Potential for measuring the vertex at colliders

E.A., Kanemura Phys. Lett. B626, 111(2005)E.A., Kanemura, Kanzaki hep-ph/0612271

Eri Asakawa (KEK)

1. Introduction2. The vertex3. Measuring the vertex at LHC4. Measuring the vertex at ILC5. Summary

H W Z

H W Z

Exploring Higgs sector What members are included? (mass? charge? parity? CP property?) What is the mass relation among the members like? What kind of couplings do Higgs bosons have?

gives us a clue to understand physics beyond SM.

2 neutral Higgs bosons (H and A)a pair of charged Higgs bosons

ex.) MSSM : + one doublet Littlest Higgs model : + one triplet

・・・

If Higgs sector is extended by adding a doublet,

for an additional doublet

will be observed.

1. IntroductionMany models beyond SM predict extended Higgs sector as a low energy effective theory.

The extended Higgs sector is strongly constrained　 from experiments (ρparameter, FCNC, )‥‥‥

additional doublet : at tree leveladditional triplet :

1 1 22

2

22 2 2

4 ( 1)

cos 2

i i i i iW i

Z W i ii

T T Y v cm

m Y v

L:SU(2) isospin

: hypercharge

: v.e.v.

i

i

i

T

Y

v

for each Higgs representation

:1 for complex representation

1/2 for real representationic

vertex depends on models.H W Z

additional doublet : zero at tree leveladditional triplet : non-zero

4 2 2 2

22 2 22 2

4 14

Z ZHWZ i i i i i

iW

g m g mf Y T T Y v

m

We discuss predictions of the vertex in 4 types of models:

1. models with additional doublet (more constrained) ⇒ MSSM

2. models with additional doublet (less constrained) ⇒ THDM

3. models with additional triplet with ⇒ Littlest Higgs model (+ 1 complex triplet)

4. models with additional triplet with “⇒ Triplet model” (+ 1 complex triplet + 1 real triplet)

H W Z

Galison (84), Georgi, Machacek(85)Chivukula, Georgi(86)

1

1

Arkani-Hamed, Cohen, Katz, Nelson (02)Han, Logan, McElrath, Wang (03)

2. The vertexH W Z

dim. 5dim. 3

dominant

. .Weff HWZ HWZ Z HWZ Z WL f H W Z g H F F h i H F F h c

2 5(10 ) for tan 3 - 4 MSSMF O 2 3(10 ) for very low tan THDMF O

THDM2

F

Kanemura(99)

MSSM

Logan & Su(02)

models with additional doublet

2 2

2 2

cos 8W

vF

v v

W

4

cos

vF

v

Littlest Higgs model

Triplet model

the bound from the ρparameter etc. puts upper limit for v5 GeV for 1 TeV

4 GeV for 2 TeV

v f

v f

2

2

0.0085 700 GeV

0.0054 1.56 TeV

H

H

F m

F m

the bound from the Zbb results puts upper limit for v3

3

3

37 GeV for 100 GeV

59 GeV for 500 GeV

71 GeV for 1 TeV

H

H

H

v m

v m

v m

2

2

2

0.26

0.64

0.96

F

F

F

: VEV of doublet

: VEV of triplet

v

vmodels with additional triplet

Chen, Dawson(03)

(+ 1 complex triplet)

(+ 1 complex triplet + 1 real triplet)

2 2

2

Littlest Higgs (10 )

Triplet Higgs (1)

F O

F O

2 5

2 3

MSSM (10 )

THDM (10 )

F O

F O

Prediction for upper limits of the vertex is hierarchical for models.

H W Z

How small F values can be observed at LHC and ILC?

E.A., Kanemura (2005)

Charged Higgs production at LHC

for light

for heavy

t bH

t bH

t H b H m m m

p p H t b X H m m m

3. Measuring the vertex at LHCH W Z

H

t

b

g

W

Z

→ ｊ ｊ

→ l l→ b l v

010 fb Br H W Z 310 for MSSM

⇒

It may be possible to measure the vertex for MSSM and THDM.But need Htb coupling, then useless for Triplet Higgs.

production via W Z fusionH

Partonic process

proton

proton

Forwardregion

Forwardregion

Central region

Central region

Small hadronic activity except for jets from produced Higgs bosons　　　 　⇒　 possible to reach THDM case???

Pure electroweak process with no color flow in the central region.

W

Z

For no-Htb-vertex models like Triplet Higgs model,

3VBF 10 pb

production 490 pb

production 26 pb

O

t t

WZ

Event generation : PYTHIA , MadGraph

Simulation : under the expected detector performance at LHC

Tools

S/B is extremely huge!!

We perform the simulation study for the WZ fusion.

So, effective event selection is indispensable.

E.A., Kanemura, Kanzaki (2006)

0H W Z j j lv

500 GeVHm

,

,

Event selection cuts which we impose for

Before cuts After cuts

Signal: 100%BG W+4j: 100% (130 pb)BG ttbar: 100% (490 pb)

Signal: 0.2%BG W+4j: 0.003% (3.5 fb)BG ttbar: 0.0001% (0.5 fb)

BG: W+4j, ttbar, ‥‥‥

800 GeVHm

Before cuts After cuts

Signal: 100%BG W+4j: 100% (130 pb)BG ttbar: 100% (490 pb)

Signal: 0.4%BG W+4j: 0.0016% (2.1 fb)BG ttbar: 0.0001% (0.5 fb)

Before cuts After cutsSignal: 0.1%BG W+4j: 0.04% (56 fb)BG ttbar: 0.0008% (3.9 fb)

Signal: 100%BG W+4j: 100% (130 pb)BG ttbar: 100% (490 pb)

200 GeVHm

500 GeVHm

Before cuts After cutsSignal: 100%BG W+4j: 100% (130 pb)BG ttbar: 100% (490 pb)

Signal: 0.2%BG W+4j: 0.003% (3.5 fb)BG ttbar: 0.0001% (0.5 fb)

0H W Z j j lv

Then, We estimate the required |F| values to satisfy S/√B > 3 for L=600 fb-1.

0 modeH W Z

modeH bt

2 2

2

Littlest Higgs (10 )

Triplet Higgs (1)

F O

F O

2 5

2 3

2 2

MSSM (10 )

THDM (10 )

Littlest Higgs (10 )

F O

F O

F O

Predictions for each model

Predictions for each model

NG

OK

NG

NG

NG

4. Measuring the vertex at ILCH W Z

Charged Higgs production at ILC

γ,

H W Z includethe vertex!!

THDM MSSM

Logan & Su(02)Kanemura(99)

⇒ 　 possible to reach even in MSSM case !!

5. Summary

H W Z The vertex is important because it directly depends on the global symmetry structure of the models.

Prediction for the vertex is hierarchical for models. Therefore, measuring the vertex is useful to test the models.

We performed the simulation study for the production process via WZ fusion. Z fusion at LHC. 2 5

2 3

2 2

2

MSSM (10 )

THDM (10 )

Littlest Higgs (10 )

Triplet Higgs (1)

F O

F O

F O

F O

NG

OK

NG

NGResults: If go to ILC, possible to measure.

⇒ 　 may be too heavy at ILC

⇒ 　 possible to measure at ILC as well.

H

H

0H W Z j j lv

800 GeVHm

Before cuts After cuts

Signal: 100%BG WZjj: 100% (560 fb)BG WZ: 100% (26 pb)

Signal: 0.09%BG WZjj: 0.036% (0.1 fb)BG WZ: (< 0.003 fb)

Before cuts After cutsSignal: 0.02%BG WZjj: 0.008% (0.02 fb)BG WZ: (< 0.003 fb)

Signal: 100%BG WZjj: 100% (560 fb)BG WZ: 100% (26 pb)

200 GeVHm

500 GeVHm

Before cuts After cutsSignal: 100%BG WZjj: 100% (560 fb)BG WZ: 100% (26 pb)

Signal: 0.03%BG WZjj: 0.004% (0.02 fb)BG WZ: (< 0.003 fb)

0H W Z l l lv BG: WZ j j, WZ, ‥‥‥

0H W Z l l lv

200 GeV

500 GeV

Hm

Hm

800 GeVHm

H bt bblv

200 GeV

700 GeV

Hm

Hm

Before cuts After cutsSignal: 0.3%BG WZjj: 0.004% (18 fb)

Signal: 100%BG ttbar: 100% (490 pb)

Before cuts After cutsSignal: 1.1%BG WZjj: 0.0008% (4 fb)

Signal: 100%BG ttbar: 100% (490 pb)

BG: ttbar, ‥‥‥

H bt bblv 200 GeV

700 GeV

Hm

Hm