[PPT] - Precision Higgs Measurements at Higgs factories LianTao Wang PowerPoint Presentation

SLIDE 1

Precision Higgs Measurements at Higgs factories

LianTao Wang University of Chicago

ICTP . Sept. 8, 2016 A first glance beyond the energy frontier

SLIDE 2

Present

No “early” discovery.
Next?

24

Model ℓ, γ Jets† Emiss T

L dt[fb−1]

Limit Reference Extra dimensions Gauge bosons CI DM LQ Heavy quarks Excited fermions Other ADD GKK + g/q − ≥ 1 j Yes 3.2 n = 2 1604.07773 6.58 TeV MD ADD non-resonant ℓℓ 2 e, µ − − 20.3 n = 3 HLZ 1407.2410 4.7 TeV MS ADD QBH → ℓq 1 e, µ 1 j − 20.3 n = 6 1311.2006 5.2 TeV Mth ADD QBH − 2 j − 15.7 n = 6 ATLAS-CONF-2016-069 8.7 TeV Mth ADD BH high pT ≥ 1 e, µ ≥ 2 j − 3.2 n = 6, MD = 3 TeV, rot BH 1606.02265 8.2 TeV Mth ADD BH multijet − ≥ 3 j − 3.6 n = 6, MD = 3 TeV, rot BH 1512.02586 9.55 TeV Mth RS1 GKK → ℓℓ 2 e, µ − − 20.3 k/MPl = 0.1 1405.4123 2.68 TeV GKK mass RS1 GKK → γγ 2 γ − − 3.2 k/MPl = 0.1 1606.03833 3.2 TeV GKK mass Bulk RS GKK → WW → qqℓν 1 e, µ 1 J Yes 13.2 k/MPl = 1.0 ATLAS-CONF-2016-062 1.24 TeV GKK mass Bulk RS GKK → HH → bbbb − 4 b − 13.3 k/MPl = 1.0 ATLAS-CONF-2016-049 360-860 GeV GKK mass Bulk RS gKK → tt 1 e, µ ≥ 1 b, ≥ 1J/2j Yes 20.3 BR = 0.925 1505.07018 2.2 TeV gKK mass 2UED / RPP 1 e, µ ≥ 2 b, ≥ 4 j Yes 3.2 Tier (1,1), BR(A(1,1) → tt) = 1 ATLAS-CONF-2016-013 1.46 TeV KK mass SSM Z ′ → ℓℓ 2 e, µ − − 13.3 ATLAS-CONF-2016-045 4.05 TeV Z′ mass SSM Z ′ → ττ 2 τ − − 19.5 1502.07177 2.02 TeV Z′ mass Leptophobic Z ′ → bb − 2 b − 3.2 1603.08791 1.5 TeV Z′ mass SSM W ′ → ℓν 1 e, µ − Yes 13.3 ATLAS-CONF-2016-061 4.74 TeV W′ mass HVT W ′ → WZ → qqνν model A 0 e, µ 1 J Yes 13.2 gV = 1 ATLAS-CONF-2016-082 2.4 TeV W′ mass HVT W ′ → WZ → qqqq model B − 2 J − 15.5 gV = 3 ATLAS-CONF-2016-055 3.0 TeV W′ mass HVT V ′ → WH/ZH model B multi-channel 3.2 gV = 3 1607.05621 2.31 TeV V′ mass LRSM W ′ R → tb 1 e, µ 2 b, 0-1 j Yes 20.3 1410.4103 1.92 TeV W′ mass LRSM W ′ R → tb 0 e, µ ≥ 1 b, 1 J − 20.3 1408.0886 1.76 TeV W′ mass CI qqqq − 2 j − 15.7 ηLL = −1 ATLAS-CONF-2016-069 19.9 TeV Λ CI ℓℓqq 2 e, µ − − 3.2 ηLL = −1 1607.03669 25.2 TeV Λ CI uutt 2(SS)/≥3 e,µ ≥1 b, ≥1 j Yes 20.3 |CRR| = 1 1504.04605 4.9 TeV Λ Axial-vector mediator (Dirac DM) 0 e, µ ≥ 1 j Yes 3.2 gq=0.25, gχ=1.0, m(χ) < 250 GeV 1604.07773 1.0 TeV mA Axial-vector mediator (Dirac DM) 0 e, µ, 1 γ 1 j Yes 3.2 gq=0.25, gχ=1.0, m(χ) < 150 GeV 1604.01306 710 GeV mA ZZχχ EFT (Dirac DM) 0 e, µ 1 J, ≤ 1 j Yes 3.2 m(χ) < 150 GeV ATLAS-CONF-2015-080 550 GeV M∗ Scalar LQ 1st gen 2 e ≥ 2 j − 3.2 β = 1 1605.06035 1.1 TeV LQ mass Scalar LQ 2nd gen 2 µ ≥ 2 j − 3.2 β = 1 1605.06035 1.05 TeV LQ mass Scalar LQ 3rd gen 1 e, µ ≥1 b, ≥3 j Yes 20.3 β = 0 1508.04735 640 GeV LQ mass VLQ TT → Ht + X 1 e, µ ≥ 2 b, ≥ 3 j Yes 20.3 T in (T,B) doublet 1505.04306 855 GeV T mass VLQ YY → Wb + X 1 e, µ ≥ 1 b, ≥ 3 j Yes 20.3 Y in (B,Y) doublet 1505.04306 770 GeV Y mass VLQ BB → Hb + X 1 e, µ ≥ 2 b, ≥ 3 j Yes 20.3 isospin singlet 1505.04306 735 GeV B mass VLQ BB → Zb + X 2/≥3 e, µ ≥2/≥1 b − 20.3 B in (B,Y) doublet 1409.5500 755 GeV B mass VLQ QQ → WqWq 1 e, µ ≥ 4 j Yes 20.3 1509.04261 690 GeV Q mass VLQ T5/3T5/3 → WtWt 2(SS)/≥3 e,µ ≥1 b, ≥1 j Yes 3.2 ATLAS-CONF-2016-032 990 GeV T5/3 mass Excited quark q∗ → qγ 1 γ 1 j − 3.2

nly u∗ and d∗, Λ = m(q∗)

1512.05910 4.4 TeV q∗ mass Excited quark q∗ → qg − 2 j − 15.7

nly u∗ and d∗, Λ = m(q∗)

ATLAS-CONF-2016-069 5.6 TeV q∗ mass Excited quark b∗ → bg − 1 b, 1 j − 8.8 ATLAS-CONF-2016-060 2.3 TeV b∗ mass Excited quark b∗ → Wt 1 or 2 e, µ 1 b, 2-0 j Yes 20.3 fg = fL = fR = 1 1510.02664 1.5 TeV b∗ mass Excited lepton ℓ∗ 3 e, µ − − 20.3 Λ = 3.0 TeV 1411.2921 3.0 TeV ℓ∗ mass Excited lepton ν∗ 3 e, µ, τ − − 20.3 Λ = 1.6 TeV 1411.2921 1.6 TeV ν∗ mass LSTC aT → W γ 1 e, µ, 1 γ − Yes 20.3 1407.8150 960 GeV aT mass LRSM Majorana ν 2 e, µ 2 j − 20.3 m(WR) = 2.4 TeV, no mixing 1506.06020 2.0 TeV N0 mass Higgs triplet H±± → ee 2 e (SS) − − 13.9 DY production, BR(H±± L → ee)=1 ATLAS-CONF-2016-051 570 GeV H±± mass Higgs triplet H±± → ℓτ 3 e, µ, τ − − 20.3 DY production, BR(H±± L → ℓτ)=1 1411.2921 400 GeV H±± mass Monotop (non-res prod) 1 e, µ 1 b Yes 20.3 anon−res = 0.2 1410.5404 657 GeV spin-1 invisible particle mass Multi-charged particles − − − 20.3 DY production, |q| = 5e 1504.04188 785 GeV multi-charged particle mass Magnetic monopoles − − − 7.0 DY production, |g| = 1gD, spin 1/2 1509.08059 1.34 TeV monopole mass Mass scale [TeV] 10−1 1 10 √s = 8 TeV √s = 13 TeV

ATLAS Exotics Searches* - 95% CL Exclusion

Status: August 2016

ATLAS Preliminary

L dt = (3.2 - 20.3) fb−1

√s = 8, 13 TeV *Only a selection of the available mass limits on new states or phenomena is shown. Lower bounds are specified only when explicitly not excluded.

SLIDE 3

This talk

Focus on longer term future.
Higgs measurements at Higgs factories and what

we can learn from it.

Assuming no LHC discovery.

General picture. (brief)
A couple of new studies.

SLIDE 4

Higgs factories

FCC-ee, CEPC, ILC, CLIC.
Physics case relatively independent of the
utcome of the LHC.

Reach further than the LHC. Address questions that LHC can’ t answer.

SLIDE 5

Probing NP with precision measurements

CEPC: clean environment, good for precision.
We are going after deviations of the form
Take for example the Higgs coupling.

LHC precision: 5-10% ⇒ sensitive to MNP < TeV However, MNP < TeV largely excluded by direct NP searches at the LHC. To go beyond the LHC, need 1% or less precision. δ ' c v2 M 2

NP

MNP : mass of new physics c: O(1) coefficient

SLIDE 6

Higgs factory processes

e− e+ Z∗ Z H e− ¯ νe e+ W ∗ W ∗ νe H e− e+ e+ Z∗ Z∗ e− H

H [GeV] f f →

e

+

e

200 250 300 350 400

(fb) σ

50 100 150 200 250 CEPC Preliminary

H → WW ) ν ν → HZ( Total HZ

Process Cross section Nevents in 5 ab−1 Higgs boson production, cross section in fb e+e− → ZH 212 1.06 × 106 e+e− → ννH 6.72 3.36 × 104 e+e− → eeH 0.63 3.15 × 103 Total 219 1.10 × 106

SLIDE 7

Zh cross section

[GeV]

µ

+

µ recoil

M

120 125 130 135 140

Entries/0.2 GeV

1000 2000 3000

CEPC Preliminary

1

Ldt = 5 ab

∫

;

µ

+

µ → Z CEPC Simulation S+B Fit Signal Background

e−

e+ f ¯ f Z h

Can use recoil mass to identify Zh process, independent of Higgs decay

zero momentum: M2

recoil = (√s − Eff)2 − p2 ff = s − 2Eff

√s + m2

ff

and are, respectively, the total energy, momentum a

⇒ inclusive measurement of Zh cross section

SLIDE 8

Higgs width.

e− e+ f ¯ f Z h

Z Z*

ΓH ∝ Γ(H → ZZ∗) BR(H → ZZ∗) ∝ σ(ZH) BR(H → ZZ∗)

e− e+ W W h b ¯ b

ΓH ∝ Γ(H → bb) BR(H → bb) ∝ σ(ννH → ννbb) BR(H → bb) · BR(H → WW ∗)

Unique capability of lepton colliders.

Main channel at 250 GeV. Needs statistics Needs to go beyond 250.

SLIDE 9

Higgs factories

HL-LHC wi/wo theo. uncertainty CEPC 250 GeV at 5 ab-1 wi/wo HL-LHC (with HL-LHC theo. uncertainty)

b c g W

Z
10-3

10-2 0.1 1 Relative Error

Precision of Higgs couplingmeasurement(Contrained Fit)

Highlights: HZ coupling to sub-percent level. Many couplings to percent level. Model independent measurement of total width. Sensitive to the triple Higgs coupling: 20-30%

κX = Measured Higgs-X coupling Standard Model Higgs-X coupling

1 2 3 4 5 6 7 8 9 10

1

250 GeV, 500 fb ⊕

1

350 GeV, 200 fb ⊕

1

500 GeV, 500 fb ILC

1

250 GeV, 2000 fb ⊕

1

350 GeV, 200 fb ⊕

1

500 GeV, 4000 fb ILC combination

1

3000 fb HL-LHC ⊕ ILC

Projected precision of Higgs coupling and width (model-independent fit)

% % % % % % % % % % %

Z

κ

W

κ

b

κ

g

κ

γ

κ

τ

κ

c

κ

t

κ

µ

κ

tot

Γ

invis

Γ

(CL95%)

18% 20%

SLIDE 10

Higgs factories

HL-LHC wi/wo theo. uncertainty CEPC 250 GeV at 5 ab-1 wi/wo HL-LHC (with HL-LHC theo. uncertainty)

b c g W

Z
10-3

10-2 0.1 1 Relative Error

Precision of Higgs couplingmeasurement(Contrained Fit)

Highlights: HZ coupling to sub-percent level. Many couplings to percent level. Model independent measurement of total width. Sensitive to the triple Higgs coupling: 20-30%

κX = Measured Higgs-X coupling Standard Model Higgs-X coupling

1 2 3 4 5 6 7 8 9 10

1

250 GeV, 500 fb ⊕

1

350 GeV, 200 fb ⊕

1

500 GeV, 500 fb ILC

1

250 GeV, 2000 fb ⊕

1

350 GeV, 200 fb ⊕

1

500 GeV, 4000 fb ILC combination

1

3000 fb HL-LHC ⊕ ILC

Projected precision of Higgs coupling and width (model-independent fit)

% % % % % % % % % % %

Z

κ

W

κ

b

κ

g

κ

γ

κ

τ

κ

c

κ

t

κ

µ

κ

tot

Γ

invis

Γ

(CL95%)

18% 20%

SLIDE 11

Big advance in electroweak precision

Large improvements across the board

Current accuracy CEPC: baseline and improvements

MZ Z MW Rb Rl Ab

FB sin2W

N 10-7 10-6 10-5 10-4 10-3 10-2 Relative Error

Precision Electroweak Measurements at the CEPC

SLIDE 12

Electroweak precision at CEPC

A big step beyond the current precision.
0.15 -0.10 -0.05

0.00 0.05 0.10 0.15

0.15
0.10
0.05

0.00 0.05 0.10 0.15 S T Electroweak Fit: S and T Oblique Parameters

Current H1sL CEPC H1sL CEPC Improved H1sL

J. Fan, M. Reece, LT Wang, 1411.1054

Current LHC Prospect ILC TLEP-Z TLEP-W TLEP-t U = 0 68 % C.L.

0.2
0.15
0.1
0.05

0. 0.05 0.1 0.15 0.2

0.2
0.15
0.1
0.05

0. 0.05 0.1 0.15 0.2 S T

SLIDE 13

Scale of new physics.

5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators 5 10 15 20 25 30 35 40 cH cT cWW cBB cWB cHW cHB c(3)

LL

c(3)

L

cL cR c(3)

Lq

cLq cRu cRd cg 95% 5σ EWPO+HO+Z-Pole

Λ/√|cj| (T eV)

New Physics Scales to be Probed at CEPC via dim-6 Operators

S. Ge, H. He, R. Xiao, 1603.03385

In the regime of multiple TeVs!

SLIDE 14

More details, more understanding.

NC, Jiayin Gu, Zhen Liu, Kechen Wang, In Progress

Truncate flat

directions in the HEFT.

!

Improve BSM

reach by using added information.

!

Distinguish

between different BSM models with similar total cross section shifts.

CEPC sensitive not

nly to coupling

shifts, but different tensor structures.

N. Craig, J. Gu, Z. Liu, K. Wang

SLIDE 15

Case study 1: Higgs rare decay

Work in progress with Zhen Liu and Hao Zhang

Some slides from Hao Zhang

SLIDE 16

vs Hadron collider

The “ultimate” Higgs factories

[TeV] s 7 8 910 20 30 40 50 60

2

10 H+X) [pb]

(pp
1

10 1 10

2

10

3

10

LHC HIGGS XS WG 2013

H (NNLO+NNLL QCD + NLO EW)

pp

H (NNLO QCD) q q

pp

WH (NNLO QCD)

pp

Z H ( N N L O Q C D )

p

p H (NLO QCD) t t

pp

= 125 GeV

H

M MSTW2008

100 TeV > 2 billion 33 TeV > 500 million 14 TeV > 150 million # of Higgses in 3 ab-1 In comparison, O(million) Higgs at Higgs factories

Hadron collider good for rare but clean signal

SLIDE 17

Compelling physics case for exotic decay?

strength of Higgs factory

SLIDE 18

Our starting point.

Exotic decays of the 125 GeV Higgs boson

David Curtin,1,a Rouven Essig,1,b Stefania Gori,2,3,4,c Prerit Jaiswal,5,d Andrey Katz,6,e Tao Liu,7,f Zhen Liu,8,g David McKeen,9,10,h Jessie Shelton,6,i Matthew Strassler,6,j Ze’ev Surujon,1,k Brock Tweedie,8,11,l and Yi-Ming Zhong1,m

1

PHYSICAL REVIEW D 90, 075004 (2014)

With list of channels and preliminary projections

SLIDE 19

Decay Topologies Decay mode Fi 2 LHC sensitivity to Br h → 2 h → / ET 0.25[14TeV, 300fb1] h → 2 → 3 h → + / ET 0.57, 0.32, 0.13 [4] h → (b¯ b) + / ET Underlying model h → 2s or ss0 h → (jj) + / ET Background mainly are h → (⌧ +⌧ ) + / ET 1) ZZ + (n) Z + X h → () + / ET 2) Zh h → ZZ⇤, WW ⇤ h → (`+`) + / ET h → 2 → 3 → 4 h → (b¯ b) + / ET 0.2[14TeV, 300fb1] h → (jj) + / ET Bkg same as above block h → (⌧ +⌧ ) + / ET 1[14TeV, 300fb1] h → () + / ET h → (`+`) + / ET h → (µ+µ) + / ET 0.07[7 + 8TeV] h → 2 → (1 + 3) h → b¯ b + / ET − last step off-shell h → jj + / ET Bkg same as above h → ⌧ +⌧ + / ET − h → + / ET − h → `+` + / ET h → 2 → 4 h → (b¯ b)(b¯ b) 0.2[14TeV, 100fb1] h → (b¯ b)(⌧ +⌧ ) 0.15[14TeV, 300fb1] h → (b¯ b)(µ+µ) (0.6 − 2) × 104[14TeV, 100fb1] h → (⌧ +⌧ )(⌧ +⌧ ) 0.2 − 0.4[7 + 8TeV] h → (⌧ +⌧ )(µ+µ) (3 − 7) × 104[14TeV, 100fb1] h → (jj)(jj) 0.1[14TeV, 300fb1] h → (jj)() 0.01[14TeV, 300fb1] h → (jj)(µ+µ) (5 − 20) × 105[14TeV, 100fb1] h → (`+`)(`+`) 4 × 105[7 + 8TeV] h → (`+`)(µ+µ) 4 × 105[7 + 8TeV] h → (µ+µ)(µ+µ) 104[7 + 8TeV] h → ()() 3 × 105[14TeV, 300fb1] h → + / ET h → 2 → 4 → 6 h → (`+`)(`+`) + / ET h → (`+`) + / ET + X inclusive measurement h → 2 → 6 h → `+``+` + / ET h → `+` + / ET + X same as above

SLIDE 20

Decay Topologies Decay mode Fi 2 LHC sensitivity to Br h → 2 h → / ET 0.25[14TeV, 300fb1] h → 2 → 3 h → + / ET 0.57, 0.32, 0.13 [4] h → (b¯ b) + / ET Underlying model h → 2s or ss0 h → (jj) + / ET Background mainly are h → (⌧ +⌧ ) + / ET 1) ZZ + (n) Z + X h → () + / ET 2) Zh h → ZZ⇤, WW ⇤ h → (`+`) + / ET h → 2 → 3 → 4 h → (b¯ b) + / ET 0.2[14TeV, 300fb1] h → (jj) + / ET Bkg same as above block h → (⌧ +⌧ ) + / ET 1[14TeV, 300fb1] h → () + / ET h → (`+`) + / ET h → (µ+µ) + / ET 0.07[7 + 8TeV] h → 2 → (1 + 3) h → b¯ b + / ET − last step off-shell h → jj + / ET Bkg same as above h → ⌧ +⌧ + / ET − h → + / ET − h → `+` + / ET h → 2 → 4 h → (b¯ b)(b¯ b) 0.2[14TeV, 100fb1] h → (b¯ b)(⌧ +⌧ ) 0.15[14TeV, 300fb1] h → (b¯ b)(µ+µ) (0.6 − 2) × 104[14TeV, 100fb1] h → (⌧ +⌧ )(⌧ +⌧ ) 0.2 − 0.4[7 + 8TeV] h → (⌧ +⌧ )(µ+µ) (3 − 7) × 104[14TeV, 100fb1] h → (jj)(jj) 0.1[14TeV, 300fb1] h → (jj)() 0.01[14TeV, 300fb1] h → (jj)(µ+µ) (5 − 20) × 105[14TeV, 100fb1] h → (`+`)(`+`) 4 × 105[7 + 8TeV] h → (`+`)(µ+µ) 4 × 105[7 + 8TeV] h → (µ+µ)(µ+µ) 104[7 + 8TeV] h → ()() 3 × 105[14TeV, 300fb1] h → + / ET h → 2 → 4 → 6 h → (`+`)(`+`) + / ET h → (`+`) + / ET + X inclusive measurement h → 2 → 6 h → `+``+` + / ET h → `+` + / ET + X same as above

LHC can do well

SLIDE 21

For example

h h h → 2 → 4

TABLE XIII. As in Table XII, estimates for various processes in h → aa if a decays only to SM gauge bosons through loops. The central columns show the case where the couplings are generated by initially degenerate SUð5Þ multiplets; the right columns show the case where the a → γγ rate is enhanced by a factor of 10. An asterisk denotes that all 14 TeV estimates shown require 300 fb−1 of data. Decay mode F i Projected/current 2σ limit

n BrðF iÞ

7 þ 8 ½14 TeV Production mode Brða → γγÞ ≈ 0.004 Brða → γγÞ ≈ 0.04 Comments

BrðF iÞ Brðnon-SMÞ

Limit on

σ σSM · Brðnon-SMÞ

7 þ 8 ½14 TeV

BrðF iÞ Brðnon-SMÞ

Limit on

σ σSM · Brðnon-SMÞ

7 þ 8 ½14 TeV jjjj > 1 W 0.99 > 1 0.92 > 1 [0.1] [0.1] [0.1] Theory study [220,269],

Sec. VII

j j j j

Note: boosted analysis, ma < 10 GeV. Weaker limit other wise.

SLIDE 22

For example

h h h → 2 → 4

TABLE XIII. As in Table XII, estimates for various processes in h → aa if a decays only to SM gauge bosons through loops. The central columns show the case where the couplings are generated by initially degenerate SUð5Þ multiplets; the right columns show the case where the a → γγ rate is enhanced by a factor of 10. An asterisk denotes that all 14 TeV estimates shown require 300 fb−1 of data. Decay mode F i Projected/current 2σ limit

n BrðF iÞ

7 þ 8 ½14 TeV Production mode Brða → γγÞ ≈ 0.004 Brða → γγÞ ≈ 0.04 Comments

BrðF iÞ Brðnon-SMÞ

Limit on

σ σSM · Brðnon-SMÞ

7 þ 8 ½14 TeV

BrðF iÞ Brðnon-SMÞ

Limit on

σ σSM · Brðnon-SMÞ

7 þ 8 ½14 TeV jjjj > 1 W 0.99 > 1 0.92 > 1 [0.1] [0.1] [0.1] Theory study [220,269],

Sec. VII

j j j j

Note: boosted analysis, ma < 10 GeV. Weaker limit other wise.

Signal at Higgs factories ee → Zh →Z jjjj

SLIDE 23

δEj Ej = 0.3 p Ej/GeV ⊕ 0.02 δE E = 0.16 p E/GeV ⊕ 0.01 ∆ ✓ 1 pT,` ◆ = 2 × 10−5 ⊕ 10−3 pT,` sin θ`

Parton level simulation.
Main SM backgrounds: e+e-→Zjjjj+X.
Important to take into account the simulation due to the ISR effect.

From CEPC pre-CDR

P (GeV/c) 1 10

2

10 PID Efficiency 0.6 0.8 1

CEPC Preliminary

)| < 0.98 θ |cos(

±

µ

±

e

±

π

0.98 0.95

SLIDE 24

Cuts and simulation.

Preselection cuts:
MadGraph5_aMC@NLO.
The ISR effect of the background is roughly mimicked by

generating events with 1 additional photon (with pT>1GeV to avoid the IR divergence).

Additional cut to suppress the ISR effect:

| cos θj,`| < 0.98, Ej,` > 10GeV, yij ≡ 2min

E2

i , E2 j

(1 − cos θij)

E2

vis

> ycut, a pair of OSSF leptons, θ`` > 80 |m`` − mZ| < 10GeV, |mrecoil − mh| < 5GeV.

Evis > 225GeV.

Similar to some LEP analysis

SLIDE 25

SM background

(GeV)

recoil

m

80 90 100 110 120 130 140

/bin (fb) σ d

3 −

10

2 −

10

1 −

10 1 10

2

10 w ISR w/o ISR

Z+4j →

e

+

= 240 GeV, e s CEPC,

SLIDE 26

SM background

(GeV)

recoil

m

80 90 100 110 120 130 140

/bin (fb) σ d

3 −

10

2 −

10

1 −

10 1 10

2

10 w ISR w/o ISR

Z+4j →

e

+

= 240 GeV, e s CEPC,

ZZ→Z+4j background

SLIDE 27

SM background

(GeV)

recoil

m

80 90 100 110 120 130 140

/bin (fb) σ d

3 −

10

2 −

10

1 −

10 1 10

2

10 w ISR w/o ISR

Z+4j →

e

+

= 240 GeV, e s CEPC,

ZZ→Z+4j background Zh→Z+4j background. Br(h→4j)~11%, σ(Zh)~240fb, without cuts, it gives ~1.75fb background.

SLIDE 28

Additional simple cut

m

R

0.1 0.2 0.3 0.4 0.5

Fraction

0.2 0.4

w ISR w/o ISR s 50 GeV s 20 GeV

= 240 GeV s CEPC,

Rm ≡ min

σ∈S4

mjσ(1)jσ(2) − mjσ(3)jσ(4)
mjσ(1)jσ(2) + mjσ(3)jσ(4)

!

SLIDE 29

Additional simple cut

m

R

0.1 0.2 0.3 0.4 0.5

Fraction

0.2 0.4

w ISR w/o ISR s 50 GeV s 20 GeV

= 240 GeV s CEPC,

Rm ≡ min

σ∈S4

mjσ(1)jσ(2) − mjσ(3)jσ(4)
mjσ(1)jσ(2) + mjσ(3)jσ(4)

! ~20%-30% improvement of significance; ~100% improvement of S/B.

SLIDE 30

(GeV)

med

m

10 20 30 40 50 60

Sensitivity of branching ratio

4 −

10

3 −

10

2 −

10

1 −

10 1

cut

m

R =0.002, w/o

cut

y cut

m

R =0.002, w

cut

y cut

m

R =0.001, w

cut

y

= 240 GeV s CEPC,

) q q )( q q ( → ) aa ( ss → h

Precision at level < 1%. In comparison, O(1) for LHC Can be improved further with reconstructing a resonance.

SLIDE 31

(GeV)

med

m

10 20 30 40 50 60

Sensitivity of branching ratio

4 −

10

3 −

10

2 −

10

1 −

10 1

cut

m

R =0.002, w/o

cut

y cut

m

R =0.002, w

cut

y cut

m

R =0.001, w

cut

y

= 240 GeV s CEPC,

) q q )( q q ( → ) aa ( ss → h

Precision at level < 1%. In comparison, O(1) for LHC Can be improved further with reconstructing a resonance.

need to supplement this with a boosted analysis similar improvement expected.

SLIDE 32

(GeV)

med

m

10 20 30 40 50 60

Sensitivity of branching ratio

4 −

10

3 −

10

2 −

10

1 −

10 1

cut

m

R =0.002, w/o

cut

y cut

m

R =0.002, w

cut

y cut

m

R =0.001, w

cut

y

= 240 GeV s CEPC,

) gg )( gg ( → ) aa ( ss → h

SLIDE 33

4 bottom final state

h h h → 2 → 4 b b b b

Decay mode F i Projected/ current 2σ limit

n BrðF iÞ

7 þ 8 ½14 TeV Production mode Quarks allowed Quarks

BrðF iÞ Brðnon-SMÞ

Limit on

σ σSM · Brðnon-SMÞ

7 þ 8 ½14 TeV

BrðF iÞ Brðnon-SMÞ

b¯ bb¯ b 0.7 W 0.8 0.9 [0.2] [0.2]

SLIDE 34

Good b-tagging performance.

With 8 – 20 mm VTX Inner radius, very good b-tagging

–

At efficiency ~ 80%: almost reject all the light background & only 8-10% c-jets misidentified as b-jets (Purity ~93-96% at Z to qq events).

light background c background

1- 1- Gang Li

SLIDE 35

(GeV)

med

m

10 20 30 40 50 60

Sensitivity of branching ratio

4 −

10

3 −

10

2 −

10 =70%

b

ε =0.002,

cut

y =70%

b

ε =0.001,

cut

y =80%

b

ε =0.001,

cut

y

= 240 GeV s CEPC,

) b b )( b b ( → ) aa ( ss → h

SLIDE 36

For example

h h h → 2 → 4 j γ γ j

mmed (GeV) 10 20 25 30 50 ycut = 0.002 0.3% 0.01% 0.009% 0.007% 0.006% ycut = 0.001 0.04% 0.01% 0.01% 0.009% 0.006%

LHC: about 1%

Main background: ZZ →Z jj γγ

SLIDE 37

Exotic decay of the SM Higgs boson (jj+met)

Another topology

h h h → 2 → 3 → 4 h → 2 → (1 + 3)

h h h → 2 → 3 → 4 h → 2 → (1 + 3) H

j

˜ χ0

1

j

˜ χ0

2

˜ χ0

2

˜ χ0

1

˜ χ0

1

˜ χ0

1

j j

m1 m2 m1 j j j j med For example:

LHC: 10(s)%

SLIDE 38

Background.

(GeV)

recoil

m

50 100 150 200

/bin (fb) σ d

5 −

10

4 −

10

3 −

10

2 −

10

1 −

10

1

= 240 GeV, 5 ab s CEPC,

2 1 2 → 1

nd e+e− → `+`−⌫`¯ ⌫`jj wi tribution of the dilepton

ee →Zh, followed by h→ Z* Z

SLIDE 39

Exotic decay of the SM Higgs boson (jj+met)

(GeV)

jj

m

20 40 60 80 100 120

/bin (fb) σ d

4 −

10

3 −

10

2 −

10

= 240 GeV s CEPC,

Z* hadronic decay

2 1 2 → 1

nd e+e− → `+`−⌫`¯ ⌫`jj wi tribution of the dilepton

Z hadronic decay

SLIDE 40

Exotic decay of the SM Higgs boson (jj+met)

(GeV)

jj

m

20 40 60 80 100 120

/bin (fb) σ d

4 −

10

3 −

10

2 −

10

= 240 GeV s CEPC,

Z* hadronic decay

2 1 2 → 1

nd e+e− → `+`−⌫`¯ ⌫`jj wi tribution of the dilepton

Z hadronic decay h 4-body decay, good sensitivity here!

SLIDE 41

h h h → 2 → 3 → 4 h → 2 → (1 + 3)

H

j

˜ χ0

1

j

˜ χ0

2

˜ χ0

2

˜ χ0

1

˜ χ0

1

˜ χ0

1

j

Exotic decay of the SM Higgs boson (jj+met)

mmed mmed

10-4 level at Higgs factories

SLIDE 42

h h h → 2 → 3 → 4 h → 2 → (1 + 3)

H

j

˜ χ0

1

j

˜ χ0

2

˜ χ0

2

˜ χ0

1

˜ χ0

1

˜ χ0

1

j j

Exotic decay of the SM Higgs boson (jj+met)

b- b- mmed mmed

10-4 level at Higgs factories

SLIDE 43

What can we learn from precision Higgs measurement.

SLIDE 44

Case studies

EWSB phase transition in early universe.
Top related couplings.

SLIDE 45

Nature of EW phase transition

h

?

What we know from LHC and upgrades won’t go much further

Order 1 deviation in triple Higgs coupling.

SLIDE 46

1st order phase transition

V (h) = m2 2 h2 + λh4 + 1 Λ2 h6 + . . .

Huang, Joglekar, Li, Wagner, 1512.00068

SLIDE 47

λ λSM ∈      [0.891, 1.115] no background syst. [0.882, 1.126] 25% hh, 25% hh + jet [0.881, 1.128] 25% hh, 50% hh + jet

Triple Higgs coupling at 100 TeV pp collider 30 ab-1

Barr, Dolan, Englert, de Lima, Spannowsky

ILC 500: 27% ILC ultimate, 1 TeV 5 ab-1: 10%

SLIDE 48

Generically, there is more

1st order EW phase transition means there is

new physics close to the weak scale.

Can be difficult to discover at the LHC.

Can only couple weakly to the Higgs.

Will leave more signature in Higgs coupling.

V (h) = m2 2 h2 + λh4 + 1 Λ2 h6 + . . .

SLIDE 49

For example

m2h†h + ˜ λ(h†h)2 + m2

SS2 + ˜

aSh†h + ˜ bS3 + ˜ κS2h†h + ˜ hS4

˜ b ˜ a ˜ a ˜ a ˜ a ˜ a S S S S S ˜ κ h h h h h h h h h h h h

˜ a ˜ a S h h h h

10 20 30 40 50 60 50 100 150 200 g111 SM

g111 Tc

8% - 13%- 30%- 50%-

shift in h-Z coupling

Profumo et al triple Higgs coupling

SLIDE 50

Probing EWSB at higgs factories

= , ()/ > 0

= “” , ()/ > 1.3 = 1,

Good coverage in model space

Huang, Long, LTW, 1608.06619

SLIDE 51

Combining with eLISA?

Pushing our understanding of early universe.

significant back.

Implications for baryogengesis, etc.

SLIDE 52

More elaborated model ⇒ more signal

=

= = = = =

= - = =

=

μ +

Γ→γγ / (Γ→γγ)

SLIDE 53

More elaborated model ⇒ more signal

=

= = = = =

= - = =

=

μ +

Γ→γγ / (Γ→γγ)

If electroweak phase transition is of first order,

Higgs factory has a great chance to see indications.

SLIDE 54

Higgs-top coupling.

Dim-6 operators parameterization.

OtH = 1 Λ2 (H†H)(¯ qL ˜ HtR), ObH = 1 Λ2 (H†H)(¯ qLHbR), ODHq = i Λ2 (H†↔ DµH)(¯ qLγµqL), O(3)

DHq =

i Λ2 (H†τ I ↔ DµH)(¯ qLγµτ IqL), ODHt = i Λ2 (H†↔ DµH)(¯ tRγµtR), ODHb = i Λ2 (H†↔ DµH)(¯ bRγµbR),

SLIDE 55

OtH = 1 Λ2 (H†H)(¯ qL ˜ HtR),

Coefficient can be complex in general. Affect h→ gg, although determining CP can be difficult. h→γγ with a different sign Sub-leading contribution to hZZ as well.

20
10

10 20

20
10

10 20 Re[Δyt] (v2/TeV2) Im[Δyt] (v2/TeV2)

CEPC 240 GeV @ 5 ab-1

H→gg ttH@LHC H→γγ σZH

★

20
10

10 20

20
10

10 20 Re[Δyt] (v2/TeV2) Im[Δyt] (v2/TeV2)

FCC-ee

240 GeV @ 10 ab-1 +350 GeV @ 2.6 ab-1

H→gg ttH@LHC H→γγ σZH

★

ObH = 1 Λ2 (H†H)(¯ qLHbR) i

↔

well constrained by h→bb

SLIDE 56

O Λ ODHq = i Λ2 (H†↔ DµH)(¯ qLγµqL), O(3)

DHq =

i Λ2 (H†τ I ↔ DµH)(¯ qLγµτ IqL), ODHt = i Λ2 (H†↔ DµH)(¯ tRγµtR), ODHb = i Λ2 (H†↔ DµH)(¯ bRγµbR),

Do not modify Higgs coupling to tops. Generate h-Z-bb … Modify Z-bb and Z-tt couplings

0.3
0.2
0.1

0.0 0.1 0.2 0.3 44.0 44.2 44.4 44.6 44.8 45.0 45.2 45.4 c (TeV-2) σ(ee→Hbb->4b) (fb) ODHq, ODHq

(3)

ODHb e+ e- 240 GeV @ 5 ab-1

0.3
0.2
0.1

0.0 0.1 0.2 0.3 24.2 24.4 24.6 24.8 25.0 25.2 25.4 c (TeV-2) σ(ee→Hbb->4b) (fb) ODHq, ODHq

(3)

ODHb e+ e- 350 GeV @ 2.6 ab-1

3-body process, ee→hbb

SLIDE 57

Z-pole

≈ ∆Zb¯

b = −

⇣ CDHq + C(3)

DHq

⌘ v2 Λ2 p g2

1 + g2 2

2 Zµ¯ bLγµbL − CDHb v2 Λ2 p g2

1 + g2 2

2 Zµ¯ bRγµbR ∆Zt¯

t =

⇣ C(3)

DHq − CDHq

⌘ v2 Λ2 p g2

1 + g2 2

2 Zµ¯ tLγµtL − CDHt v2 Λ2 p g2

1 + g2 2

2 Zµ¯ tRγµtR

0.25
0.20
0.15
0.10
0.05

0.00 0.05 0.10

1.0
0.8
0.6
0.4
0.2

0.0 0.2 cΦq+cΦq

(3) (TeV-2)

cΦd (TeV-2) Current Z-pole 95% & 68% CEPC Z-pole 99% CEPC Z-pole+ 99% CEPC 240 GeV ee→Hbb @ 5 ab-1 95% & 68%

0.25
0.20
0.15
0.10
0.05

0.00 0.05 0.10

1.0
0.8
0.6
0.4
0.2

0.0 0.2 cΦq+cΦq

(3) (TeV-2)

cΦd (TeV-2) Current Z-pole 95% & 68% ILC Z-pole 99% FCC-ee Tera-Z 99% FCC-ee ee→Hbb 240 GeV@ 10 ab-1 350 GeV @ 2.6 fb-1 95% & 68%

SLIDE 58

At ttbar threshold

25
20
15
10
5

5 10

10

10 20 cΦq

(3) -cΦq (1) (TeV-2)

cΦu (TeV-2) ttW(4j)@LHC 3000 fb-1 ttW(3j)@LHC 3000 fb-1 ttZ@LHC 300, 3000 fb-1 e+e- 350-500 GeV

3
2
1

1 2 3

3
2
1

1 2 3 cΦq

(3) -cΦq (1) (TeV-2)

cΦu (TeV-2) e+e- 350 GeV @2.6 ab-1 e+e- 500 GeV @ 500 fb-1 ttZ@LHC 3000 fb-1 e+e- 350 GeV @2.6 ab-1

SLIDE 59

Sensitivity to new physics scales

HL-LHC+LEP CEPC 90/250 GeV FCCee 90/250/350 GeV

R e [ Δ yt ] I m [ Δ yt ] | Δ yb | D H q ( 3 ) + D H q D H b D H q ( 3 )

D

H q D H t

4
2

2 4 Λ/ c excluded (TeV) Sensitivity to new physics scale Λ/ c Z-pole dominant tt-pair dominant Higgs Precision dominant × 1 3 × 1 3

SLIDE 60

Open questions

SLIDE 61

In general

Cover more detailed aspects of Higgs factory

phenomenology.

More channels, better simulations…

What are the other “killer-apps”?

SLIDE 62

On the Z-pole

“Bread and butter” precision measurement

Gain a factor of 10 with about Giga Z. Very valuable information, complimentary to Higgs measurements

0.15 -0.10 -0.05

0.00 0.05 0.10 0.15

0.15
0.10
0.05

0.00 0.05 0.10 0.15 S T Electroweak Fit: S and T Oblique Parameters

Current H1sL CEPC H1sL CEPC Improved H1sL Current LHC Prospect ILC TLEP-Z TLEP-W TLEP-t U = 0 68 % C.L.

0.2
0.15
0.1
0.05

0. 0.05 0.1 0.15 0.2

0.2
0.15
0.1
0.05

0. 0.05 0.1 0.15 0.2 S T

SLIDE 63

Z-factory

Tera-Z or more?

Can do a lot more with precision measurements. Many interesting topics. Exotic Z-decay, sterile neutrino, dark sector… tau, B, QCD…

More work needed to make concrete physics cases.

SLIDE 64

CEPC: ttbar threshold?

Seems not as crucial for precision electroweak.
A small improvement for the fit to S and T.
Is this optimistic or pessimistic on the

systematics?

0.04
0.02

0.00 0.02 0.04

0.04
0.02

0.00 0.02 0.04 S T Electroweak Fit: S and T Oblique Parameters

CEPC baseline H1sL Improved GZ, sin2q H1sL Improved GZ, sin2q, mt H1sL

SLIDE 65

CEPC: higher energy, ttbar

However, going up from 250 to 350 can improve
ther measurements.
Scan, energy dependence brings in more

discovery and distinguishing power.

Many more studies needed.

(GeV) s 200 220 240 260 280 300 320 340 360 Cross section (fb) 50 100 150 200 250

HZ →

e

+

e ν ν → HZ, Z H → WW H → ZZ Total

Unpolarized,cross,sections,

For example:

SLIDE 66

More “service” work needed.

SLIDE 67

Λ: a cut-off. The energy scale of new physics responsible for EWSB Electroweak scale, 100 GeV. mh , mW … What is Λ? Can it be very high, such as MPlanck = 1019 GeV, …? If so, why is so different from 100 GeV?

Explaining EWSB: naturalness

SLIDE 68

Naturalness, fine-tuning

LHC searches model dependent, many blind spots.
Precision measurement at CEPC provides a

powerful and complementary probe.

2000

~=
~=
~=
()

()

500 1000 1500 2000 500 1000 1500 2000

~

[]

~

[]

=

~ []

J. Fan, M. Reece, LT Wang, 1412.3107
Testing fine-tuning down to percent level.

SLIDE 69

Composite Higgs at lepton collider

Higgs is not (quite) elementary, will have deviations in Higgs couplings.

δWh ∼ δZh ∼ v2 f 2

Composite resonances couples to W and Z. Will give rise to deviation in EW precision observables.

S ' N 4π v2 f 2

Experiment κZ (68%) f (GeV) HL-LHC 3% 1.0 TeV ILC500 0.3% 3.1 TeV ILC500-up 0.2% 3.9 TeV CEPC 0.2% 3.9 TeV TLEP 0.1% 5.5 TeV

Lesson: when both type of corrections generated at the same order, Higgs coupling measurement is typically stronger.

SLIDE 70

Folded SUSY

Top partner has SM electroweak couplings
nly.
No hgg. Only hγγ. Weaker.

0.1 0.1 0.1 0.2 0.2 0.2

100 200 300 400 500 600 100 200 300 400 500 600

mF-t

é

1@GeVD

mF-t

é

2@GeVD

Folded SUSY at CEPC & HL-LHC

0.1 0.1 0.1 0.2

100 200 300 400 500 600 100 200 300 400 500 600

mF-t

é

1@GeVD

mF-t

é

2@GeVD

Folded SUSY at FCC-ee & HL-LHC

J. Fan, M. Reece, LTW, 1412.3107

SLIDE 71

80+ km vs 50 km

Prefer longer.
Main physics motivation, beyond CEPC. SppC.

The bigger, the better. 100 TeV seems to be the highest that is doable. Can measure Higgs self coupling, probe dark matter, test naturalness. Completely discover and study the new physics showing up in precision measurements of CEPC. Other benefits, easier to go to higher energy, tt threshold?

SLIDE 72

Electroweak precision tests: roughly estimated targets

δmW < 5 MeV
δsin2θeff < 2x10-5 (and/or ΓZ about 100 keV)
δmZ < 500 keV
δmt < 100 MeV
Theoretical/

experimental improvement ofΔαhad Much more work needed to produce more accurate and realistic numbers.

SLIDE 73

Current Status of CEPC

Pre-CDR completed
No show-stoppers
Technical challenges identified R&D issues
Preliminary cost estimate
R&D issues identified and funding request underway
Seed money from IHEP available: 12 M RMB/3 years
MOST: ~ 80 M RMB / 5yr, 36M RMB has been proved in June 2016
Onters topical issue funds from NSFC, CAS and the Science and

Technoogy Bureau of Beijing Municipal: ~9M RMB

Working towards CDR, Accelerator by 2016 and Detector by

2017

A working machine on paper solving the problems left by Pre-CDR
Site selections
Internationalization & organization
J. Gao

SLIDE 74

X. Lou

SLIDE 75

Site selections (some main places)

1) Qinhuangdao 2) Shanxi Province 3) Near Shenzhen and Hongkong

1) 2) 3)

J. Gao

SLIDE 76

My personal sense

R&D is moving forward.
Biggest challenge

Time is tight. CDR in a year. “shovel ready” in 5- ish years? Domestic man-power and expertise growing (not enough yet). Need a lot of international collaboration.

SLIDE 77

Inputs for the further study

Present data CEPC fit αs(M2

Z)

0.1185 ± 0.0006 [17] ±1.0 × 10−4 [18] ∆α(5)

had(M2 Z)

(276.5 ± 0.8) × 10−4 [19] ±4.7 × 10−5 [20] mZ [GeV] 91.1875 ± 0.0021 [21] ±0.0005 mt [GeV] (pole) 173.34 ± 0.76exp [22] ±0.5th [20] ±0.6exp ± 0.25th [20] mh [GeV] 125.14 ± 0.24 [20] < ±0.1 [20] mW [GeV] 80.385 ± 0.015exp [17]±0.004th [23] (±3exp ± 1th) × 10−3 [23] sin2 θ`

eff

(23153 ± 16) × 10−5 [21] (±4.6exp ± 1.5th) × 10−5 [24] ΓZ [GeV] 2.4952 ± 0.0023 [21] (±5exp ± 0.8th) × 10−4 [25] Rb ≡ Γb/Γhad 0.21629 ± 0.00066 [21] ±1.7 × 10−4 R` ≡ Γhad/Γ` 20.767 ± 0.025 [21] ±0.007

CEPC sin2 θ`

eff

ΓZ [GeV] mt [GeV] Improved Error (±2.3exp ± 1.5th) × 10−5 (±1exp ± 0.8th) × 10−4 ±0.03exp ± 0.1th

Baseline option With possible improvements. x4 statistics off Z-pole energy calibration ILC?

SLIDE 78

X. Lou

SLIDE 79

X. Lou

SLIDE 80

As data accumulates

2 TeV, e.g. pair of 1 TeV gluino.

)

1

luminosity (fb

10 20 30 40 50 60 70 80 90 100

low

m /

high

m

0.5 1 1.5 2 2.5

14 TeV / 8 TeV

= 2 TeV

low

m

qq q q qg gg

Rapid gain initial 10s fb-1, slow improvements afterwards.

)

1

luminosity (fb

10 20 30 40 50 60 70 80 90 100

low

m /

high

m

0.5 1 1.5 2 2.5

14 TeV / 8 TeV

= 500 GeV

low

m

qq q q qg gg

500 GeV, e.g. pair of 250 GeV electroweak-ino Run 1 limit

Reaching the “slow” phase after Moriond 2017

SLIDE 81

Beyond the LHC, future facilities

ILC in Japan

来自中国的建议

年月“第二届中国高能加速器物理战略发展研讨会”提出了

建造周长为环形加速器的建议： – ：质心能量为的高能正负电子对撞机工厂） – ：在同一隧道建造质心能量为的强子对撞机。

年月

日香山会议共识：“环形正负电子对撞机工厂超级质子对撞机是我国高能物理发展的重要选项和机遇”

年月

日“第三届中国高能加速器物理战略发展研讨会”结论：“环形正负电子对撞机工厂超级质子对撞机是我国未来高能物理发展的首要选项”

ee+ Higgs Factory pp collider

Circular. “Scale up” LEP+LHC

CLIC 250 GeV FCC-ee (CERN), CEPC(China) ~100 TeV FCC-hh (CERN), SppC(China) My talk have more content on CEPC