More 2HDM checks Nick Amin October 27, 2018 Overview Goal is to - - PowerPoint PPT Presentation

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More 2HDM checks Nick Amin October 27, 2018 Overview Goal is to - - PowerPoint PPT Presentation

Jan 18, 2023 367 likes •499 views

More 2HDM checks Nick Amin October 27, 2018 Overview Goal is to compare 2HDM results from CMS + ATLAS +N. Craig's paper results on equal footing And also I have some misc plots/dumps 2 2 ) [pb] ATLAS ATLAS tan tan Excluded

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SLIDE 1

More 2HDM checks

Nick Amin October 27, 2018

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SLIDE 2

⚫ Goal is to compare 2HDM results from CMS + ATLAS +N.

Craig's paper results on equal footing

⚫ And also I have some misc plots/dumps

Overview

2

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 [TeV]

H

m

3 −

10

2 −

10

1 −

10 1 ) [pb] t t → BR(H × H) t t → (pp σ

Theory (NNLO): = 0.3 β tan = 0.5 β tan = 1.0 β tan Observed limit Expected limit σ 1 ± σ 2 ± All limits at 95% C.L.
  • 1

= 13 TeV, 36.1 fb s SS dilepton / trilepton + b-jets t t → 2HDM type-II H ATLAS [GeV]

H

m 400 500 600 700 800 900 1000 β tan 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Excluded region Observed Expected σ 1 ± σ 2 ± All limits at 95% C.L.

ATLAS

  • 1

= 13 TeV, 36.1 fb s SS dilepton / trilepton + b-jets t t → 2HDM type-II H

(b)

[GeV]

H/A

m 400 500 600 700 800 900 1000 β tan 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Excluded region Observed Expected σ 1 ± σ 2 ± All limits at 95% C.L.

ATLAS

  • 1

= 13 TeV, 36.1 fb s SS dilepton / trilepton + b-jets t t → 2HDM type-II A/H

(GeV)

H

m

350 400 450 500 550

) (fb) t t → BR(H × ,tW,tq)+H) t (t → (pp σ

20 40 60 80 100 120 140 160

95% CL Observed scalar theory σ experiment σ 2 ± 1 and ± 95% CL Expected

(13 TeV)

  • 1

35.9 fb

CMS

(a) (GeV)

A

m

350 400 450 500 550

) (fb) t t → BR(A × ,tW,tq)+A) t (t → (pp σ

20 40 60 80 100 120 140 160

95% CL Observed pseudoscalar theory σ experiment σ 2 ± 1 and ± 95% CL Expected

(13 TeV)

  • 1

35.9 fb

CMS

(b)

Figure 8: Limits at 95% CL on the production cross section for heavy scalar (a) and pseudoscalar

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SLIDE 3

⚫ Using 2HDMtII_NLO model out of the box with the proc card below

  • Default (dynamical) MG factorization/renormalization scales, nn23lo1 PDF
  • Using 5FS via define p = p b b~

⚫ Scan over particle mass, tan(𝛾), sin(𝛾-𝛽) for ttX, ttX+1jet, tXW, tXq for X=h2 (H), h3 (A) ⚫ Important note:

  • Cannot decay via "pp > t t~ h2, h2 > t t~" since the widths for h2 and h3 are

set to 1.0 by default. Without properly recalculating the widths as a function of mass/other parameters, the output cross-sections are meaningless.

  • This means I’m just calculating the production cross-section and can’t decay the

h2/h3 in MG, but the numbers will then be directly comparable with values for 𝜏(pp→tt̅H/A)×BR(H/A→tt̅).

Technical Details

3

set nb_core 10 set automatic_html_opening False import model 2HDMtII_NLO define tpm = t t~ define wpm = w+ w- define p = p b b~ define j = g u c d s u~ c~ d~ s~ b b~ define qpm = u c d s u~ c~ d~ s~ b b~ generate p p > tpm tpm h2

  • utput output_scan_v1/thw -nojpeg

launch set param_card mass 25 125 # h1 set param_card frblock 1 scan:[0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,1.1,1.2,1.4,1.6,1.8,2.0,2.2,2.5,3.0,3.5,4.0] set param_card frblock 2 1.0 # sinbma set param_card mass 35 scan:[350,400,450,500,550,600,650,700,750,800,850,900,1000]

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SLIDE 4 ⚫ Take ATLAS cross sections for 2HDM at tan𝛾=0.3,0.5,1.0 assuming sin(𝛾-𝛽)=1

for alignment limit (solid lines on right) and compare against what I get from NLO MG (dotted lines of the same color)

  • This is only considering tt̅H
  • My calculated ones are ~15-20% lower, though the trend is identical

between the two

  • For reference, dashed purple line on right is what we used in 2016 for tt̅H

→ agreement with dashed blue line suggests we have been using tan𝛾=1

⚫ Possible differences
  • ATLAS writes "NNLO" on their plot while I’m using NLO
  • ATLAS could also not be using sin(𝛾-𝛽)=1 exactly
  • Different PDFs/scales?
  • Turning a log scale plot into x,y pairs

Reproducing ATLAS xsecs

4

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 [TeV]

H

m

3 −

10

2 −

10

1 −

10 1 ) [pb] t t → BR(H × H) t t → (pp σ

Theory (NNLO): = 0.3 β tan = 0.5 β tan = 1.0 β tan Observed limit Expected limit σ 1 ± σ 2 ± All limits at 95% C.L.

  • 1

= 13 TeV, 36.1 fb s SS dilepton / trilepton + b-jets t t → 2HDM type-II H ATLAS

log linear

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SLIDE 5

⚫ As a less rigorous check of what our tan𝛾 was in 2016, make use of some numerology ⚫ Focus on the m(H/A)=400 GeV point only

  • ATLAS only considers tt̅H/A, while CMS considers the two separately but adds (tt̅+tW+tq)H/A
  • Fortunately this works out nicely if I use the 2016 cross-sections
  • ttH+ttA is ~40fb
  • (tt̅+tW+tq)A is ~40fb
  • So I should be able to compare the expected exclusion points (★) which correspond to

the same cross-section

  • (Well, the CMS one is 410GeV, not 400, but it’s close still)
  • Again, this seems to indicate we had tan𝛾~1 in 2016

Confirming our tan𝛾

5

[GeV]

H/A

m 400 500 600 700 800 900 1000 β tan 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Excluded region Observed Expected σ 1 ± σ 2 ± All limits at 95% C.L.

ATLAS

  • 1

= 13 TeV, 36.1 fb s SS dilepton / trilepton + b-jets t t → 2HDM type-II A/H

550

(GeV)

A

m

350 400 450 500 550

) (fb) t t → BR(A × ,tW,tq)+A) t (t → (pp σ

20 40 60 80 100 120 140 160

95% CL Observed

pseudoscalar theory

σ

experiment

σ 2 ± 1 and ± 95% CL Expected

(13 TeV)

  • 1

35.9 fb

CMS

(b)

cross section for heavy scalar (a) and pseudoscalar

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SLIDE 6

⚫ Plot our new NLO calculated cross-sections in solid lines

for ttH, ttA, tHq, tAq, tHW, tAW with their 2016 counterparts

🙃 ttH/A agree within 5-7% ☹ tHq/tAq scale differently ☹ tHW/tAW xsecs differ by an order of magnitude

Other processes

6 log linear

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SLIDE 7

⚫ Add another jet to ttH

  • define j = g u c d s u~ c~ d~ s~ b b~
  • generate p p > t t~ h2
  • add process p p > t t~ j h2

☹ xsecs increase by more than a factor of 2 (compare with s4)

Adding an extra parton to ttH

7

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SLIDE 8

⚫ How much different are xsecs for slightly

lower sin(𝛾-𝛽)<1 (approximate alignment limit)

  • For ttH with tan𝛾=1, using sin(𝛾-

𝛽)=0.999/0.99/0.9 gives 10/20/80% lower xsec

  • Small changes in s𝛾𝛽 can change

xsec by a lot

⚫ ttA xsec independent of sin(𝛾-𝛽), and

since the ttA xsec is a bit larger than ttA, this flattens out the dependence on sin(𝛾-𝛽) a little bit

sin(𝛾-𝛽)<1

8

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SLIDE 9

Other stuff

9

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SLIDE 10

⚫ Just for reference, plot 𝜏 [pb] vs tan𝛾 for a fixed m(H/A)

mass of 400 GeV

Cross-section vs tan𝛾

10 log linear

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SLIDE 11

⚫ 8TeV ATLAS analysis in https://arxiv.org/pdf/1707.06025.pdf uses H/A→tt̅ interference with regular tt̅ to set

2HDM limits

  • 2HDM, alignment limit, mH/mA considered separately and also mH=mA degenerate case
  • At mA=mH=550GeV, excludes tan𝛾<0.92 (1.1), expected (observed)
  • The ATLAS SS paper excludes tan𝛾<0.85 (0.6), expected (observed)

⚫ At higher masses (700+), SS has tighter exclusion than tt̅ interference analysis

Comparing with another ATLAS 2HDM exclusion

11

500 550 600 650 700 750 mA [GeV] 0.5 1.0 1.5 2.0 tanβ Obs.

  • Exp. ± 1σ/2σ

Signal Samples 500 550 600 650 700 750 mH [GeV] 500 550 600 650 700 750 mA = mH [GeV] √s = 8 TeV, 20.3 fb−1, all limits at 95% CL

Figure 3: The 95% CL observed and expected exclusion regions for the type-II 2HDM (µ = 1) considering only a pseudoscalar A (left), only a scalar H (middle), and the mass-degenerate scenario mA = mH (right). Blue points indicate parameter values at which signal samples are produced. Table 3: The 95% CL observed and expected exclusion limits on tan β for a type-II 2HDM in the alignment limit considering only a pseudoscalar A (left), only a scalar H (middle), and the mass-degenerate scenario mA = mH (right). A bar (–) indicates that no value of tan β ≥ 0.4 is excluded.

Mass mA mH mA = mH [GeV] tan β:

  • bs.

exp.

  • bs.

exp.

  • bs.

exp. 500 < 1.00 < 1.16 < 1.00 < 0.77 < 1.55 < 1.50 550 < 0.69 < 0.79 < 0.72 < 0.52 < 1.10 < 0.92 600 – < 0.59 < 0.73 – < 1.09 < 0.93 650 – – – – – < 0.62

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SLIDE 12

⚫ Not really relevant to 2HDM stuff, but I saw the plots in Nathaniel’s paper comparing

BDT and cut-based analyses for ttH→tttt

⚫ Lowest mass is 0.5TeV, close to SM tttt ⚫ Solid orange line (BDT) is at 1.05fb and dashed line (cut-based) is at 1.15 (~10% better)

  • Grows to 0.19fb vs 0.38fb (~50% better) at mass of 2TeV where presumably MET/

HT/Boostedness helps a lot

BDT vs cut-based

12

0.5 0.75 1 1.5 2 0.1 0.3 1 2 5

mA [TeV ] (ppH/Atttttt) [fb]

(a) pp → t¯ tH(A) → t¯ tt¯ t

0.5 0.75 1 1.5 2 0.1 0.3 1 2 5

mA [TeV ] (ppH/AtW±tttW±) [fb]

(b) pp → tWH(A) → tW ±t¯ t

Figure 10: (a) Model independent exclusion (orange) and discovery (green) limits at the 14 TeV LHC in the four-top channel. (b) Exclusion (orange) and discovery (green) limits in the three-top

  • channel. The dashed limits are derived with the cut based analysis presented in Section 4.2 while

the solid limits are derived with the BDT analysis presented in Section 4.3.