Chikuma Kato on behalf of ATLAS collaboration

BLV2017

Cleveland OH USA 15th May 2017

1

Searches for new phenomena in leptonic final states

using the ATLAS detector

Introduction •  Standard Model (SM) needs extension

–  Naturalness, baryon number, dark matter, neutrino mass

•  Models with extended gauge groups (left-right symmetric, E6-motivated) predict heavy gauge boson (W'/Z') –  W' à lv @ 13 TeV, 36.1 fb-1 [ATLAS-CONF-2017-016] –  Z' à ll @ 13 TeV, 36.1 fb-1 [ATLAS-CONF-2017-027]

•  Models with extended Higgs sector (MSSM, 2HDM) predict a CP-odd (A) and two CP-even (h, H) and two charged (H±) Higgs bosons –  H/A à ττ @ 13 TeV, 13.3 fb-1 [ATLAS-CONF-2016-085] –  A à Zh @ 13 TeV, 3.2 fb-1 [ATLAS-CONF-2016-015]

2

W' à lv : Overview •  Signal

–  Sequential Standard Model (SSM) W'SSM à couplings to fermions are identical to SM W

•  Selection –  eν : 1 electron pT

> 65 GeV, ETmiss > 65 GeV, mT > 130 GeV

–  µν : 1 muon pT > 55 GeV, ETmiss > 55 GeV, mT > 110 GeV

•  Background –  W, top, Z, di-boson, multi-jet, heavy flavor quark, γ+jets

•  multi-jet is estimated from data using matrix method •  top, di-boson and multi-jet are extrapolated into high mT

•  Discriminant –  mT = √( 2pTET

miss(1-cosφlv))

3 ν

±lq

q

±W’

W' à lv : mT

•  eν (left) and µν (right) •  Local significance 2.3 σ at 1.1 TeV in eν •  No significant excess

4

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DataWTop quarkMultijet

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selectionν e→W’

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W' à lv : Limit

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[TeV]W’m1 2 3 4 5 6

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]νe

→ B

R(W

’×

W’)

→(p

pσ

4−10

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Expected limit

σ 1±Expected

σ 2±Expected

Observed limit

SSMW’

PreliminaryATLAS

ν e→W’ -1 = 13 TeV, 36.1 fbs

95% CL

[TeV]W’m1 2 3 4 5 6

) [pb

]νµ

→ B

R(W

’×

W’)

→(p

pσ

4−10

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σ 1±Expected

σ 2±Expected

Observed limit

SSMW’

PreliminaryATLAS

νµ →W’ -1 = 13 TeV, 36.1 fbs

95% CL

[TeV]W’m1 2 3 4 5 6

) [pb

]νl

→ B

R(W

’×

W’)

→(p

pσ

4−10

3−10

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Expected limit

σ 1±Expected

σ 2±Expected

Observed limit

SSMW’

PreliminaryATLAS

ν l→W’ -1 = 13 TeV, 36.1 fbs

95% CL

•  eν (left) and µν (right) •  Combined (bottom) •  Stronger limit in eν because

acceptance and momentum resolution is better in eν

•  Lower mass limit for W'SSM : 5.22 TeV

Z' à ll : Overview •  Signal

–  Generic Z' (1~32% width), Z'SSM and E6-motivated Z'ψ, Z'χ : in this slides

–  Minimal Z' and Contact Interaction (CI) : also in the note •  Selection

–  ee : At least 2 electon ET > 30 GeV, –  µµ : At least 2 muon pT > 30 GeV, opposite charge

•  Background –  Z, top, di-boson, multi-jet, W+jets –  Multi-jet and W+jets are estimated from data using matrix method

•  Negligible in µµ •  Discriminant

–  m(ll)

6 -l

+lq

q

Z’Z’

Z' à ll : m(ll)

•  ee (left) and µµ (right) •  Local significance 2.5 σ at 2.37 TeV •  No significant excess

7

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Dielectron Search Selection

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Dimuon Search Selection

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Z' à ll : Limits

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PreliminaryATLAS

ll→Z’ -1 = 13 TeV, 36.1 fbs

expected limits

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B [p

b]σ

A

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PreliminaryATLAS

ll→Z’ -1 = 13 TeV, 36.1 fbs

observed limits

•  Limit on generic Z' expected (left) and observed (right)

•  Limit on Z'SSM and E6-motivated Z'ψ, Z'χ (bottom) –  Lower mass limit for Z'SSM :

4.5 TeV

[TeV]Z’M0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

B [p

b]σ

-510

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1 Expected limitσ 1±Expected σ 2±Expected

Observed limitSSMZ’χZ’ψZ’

PreliminaryATLAS

ll→Z’

-1 = 13 TeV, 36.1 fbs

H/A à ττ : Overview •  Signal

–  gluon-gluon fusion (ggH/A) and b-quark associated (bbH/A) –  large tanβ à couplings to down type fermions à b-tag category

•  Selection –  τlepτhad : ET

miss > 150 GeV à high-ETmiss category, 1 lepton pT > 30

GeV, τhad-vis pT > 25 GeV, opposite charge, Δφ(τhad-vis, l) > 2.4, mT(l, ET

miss) < 40 GeV, veto 80 < mvis(e, τhad-vis) < 110 GeV –  τhadτhad : τ1 pT > 110 ~ 140 GeV, Δφ(τ1, τ2) > 2.7, τ refers to visible

•  Background –  Z+jets, W+jets, top (in b-tag category), di-boson, multi-jet –  Fake is estimated from data using fake factor and fake rate method

•  Discriminant –  mT

tot = √(mT2(ET

miss, τ1)+mT2(ET

miss, τ2)+mT2(τ2, τ1))

9

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Dibosonµµ ee / →Z

UncertaintyPre-fit background

ATLAS Preliminary -1 = 13 TeV, 13.3 fbs

hadτlepτ →H/A b-veto

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hadτlepτ →H/A missT

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•  τlepτhad : b-veto (left), b-tag (middle) and high-ET

miss (right) •  τhadτhad : b-veto (left)

and b-tag (right) •  No significant excess

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H à ττ : mTtot

H/A à ττ : Limits

•  ggH/A (left) and bbH/A (right) •  Upper limit on σ x BR : 2.0 (2.1) ~ 0.0013 (0.0014) pb for ggA (bbA) at

m(H/A) = 200 ~ 1200 GeV •  mA vs tanβ for MSSM : also in the note 11

[GeV]Am200 400 600 800 1000 1200

)[pb]

ττ→

BR(

H/A

×σ

2−10

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10 PreliminaryATLAS

, 95 % CL limitsττ →H/A -1 13.3 fb≤ = 13 TeV, s

gluon-gluon fusion

ObservedExpectedσ1±σ2±

(Obs.)-12015, 3.2 fb

(Exp.)hadτhadτ

(Exp.)hadτlepτ

[GeV]Am200 400 600 800 1000 1200

)[pb]

ττ→

BR(

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×σ

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, 95 % CL limitsττ →H/A -1 13.3 fb≤ = 13 TeV, s

b-associated production

ObservedExpectedσ1±σ2±

(Obs.)-12015, 3.2 fb

(Exp.)hadτhadτ

(Exp.)hadτlepτ

A à Zh : Overview •  Signal

–  ggA and bbA •  Selection

–  llbb : in this slides à –  ννbb : also in the note –  pT

Z >500 GeV à high-pT

Z category

•  Background –  Z+jets, top, di-boson, W+jets –  multi-jet is negligible

•  Discriminant –  llbb : m(Zh) –  ννbb : mT(Zh)

12

-l

+l

bh

Z

bA

g

g

t

low-pTz high-pTz

pTz [GeV] < 500 > 500

# of b-tag 1, 2 1, 2

# of dR = 0.4 jets ≧ 2 -

# of dR = 1.0 jets - ≧ 1

m(jj), m(J) [GeV] 110 ~ 140 75 ~ 145

m(ee) [GeV] 70 ~ 110 70 ~ 110

m(µµ) [GeV] 70 ~ 110 75 ~ 125

ETmiss/√ΣpT [√GeV] < 3.5 -

•  low-pTz, 1 tag (left) and 2 tag (right)

•  Local significance about 2 σ at m(A) = 260, 440 GeV

13

A à Zh : m(Zh)

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ATLAS Preliminary -1Ldt = 3.2 fb∫ = 13 TeV s

2 jets, 1 tag≥2 lep., < 500 GeVV

Tp

< 140 GeVbb m≤110 GeV

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DibosonVhtt

Single topW+(bb,bc,cc,bl)Z+(bl,cl)Z+(bb,bc,cc)UncertaintyPre-fit background

ATLAS Preliminary -1Ldt = 3.2 fb∫ = 13 TeV s

2 jets, 2 tags≥2 lep., < 500 GeVV

Tp

< 140 GeVbb m≤110 GeV

m(Vh) [GeV]200 300 400 500 600 700 800 900D

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A à Zh : m(Zh)

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=600 GeVAmDibosonZ+(bl,cl)Z+(bb,bc,cc)Z+lUncertaintyPre-fit background

ATLAS Preliminary -1Ldt = 3.2 fb∫ = 13 TeV s

1 large-R jets, 1 tag≥2 lep., VT

p≤500 GeV < 145 GeVbb m≤75 GeV

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ATLAS Preliminary -1Ldt = 3.2 fb∫ = 13 TeV s

1 large-R jets, 2 tags≥2 lep., VT

p≤500 GeV < 145 GeVbb m≤75 GeV

m(Vh) [GeV]600 800 1000 1200 1400 1600 1800 2000D

ata/

Pred

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11.5

2

•  high-pTz , 1 tag (left) and 2 tag (right)

•  No significant excess

•  ggA (left) and bbA (right) •  Upper limit on σ x BR : 4.0 ~ 0.0017 (6.9 ~ 0.026) pb for ggA (bbA) at

m(A) = 220 ~ 2000 GeV •  cos(β-α) vs tan(β) for 2HDM : also in the note

15

A à Zh : Limits

[GeV]A m200 400 600 800 1000 1200 1400 1600 1800 2000

bb) [

pb]

→BR

(h⋅

Zh)

→(A

σ 9

5% C

.L. l

imit

on

2−10

1−10

1

10 Observed (CLs)Expected (CLs)

σ 1±σ 2±

expected (CLs)νν→Z ll expected (CLs)→Z

b Zb→Zh→A

ATLAS Preliminary-1 Ldt = 3.2 fb∫ = 13 TeV, s

[GeV]A m200 400 600 800 1000 1200 1400 1600 1800 2000

bb) [

pb]

→BR

(h⋅

Zh)

→(A

σ 9

5% C

.L. l

imit

on

2−10

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10 Observed (CLs)Expected (CLs)

σ 1±

σ 2±b Zb→Zh→A

ATLAS Preliminary-1 Ldt = 3.2 fb∫ = 13 TeV, s

Summary •  W' à lv @ 13 TeV, 36.1 fb-1 [ATLAS-CONF-2017-016]

–  Local significance 2.3 σ at 1.1 TeV in eν –  Lower mass limit for W'SSM : 5.22 TeV

•  Z' à ll @ 13 TeV, 36.1 fb-1 [ATLAS-CONF-2017-027] •  Local significance 2.5 σ at 2.37 TeV •  Lower mass limit for Z'SSM : 4.5 TeV

•  H/A à ττ @ 13 TeV, 13.3 fb-1 [ATLAS-CONF-2016-085] –  Upper limit on σ x BR : 2.0 (2.1) ~ 0.0013 (0.0014) pb for ggA (bbA)

at m(H/A) = 200 ~ 1200 GeV •  A à Zh @ 13 TeV, 3.2 fb-1 [ATLAS-CONF-2016-015]

–  Local significance about 2 σ at m(A) = 260, 440 GeV –  Upper limit on σ x BR : 4.0 ~ 0.0017 (6.9 ~ 0.026) pb for ggA (bbA) at

m(A) = 220 ~ 2000 GeV 16