⌫

`˜_L/˜⌫

`˜_L/˜⌫

˜⁰₁

˜⁰₁ p

p

`/⌫

`

`

⌫

`/⌫ `

`

⌫

CPAN Days

C. Moreno-Martínez

!15

21 March 2022

EWK 4L - SR definitions

CPAN Days

C. Moreno-Martínez

!16

21 March 2022

EWK 4L - Uncertainties

loose SR0-ZZ tight SR0-ZZ loose bvetoSR0-ZZ tight bvetoSR0-ZZ loose bvetoSR0 tight bvetoSR0 breqSR0 loose bvetoSR1 tight bvetoSR1 breqSR1 loose bvetoSR2 tight bvetoSR2 breqSR2 SR5L

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Relative Uncertainty

Total Uncertainty MC Statistical Normalisation Theoretical

Reducible background

Experimental e/µ

Experimental τ

Jet Experimental Experimental

miss

ET

= 13 TeV, 139 fb

-1

ATLAS s

CPAN Days

C. Moreno-Martínez

!17

21 March 2022

EWK 3L+MET - SR definitions

Selection requirements n_jets =0

m_T [GeV] E_T^miss [GeV]

[100, 160] SR^WZ-1: [50, 100] SR^WZ-2: [100, 150] SR^WZ-3: [150, 200] SR^WZ-4: > 200

>160 SR^WZ-5: [50, 150] SR^WZ-6: [150, 200] SR^WZ-7: [200, 350] SR^WZ-8: >350 n_jets >0,H_T < 200GeV

m_T [GeV] E_T^miss [GeV]

[100, 160] SR^WZ-9: [100, 150] SR^WZ-10: [150, 250] SR^WZ-11: [250, 300] SR^WZ-12: > 300

>160 SR^WZ-13: [50, 150] SR^WZ-14: [150, 250] SR^WZ-15: [250, 400] SR^WZ-16: > 400 n_jets > 0, H_T >200GeV, H_T^lep < 350GeV

m_T [GeV] E_T^miss [GeV]

>100 SR^WZ-17: [150, 200] SR^WZ-18: [200, 300] SR^WZ-19: [300, 400] SR^WZ-20: > 400

Selection requirements

m_``  75GeV, n_jets = 0

m_T [GeV] E_T^miss [GeV]

[0, 100] ^SRWh_SFOS^-1: [50, 100] ^SRWh_SFOS^-2: [100, 150] ^SRWh_SFOS^-3> 150 [100, 160] ^SRWh_SFOS^-4: [50, 100] ^SRWh_SFOS^-5: > 100

> 160 ^SRWh_SFOS^-6: [50, 100] ^SRWh_SFOS^-7: > 100 m_``  75GeV, n_jets > 0, H_T < 200GeV

m_T [GeV] E_T^miss [GeV]

[0, 50] ^SRWh_SFOS^-8: [50, 100]

[50, 100] ^SRWh_SFOS^-9: [50, 100]

[0, 100] ^SRWh_SFOS^-10: [100, 150] ^SRWh_SFOS^-11: > 150 [100, 160] ^SRWh_SFOS^-12: [50, 100] ^SRWh_SFOS^-13: [100, 150] ^SRWh_SFOS^-14: > 150

> 160 ^SRWh_SFOS^-15: [50, 150] ^SRWh_SFOS^-16: > 150 m_`` 105GeV, n_jets = 0

m_T [GeV] E_T^miss [GeV]

> 100 ^SRWh_SFOS^-17: [50, 100] ^SRWh_SFOS^-18: [100, 200] ^SRWh_SFOS^-19: > 200

Selection requirements Variable SR^Wh_DFOS-1 SR^Wh_DFOS-2