SUSY at LHC now and future Mihoko Nojiri KEK& IPMU FermiLab - - PowerPoint PPT Presentation

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SUSY at LHC now and future Mihoko Nojiri KEK& IPMU FermiLab - - PowerPoint PPT Presentation

Sep 15, 2022 47 likes •302 views

SUSY at LHC now and future Mihoko Nojiri KEK& IPMU FermiLab 9/29 SUSY after LHC Checking current excess (ATLAS 1l+ missing +jets Han, Nojiri, Takeuchi, Yanagida (arXiv tomorrow) Future: various direction ex : application of

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SLIDE 1

SUSY at LHC now and future

Mihoko Nojiri KEK& IPMU

FermiLab 9/29

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SLIDE 2

SUSY after LHC

Checking current excess (ATLAS 1l+ missing +jets

Han,Nojiri, Takeuchi, Yanagida (arXiv tomorrow…)

Future: various direction… ex : application of quark gluon separation to get max sensitivity

Bhattacherjee, Mukhopadhyay, Nojiri, Sakaki, Webber arXiv Today 1609.08781

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SLIDE 3

SUSY at LHC Now

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SLIDE 4

current excess (stop channel)

ATLAS 1l + missing + jets

Signal region SR1 tN high bC2x diag bC2x med bCbv DM low DM high (nj, nb) (≥ 4, ≥ 1) (≥ 4, ≥ 1) (≥ 4, ≥ 2) (≥ 4, ≥ 2) (≥ 2, = 0) (≥ 4, ≥ 1) (≥ 4, ≥ 1) E /T [GeV] 260 450 230 210 360 300 330 mT [GeV] 170 210 170 140 200 120 220 amT 2 [GeV] 175 175 170 210

  • 140

170 Total background 24 ± 3 3.8 ± 0.8 22 ± 3 13 ± 2 7.8 ± 1.8 17 ± 2 15 ± 2 Observed 37 5 37 14 7 35 21 p0() 0.012(2.2) 0.26(0.6) 0.004(2.6) 0.40(0.3) 0.50(0) 0.0004(3.3) 0.09(1.3) N limit

  • bs. (95% CL)

26.0 7.2 27.5 9.9 7.2 28.3 15.6 TABLE I: Summary of some of the selection cuts and the results of the seven signal regions defined in ATLAS stop ` + jets + / E

miss T

channel.

excess in various channel though all correlated (stop? )

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SLIDE 5

Some distribution

Assume top partner decay into LPS and top Not happy because it is analyzed by simplified model (Kinematics are taken care of, but assume 100% branching ratio to draw contours )

[GeV]

1

t ~

m 200 300 400 500 600 700 800 900 1000 [GeV]

1

χ ∼

m 100 200 300 400 500 600 700

< 0

t
  • m
1 χ ∼
  • m
1 t ~

m

1

χ ∼ t+ →

1

t ~ production,

1

t ~

1

t ~

)

th

σ 1 ± Observed limit ( )

exp

σ 1 ± Expected limit (

)
  • 1
8 TeV + 13 TeV (3.2 fb ATLAS stop1L

ATLAS Preliminary

  • 1

= 13 TeV, 13.2 fb s Limit at 95% CL

production,

[GeV]

miss T

E 200 250 300 350 400 450 500 550 600 events / 30 GeV 2 4 6 8 10 12 14 16

Data Total SM t t Z+jets W+jets Wt Diboson +V t t

)=(600,200)

1

χ ∼ , t ~ m( )=(800,1)

1

χ ∼ , t ~ m(

ATLAS Preliminary

  • 1

= 13 TeV, 13.2 fb s SR1

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SLIDE 6

Why simplified model do not capturing the case

Han,Nojiri, Takeuchi, Yanagida(arXiv tomorrow

  • r next week)

[GeV]

t ~

m

200 400 600 800 1000 1200

[GeV]

1 χ ∼

m

100 200 300 400 500 600 700
  • 3
10
  • 2
10
  • 1
10 1 10 2 10 1 χ ∼ + m t = m t ~ m 1 χ ∼ + m t = m t ~ m

(13 TeV)

  • 1

12.9 fb

CMS

Preliminary NLO+NLL exclusion 1 χ ∼ t → t ~ , t ~ t ~ → pp theory

σ 1 ± Observed

experiment

σ 1 ± Expected

95% CL upper limit on cross section [pb]

CMS_boosted CMS_hadronic ATLAS_1L

2σ lower 2 σ u p p e r 1σ lower 1σ upper central

500 600 700 800 900 1000 100 200 300 400 500 600 700 Mstop[GeV] Mχ0[GeV] Bino LSP

stop_R→Bino LSP case is almost exclude by CMS boosted top search :-( marginal possibility in degenerate region

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SLIDE 7

How about light Higgsino?

CMS_boosted CMS_hadronic ATLAS_1L LEP

2σ lower 1σ lower 1σ upper central

500 600 700 800 900 1000 100 200 300 400 500 600 700 Mstop[GeV] Mχ0[GeV] Higgsino LSP

50% t 50 %b

even worse? :-(

SR42 SR 40, 41 CMS PAS SUS-16-029 SR 40,41 2 b jet ETmiss and b is not consistent with t Nj=5~7, not boosted top and W, ETmiss> 450

channels less than expected

Note: channels more than expected and channels less than expected tend to overlap

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SLIDE 8

more complicated decay pattern

CMS_boosted CMS_hadronic ATLAS_1L BP ⨯ ⨯ ⨯ ⨯ LUX

2 σ l
  • w
e r 2 σ u p p e r 1σ lower 1σ upper central

500 600 700 800 900 1000 100 200 300 400 500 600 700 Mstop[GeV] Mχ0[GeV] Higgsino-Bino 650-350 750-300 800-200 200 300 400 500 600 5 10 15 ET

miss(GeV)

events/30 GeV

  • bottom line:

We need to wait

Need to

  • 1. Reduce branch into stop to t chi
  • 2. Keep lepton branch

stop(right handed) →higgsino→ bino W . * * *dark matter search constraint from Higgsino Bino mixing *Dark matter density can be adjusted by bin-slepton co-annihiliation

distribution is not sexy but OK

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SLIDE 9

SUSY at LHC Future

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SLIDE 10

BSM search in Future

High Luminosity is possible but No large energy increase for a moment. Significance is expressed at S/√( B + (δ B)^2 ) where δB is systematical error of the background clean channel extend with

  • luminosity. → Theoretical error

will reduce drastically at NNLO New method which can reduce background might also be useful.

100 TeV, 30 ab-1 100 TeV, 3 ab-1 14 TeV, 3 ab-1

500 1000 1500 2000 1 2 3 4 5 6 Mc @GeVD Significance Monojet

1% syst 5% syst

Figure 2. Reach of monojet searches.

I am going to talk about application of quark/gluon separation Cirelli et al ‘14

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SLIDE 11

What we may expect ex： gluino→ qq X

quark and gluon initiated jet are different: In parton shower, quark split into hard quark and soft gluon and gluon split into two gluon more equally. ME level pp-> gluino gluino-> 4q +missing: background Z+jets more gluons.

− Process f j1

q

f j2

q

f j3

q

f j4

q

˜ g˜ g+jets 0.92 0.87 0.77 0.64 Z+jets 0.64 0.55 0.27 0.16

(Mgluino, Mchi) =(1750 GeV,750GeV ) Meff> 1.8TeV

(we have checked Matrix level ISR generation is not necessary for this level of compressed spectrum

contamination of ISR especially compressed spectrum background also contains quark especially for the first jet. (Fraction is calculated following parton shower history)

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SLIDE 12

experimental data

recent experimental study in data driven approach.

  • γ j or Z j: jet is more likely to be quark
  • 2j event: Low pt: dominated by gluon jet, High pt quark

and gluon jet

Quark-Gluon Likelihood Discriminant

0.2 0.4 0.6 0.8 1

Normalized To Unity

0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

< 50 GeV

T

40 < p Quark Jets Gluon Jets

= 8 TeV s CMS Simulation Preliminary,

| < 2 η |

Gluon Jet Rejection

0.2 0.4 0.6 0.8 1

Quark Jet Efficiency

0.2 0.4 0.6 0.8 1

Quark-Gluon LD < 50 GeV

T

| < 2, 40 < p η | < 100 GeV

T

| < 2, 80 < p η | < 50 GeV

T

| < 4.7, 40 < p η 3 < |

= 8 TeV s CMS Simulation Preliminary,

Discriminant ( BDT score)

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SLIDE 13

What is discriminant

wtrk = P

trk∈jet pT,trk∆Rtrk,jet

P

trk∈jet pT,trk

ntrk = X

trk∈jet wcalo = P

const∈jet pT,const∆Rconst,jet

P

const∈jet pT,const

Cβ = P

i, j ∈jet ET,iET, j(∆Ri, j)β

⇣P

i∈jet ET,i

⌘2

Quark-Gluon Likelihood Discriminant

0.2 0.4 0.6 0.8 1

Normalized To Unity

0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

< 50 GeV

T

40 < p Quark Jets Gluon Jets = 8 TeV s CMS Simulation Preliminary, | < 2 η |

Gluon Jet Rejection

0.2 0.4 0.6 0.8 1

Quark Jet Efficiency

0.2 0.4 0.6 0.8 1

Quark-Gluon LD < 50 GeV

T

| < 2, 40 < p η | < 100 GeV

T

| < 2, 80 < p η | < 50 GeV

T

| < 4.7, 40 < p η 3 < | = 8 TeV s CMS Simulation Preliminary,

Preliminary Preliminary trk w Preliminary Preliminary 1/Events 0.02 0.04 0.06 0.08 0.1 0.12 0.14 Light Quarks trk w 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 1/Events 0.02 0.04 0.06 0.08 0.1 0.12 0.14 Gluons Extracted Herwig++ Pythia 8 ATLAS Preliminary
  • 1
= 8 TeV 20.3 fb s | < 0.8 η < 120 GeV, | T 90 GeV < P

……….. build a function which give gluon jet ~0 an quark~1 This function depend

  • n method you use to

build the function ROC experimentally different soft physics re-sum needed

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SLIDE 14

(GeV)

T

Jet P 50 100 150 200 250 300 350 400

Fraction of Events

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Dijet Pythia 8 Herwig++ Gluons Light Quarks Charms Bottoms

ATLASPreliminary = 8 TeV s Simulation, | < 0.8 η | (GeV)

T

Jet P 50 100 150 200 250 300 350 400

Fraction of Events

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Dijet Pythia 8 Herwig++ Gluons Light Quarks Charms Bottoms

ATLASPreliminary = 8 TeV s Simulation, | < 2.1 η 1.2 < | (GeV)

T

Jet P 50 100 150 200 250 300 350 400

Fraction of Events

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

+jet γ Pythia 8 Herwig++ Gluons Charms Bottoms

ATLASPreliminary = 8 TeV s Simulation, | < 0.8 η | (GeV)

T

Jet P 50 100 150 200 250 300 350 400

Fraction of Events

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

+jet γ Pythia 8 Herwig++ Gluons Charms Bottoms

ATLASPreliminary = 8 TeV s Simulation, | < 2.1 η 1.2 < |

Fraction of quark gluon jet in MC

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SLIDE 15

(GeV)

T

Jet P 100 200 300 400 500

>

trk

<w

0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Extracted Pythia 8 Herwig++ Gluons Light Quarks

ATLAS Preliminary s = 8 TeV 20.3 fb-1 |η| < 0.8

(GeV)

T

Jet P

100 200 300 400 500

Simulation Extracted

0.8 1 1.2

(GeV)

T

Jet P 100 200 300 400 500

>

calo

<w

0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Extracted Pythia 8 Herwig++ Gluons Light Quarks

ATLAS Preliminary s = 8 TeV 20.3 fb-1 |η| < 0.8

(GeV)

T

Jet P

100 200 300 400 500

Simulation Extracted

0.8 1 1.2

(GeV)

T

Jet P 100 200 300 400 500

>

trk

<w

0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Extracted Pythia 8 Herwig++ Gluons Light Quarks

ATLAS Preliminary s = 8 TeV 20.3 fb-1 1.2 < |η| < 2.1

(GeV)

T

Jet P

100 200 300 400 500

Simulation Extracted

0.8 1 1.2

(GeV)

T

Jet P 100 200 300 400 500

>

calo

<w

0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Extracted Pythia 8 Herwig++ Gluons Light Quarks

ATLAS Preliminary s = 8 TeV 20.3 fb-1 1.2 < |η| < 2.1

(GeV)

T

Jet P

100 200 300 400 500

Simulation Extracted

0.8 1 1.2

Figure 5: Means of extracted templates for wtrk (left) and wcalo (right) comparing data (solid line), P (dotted line) and Herwig++ (dashed line). The top plots show the distribution for |η| < 0.8, the bottom plots are for 1.2 < |η| < 2.1. The bottom panel of each plot shows the ratio of the P and Herwig++ distributions to the extracted templates. The last pT bin in all plots includes overflow events.

distribution of basic parameter (Pythia8 and Herwig++) compared with dat

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SLIDE 16

(GeV)

T

Jet P 100 200 300 400 500

>

calo

<w

0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Extracted Validation Gluons Light Quarks

ATLAS Preliminary s = 8 TeV 20.3 fb-1 |η| < 0.8

(GeV)

T

Jet P

100 200 300 400 500

Extracted Validation

0.8 1 1.2

(GeV)

T

Jet P 100 200 300 400 500

>

calo

<w

0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Extracted Validation Gluons Light Quarks

ATLAS Preliminary s = 8 TeV 20.3 fb-1 1.2 < |η| < 2.1

(GeV)

T

Jet P

100 200 300 400 500

Extracted Validation

0.8 1 1.2

(GeV)

T

Jet P 100 200 300 400 500

>

trk

<n

2 4 6 8 10 12 14 16 18 20

Extracted Validation Gluons Light Quarks

ATLAS Preliminary s = 8 TeV 20.3 fb-1 |η| < 0.8

(GeV)

T

Jet P

100 200 300 400 500

Extracted Validation

0.8 1 1.2

(GeV)

T

Jet P 100 200 300 400 500

>

trk

<n

2 4 6 8 10 12 14 16 18 20

Extracted Validation Gluons Light Quarks

ATLAS Preliminary s = 8 TeV 20.3 fb-1 1.2 < |η| < 2.1

(GeV)

T

Jet P

100 200 300 400 500

Extracted Validation

0.8 1 1.2

Figure 7: Comparison between the means of discriminating variables as a function of pT. Templates were extracted using dijet and Z+jet samples in 25 GeV< pT < 40 GeV, all three samples in 40 GeV< pT < 90 GeV and dijet and γ+jet samples for pT > 90 GeV. The leading jet has |η| < 0.8 (left) or 1.2 < |η| < 2.1 (right). The last pT bin in all plots includes overflow events.

consistency among the sample (note agreement of av is not enough)

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SLIDE 17

Quark-Gluon Likelihood Discriminant

0.2 0.4 0.6 0.8 1

Events / (0.04)

1000 2000 3000 4000 5000 6000

Z+Jets Data Quark Gluon Unmatched+PU | < 2 η | < 50 GeV T 40 < p = 8 TeV s at
  • 1
CMS Preliminary, L = 18.3 fb

Quark-Gluon Likelihood Discriminant

0.2 0.4 0.6 0.8 1

Events / (0.04)

1000 2000 3000 4000 5000

Z+Jets Data Quark Gluon Unmatched+PU | < 2 η | < 100 GeV T 80 < p = 8 TeV s at
  • 1
CMS Preliminary, L = 18.3 fb

Quark-Gluon Likelihood Discriminant

0.2 0.4 0.6 0.8 1

Events / (0.04)

50 100 150 200 250 300

Z+Jets Data Quark Gluon Unmatched+PU | < 5 η 3 < | < 50 GeV T 40 < p = 8 TeV s at
  • 1
CMS Preliminary, L = 18.3 fb

Quark-Gluon Likelihood Discriminant

0.2 0.4 0.6 0.8 1

Events / (0.04)

1000 2000 3000 4000 5000 6000 7000

DiJets Data Quark Gluon Unmatched+PU | < 2 η | < 50 GeV T 40 < p = 8 TeV s at
  • 1
CMS Preliminary, L = 13.1 nb

Quark-Gluon Likelihood Discriminant

0.2 0.4 0.6 0.8 1

Events / (0.04)

200 400 600 800 1000 1200

DiJets Data Quark Gluon Unmatched+PU | < 2 η | < 100 GeV T 80 < p = 8 TeV s at
  • 1
CMS Preliminary, L = 13.1 nb

Quark-Gluon Likelihood Discriminant

0.2 0.4 0.6 0.8 1

Events / (0.04)

100 200 300 400 500 600 700 800 900

DiJets Data Quark Gluon Unmatched+PU | < 5 η 3 < | < 50 GeV T 40 < p = 8 TeV s at
  • 1
CMS Preliminary, L = 13.1 nb

Figure 3: Data-MC comparison for the quark-gluon discriminant in Z+jets (top) and dijet (bot- tom) events for jets in the central region (40 < pT < 50 GeV to the left, 80 < pT < 100 GeV in the center) and in the forward region with 40 < pT < 50 GeV (right). The data (black markers) are compared to the MADGRAPH/PYTHIA simulation, on which the different components are shown: quarks (blue), gluon (red) and unmatched/pileup (grey).

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SLIDE 18

Z+q and Z+g (instead of di-jet) pT dependent profile of C1, mj/pT, nch)

Delphes3 B(C1, mj/pt,nch, pT) 2 gluino -> 4j +missing Z+3j (not Z+4j matched) Delphes3 & B ROOT, TMVA(BDT) TMVA with ETmiss, Meff pT,B up to 4th jet (4th jet is PS)

scale Z+3j to reproduce 13TeV total background (Z+jets, W+jets, tt )

use ROC to find bast S/sqrt(B+(delB)^2)

Checking if this is useful for BSM (gluino search )

Bhattacherjee, Mukhopadhyay, Nojiri, Sakaki, Webber

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SLIDE 19

ROC curve(gluino 2TeV LSP 1TeV)

  • / (# +)

++ + +

  • +
  • ℒ= -

=

  • (

∼χ ∼

  • )=()
  • / (# +)

++ + +

  • +
  • ℒ= -

=

  • (

∼χ ∼

  • )=()

Gain by quark gluon separation: No new kinematical cut (no new systematics by reducing phase space out) factor 3 gain over background Worse in Herwig++

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SLIDE 20
  • Fig. 2

0.2 0.4 0.6 0.8 1.0 1 10 100 1000 104

eS

1 eB ET

miss, meff, pT 1, pT 2, pT 3, pT 4, B1, B2, B3, B4

ET

miss, meff, pT 1, pT 2, pT 3, pT 4

ET

miss, meff, B1, B2, B3, B4

ET

miss, meff, pT 3, pT 4, B3, B4

ET

miss, meff, pT 3, pT 4

ET

miss, meff, B3, B4

ET

1, pT 2, pT 3, pT 4

B1, B2, B3, B4 ET

miss, meff

meff

ET

miss

HT

> 10 GeV1ê2

ET

miss

HT

> 10 GeV1ê2 & meff > 2.5 TeV

ET

miss

HT

> 10 GeV1ê2 & meff > 3.0 TeV

ET

miss

HT

> 10 GeV1ê2 & meff > 3.4 TeV

using (pT3, B3) and (pT4, B4) give about same results using pT_i (i=1,4) list of discriminant consistent with cut based results

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SLIDE 21
  • ∼ []

χ

∼

  • []

++ +

  • ℒ= -

= % δ=δ=δ=%

contour of maxBDT (S/√(B+(ΣδB)^2) =2 not much improvement ISR is important here max (S/√(B+(ΣδB)^2) =2 too small statistics anyway(next side)

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SLIDE 22

generator dependence + statistics

  • ∼ []

χ

∼

  • []

++ () ++ () () () () ()

ℒ= - = % δ=δ=δ=%

Systematics added namely we use 30%

(7.5, 8.1)

(7.5, 8.2)

(12,15)

contour of maxBDT (S/√(B+(ΣδB)^2) =2 (S/√(B+(ΣδB)^2) =2

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SLIDE 23

conclusion

Current excess: Just wait For future: we need systematic control NNLO, jet substructure ( boost object, quark gluon separation)

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SLIDE 24

Backups

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SLIDE 25

Meff cut

  • Fig. 2:

eV eV eV eV L eV 700

We apply different Meff cut for each parameter region