Resonance and VLQs @ HL-LHC Sadia Khalil University of Kansas On - - PowerPoint PPT Presentation

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Resonance and VLQs @ HL-LHC Sadia Khalil University of Kansas On - - PowerPoint PPT Presentation

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Resonance and VLQs @ HL-LHC Sadia Khalil University of Kansas On behalf of CMS Collaboration HE/HL LHC Workshop, Fermilab, USA; Apr 5, 2018 Outlook In this talk I will be summarizing the prospects and plans of discovering new physics that

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Resonance and VLQs @ HL-LHC

Sadia Khalil University of Kansas

On behalf of CMS Collaboration

HE/HL LHC Workshop, Fermilab, USA; Apr 5, 2018

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Outlook

2

  • In this talk I will be summarizing the prospects and plans of

discovering new physics that could show up as a heavy resonances at the HL-LHC with CMS experiment.

  • Z' → tt
  • W' → tb
  • W' → eν, 𝜐ν
  • LQ3 →𝜐 b
  • VBF di-Higgs→ 4b
  • Vector-like quarks: Single T →tH (l+jets)

Also see talk by Kerstin in Flavor BSM model this morning

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Z' → tt

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t t Z′

  • CMS published Z´ → tt searches distinguished by decay of W

(from t → Wb) in two channels

  • l+jets (B2G-15-002), all-hadronic (B2G-15-003)
  • Discriminating variable: M(tt) reconstructed from final states, and

total of six channels in both analyses are used

  • Projections for HL-LHC are performed using two scenarios
  • Same systematic uncertainties @13 TeV
  • Remove all systematic uncertainties
  • The realistic case should be in between since reduction in systematic uncertainties is

expected, e.g; QCD multijet background is derived from data and scales with L, ttbar x-section, jet energy scale and resolution, lepton ID efficiencies

CMS-PAS-FTR-16-005

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Z' → tt

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Projections of Z′ in 𝑚+jets and all-had @ 13 TeV

Z′ with NWA RS KK Gluon

Discovery reach in hadronic @ 13 TeV

Z′ with NWA RS KK Gluon

CMS-PAS-FTR-16-005

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Z' → tt

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  • CMS has plans to perform the study using full simulations with

HGCal upgraded detector

  • Combine the l+jets and all-hadronic channels
  • Adapt analysis strategy for Z´ masses above 4 TeV where off-

shell production becomes important

New Plans

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

W' → tb

  • A search that probes for W' when m(νR)>m(W’),

hence forbidding W' → lν decay

  • Projections using the baseline analysis at √s=13

TeV with 12.9 fb-1 data that excludes W' up to 2.67 TeV @ 95% CL (B2G-15-004, B2G-16-017)

  • Projection techniques
  • Events require high pT > 180 GeV isolated e/µ

with additional lepton veto, and AK4 jets with |𝜃| <2.4 with 1 or 2 b-jets

  • Discriminating variable: M(tb), such as pT >

(jet1 + jet2) > 350 GeV and pT (top) > 250 GeV

  • Background samples are simulated at 13 TeV

and xsec are scaled to 14 TeV

  • W´R signal MC is simulated at 13 TeV with

COMPHEP up to 4 TeV mass

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CMS-PAS-FTR-16-005

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

W' → tb

  • Two scenarios to extrapolate systematic uncertainties from 12.9 fb
  • 1 to 3000 fb
  • 1
  • 1. Leave systematics unchanged ⇒ scale by √L
  • 2. Reduce experimental uncertainties to few percent level, theory uncertainties

by factor 2 and top pT reweighing by 3

  • 3. No systematic uncertainty

7

CMS-PAS-FTR-16-005

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SLIDE 8

Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

W' → tb

  • The two uncertainty scenarios have small impact on projected

exclusion limit: 4(4.2) TeV for case 1(2)

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  • For masses beyond 4 TeV, where the off-shell part starts to

become important, the selection needs to be re-optimized

Discovery Scenario

CMS-PAS-FTR-16-005

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

W' → eν

  • Complementary to W´ → tb, the analysis was performed using Delphes

simulations assuming SSM W´

  • Final state consists of a high pT electron and ET

miss

  • Discriminator: Transverse mass of W´

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  • High luminosities are necessary to reach low couplings of the order 0.1 to

0.01 for a five sigma discovery. Is it worth to repeat with full sim?

CMS-PAS-EXO-14-007

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

W' → 𝜐ν

  • Non-universal gauge interaction model (NUGIM) suggest enhance

couplings to 3rd generation, where BR depends on the mixing angle cotθE

  • SU(2)l ⊗ SU(2)h → SU(2)SM ⊗ SU(2)extended
  • Plan to project the CMS Run2 analysis to HL-LHC

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New Plans

To be based on CMS-PAS-EXO-17-008

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

LQ3 → 𝜐b

Redo the analysis from existing Run 2 result

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New Plans

To be based on CMS-PAS-EXO-17-029

  • Model R2 ~ as described in Phys. Rept. 641 (2016)
  • Signal xsec and k-factor from theorist
  • Signals simulated in LO with MG
  • Sensitive to high-mass/ coupling region
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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

VBF HH→ bbbb

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  • Search for a massive spin-2 bulk

graviton decaying to160 two Higgs bosons.

  • VBF x-sec is the 2nd largest after gluon

fusion production

  • A 4-jet signal topology that will profit

from the forward HGCal regions and increased coverage in tracker and calorimeter

  • 2 boosted Higgs jets decay
  • 2 light forward VBF-jets with large Δη

and di-jet mass

New Plans

Work in progress

Based on CMS-PAS-B2G-16-026 arXiv:

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

VBF HH→ bbbb

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Work in progress

  • Signal MC is normalized to 1 fb-1 for better visualization

PU=0 PU=200 Challenge!

  • Large QCD multi-jet background
  • Evaluate Higgs mistag rate using an inclusive QCD MC

and apply to the events passing the VBF jets selection

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Single VLQ: T →tH (l+jets)

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t H W b

  • Models: qg→ Tbq (Ttq) with L (R) EWK couplings, where T → tH
  • Signal topology:
  • T → t H → (lνb) (bb) : single lepton + jets + Higgs candidate
  • Study sensitivity to the EWK couplings at HL-LHC attributed due to

luminosity, tracking in forward region, endcap extension, jet substructure tools, subjet b-tagging

  • Signal MC generated using MG+Pythia8 for T masses 1, 1.5, 2, 2.5,

and 3 TeV each using NWA (10 GeV)

  • Backgrounds: tt+jets, V+jets, single top and dibosons

W+ b g q b T q′

Z t g q t T q

CMS-PAS-FTR-16-005

Ttq, cR Tbq, cL

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SLIDE 15

Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Single VLQ: T →tH (l+jets)

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Event Selection:

  • Exactly one lepton (e/mu) with pt > 30 GeV, |η| < 4.0
  • Using PUPPI jet apply 2D isolation:
  • reject event if dR(l,j) > 0.4 and ΔpT,rel> 40 GeV, where ΔpT,rel is the relative pT of lepton w.r.t

the closest jet

  • ≥ 1 forward jet: 2.4 < |η| < 5.0, jet pT > 30 GeV
  • ≥ 3 central jets: |η| < 2.4; leading (sub-leading) jet pT > 200 (80) GeV
  • ≥ 1 b-jet with 70% tagging efficiency
  • ET

miss > 20 GeV

CMS-PAS-FTR-16-005

Higgs Tagging:

  • AK8 jets pT > 300 GeV, |η| < 2.4
  • N subjettiness: 𝜐21 < 0.6
  • 2 hard softdrop subjets
  • ΔR(l, H) > 1.0
  • 90 < softdrop mass < 160 GeV
  • No subjet b-tagging

Mass Reconstruction

  • Solve for neutrino pZ
  • Permute Higgs candidate with up to two AK4Jets and

minimize a 𝝍

2

  • Keep the results with ΔR(t,H) > 2
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SLIDE 16

Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Single VLQ: T →tH (l+jets)

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CMS-PAS-FTR-16-005

[GeV]

T,reco

M

500 1000 1500 2000 2500 3000 3500

Events/36 GeV

10

2

10

3

10

4

10

5

10

6

10

(14 TeV)

  • 1

3000 fb Delphes Simulation CMS tH → T

t t V+Jets single t Diboson Tbq, M(T) = 1 TeV Tbq, M(T) = 2 TeV Tbq, M(T) = 3 TeV Ttq, M(T) = 1 TeV Ttq, M(T) = 2 TeV Ttq, M(T) = 3 TeV

Tbq, cL Ttq, cR

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SLIDE 17

Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Single VLQ: T →tH (l+jets)

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New Plans

  • Using full simulation with phase 2 upgrade machine, perform the

analysis using for model qg→ Tbq with left EWK couplings

  • Signal topology:
  • T → t H → (lνb) (bb) : single lepton + jets + Higgs candidate
  • Main change
  • lepton identification using MVA, subjet b-tagging in H-tagging
  • Signal MC generated using MG+Pythia8 for T masses 1, 2 and 3

TeV each for

  • Widths = 10, 20, 30%
  • More realistic systematic uncertainties per CMS recommendations
  • Methodology will remain same, i.e, T mass reconstruction
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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018 18

  • Described prospects of discovering many new physics

models at LH-LHC that can show up as resonances

  • Z' → tt
  • W' → tb, eν, 𝜐ν
  • LQ3 →𝜐 b
  • VBF di-Higgs→ 4b
  • Single VLQ T →tH
  • Many of them are currently work in progress either as updates

to previous analyses or new analyses, all aiming for LHC Yellow Report

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Thank you!

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SLIDE 20
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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Z' → tt

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Discovery reach in 𝑚+jets @ 13 TeV

CMS-PAS-FTR-16-005

Z′ with NWA RS KK Gluon Z′ with NWA RS KK Gluon

Discovery reach in hadronic @ 13 TeV

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Sadia Khalil, HL/HE-LHC BSM workshop, Fermilab, USA, Apr 4-6, 2018

Single VLQ: T →tH (l+jets)

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Systematic Uncertainties