Fermionic Top Partners at 100 TeV Lian-Tao Wang University of - - PowerPoint PPT Presentation

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Fermionic Top Partners at 100 TeV Lian-Tao Wang University of Chicago Workshop on Physics at a 100 TeV Collider, SLAC, April 23, 2014 Wednesday, April 23, 14 Why top partner 100 TeV - Understanding EWSB requires going beyond LHC. - Top

slide-1
SLIDE 1

Fermionic Top Partners at 100 TeV

Lian-Tao Wang University of Chicago

Workshop on Physics at a 100 TeV Collider, SLAC, April 23, 2014

Wednesday, April 23, 14

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SLIDE 2

Why top partner ⇔ 100 TeV

  • Understanding EWSB requires going beyond LHC.
  • Top quark plays a significant role in EWSB. It’

s a main source of its puzzles.

  • Therefore, as part of many possible “answers”,

top partners.

  • More than just a new particle. We will learn

something from the search of top partner!

Wednesday, April 23, 14

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SLIDE 3

The top partner in everybody’ s mind

  • SUSY stop.
  • Talk on SUSY simplified models later in this

workshop

) = h0 t + h0 ˜ t + h0 ˜ t

Wednesday, April 23, 14

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SLIDE 4

This talk: fermionic top partner T’

  • Plays a qualitatively similar role in non-SUSY

models.

  • Not as well studied as the stop.
  • I will

Survey of possible signals. Make some guestimate for 100 TeV . (scaling up)

  • Hopefully serves as a todo list.

(for me, 8 yrs ago)

Wednesday, April 23, 14

slide-5
SLIDE 5

Why fermionic T’

  • Unlike stop, T’ comes in larger varieties.

New kinds of signals.

  • In many cases, MT’ “setting the scale” for the

Higgs potential.

  • Leading indicator of fine-tuning ∝ !MT’2

No severe tuning: MT’ = 600-ish GeV .

  • Strong correlation with Higgs mass in large class
  • f composite Higgs models.

Panico, Wulzer et al, 2012

Wednesday, April 23, 14

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SLIDE 6

Stop like T’

  • T’ can cancel top quadratic divergence, implemented

with some symmetry in couplings (Little Higgs Model).

  • Really stop-like, safe from tree-level corrections.

Z2 parity, similar to R-parity. For example, T-parity. Stable LTP, T’→t + LTP.

T T c h h h h

h0 t

Wednesday, April 23, 14

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SLIDE 7

Stop like T’ search at hadron collider

  • Larger production rate than the stop.
  • Studied quite a bit back then, as a “counter

example” of SUSY .

[GeV]

T

m 600 800 1000 1200 1400 Production cross-section [pb]

  • 3

10

  • 2

10

  • 1

10 1 10

2

10

3

10

MadGraph5

14 TeV Fermion Scalar QCD top ttZ [GeV]

T

m 2000 4000 6000 8000 Production cross-section [pb]

  • 4

10

  • 3

10

  • 2

10

  • 1

10 1 10

2

10

3

10

4

10

5

10

MadGraph5

100 TeV Fermion Scalar QCD top ttZ

Meade and Reece, Han, Mabhubani, Walker and LTW, etc

Wednesday, April 23, 14

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SLIDE 8

Reach

  • pp → T’T’, T’→t + LTP
  • Crude estimate. Scaled up from the stop result

by matching the signal rate and mass gap.

[TeV]

T

m 2 4 6 8 [TeV]

χ

m 1 2 3 4 5 6 7 8 9

  • 1

MadGraph5, 100 TeV, 140 PU, 3000 fb

discovery σ 5 Scalar Fermion [TeV]

T

m 2 4 6 8 [TeV]

χ

m 1 2 3 4 5 6 7 8 9

  • 1

MadGraph5, 100 TeV, 140 PU, 3000 fb

95% CL exclusion Scalar Fermion

Stop result from Snowmass report, 1311.0299

Wednesday, April 23, 14

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SLIDE 9

We can hide T’ very well.

  • Top partner not colored.

Twin Higgs. General Higgs portal.

  • Study to be done!

Reach probably very limited, 100s GeV (my guess)

T ′ T ′ h

T ′ T ′ h h

Chacko, Harnik, et al

Wednesday, April 23, 14

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SLIDE 10

Anything else we can do?

  • A case for precision Higgs measurement.

200 400 600 800 0.1 0.2 0.5 1.0 2.0 5.0 10.0 mf @GeVD dsZh @%D

dsZh> 2.5% dsZh> 0.5%

nf=1 nf=6

T’

Craig, Englert, McCullough, 2013 Wavefunction renormalization Induce shift in Higgs coupling.

Wednesday, April 23, 14

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SLIDE 11

More generic top partners

  • Similar quantum number as top. Mixes with top.
  • Probably not chiral 4th generation.
  • Almost “everywhere”.

Playing crucial role in the electroweak symmetry breaking in composite Higgs modes. Also in other places, such as help raising Higgs mass in SUSY .

Wednesday, April 23, 14

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SLIDE 12

Minimal model

  • Singlet top partner.
  • Branching ratio for large MT’

0.5 BR(T’→Wb) = BR(T’→Zt) = BR(T’→ht). L = MT ¯ T 0T 0 + cythtLT 0 + ythtLtR + h.c.

Wednesday, April 23, 14

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SLIDE 13

Single vs pair production

b X V

500 600 700 800 900 1000 0.1 1 10 100 1000

MT

⇥ GeV⇥

fb ⇥

+ . . . T ′ T ′

De Simone, Matsedonskyi, Rattazzi, Wulzer, 1211.5663 bT’ T’T’ tT’ Importance of the single production have been emphasized For example: Perelstein, Peskin, Pierce, 2003; Han, Logan, McElrath, LTW, 2003

Wednesday, April 23, 14

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SLIDE 14

LHC vs 100 TeV (pair production)

  • Scaling up using parton luminosity.
  • Possible improvement: single production, ...

95% exclusion projection for mT comparing analysis and parton luminosity scaling using arXiv:1309.0026 (Bhattacharya, et al.) with 3000 fb−1 PDF set 14 TeV 33 TeV 100 TeV 33 TeV 100 TeV MSTW2008nnlo68cl 1.8 TeV 3.4 TeV 7.4 TeV 3.4 TeV 7.4 TeV NNPDF23 nnlo as 0018 1.8 TeV 3.4 TeV 7.5 TeV 3.4 TeV 7.5 TeV CT10nlo 1.8 TeV 3.4 TeV 7.3 TeV 3.4 TeV 7.4 TeV 5σ discovery projection for mT comparing analysis and parton luminosity scaling using arXiv:1309.0026 (Bhattacharya, et al.) with 3000 fb−1 PDF set 14 TeV 33 TeV 100 TeV 33 TeV 100 TeV MSTW2008nnlo68cl 1.5 TeV 2.8 TeV 5.8 TeV 2.6 TeV 5.5 TeV NNPDF23 nnlo as 0018 1.5 TeV 2.8 TeV 5.9 TeV 2.6 TeV 5.5 TeV CT10nlo 1.5 TeV 2.7 TeV 5.8 TeV 2.6 TeV 5.4 TeV

Salam and Weiler http://collider-reach.web.cern.ch/collider-reach/

Wednesday, April 23, 14

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SLIDE 15

Variation on the BR.

= UHuq3U + ′

UHuQu3 − DHdQd3,

Extended top partner sector. U: singlet, Q: doublet

e.g., S. Martin, 0910.2732

300 400 500 600 700 800

mt’ [GeV]

0.2 0.4 0.6 0.8 1

t’ Branching Ratios

ht Wb Zt

300 400 500 600 700 800

mt’ [GeV]

0.2 0.4 0.6 0.8 1

t’ Branching Ratios

ht Wb Zt

𝟅U ¡ ¡dominated 𝟅’U ¡ ¡dominated

Wednesday, April 23, 14

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SLIDE 16

Current LHC searches (general BR)

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 700 GeV

T

m

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 750 GeV

T

m

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 800 GeV

T

m

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 850 GeV

T

m

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 500 GeV

T

m

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 550 GeV

T

m

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 600 GeV

T

m

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 650 GeV

T

m

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 350 GeV

T

m

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 400 GeV

T

m

0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Forbidden

= 450 GeV

T

m ATLAS Preliminary

Status: Lepton-Photon 2013

95% CL exp. excl.

95% CL obs. excl.

= 8 TeV, s

  • 1

L dt = 14.3 fb

∫

SU(2) singlet SU(2) (T,B) doub.

] ATLAS-CONF-2013-018 Ht+X [ ] ATLAS-CONF-2013-051 Same-Sign [ ] ATLAS-CONF-2013-056 Zb/t+X [ ] ATLAS-CONF-2013-060 Wb+X [

Wb) → BR(T Ht) → BR(T

Reasonable coverage up to 650 GeV. On the “border” of getting into more tuned region

Wednesday, April 23, 14

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SLIDE 17

Going up to 100 TeV

  • Again, room for improvement by using single

production, boosted technique, etc.

Wednesday, April 23, 14

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SLIDE 18

Top partner in a multiplet.

  • BR(X2/3 → Zt)≈ BR(X2/3 → ht)≈50%.

XbW coupling suppressed.

∆m2 ∼ y2v2 ∆m2 = 0 ∆m2 ∼ y2f2 B T t X2/3 X5/3

Coset SO(5)/SO(4). Top partner in 4 of SO(4)

For review, see De Simone, Matsedonskyi, Rattazzi, Wulzer, 1211.5663

Wednesday, April 23, 14

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SLIDE 19

Single production

  • Single production dominated by t+X channel.
  • Signal, X decay + extra top.

t X V

400 500 600 700 800 900 1000 1 5 10 50 100 500 1000

MX2⇤3 GeV⇥ Σ fb⇥

De Simone, Matsedonskyi, Rattazzi, Wulzer, 1211.5663

Wednesday, April 23, 14

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SLIDE 20

X5/3: new exotic top partner.

  • Both pair production and single production t+X.
  • Multi-top + W(s) final state.

Same sign dilepton, trilepton, etc.

X5/3 t+ W +

100%

Wednesday, April 23, 14

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SLIDE 21

X5/3: new exotic top partner.

  • Both pair production and single production t+X.
  • Multi-top + W(s) final state.

Same sign dilepton, trilepton, etc.

X5/3 t+ W +

100%

95% exclusion projection for mT (Q = +5/3) with 3000 fb−1 comparing analysis and parton luminosity scaling using arXiv:1312.2391 (CMS, 19.5 fb−1) PDF set 8 TeV 14 TeV 33 TeV 100 TeV MSTW2008nnlo68cl 0.8 TeV 2.2 TeV 4.2 TeV 9.6 TeV NNPDF23 nnlo as 0018 0.8 TeV 2.2 TeV 4.2 TeV 9.6 TeV CT10nlo 0.8 TeV 2.2 TeV 4.3 TeV 9.6 TeV

Scaling up pair production search

Wednesday, April 23, 14

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SLIDE 22

Seeing everything at the LHC 14?

Wednesday, April 23, 14

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SLIDE 23

Seeing everything at the LHC 14?

  • That would be great.

Wednesday, April 23, 14

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SLIDE 24

Seeing everything at the LHC 14?

  • That would be great.
  • But, unlikely.

Wednesday, April 23, 14

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SLIDE 25

Seeing everything at the LHC 14?

  • That would be great.
  • But, unlikely.
  • Top partner usually not the full story.

Cancellation at 1-loop, part of full composite model...

Wednesday, April 23, 14

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SLIDE 26

Seeing everything at the LHC 14?

  • That would be great.
  • But, unlikely.
  • Top partner usually not the full story.

Cancellation at 1-loop, part of full composite model... Light top partner “As natural as possible” the rest

O(TeV)

Wednesday, April 23, 14

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SLIDE 27

Seeing everything at the LHC 14?

  • That would be great.
  • But, unlikely.
  • Top partner usually not the full story.

Cancellation at 1-loop, part of full composite model... Light top partner “As natural as possible” the rest

O(TeV)

Hard to see the full spectrum with the increase of reach from 8 to 14 TeV

Wednesday, April 23, 14

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SLIDE 28

For example

  • Maybe we can be very lucky.
  • Otherwise, need to go beyond LHC.

∆m2 ∼ y2v2 ∆m2 = 0 ∆m2 ∼ y2f2 B T t X2/3 X5/3

f≈TeV

current limit ≈ 700 GeV LHC 14 can discover T’ about 1.5 TeV

Wednesday, April 23, 14

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SLIDE 29

Measuring properties.

  • Coupling to Higgs? SUSY or not? ....
  • Difficult. For sure, need a lot of statistics.
  • For given mass, rate ∝ !(Ecollider)4-6

[TeV] s 10

2

10 Cross-section [pb]

  • 4

10

  • 3

10

  • 2

10

  • 1

10 1 10

2

10

MadGraph5

pair production T T = 1.2 TeV

T

m

Wednesday, April 23, 14

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SLIDE 30

Conclusion.

  • Fermionic top partner can play a crucial role in

electroweak symmetry breaking.

Limit or discovery can dramatically change our mind.

  • Like stop, it’

s the most prominent indicator of naturalness.

  • Going to 100 TeV significantly improve the reach
  • f top partner, to 8-9 TeV

.

  • Richer signal than the SUSY stop. More challenge

and opportunities.

Wednesday, April 23, 14

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SLIDE 31

Conclusions

  • Looking forward to new detailed studies.

Single production. Boosted object id. Top PDF . Such as in t+X associated production. ...

Wednesday, April 23, 14