[PPT] - Direct electroweakino, slepton and stop searches at CMS Lukas PowerPoint Presentation

SLIDE 1

Direct electroweakino, slepton and stop searches at CMS

Lukas Vanelderen (University of Hamburg)

n behalf of the CMS collaboration

29.05.13, ECFA LC2013

0/21 0/21

SLIDE 2

Direct production of stops

1/21

SLIDE 3

CMS stop searches

main challenge:

◮ small stop mass: large cross section but signal looks like bkg ◮ large stop mass: different kinematics, but small cross section

7 TeV results:

◮ SUS-11-030: all-hadronic channel, jets and MET, 5/fb ◮ SUS-12-009: all-hadronic channel, razor, 5/fb

8 TeV results:

◮ SUS-12-023: single-lepton channel, 9.7/fb ◮ SUS-13-003: RPV, ≥ 3 leptons, 19.5/fb ◮ SUS-13-011: single lepton channel, 19.5/fb

→ THIS TALK

2/21

SLIDE 4

Event pre-selection

◮ 1 iso e/µ, pT > 30/25 GeV ◮ 2nd lepton veto:

no loose e/µ
no iso track
no had tau

◮ ≥ 4 jets, pT > 30 GeV, |η| < 2.4 ◮ 1 of which is b-tagged ◮ MET > 100 GeV P1 P2 ˜ t∗ ˜ t ¯ t t ¯ b W − ˜ χ0

1

˜ χ0

1

W + b P1 P2 ˜ t∗ ˜ t ˜ χ− W − ˜ χ+ W + ¯ b ˜ χ0

1

˜ χ0

1

b

3/21

SLIDE 5

Discriminating variables

[GeV]

T

M 50 100 150 200 250 300 Entries / 30 GeV 10

2

10

3

10

4

10

5

10

6

10

Data top l 1 ll → t t W+jets rare (650/50) x1000

1

χ ∼ t → t ~

Pre-selection

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

Data/MC 0.5 1 1.5 2

MT

[GeV]

miss T

E 100 150 200 250 300 350 Entries / 25 GeV 10

2

10

3

10

4

10

5

10

6

10

Data top l 1 ll → t t W+jets rare (650/50) x1000

1

χ ∼ t → t ~

Pre-selection

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

Data/MC 0.5 1 1.5 2

MET

[GeV]

W T2

M 100 150 200 250 300 350 400 450 500 Entries / 25 GeV 1 10

2

10

3

10

4

10

5

10

6

10

Data top l 1 ll → t t W+jets rare (650/50) x1000

1

χ ∼ t → t ~

Pre-selection

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

Data/MC 0.5 1 1.5 2

MW

T2

ratio T

H 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Entries / 0.04

1

10 1 10

2

10

3

10

4

10

5

10

6

10

7

10

Data top l 1 ll → t t W+jets rare (650/50) x1000

1

χ ∼ t → t ~

Pre-selection

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

Data/MC 0.5 1 1.5 2

Hratio

T

) [GeV]

1

(b

T

p 50 100 150 200 250 300 350 400 Entries / 15 GeV

1

10 1 10

2

10

3

10

4

10

5

10

6

10

Data top l 1 ll → t t W+jets rare (650/50/0.5) x1000 ± 1 χ ∼ b → t ~

Pre-selection

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

Data/MC 0.5 1 1.5 2

pT(b1)

)

1

, b l R( ∆ 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Entries / 0.33 1 10

2

10

3

10

4

10

5

10

6

10

7

10

Data top l 1 ll → t t W+jets rare (650/50/0.5) x1000 ± 1 χ ∼ b → t ~

Pre-selection

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

Data/MC 0.5 1 1.5 2

∆R(l, b1)

4/21

SLIDE 6

Signal regions

◮ MT > 120 GeV ◮ cut on BDT output,

multiple BDTs trained for particular stop scenarios:

P1 P2 ˜ t∗ ˜ t ¯ t t ¯ b W − ˜ χ0

1

˜ χ0

1

W + b P1 P2 ˜ t∗ ˜ t ˜ χ− W − ˜ χ+ W + ¯ b ˜ χ0

1

˜ χ0

1

b

m ˜

χ±

1 = m ˜

χ0

1 + x(m˜

t − m ˜ χ0

1) 2 ( l

w

Δ M )

200 300 400 500 600 700

100 200 300 400 500 600

ΔM = mtop

3 ( m e d i u m Δ M )

4

( h i g h Δ M )

5

(

f

f

s

h e l l t

p

)



t → t  χ1

1 (low mass)

mt [GeV]

~

m𝛙 [GeV]

~ 1

1 ( l

w

Δ M )

200 300 400 500 600 700

100 200 300 400 500 600

2 (medium ΔM) 3 (high ΔM) mt [GeV]

~

m𝛙 [GeV]

~ 1

 t → b  χ1

+ → bW 

χ1

0 (x=0.5)

ΔM = MW

x = 0.5 more BDTs for x = 0.25, 0.75

5/21

SLIDE 7

Results

[GeV]

T

M 100 200 300 Entries / 60 GeV 1 10

2

10

3

10 Data top l 1 ll → t t W+jets rare

BDT5

1

χ ∼ t → t ~

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

Data/MC 0.5 1 1.5 2

MT, pass BDT5

BDT Output 0.2 0.4 0.6 Entries / 0.05 100 200 300 400 500 600 Data top l 1 ll → t t W+jets rare

BDT5

1

χ ∼ t → t ~

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

Data/MC 0.5 1 1.5 2

BDT5, MT > 120 no excess observed, we proceed with SMS interpretation...

6/21

SLIDE 8

˜ t → t ˜ χ0

1

P1 P2 ˜ t∗ ˜ t ¯ t t ¯ b W − ˜ χ0

1

˜ χ0

1

W + b ◮ unpolarized top ◮ results from 6 BDTs ◮ per point, use most

sensitive signal region

[GeV]

t ~

m

200 300 400 500 600 700 800

[GeV]

1

χ ∼

m

50 100 150 200 250 300 350 400

upper limit [pb] σ

3

10

2

10

1

10 1 10

2

10

unpolarized top BDT analysis

1

χ ∼ t → t ~ *, t ~ t ~ → pp

)

theory

σ 1 ± Observed ( ) σ 1 ± Expected ( )

1

Observed (9.7 fb

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

t

= M

1

χ ∼

m

t ~

m

W

= M

1

χ ∼

m

t ~

m

7/21

SLIDE 9

˜ t → b˜ χ±

1

P1 P2 ˜ t∗ ˜ t ˜ χ− W − ˜ χ+ W + ¯ b ˜ χ0

1

˜ χ0

1

b ◮ results from 4 BDTs ◮ per point, use most

sensitive signal region

◮ unpolarized top ◮ m ˜ χ±

1 = m ˜

χ0

1+x(m˜

t−m ˜ χ0

1)

[GeV]

t ~

m

200 300 400 500 600 700 800

[GeV]

1

χ ∼

m

50 100 150 200 250 300 350 400

upper limit [pb] σ

3

10

2

10

1

10 1 10

2

10

BDT analysis

+ 1

χ ∼ b → t ~ *, t ~ t ~ → pp

)

theory

σ 1 ± Observed ( ) σ 1 ± Expected ( )

1

Observed (9.7 fb

1

χ ∼

+ 0.5 m

t ~

= 0.5 m

± 1

χ ∼

m

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

W

= m

1

χ ∼

m

± 1

χ ∼

m

x=0.5

[GeV]

t ~

m

350 400 450 500 550 600 650 700 750 800

[GeV]

1

χ ∼

m

50 100 150 200 250 300 350 400

upper limit [pb] σ

3

10

2

10

1

10 1 10

2

10

BDT analysis

+ 1

χ ∼ b → t ~ *, t ~ t ~ → pp

)

theory

σ 1 ± Observed ( ) σ 1 ± Expected (

1

χ ∼

+ 0.75 m

t ~

= 0.25 m

± 1

χ ∼

m

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

W

= m

1

χ ∼

m

± 1

χ ∼

m

x=0.75

8/21

SLIDE 10

Impact of polarization

◮ different scenarios tested for

top polarization,
chargino polarization and W ˜

χ0

1 ˜

χ±

1 coupling ◮ accomodates for different stop and ewkino mixing scenarios ◮ typical impact on limits ±20 GeV

[GeV]

t ~

m

200 300 400 500 600 700 800

[GeV]

1

χ ∼

m

50 100 150 200 250 300 350 400 BDT analysis

1

χ ∼ t → t ~ , t ~ t ~ → pp Observed (unpolarized top) Observed (right-handed top) Observed (left-handed top)

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

t

= m

1

χ ∼

m

t ~

m

W

= m

1

χ ∼

m

t ~

m

[GeV]

t ~

m

200 300 400 500 600 700 800

[GeV]

1

χ ∼

m

50 100 150 200 250 300 350 400 BDT analysis

+ 1

χ ∼ b → t ~ *, t ~ t ~ → pp

Observed (nominal) )

± 1

χ ∼

1

χ ∼ , right W

R ±

χ ∼ Observed ( )

± 1

χ ∼

1

χ ∼ , left W

R ±

χ ∼ Observed ( )

± 1

χ ∼

1

χ ∼ , right W

L ±

χ ∼ Observed ( )

± 1

χ ∼

1

χ ∼ , left W

L ±

χ ∼ Observed (

1

Ldt = 19.5 fb

∫

= 8 TeV, s CMS Preliminary

1

χ ∼

+ 0.5 m

t ~

= 0.5 m

± 1

χ ∼

m

W

= m

1

χ ∼

m

± 1

χ ∼

m

9/21

SLIDE 11

Direct production of ewkinos and sleptons

10/21

SLIDE 12

CMS ewkino and slepton searches

◮ low cross sections compared to strong production ◮ but might dominate if squarks and gluinos are heavy ◮ CMS results from 5/fb at 7TeV:

JHEP11(2012)147, arXiv:1209.6620

◮ CMS results from 9.2/fb at 8TeV:

CMS-SUS-12-022 → THIS TALK

11/21

SLIDE 13

Targetted topologies

production of ˜ χ±

1 ˜

χ0

2, ˜

χ±

1 ˜

χ±

1 , ˜

l˜ l, ˜ χ0

2 ˜

χ0

2 ◮ w/ and w/o intermediate sparticles ◮ w/ and w/o on-shell W/Z p1 p2 ˜ χ±

1

˜ χ0

2

˜ ℓ ˜ ℓ ν ℓ ˜ χ0

1

˜ χ0

1

ℓ ℓ p1 p2 ˜ χ±

1

˜ χ0

2

W Z ˜ χ0

1

˜ χ0

1

P1 P2 ˜ χ∓ ˜ χ± ˜ ℓ ˜ ν ν ℓ ˜ χ0

1

˜ χ0

1

ν ℓ P1 P2 ˜ ℓ ˜ ℓ ℓ ˜ χ0

1

˜ χ0

1

ℓ

search in a variety of lepton + MET channels

12/21

SLIDE 14

3-lepton channel

event selection

◮ 3 iso leptons, ◮ at most 1 τhad ◮ MET > 50 GeV ◮ b-jet veto

kinematic variables

◮ Mll: mass of lepton pair

most compatible with Z,

◮ MT: transverse mass of

remaining lepton and MET search regions

◮ w/ and w/o OSSF ◮ w/ and w/o τ ◮ binned: MET, Mll, MT

1

= 9.2 fb

int

= 8 TeV, L s CMS Preliminary

[GeV]

miss T

E 50 100 150 200 events / 50 GeV 1 2 3 4 5 6 7 [GeV]

miss T

E 50 100 150 200 events / 50 GeV 1 2 3 4 5 [GeV]

miss T

E 50 100 150 200 events / 50 GeV 0.5 1 1.5 2 2.5 [GeV]

miss T

E 50 100 150 200 events / 50 GeV 1 2 3 4 5 [GeV]

miss T

E 50 100 150 200 events / 50 GeV 2 4 6 8 10 12 14 16 [GeV]

miss T

E 50 100 150 200 events / 50 GeV 0.5 1 1.5 2 2.5 3 3.5 4 4.5 [GeV]

miss T

E 50 100 150 200 events / 50 GeV 10 20 30 40 50 60 70 [GeV]

miss T

E 50 100 150 200 events / 50 GeV 50 100 150 200 250 300 350 400 [GeV]

miss T

E 50 100 150 200 events / 50 GeV 5 10 15 20 25

>160 GeV

T

M <75 GeV

l

+

l

M <105 GeV

l

+

l

75 GeV<M >105 GeV

l

+

l

M <160 GeV

T

120 GeV<M <120 GeV

T

M

Channels: e

±

e

±

e µ

±

e

±

e e

±

µ

±

µ µ

±

µ

±

µ Data ZZ * γ Z WZ Non-prompt Rare SM uncertainty Total bkg

with OSSF w/o τ

p1 p2 ˜ χ±

1

˜ χ0

2

˜ ℓ ˜ ℓ ν ℓ ˜ χ0

1

˜ χ0

1

ℓ ℓ p1 p2 ˜ χ±

1

˜ χ0

2

W Z ˜ χ0

1

˜ χ0

1

13/21

SLIDE 15

4-lepton channel

◮ 4 iso leptons, at most 1 τ ◮ at least one Z ◮ SR: bins in MET, NOSSF, Nτ

Same-sign di-lepton channel

◮ 2 light iso leptons, SS, Z-veto ◮ SR: 120 < MET < 200, MET > 200 GeV p1 p2 ˜ χ0

2

˜ χ0

3

Z Z ˜ χ0

1

˜ χ0

1

p1 p2 ˜ χ±

1

˜ χ0

2

˜ ℓ ˜ ℓ ν ℓ ˜ χ0

1

˜ χ0

1

ℓ ℓ P1 P2 ˜ χ∓ ˜ χ± ˜ ℓ ˜ ν ν ℓ ˜ χ0

1

˜ χ0

1

ν ℓ

14/21

SLIDE 16

Z(ll) + W/Z(jj) channel

◮ 1 Z(ee)/Z(µµ) candidate,

|mll − mZ| < 10 GeV

◮ 1 W/Z(jj) candidate,

70 < mjj < 110 GeV

◮ SR: bins in MET

OS, no Z channel

◮ 2 light iso leptons, OS ◮ Z veto, MET > 60 GeV,

MCT⊥ > 100 GeV

◮ SR: same flavor, opposite flavor p1 p2 ˜ χ0

2

˜ χ0

3

Z Z ˜ χ0

1

˜ χ0

1

p1 p2 ˜ χ±

1

˜ χ0

2

W Z ˜ χ0

1

˜ χ0

1

P1 P2 ˜ χ∓ ˜ χ± ˜ ℓ ˜ ν ν ℓ ˜ χ0

1

˜ χ0

1

ν ℓ

15/21

SLIDE 17

Results

no excess observed, we proceed with SMS interpretation...

16/21

SLIDE 18

˜ χ±

1 ˜

χ0

2, intermediate ˜

l/˜ ν,

flavor democratic

◮ 3-lepton and SS di-lepton ◮ “flavor democratic” ◮ m ˜ χ±

1 = m ˜

χ0

2

◮ m˜ l = m ˜ χ0

1 + x(m ˜

χ0

2 − m ˜

χ0

1)

p1 p2 ˜ χ±

1

˜ χ0

2

˜ ℓ ˜ ℓ ν ℓ ˜ χ0

1

˜ χ0

1

ℓ ℓ

flavor democratic, x = 0.5

[GeV]

2

χ ∼

=m

± 1

χ ∼

m

100 200 300 400 500 600 700 800

[GeV]

1

χ ∼

m

100 200 300 400 500 600

[fb] σ 95% CL upper limit on

1 10

2

10

3

10

1

χ ∼

> m

± 1

χ ∼

= m

2

χ ∼

m

1

= 9.2 fb

int

= 8 TeV, L s CMS Preliminary 95% C.L. CLs NLO Exclusions

theory

σ 1 ± l Observed 3

theory

σ 1 ± l Expected 3

2

χ ∼

± 1

χ ∼ → pp

τ

ν τ ∼ ,

µ

ν µ ∼ ,

e

ν e ~ →

± 1

χ ∼ τ τ ∼ , µ µ ∼ , e e ~ →

2

χ ∼ ) = 0.5

l

+

l ~ →

2

χ ∼ ( Br

1

χ ∼

+ 0.5m

± 1

χ ∼

= 0.5m

l ~

m

flavor democratic, x = 0.95

[GeV]

2

χ ∼

=m

± 1

χ ∼

m

100 200 300 400 500 600 700 800

[GeV]

1

χ ∼

m

100 200 300 400 500 600

[fb] σ 95% CL upper limit on

1 10

2

10

3

10

1

χ ∼

> m

± 1

χ ∼

= m

2

χ ∼

m

1

= 9.2 fb

int

= 8 TeV, L s CMS Preliminary 95% C.L. CLs NLO Exclusions

theory

σ 1 ± +SS l Observed 3 σ 1 ± +SS l Expecteded 3

nly

l Observed 3 Observed SS only

2

χ ∼

± 1

χ ∼ → pp

τ

ν τ ∼ ,

µ

ν µ ∼ ,

e

ν e ~ →

± 1

χ ∼ τ τ ∼ , µ µ ∼ , e e ~ →

2

χ ∼ ) = 0.5

l

+

l ~ →

2

χ ∼ ( Br

1

χ ∼

+ 0.95m

± 1

χ ∼

= 0.05m

l ~

m

17/21

SLIDE 19

˜ χ±

1 ˜

χ0

2, intermediate ˜

l/˜ ν, τ-enriched/dominated

◮ 3-lepton and SS di-lepton ◮ m ˜ χ±

1 = m ˜

χ0

2

◮ m˜ l = m ˜ χ0

1 + x(m ˜

χ0

2 − m ˜

χ0

1)

p1 p2 ˜ χ±

1

˜ χ0

2

˜ ℓ ˜ ℓ ν ℓ ˜ χ0

1

˜ χ0

1

ℓ ℓ

τ-enriched, x = 0.5

[GeV]

2

χ ∼

=m

± 1

χ ∼

m

100 200 300 400 500 600 700 800

[GeV]

1

χ ∼

m

100 200 300 400 500 600

[fb] σ 95% CL upper limit on

1 10

2

10

3

10

1

χ ∼

> m

± 1

χ ∼

= m

2

χ ∼

m

1

= 9.2 fb

int

= 8 TeV, L s CMS Preliminary 95% C.L. CLs NLO Exclusions

theory

σ 1 ± +SS l Observed 3 σ 1 ± +SS l Expecteded 3

2

χ ∼

± 1

χ ∼ → pp

τ

ν τ ∼ →

± 1

χ ∼ τ τ ∼ , µ µ ∼ , e e ~ →

2

χ ∼ ) = 1

l

+

l ~ →

2

χ ∼ ( Br

1

χ ∼

+ 0.5m

± 1

χ ∼

= 0.5m

l ~

m

τ-dominated, x = 0.5

[GeV]

2

χ ∼

=m

± 1

χ ∼

m

100 150 200 250 300 350

[GeV]

1

χ ∼

m

50 100 150 200 250

[fb] σ 95% CL upper limit on

10

2

10

3

10

4

10

1

= 9.2 fb

int

= 8 TeV, L s CMS Preliminary 95% C.L. CLs NLO Exclusions

theory

σ 1 ± l Observed 3

theory

σ 1 ± l Expected 3

2

χ ∼

± 1

χ ∼ → pp

τ

ν τ ∼ →

± 1

χ ∼ τ τ ∼ →

2

χ ∼

1

χ ∼

+ 0.5m

± 1

χ ∼

= 0.5m

l ~

m

18/21

SLIDE 20

˜ χ±

1 ˜

χ0

2, on-shell W, Z

◮ 3-lepton and Z(ll) + W/Z(jj) ◮ m ˜ χ±

1 = m ˜

χ0

2

p1 p2 ˜ χ±

1

˜ χ0

2

W Z ˜ χ0

1

˜ χ0

1

[GeV]

2

χ ∼

=m

± 1

χ ∼

m

100 150 200 250 300 350 400

[GeV]

1

χ ∼

m

50 100 150 200

[fb] σ 95% CL upper limit on

2

10

3

10

Z

< m

1

χ ∼

m

2

χ ∼

m

1

= 9.2 fb

int

= 8 TeV, L s CMS Preliminary 95% C.L. CLs NLO Exclusions

theory

σ 1 ± l +3 j 2 l Observed 2 σ 1 ± l 2j+3 l Expecteded 2

nly

l Observed 3

nly

j 2 l Observed 2

± 1

χ ∼

2

χ ∼ → pp

1

χ ∼ Z →

2

χ ∼

1

χ ∼ W →

± 1

χ ∼

˜ l˜ l

◮ SS P1 P2 ˜ ℓ ˜ ℓ ℓ ˜ χ0

1

˜ χ0

1

ℓ

[GeV]

l ~

m

100 150 200 250 300

[GeV]

1

χ ∼

m

50 100 150 200

[fb] σ 95% CL upper limit on

1 10

2

10

1

= 9.2 fb

int

= 8 TeV, L s CMS Preliminary 95% C.L. CLs NLO Exclusions

theory

σ 1 ± Observed σ 1 ± Expecteded

L

µ ∼

L

µ ∼ ,

L

e ~

L

e ~ → pp ) = 1

1

χ ∼ l →

L

l ~ ( Br

19/21

SLIDE 21

Summary

20/21

SLIDE 22

Latest CMS stop results in SUS-13-008:

◮ 1-lepton + MET channel ◮ multitude of search regions dedicated to different stop scenarios ◮ no excess observed, exclusion scenarios up to 650 GeV ◮ but, compressed scenarios stay under the radar

Latest CMS ewk susy results in SUS-12-022:

◮ variety of channels cover many production/decay topologies ◮ no hints of SUSY

excluding charginos up to 650 GeV
excluding sleptons up to 250 GeV

◮ but, compressed scenarios stay under the radar

21/21