ATLAS results on searches for exotic particles - cds.cern.ch fileIntroduction L Many BSM theories: Ì Grand Unification Theory Ì Sequential Standard Model Ì Dark sector extensions

ATLAS results onsearches for exotic new particles

Sara Alderweireldton behalf of the ATLAS Collaboration

Aspen 2018 – The Particle FrontierAspen, CO

March 28, 2018

Introduction Many BSM theories:

∎ Grand Unification Theory∎ Sequential Standard Model∎ Dark sector extensions∎ Two-Higgs-doublet model

Many final states and many regions of phase space to consider∎ Search for any deviation from the SM prediction

Pushing limits both at high and low mass

2015+2016 dataset: 36.1 fb−1

∎ Triplets∎ Extra dimensions∎ Gravitons∎ . . .

Month in YearJan Apr Jul

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fb

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ATLAS Online Luminosity = 7 TeVs2011 pp

= 8 TeVs2012 pp

= 13 TeVs2015 pp

= 13 TeVs2016 pp

= 13 TeVs2017 pp

2/1

8 c

alib

ratio

n

Model ℓ, γ Jets† EmissT

∫L dt[fb−1] Limit Reference

Ext

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MLQ

Hea

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ADD GKK + g/q 0 e, µ 1 − 4 j Yes 36.1 n = 2 ATLAS-CONF-2017-0607.75 TeVMD

ADD non-resonant γγ 2 γ − − 36.7 n = 3 HLZ NLO CERN-EP-2017-1328.6 TeVMS

ADD QBH − 2 j − 37.0 n = 6 1703.092178.9 TeVMth

ADD BH high∑pT ≥ 1 e, µ ≥ 2 j − 3.2 n = 6, MD = 3 TeV, rot BH 1606.022658.2 TeVMth

ADD BH multijet − ≥ 3 j − 3.6 n = 6, MD = 3 TeV, rot BH 1512.025869.55 TeVMth

RS1 GKK → γγ 2 γ − − 36.7 k/MPl = 0.1 CERN-EP-2017-1324.1 TeVGKK mass

Bulk RS GKK →WW → qqℓν 1 e, µ 1 J Yes 36.1 k/MPl = 1.0 ATLAS-CONF-2017-0511.75 TeVGKK mass

2UED / RPP 1 e, µ ≥ 2 b, ≥ 3 j Yes 13.2 Tier (1,1), B(A(1,1) → tt) = 1 ATLAS-CONF-2016-1041.6 TeVKK mass

SSM Z ′ → ℓℓ 2 e, µ − − 36.1 ATLAS-CONF-2017-0274.5 TeVZ′ mass

SSM Z ′ → ττ 2 τ − − 36.1 ATLAS-CONF-2017-0502.4 TeVZ′ massLeptophobic Z ′ → bb − 2 b − 3.2 1603.087911.5 TeVZ′ massLeptophobic Z ′ → tt 1 e, µ ≥ 1 b, ≥ 1J/2j Yes 3.2 Γ/m = 3% ATLAS-CONF-2016-0142.0 TeVZ′ mass

SSM W ′ → ℓν 1 e, µ − Yes 36.1 1706.047865.1 TeVW′ massHVT V ′ →WV → qqqq model B 0 e, µ 2 J − 36.7 gV = 3 CERN-EP-2017-1473.5 TeVV′ massHVT V ′ →WH/ZH model B multi-channel 36.1 gV = 3 ATLAS-CONF-2017-0552.93 TeVV′ massLRSM W ′

R → tb 1 e, µ 2 b, 0-1 j Yes 20.3 1410.41031.92 TeVW′ massLRSM W ′

R → tb 0 e, µ ≥ 1 b, 1 J − 20.3 1408.08861.76 TeVW′ mass

CI qqqq − 2 j − 37.0 η−LL 1703.0921721.8 TeVΛ

CI ℓℓqq 2 e, µ − − 36.1 η−LL ATLAS-CONF-2017-02740.1 TeVΛ

CI uutt 2(SS)/≥3 e,µ ≥1 b, ≥1 j Yes 20.3 |CRR | = 1 1504.046054.9 TeVΛ

Axial-vector mediator (Dirac DM) 0 e, µ 1 − 4 j Yes 36.1 gq=0.25, gχ=1.0, m(χ) < 400 GeV ATLAS-CONF-2017-0601.5 TeVmmed

Vector mediator (Dirac DM) 0 e, µ, 1 γ ≤ 1 j Yes 36.1 gq=0.25, gχ=1.0, m(χ) < 480 GeV 1704.038481.2 TeVmmed

VVχχ EFT (Dirac DM) 0 e, µ 1 J, ≤ 1 j Yes 3.2 m(χ) < 150 GeV 1608.02372700 GeVM∗

Scalar LQ 1st gen 2 e ≥ 2 j − 3.2 β = 1 1605.060351.1 TeVLQ mass

Scalar LQ 2nd gen 2 µ ≥ 2 j − 3.2 β = 1 1605.060351.05 TeVLQ mass

Scalar LQ 3rd gen 1 e, µ ≥1 b, ≥3 j Yes 20.3 β = 0 1508.04735640 GeVLQ mass

VLQ TT → Ht + X 0 or 1 e, µ ≥ 2 b, ≥ 3 j Yes 13.2 B(T → Ht) = 1 ATLAS-CONF-2016-1041.2 TeVT mass

VLQ TT → Zt + X 1 e, µ ≥ 1 b, ≥ 3 j Yes 36.1 B(T → Zt) = 1 1705.107511.16 TeVT mass

VLQ TT →Wb + X 1 e, µ ≥ 1 b, ≥ 1J/2j Yes 36.1 B(T →Wb) = 1 CERN-EP-2017-0941.35 TeVT mass

VLQ BB → Hb + X 1 e, µ ≥ 2 b, ≥ 3 j Yes 20.3 B(B → Hb) = 1 1505.04306700 GeVB mass

VLQ BB → Zb + X 2/≥3 e, µ ≥2/≥1 b − 20.3 B(B → Zb) = 1 1409.5500790 GeVB mass

VLQ BB →Wt + X 1 e, µ ≥ 1 b, ≥ 1J/2j Yes 36.1 B(B →Wt) = 1 CERN-EP-2017-0941.25 TeVB massVLQ QQ →WqWq 1 e, µ ≥ 4 j Yes 20.3 1509.04261690 GeVQ mass

Excited quark q∗ → qg − 2 j − 37.0 only u∗ and d∗, Λ = m(q∗) 1703.091276.0 TeVq∗ mass

Excited quark q∗ → qγ 1 γ 1 j − 36.7 only u∗ and d∗, Λ = m(q∗) CERN-EP-2017-1485.3 TeVq∗ mass

Excited quark b∗ → bg − 1 b, 1 j − 13.3 ATLAS-CONF-2016-0602.3 TeVb∗ massExcited quark b∗ →Wt 1 or 2 e, µ 1 b, 2-0 j Yes 20.3 fg = fL = fR = 1 1510.026641.5 TeVb∗ massExcited lepton ℓ∗ 3 e, µ − − 20.3 Λ = 3.0 TeV 1411.29213.0 TeVℓ∗ massExcited lepton ν∗ 3 e,µ, τ − − 20.3 Λ = 1.6 TeV 1411.29211.6 TeVν∗ mass

LRSM Majorana ν 2 e, µ 2 j − 20.3 m(WR ) = 2.4 TeV, no mixing 1506.060202.0 TeVN0 massHiggs triplet H±± → ℓℓ 2,3,4 e,µ (SS) − − 36.1 DY production ATLAS-CONF-2017-053870 GeVH±± massHiggs triplet H±± → ℓτ 3 e,µ, τ − − 20.3 DY production, B(H±±

L→ ℓτ) = 1 1411.2921400 GeVH±± mass

Monotop (non-res prod) 1 e, µ 1 b Yes 20.3 anon−res = 0.2 1410.5404657 GeVspin-1 invisible particle mass

Multi-charged particles − − − 20.3 DY production, |q| = 5e 1504.04188785 GeVmulti-charged particle mass

Magnetic monopoles − − − 7.0 DY production, |g | = 1gD , spin 1/2 1509.080591.34 TeVmonopole mass

Mass scale [TeV]10−1 1 10√s = 8 TeV

√s = 13 TeV

ATLAS Exotics Searches* - 95% CL Upper Exclusion LimitsStatus: July 2017

ATLAS Preliminary∫L dt = (3.2 – 37.0) fb−1

√s = 8, 13 TeV

*Only a selection of the available mass limits on new states or phenomena is shown.†Small-radius (large-radius) jets are denoted by the letter j (J).

Mediator Mass [TeV]

0 0.5 1 1.5 2 2.5 3

DM

Mas

s [T

eV]

0.2

0.4

0.6

0.8

1

1.2DM Simplified Model Exclusions Preliminary July 2017ATLAS

= 1DM

= 0, gl

= 0.25, gq

gAxial-vector mediator, Dirac DM

All limits at 95% CL

Per

turb

ativ

e U

nita

rity

Dije

t

arXiv:1703.09127 [hep-ex]

-1 = 13 TeV, 37.0 fbs

Dijet

Dije

t 8 T

eV

Phys. Rev. D. 91 052007 (2015)

-1 = 8 TeV, 20.3 fbs

Dijet 8 TeV

Dije

t TLA

ATLAS-CONF-2016-030

-1 = 13 TeV, 3.4 fbs

Dijet TLA

Dije

t + IS

R

ATLAS-CONF-2016-070

-1 = 13 TeV, 15.5 fbs

Dijet + ISR

γ+missTE

Eur. Phys. J. C 77 (2017) 393

-1 = 13 TeV, 36.1 fbs

γ+missTE

+jetmissTE

ATLAS-CONF-2017-060

-1 = 13 TeV, 36.1 fbs

+jetmissTE

+ZmissTE

ATLAS-CONF-2017-040

-1 = 13 TeV, 36.1 fbs

+ZmissTE

DM

Mas

s = M

ediat

or M

ass

×2

= 0

.12

2hcΩ

Therm

al Reli

c

S. Alderweireldt ATLAS results on searches for exotic new particles (28/Mar 2018) 2 / 24

OverviewSearch for Higgs decays to beyond the standard model light gaugebosons in four-lepton events with the ATLAS detector at

√s = 13 TeV

H(125)→ XX → 4l EXOT-2016-22 W leptonic low mass

Search for doubly charged Higgs boson production in multi-leptonfinal states with the ATLAS detector using proton–proton collisions at√

s = 13 TeV

pp → H++H−−→ l+l+l−l−EXOT-2016-07 W leptonic high mass

Search for heavy resonances decaying into a W or Z boson and a Higgsboson in final states with leptons and b-jets in 36 fb−1 of

√s = 13 TeV

pp collisions with the ATLAS detector

V ′ → VH→ (lν/ll/νν)bb EXOT-2016-10 W semi-leptonic

intermediate/high mass

Search for WW/WZ resonance production in lνqq final states in ppcollisions at

√s = 13 TeV with the ATLAS detector

X → WV → lνqq EXOT-2016-28 W semi-leptonic


Search for light resonances decaying to boosted quark pairs and pro-duced in association with a photon or a jet in proton–proton colli-sions at


ISR(γ/j)+ boosted jjEXOT-2017-01 W hadronic low mass

Search for dark maer and other new phenomena in events with anenergetic jet and large missing transverse momentum using theATLAS detector

jet + EmissT EXOT-2016-27 W hadronic high mass

Search for pair production of up-type vector-like quarks and 4t-quarkevents in final states with multiple b-jets with the ATLAS detector

TT → Ht + X EXOT-2016-13 W hadronic high mass

Search for W ′ → tb decays in the hadronic final state using ppcollisions at


W ′ → tb EXOT-2017-02 W hadronic high mass

A search for high-mass resonances decaying to τν in pp collisions at√s = 13 TeV with the ATLAS detector

W ′ → τν EXOT-2017-06 W hadronic high mass


https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2016-22










√s = 13 TeV



s = 13 TeV



√s = 13 TeV






























Higgs decays to light bosons H(125)→ XX → 4l

motivation: higgs portal models, hidden sectors, dark maer

→ seing upper limits on the Higgs boson branching ratio to BSM particles

three analysis regions targeing dierent processes∎ H(125)→ZX→4l (2l2e and 2l2µ)

∎ H(125)→XX→4l, m(X) ∈ [15,60] GeV (4e, 2e2µ and 4µ)

∎ H(125)→XX→4l, m(X) ∈ [1,15] GeV (4µ)

X is new vector boson Zd or pseudoscalar a with low mass

[GeV]⟩ll

m⟨2 4 6 8 10 12 14 16 18

Eve

nts

/ 0.2

GeV

0.002

0.004

0.006

0.008

0.01

0.012

0.014 Data Total BackgroundHeavy Flavour VVV/VBS

4l→*

ZZ 4l→ ZZ* →H

ATLAS-113 TeV, 36.1 fb

4l→ XX →H

[GeV]⟩ll

m⟨0 10 20 30 40 50 60

Eve

nts

/ GeV

3−10

2−10

1−10

1

10

210Data Total BackgroundReducible bkg )Υ/Ψ/J/tZ+(tVVV/VBS 4l→ZZ*→H

4l→ZZ* =15 GeVZdm=35 GeVZdm =55 GeVZdm

ATLAS-113 TeV, 36.1 fb

4l→ XX →H

lept

onic

–EX

OT-

2016

-22W



Higgs decays to light bosons H(125)→ XX → 4l

set 95% CL upper limits on the fiducial cross sectionfor H→ZX→4l & H→XX→4l (model independent)

upper limits are applicable to any model with H(125) decays to 4 leptonsvia two intermediate, on-shell, narrow, promptly-decaying bosons

[GeV]Xm10 20 30 40 50 60

[fb]

fidσ95

% C

L up

per

limit

on

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

Expectedσ 2±

Observed

µ 4µ4e 2e2ATLAS

-113 TeV, 36.1 fb

4l→ XX →H

15 20 25 30 35 40 45 50 55

[GeV]Xm

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

[fb

]fids

95%

CL u

pper

limit o

n

2l2e m2l2

Observed

Expected

s 2±

ATLAS

4l® ZX®H1

13 TeV, 36.1 fb

H(125)→XX→4l H(125)→ZX→4l

lept

onic

–EX

OT-

2016

-22W



Doubly Charged Higgs pp → H++H−− → l+l+l−l−

Eve

nts

1−10

1

10

210

310

410

510

CRs VRs SRs

ATLAS1=13 TeV, 36.1 fbs

Data Total SM

DrellYan Diboson

Fakes Top

±

e±e

±

e±e±

e

±

l± µ±e

±

µ± µ± µ

±

l±

l± l± l

±e±

e

± µ±e

± µ± µ

±

e±e±

e

±

l± µ±e

±

µ± µ± µ

±

l’± l± l

±

l±

l± l± l

±e±

e

± µ±e

± µ± µ

±

e±e±

e

±l± µ±

e

±

µ± µ± µ

±

l’± l± l

±

l±

l± l± l

Data

/SM

0.5

1

1.5

Eve

nts

0

10

20

30

40

50ATLAS

1=13 TeV, 36.1 fbs

)±µ±SR1P2L (e

Data Total SM

Diboson FakesTop

(X) = 80%B) = 20%, ±µ±(eB

) = 450 GeV± ±m(H

(X) = 50%B) = 50%, ±µ±(eB

) = 650 GeV± ±m(H

(X) = 50%B) = 50%, ±µ±(eB

) = 850 GeV± ±m(H

) [GeV]±µ±m(e300 400 500 1000 2000

Data

/SM

00.5

11.5

2

dedicated 2-, 3-, and 4-lepton channels to optimize signal acceptance

fit invariant mass∎ invariant mass of same-charge lepton pair in 2- and 3-lepton channels∎ average mass in 4-lepton channel

dominant systematic uncertainties∎ fake leptons∎ charge misidentification∎ background estimation

lept

onic

–EX

OT-

2016

-07W




) [GeV]±±m(H

300 400 500 600 700 800 900 1000 1100 1200

[fb]

)--

H+

+ H

→(p

pσ

2−10

1−10

1

10

210

310Observed 95% CL limitExpected 95% CL limit

σ 1±Expected limit σ 2±Expected limit

)--LH++

L H→(ppσ

)--RH++

R H→(ppσ

ATLAS-1 = 13 TeV, 36.1 fbs

)=30%±e±(eB)=40%±µ±(eB)=30%±µ±µ(B

) lim

it [

Ge

V]

Le

xp

ecte

d 9

5%

CL

m(H

840

845

850

855

860

850 849 847 846 846 847 848 849 851 854 857

848 847 845 844 844 844 845 847 849 852

846 845 843 842 842 842 843 845 847

845 844 842 841 841 841 842 843

845 843 841 840 840 840 841

845 843 842 841 841 840

846 845 843 843 842

849 847 846 845

852 851 850

857 856

863

) [%]±e± e→±±L

(HB

0 20 40 60 80 100

) [%

]± µ± µ

→±± L(H

B

0

20

40

60

80

100 ATLAS1=13 TeV, 36.1 fbs

)=100%±l± l→±±L

(HB

set lower limit on m(H±±) at 95% CL

B(H±±→e±e±) + B(H±±

→e±µ±) + B(H±±→ µ±µ±) = B(H±±

→l±l±)

mass limit derived for all combinations of the partial branching ratios∎ lower limit above 770 (450) GeV for B(H±±→l±l±) = 100(10)% for H±±L∎ lower limit above 670 (320) GeV for B(H±±→l±l±) = 100(10)% for H±±R

lept

onic

–EX

OT-

2016

-07W




the muon channel is the most powerful, but the dierences are small

minimum limit as a function of B(H±±→l±l±)

limits derived for H±±L and H±±

R∎ lower limit above 770 (450) GeV for B(H±±→l±l±) = 100(10)% for H±±L∎ lower limit above 670 (320) GeV for B(H±±→l±l±) = 100(10)% for H±±R

) [GeV]±±L

m(H

300 400 500 600 700 800 900 1000

X)

[%]

→±± L(H

B)

= 1

± l± l

→±± L(H

B

1

2

34

10

20

3040

100

Observed 95% CL limit

Expected 95% CL limitσ1±Expected limit

σ2±Expected limit

ATLAS1=13 TeV, 36.1 fbs)±±

Llower limit of m(H

minimum limit) [GeV]±±

Lm(H

300 400 500 600 700 800 900 1000

X)

[%]

→±± L(H

B)

= 1

±

e± e

→±± L(H

B

1

2

34

10

20

3040

100



σ2±Expected limit


Llower limit of m(H

) [GeV]±±L

m(H

300 400 500 600 700 800 900 1000

X)

[%]

→±± L(H

B)

= 1

± µ± µ

→±± L(H

B

1

2

34

10

20

3040

100



σ2±Expected limit


Llower limit of m(H

) [GeV]±±L

m(H

300 400 500 600 700 800 900 1000

X)

[%]

→±± L(H

B)

= 1

± µ±

e→±± L

(HB

1

2

34

10

20

3040

100



σ2±Expected limit


Llower limit of m(H

e±e±

µ±µ±

e±µ±

lept

onic

–EX

OT-

2016

-07W




√s = 13 TeV



s = 13 TeV



√s = 13 TeV






























Heavy resonance → VH in semi-leptonic decaysW ′/Z ′/ggF A/bbA→ VH → (lν/ll/νν)bb

motivation: heavy resonances, 2HDM, heavy vector triplets, . . .

analysis setup using dedicated categories∎ 0-2 lepton channels

∎ resolved or merged bb regimes (small- and large-R jets)

∎ various multiplicities of main and additional b-jets

reconstruced resonance mass dependent on channel: mVh and mT ,Vh

Eve

nts/

GeV

4−10

3−10

2−10

1−10

1

10

210

310

410

510

610 data1.5 TeV HVT x 10

, single topttW+(bb,bc,cc)W+(bl,cl), W+lZ+(bb,bc,cc)Z+(bl,cl), Z+lmultijetotheruncertainty


2 jets≥1 lep., 2 jets, 1 b-tag≥1 lep.,

< 140 GeVjj110 GeV < m

[GeV]Vhm300 1000 2000da

ta /

bkg

0.5

1

1.5

Eve

nts/

GeV

5−10

4−10

3−10

2−10

1−10

1

10

210

310

410

510


, single topttW+(bb,bc,cc)W+(bl,cl), W+lZ+(bb,bc,cc)Z+(bl,cl), Z+lotheruncertainty


2 jets≥2 lep., 2 jets, 2 b-tags≥2 lep.,

< 145 GeVjj100 GeV < m

[GeV]Vhm300 1000 2000 3000da

ta /

bkg

0.5

1

1.5

Eve

nts/

GeV

5−10

4−10

3−10

2−10

1−10

1

10

210

310


, single topttW+(bb,bc,cc)W+(bl,cl), W+lZ+(bb,bc,cc)Z+(bl,cl), Z+lotheruncertainty


1 large-R jets≥0 lep., 1 large-R jets≥0 lep.,

2 b-tags, 0 add. b-tags

< 145 GeVJ75 GeV < m

[GeV]T,Vhm500 1000 2000 3000da

ta /

bkg

0.5

1

1.5

resolved, 1 lep, 2+ jets, 1 b-tag resolved, 2 lep, 2+ jets, 2 b-tags merged, 0 lep, 1+ large-R jet, 2+0 b-tags

sem

i-le

pton

ic–

EXO

T-20

16-1

0W



Heavy resonance → VH in semi-leptonic decaysW ′/Z ′/ggF A/bbA→ VH → (lν/ll/νν)bb

95% CL upper limits for Z′→Zh & W′→Wh production

observed exclusion contours in the HVT parameter space

95% CL upper limits for A→Zh with h→bb

interpretations following various models available in the paper

[GeV]Z’m500 1000 1500 2000 2500 3000 3500 4000 4500 5000

) [p

b]c

,cbb→

B(h

⋅Z

h)→

Z’

→(p

pσ

4−10

3−10

2−10

1−10

1

10 ATLAS

-1 = 13 TeV, 36.1 fbs

95% CL limit

Observed (CLs)

Expected (CLs)

σ1±Expected

σ2±Expected

=1V

HVT Model A, g

=3V

HVT Model B, g

HcV

g3− 2− 1− 0 1 2 3

V /

gFc2 g

0.6−

0.4−

0.2−

0

0.2

0.4

0.6ATLAS

= 13 TeVs-136.1 fb

1.2 TeV

2.0 TeV

3.0 TeV

=1)v

A(g

=3)v

A(g

=3)v

B(g

[GeV]A m

200 400 600 800 1000 1200 1400 1600 1800 2000

) [p

b]b

b→

B(h

⋅Z

h)→

A→

(pp

σ

3−10

2−10

1−10

1

10Observed (CLs)Expected (CLs)

σ 1±Expected σ 2±Expected

b b→Zh , h→Agluon-gluon fusion


95% CL limit

Z′→Zh HVT exclusion contours A→Zh with h→bb

sem

i-le

pton

ic–

EXO

T-20

16-1

0W



Heavy resonance → WV in semi-leptonic decaysX →WV → lνqq

motivation: composite H, extra dimensions, heavy vector triplets, . . .

analysis using dedicated categorization∎ merged (lvJ) or resolved (lvjj) quark pair∎ low- or high purity boson tagging (D2)∎ WW or WZ signal∎ DY or VBF production

Resolved CRResolved

CR

mjj [GeV]66 82 94 106 200

Resolved SR (WW)ResolvedSR (WZ) HP CRHP

CR

LP CR LP CR

D2

mJ [GeV]50

LP SR (WW) LP SR (WZ)HP SR (WW) HP SR (WZ)

(β=1

)

mW mZ

εV=50%

εV=80%

resolved merged

0 0.5 1 1.5 2 2.5 3 3.5 4

Events

/ 0

.4

1-10

1

10

210

310

410

510

610

710

810

910

1010Data

W+jets

tt

Singlet

Dibosons

Z+jets

Postfit uncertainty

HVT Model A Z´ 1.0 TeV

Data

W+jets

tt

Singlet

Dibosons

Z+jets

Postfit uncertainty

HVT Model A Z´ 1.0 TeV

ATLAS

1 = 13 TeV, 36.1 fbs

CategoryqggF/q

2D

0 0.5 1 1.5 2 2.5 3 3.5 4

Data

/ S

M

0.6

0.8

1

1.2

1.4

D2 variable

sem

i-le

pton

ic–

EXO

T-20

16-2

8W



Heavy resonance → WV in semi-leptonic decaysX →WV → lνqq

motivation: composite H, extra dimensions, heavy vector triplets, . . .

analysis using dedicated categorization∎ merged (lvJ) or resolved (lvjj) quark pair∎ low- or high purity boson tagging (D2)∎ WW or WZ signal∎ DY or VBF production

perform simultaneous binned ML fitto m(WV) distributions

Events

/ 0

.34 T

eV

1

10

210

310

410 DataW+jetstt

Single tDibosonsZ+jetsPostfit uncertaintyHVT VBF Model Z´

500)´1200 GeV (

ATLAS1

= 13 TeV, 36.1fbsWW Signal Region (HP)VBF Category

[TeV]Jnlm0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

Data

/ S

M

0.5

1

1.5

Events

/ 0

.42 T

eV

1

10

210

310

410

510

610

710DataW+jetstt

Single tDibosonsZ+jetsPostfit uncertaintyHVT Model A W´

5)´2000 GeV (

ATLAS1

= 13 TeV, 36.1fbsWZ Signal Region (LP)

CategoryqggF/q

[TeV]Jnlm0.5 1 1.5 2 2.5 3 3.5 4

Data

/ S

M

0.5

1

1.5

Events

/ 0

.525 T

eV

1

10

210

310

410

510

610Data

W+jets

ttMisid. lepton

Single t

Dibosons

Z+jetsPostfit uncertainty

HVT VBF Model Z´

500)´500 GeV (

ATLAS1

= 13 TeV, 36.1fbsWW Signal Region (Res.)VBF Category

[TeV]jjnl

m0.4 0.6 0.8 1 1.2 1.4

Data

/ S

M

0.5

1

1.5

merged, VBF, WW, high-purity merged, ggF, WZ, low-purity resolved, VBF, WW

sem

i-le

pton

ic–

EXO

T-20

16-2

8W



Heavy resonance → WV in semi-leptonic decaysX →WV → lνqq 95% CL upper limits for various models; more in the paper

largest excess 2.7σ local

m(Z´) [TeV]0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

WW

) [p

b]

®Z

´®

(pp

s

310

210

110

1

10

210

310ATLAS

1 = 13 TeV, 36.1 fbsqq Categoryn lqggF/q

HVT model Z´

Observed 95% CL upper limit

Expected 95% CL upper limit

)s 1±Expected limit (


=1v

WW) HVT Model A, g®Z´®(pps

=3v

WW) HVT Model B, g®Z´®(pps

m(Scalar) [TeV]0.5 1 1.5 2 2.5 3

WW

jj) [

pb

]®

Hjj

®(p

ps

310

210

110

1

10

210

310ATLAS

1 = 13 TeV, 36.1 fbsVBF lvqq CategoryHeavy scalar model





m(W´) [TeV]0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

WZ

) [p

b]

®W

´®

(pp

s

310

210

110

1

10

210

310ATLAS


HVT model W´





=1v

WZ) HVT Model A, g®W´®(pps

=3v

WZ) HVT Model B, g®W´®(pps

) [TeV]KK

m(G0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

WW

) [p

b]

®K

KG®

(pp

s310

210

110

1

10

210

310ATLAS


=1.0plMBulk RS model k/





=1pl

MWW) k/®KK

G®(pps

VBF, HVT model Z′ VBF, Heavy-scalar model

ggF, HVT model W′ ggF, graviton model

sem

i-le

pton

ic–

EXO

T-20

16-2

8W




√s = 13 TeV



s = 13 TeV



√s = 13 TeV






























Light resonances decaying to boosted quark pairsISR(γ/j) + boosted jj motivation: many models with mediators coupling to quarks & gluons

∎ look at lower mass with ISR (mZ ′ < 200 GeV)∎ ISR allows highly eicient triggering at lower masses

(compared to regular triggering on the resonance decay products)

topologies:∎ 1 isolated γ + 1 large-R jet ∎ 1 small-R jet + 1 large-R jet

making use of τ21 substructure variable and Designed Decorrelated Tagger(DDT;removing dependence of τ21 on jet mass and pT )

∎ τN a measure of a jet’s compatibility with being fully aligned along N axes

∎ τ21 = τ2/τ1 dierentiates two-particle jets from the decay ofa boosted resonance & a single-particle jet

∎ aim to separate large-R signal jets and QCD γ+jet background

background estimate using transfer factor method

jet mass [GeV]RLarge-50 100 150 200 250 300

⟩ D

DT

21τ ⟨

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

SimulationATLAS = 13 TeVs

Jet channel

< 700 GeVJ

TBkg., 500 < p < 700 GeVJ

TSig., 500 < p

< 900 GeVJ

TBkg., 700 < p < 900 GeVJ

TSig., 700 < p

< 1300 GeVJ

TBkg., 900 < p < 1300 GeVJ

TSig., 900 < p


⟩ D

DT

21τ ⟨

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Photon channel

< 700 GeVJ

TBkg., 500 < p < 700 GeVJ

TSig., 500 < p

< 900 GeVJ

TBkg., 700 < p < 900 GeVJ

TSig., 700 < p

< 1300 GeVJ

TBkg., 900 < p < 1300 GeVJ

TSig., 900 < p

jet

γ

hadr

onic

–EX

OT-

2017

-01W



Light resonances decaying to boosted quark pairsISR(γ/j) + boosted jj

fit of large-R jet mass in jet & photon channels∎ background estimated separately per candidate mass

95% CL limits on the Z′ cross section

channels combined for limit on coupling gq

largest excess in the jet (γ) channel at mZ ′ = 150(140) GeV with local significance 2.5 (2.2)σ

Eve

nts

/ GeV

10

210

310

410

510

610

710 ATLAS

-1 = 13 TeV, 36.1 fbsJet channel

SR

DataBackground est.W/Z + jetsZ' (220 GeV)Bkg. stat. uncert.

syst.⊕Bkg. stat.


Dat

a / e

st.

0.98

0.99

1

1.01

1.02

Eve

nts

/ GeV

1

10

210

310

410

510

610 ATLAS

-1 = 13 TeV, 36.1 fbsPhoton channel

SR

DataBackground est.

γW/Z + Z' (160 GeV)Bkg. stat. uncert.

syst.⊕Bkg. stat.


Dat

a / e

st.

0.9

1

1.1

[GeV]Z’m

100 120 140 160 180 200 220

A [

pb

]´

qq

) ®

Z’

® (

pp

s

2-10

1-10

1

10

210

=0.5)q

Theory (g


Expected 95% CL limit

s1 ±Expected limit

s2 ±Expected limit

ATLAS

1 = 13 TeV, 36.1 fbs

Jet channel

[GeV]Z’m

100 120 140 160 180 200 220

A [

pb

]´

qq

) ®

Z’

® (

pp

s

3-10

2-10

1-10

1

10

=0.5)q

Theory (g



s1 ±Expected limit

s2 ±Expected limit

ATLAS

1 = 13 TeV, 36.1 fbs

Photon channel

[GeV]Z’m

100 120 140 160 180 200 220

qg

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4



s1 ±Expected limit

s2 ±Expected limit

ATLAS

1 = 13 TeV, 36.1 fbs

hadr

onic

–EX

OT-

2017

-01W



Monojets and missing transverse momentumjet + Emiss

T motivation: dark maer, compressed SUSY, extra dimensions, . . .∎ many possible diagrams

requiring: large missing transverse energy + 1 high-pT jet + ≤3 more jets (pT >30 GeV) + no leptons

background is constrained using a likelihood fit to the EmissT distribution in a set of control regions,

taking into account systematic uncertainties

300 400 500 600 700 800 900 1000 1100 1200

Events

/ G

eV

1-10

1

10

210

310

410

510

610

710Data 2015+2016

Standard Model

) + jetsnn ®Z(

) + jetsn l®W(

ll) + jets®Z(

+ single toptt

Diboson

multijets + ncb

) = (500, 495) GeV0

)c~, b~

m(

)= (400, 1000) GeVmed

, MDM

(m

=6400 GeVD

ADD, n=4, M

ATLAS1 = 13 TeV, 36.1 fbs

Signal Region>250 GeV

miss

T(j1)>250 GeV, E

Tp

[GeV]missTE

300 400 500 600 700 800 900 1000 1100 1200

Data

/ S

M

0.8

1

1.2Stat. + Syst. Uncertainties

Events

/ 5

0 G

eV

1

10

210

310

410

510

610

710

810

ATLAS 1 = 13 TeV, 36.1 fbs

Signal Region>250 GeV

miss

T(j1)>250 GeV, E

Tp

Data 2015+2016

Standard Model

) + jetsnn ®Z(

) + jetsn l®W(

ll) + jets®Z(

+ single toptt

Diboson

) = (500, 495) GeV0c~, b

~m(

)= (400, 1000) GeVmed

, MDM

(m

=6400 GeVD

ADD, n=4, M

[GeV]T

Leading jet p400 600 800 1000 1200 1400

Data

/ S

M0.8

1

1.2 Stat. + Syst. Uncertainties

hadr

onic

–EX

OT-

2016

-27W



Monojets and missing transverse energymonojet + Emiss

T seing model-independent limits using inclusive signal regions

providing exclusion limits for a wide range of models (more in the paper)

[GeV]AZm

0 1000 2000

[GeV

]χ

m

0

500

1000expσ 2 ±Expected limit

)expσ 1 ±Expected limit (

)PDF, scaletheoryσ 1 ±Observed limit (

Perturbativity Limit

Relic Density (MadDM)-1 = 13 TeV, 3.2 fbsATLAS


Axial-Vector Mediator

Dirac Fermion DM

= 1.0χ

= 0.25, gq

g

95% CL limits

χ

= 2

mAZm

[GeV]χm1 10 210 310 410

]2-p

roto

n) [c

mχ

(S

Dσ

46−10

44−10

42−10

40−10

38−10

36−10

PICO-60

Axial-Vector Mediator

90% CL limits

Dirac Fermion DM

= 1.0χ

= 0.25, gq

g


[GeV]VZm

0 1000 2000

[GeV

]χ

m

0

500

1000 expσ 2 ±Expected limit

)expσ 1 ±Expected limit (

)PDF, scaletheory

σ 1 ±Observed limit (

Relic Density (MadDM)


Vector Mediator

Dirac Fermion DM

= 1.0χ

= 0.25, gq

g

95% CL limits

χ

= 2

mVZm

[GeV]1t~m

300 400 500 600

[GeV

]10

χ∼m

250

300

350

400

450

500

550

600

650-1=13 TeV, 36.1 fbs

1

0χ∼c→

1t~

production, 1t~1t~

All limits at 95% CL

ATLAS

-1=13 TeV, 3.2 fbsATLAS

)theory

SUSYσ1 ±Observed limit (

)expσ1 ±Expected limit (

expσ2 ±Expected limit

c+ m

0

1χ∼

< m

1t~m

W+ m

b+ m

0

1χ∼

> m

1t~m

Number of extra dimensions

2 3 4 5 6

[TeV

]D

Low

er li

mit

on M

3

4

5

6

7

8

9

10

11

Observed limitσ 1 ±Observed limit

Expected limitσ 1 ±Expected limit σ 2 ±Expected limit

-1 = 13 TeV, 3.2 fbsATLAS

ATLAS

> 400 GeVmiss

T95% CL Limits, E

-1 = 13 TeV, 36.1 fbs

DM axial-vector

→

DM vector

SUSY t extra dimensions

hadr

onic

–EX

OT-

2016

-27W



Pair production of vector-like quarks TT → Ht + X

motivation: alternative for 4th generation quarks; hierarchy problemdecays to vector bosons and 3rd generation quarks

approach: 0/1-lepton + (many) jets, some b-tagged∎ 1-lepton = lepton + jets: sensitive to T → tH(bb) (12 regions)

∎ 0-lepton = jets + MET: sensitive to T → tZ(νν) (22 regions)

make use of Higgs and top tagging: categorize using N(H), N(t), N(b), N(j) multiplicities

ML fit of eective mass

derive 95% CL limit on production cross section

Top-tagged jet multiplicity0 1 2 3 4 5

Fra

ctio

n of

eve

nts

0

0.2

0.4

0.6

0.8

1

1.2

2b≥7j, ≥0-lepton =13 TeVs

Simulation PreliminaryATLAS

Total background doublet (1 TeV)TT singlet (1 TeV)TT

(1 TeV)t ZtZ→ TT

6j, 3

b≥

0t, 0

H,

6j, 3

b≥

1t, 0

H,

6j, 3

b≥

0t, 1

H,

6j, 3

b≥

1t, 1

H,

6j, 3

b≥

2t, 0

-1H

, ≥

6j, 3

b≥

2H,

≥0t

, ≥

4b≥6j

, ≥

0t, 0

H,

4b≥6j

, ≥

1t, 0

H,

4b≥6j

, ≥

0t, 1

H,

4b≥6j

, ≥

1t, 1

H,

4b≥6j

, ≥

2t, 0

-1H

, ≥

4b≥6j

, ≥

2H,

≥0t

, ≥

7j, 2

b, H

M≥

0t, 0

H,

7j, 2

b, H

M≥

1t, 0

H,

7j, 2

b, H

M≥

0t, 1

H,

7j, 2

b, H

M≥

2tH

, ≥

7j, 3

b, L

M≥

0t, 0

H,

7j, 3

b, L

M≥

1t, 0

H,

7j, 3

b, L

M≥

0t, 1

H,

7j, 3

b, L

M≥

1t, 1

H,

7j, 3

b, L

M≥

2t, 0

-1H

, ≥

7j, 3

b, H

M≥

0t, 0

H,

7j, 3

b, H

M≥

1t, 0

H,

7j, 3

b, H

M≥

0t, 1

H,

7j, 3

b, H

M≥

1t, 1

H,

7j, 3

b, H

M≥

2t, 0

-1H

, ≥

7j, 3

b≥

2H,

≥0t

, ≥

4b, L

M≥

7j,

≥0t

, 0H

,

4b, L

M≥

7j,

≥1t

, 0H

,

4b, L

M≥

7j,

≥0t

, 1H

,

4b, H

M≥

7j,

≥0t

, 0H

,

4b, H

M≥

7j,

≥1t

, 0H

,

4b, H

M≥

7j,

≥0t

, 1H

,

4b≥7j

, ≥

2tH

, ≥

Dat

a / B

kg

00.5

11.5

2

Eve

nts

1

10

210

310

410

510 ATLAS Preliminary-1 = 13 TeV, 36.1 fbs

Search regionsPost-fit (Bkg-only)

Data + light-jetstt1c≥ + tt 1b≥ + tttNon-t Total Bkg unc.

1-lepton 0-lepton

[GeV]Tm

700 800 900 1000 1100 1200 1300 1400 1500

) [p

b]T

T→

(pp

σ

3−10

2−10

1−10

1

10)σ1±Theory (NNLO prediction

95% CL observed limit95% CL expected limit

σ1±95% CL expected limit σ2±95% CL expected limit

ATLAS Preliminary-1 = 13 TeV, 36.1 fbs

1-lepton + 0-lepton combination

SU(2) doublet

hadr

onic

–EX

OT-

2016

-13W



Hadronic W′→ tb

motivation: universal extra dimensions, lile Higgs, top assistedtechnicolor, Kaluza-Klein gravitons, . . .∎ tb final state sensitive to right handed W′s

topology: 1 high-pT b-jet + 1 large-R top-jet (bqq) categorize:

∎ 0 or 1 b-tag∎ 6 regions each based on b- and top tagging criteria

making use of shower deconstruction top tagger [1] hps://journals.aps.org/prd/abstract/10.1103/PhysRevD.84.074002 W

[2] hps://journals.aps.org/prd/abstract/10.1103/PhysRevD.87.054012 W

Eve

nts

0

100

200

300

400

500

600

700 ATLAS-1 = 13 TeV, 36.1 fbsData

MCtt MCtNon t

SD unc.

| < 2.0Jη > 420 GeV, |J

Tp

)SD

χlog(-3 -2 -1 0 1 2 3 4 5 6 7D

ata

/ Pre

d.

00.5

11.5

2

hadr

onic

–EX

OT-

2017

-02W


https://journals.aps.org/prd/abstract/10.1103/PhysRevD.84.074002

https://journals.aps.org/prd/abstract/10.1103/PhysRevD.87.054012


Hadronic W′→ tb

fit reconstructed mtb in signal and validation regions

derived 95% CL limits on the cross section

largest excess at m = 2.25 TeV with local significance of 2.0σ

1−10

1

10

210

310

410

Eve

nts

/ 100

GeV ATLAS

-1 = 13 TeV, 36.1 fbs

SR1

Datamulti-jet + W/Z+jets

tall-had ttnon all-had t

uncertaintypre-fit3 TeV W'

1000 2000 3000 4000 5000 6000

[GeV]tbm

0.60.8

11.21.4

Dat

a / P

red

2−10

1−10

1

10

210

310

410

510

Eve

nts

/ 100

GeV ATLAS

-1 = 13 TeV, 36.1 fbs

SR2




1000 2000 3000 4000 5000 6000

[GeV]tbm

0.60.8

11.21.4

Dat

a / P

red

1−10

1

10

210

310

410

Eve

nts

/ 100

GeV ATLAS

-1 = 13 TeV, 36.1 fbs

SR3




1000 2000 3000 4000 5000 6000

[GeV]tbm

0.60.8

11.21.4

Dat

a / P

red

1000 1500 2000 2500 3000 3500 4000 4500 5000) [GeV]

Rm(W'

2−10

1−10

1

10

tb)

[pb]

→ R

B(W

'×

) R

W'

→(p

p σ

ATLAS

-1 = 13 TeV, 36.1 fbs



σ1±Expected 95% CL limit


NLO W' cross-section (ZTOP)

1000 1500 2000 2500 3000 3500 4000 4500 5000) [GeV]

Lm(W'

2−10

1−10

1

10

tb)

[pb]

→ L B

(W'

×) L

W'

→(p

p σ

ATLAS

-1 = 13 TeV, 36.1 fbs





NLO W' cross-section (ZTOP)

hadr

onic

–EX

OT-

2017

-02W



Heavy resonances decaying to taus W ′→ τν

motivation: W′ preferential coupling to 3rd gen as explanation for anomalies, mass hierarchy, . . .∎ might not appear in e/µ final states and therefore requires targeed τ search

selecting events with taus and large missing transverse energy

deriving model-independent 95% CL limits

interpretations in SSM and non-universal G(221)

3−10

2−10

1−10

1

10

210

Eve

nts

/ GeV ATLAS

-1 = 13 TeV, 36.1 fbs

Dataντ→W

JetOthersUncertainty

(3 TeV)SSMW' (3 TeV)NUW'

[GeV]Tm

0.81

1.2

Dat

a / S

M

300 500 700 1000 2000 500 1000 1500 threshold [GeV]Tm

4−10

3−10

2−10

1−10

[pb]

ε × A ×

) X

+

ντ →

pp(σ


Model independent 95% CL limitsντ → pp

Observed

Expected

σ 1±σ 2±

1000 2000 3000 4000 [GeV]W'm

3−10

2−10

1−10

1) [p

b]ντ

→ W

'(

B ×)

X +

W

'

→ pp(

σ


95% CL limitsντ → SSMW'

Observed

Expected

σ 1±σ 2±

SSMW'

σ 1±

hadr

onic

–EX

OT-

2017

-06W



Summary presented 9 recent ATLAS exotics searches using

the 2015+2016 dataset (36.1 fb−1)

results covering many final states anda wide range of masses

derivation of model-independent limits as well asinterpretations testing a large number of models

no hints of new physics yet

for the future

∎ more data to be analysed (2017+2018)

∎ several more results in the pipeline

∎ all public results at: hps://twiki.cern.ch/twiki/bin/view/AtlasPublic/ExoticsPublicResults W


√s = 13 TeV



s = 13 TeV



√s = 13 TeV






















https://twiki.cern.ch/twiki/bin/view/AtlasPublic/ExoticsPublicResults

Backup


ATLAS


Jet substructure

DDTρ1 2 3 4 5 6

⟩ 21τ ⟨

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Jet channel < 700 GeVJ

TBkg., 500 < p

< 900 GeVJ

TBkg., 700 < p

< 1300 GeVJ

TBkg., 900 < p

< 700 GeVJ

TSig., 500 < p

< 1300 GeVJ

TSig., 900 < p

< 900 GeVJ

TSig., 700 < p

crucial tool in searches for resonances decaying to highly boosted

∎ quark pairs, SM bosons, top quarks

τ21 and D2 variables to track two-pronged signal jets [2],[3]

designed decorrelated tagger (DDT) [4] to remove dependence on mass & pT

important for∎ ISR + boosted quark pair∎ W ′ → tb∎ X →WV → lνqq

[1] R. Jansky W

[2] EXOT-2017-01 W


https://arxiv.org/pdf/1108.2701.pdf

https://arxiv.org/pdf/1507.03018.pdf

https://arxiv.org/abs/1603.00027

https://cds.cern.ch/record/2305903/files/ATL-COM-PHYS-2018-169.pdf

https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2017-01/

Jet substructure

[1] R. Jansky W

jet mass:

¿ÁÁÀ(∑

i∈J Ei)2

− (∑i∈J pi)

2

currently mostly using calorimeter-based jet substructure

gain from including tracker information in substructure measurements



Jetsresolved boosted/merged

[1] R. Jansky W



Documents

ATLAS results on searches for exotic particles - cds.cern.ch fileIntroduction L Many BSM theories: Ì Grand Unification Theory Ì Sequential Standard Model Ì Dark sector extensions