Takehiro Nabeshima University of Toyama

Takehiro NabeshimaUniversity of Toyama

ILC physics general meeting 9 jun. 2012

Phenomenology at a linear collider in a radiative seesaw model from TeV scale B-L breaking

S. Kanemura, T.N., H. Sugiyama, Phys. Lett. B703:66-70S. Kanemura, T.N., H. Sugiyama, Phys. Rev. D85, 033004

1.Introduction

1. Neutrino oscillation2. Dark matter3. Baryon asymmetry of the Universe

The standard model (SM) is a very successful model to describe physics below O(100)GeV.However, we know the phenomena of the beyond-SM.

Especially, neutrino oscillation and dark matter would be explained by radiative seesaw models at TeV scale.

Neutrino masses

νL νL

ΦΦ

νR

1.Introduction

Aoki,Kanemura,Seto (2008)

νR νRM ～ O(1) TeV→ c ～ O(10-6)

M ～ O(1) TeV→ c ～ O(10-4)

M ～ O(1) TeV→ c ～ O(1)

Neutrino masses

1.Introduction


Φ

νL νR

Φ Φ

νL

νRνL

νL νL

ΦΦ

νR νR νRM ～ O(1) TeV→ c ～ O(10-6)

M ～ O(1) TeV→ c ～ O(10-4)

M ～ O(1) TeV→ c ～ O(1)

Kanemura, T.N., Sugiyama (2011)


M ～ O(1) TeV → c ～ O(10-2-10-1) νR are not

stable.

Neutrino masses

1.Introduction


Φ

νL νR

Φ Φ

νL

νRνL

νL νL

ΦΦ

νR νR νRM ～ O(1) TeV→ c ～ O(10-6)

M ～ O(1) TeV→ c ～ O(10-4)

M ～ O(1) TeV→ c ～ O(1)



We consider this case.

M ～ O(1) TeV → c ～ O(10-2-10-1) νR are not

stable.

1.Introduction

100 GeV

1TeV

U(1)B-L <s>

yDM Y Y s

Y(DM)

What is the origin of MDM?If U(1)B-L gauge symmetry is broken by the vev of additional scalar boson s at O(1-10)TeV , MDM is given by this vev through yDM Y Y s coupling.

・ WIMP dark matter mass: MDM ～ O(100-1000)GeV

WIMP dark matter

1.Introduction

100 GeV

1TeV

U(1)B-L <s>

yDM Y Y s

Y(DM)

・ WIMP dark matter mass: MDM ～ O(100-1000)GeV

WIMP dark matter

Dark matter and neutrino masses could be naturally explain by TeV scale physics with U(1)B-L gauge symmetry.

What is the origin of MDM?If U(1)B-L gauge symmetry is broken by the vev of additional scalar boson s at O(1-10)TeV , MDM is given by this vev through yDM Y Y s coupling.

・ SU(3)C×SU(2)I×U(1)Y×U(1)B-L

・ New matter particle:　　 -B-L Higgs scalar 　 σ -Right handed neutrinos 　 νR

1,2

　　 -SU(2)I singlet scalar 　 s　　 -SU(2)I doublet scalar 　 η - Chiral fermion 　 ΨR

1,,2

L

Half unit of U(1)B-L charge→ U(1)DMU(1)B-L protect: Tree-level LfSMnR

Majorana mass of nR

Dirac mass of Y

2.Model

Electroweak symmetry breaking

2.Model

・ f, s, s and h

→

Physical state: h,H,S1,S2,η±

U(1)B-L symmetry breaking・ nR, YR and YL

U(1)B-L : Neutrino masses The dark matter mass Stability of the dark matter

→

← 　 tree level

Global U(1)DM remains after U(1)B-L gauge symmetry breaking.We assume that the Ψ1

is the lightest U(1)DM particle.

Neutrino masses

The O(0.1) eV neutrino masses can be naturally deduced from TeV scale physics with O(0.01-0.1) coupling constant

Φ

νL νR

νL

νL νL

νL

νR

νR

<σ>

<σ><σ>

<σ>

<σ><σ>

<σ>

<Φ><Φ>

<Φ>

<Φ>

YLYR

YL YRYLYR

YLYR

YL YR

h s

h s hs

h s

hs

U(1)B-LEW

2.Model

f

fΨ1

Ψ1

σ φyY yf

Mh=120GeVMH=140GeVcosα=1/√2

Okada and Seto (2010)Kanemura, Seto and Shimomura (2011)

s channel

Higgs resonance is important

f

fΨ1

Ψ1

Z’gB-L gB-L

Maximal mixing between s and f is required!

η+

f

f

Ψ1

Ψ1e

e

Z’ is heavy constraint by m→eg

Abundance of Ψ1

2.Model

BR(μ→e,γ) < 2.4×10-12Experimental bound(MEG):

LFV constraint

e

η±

μ Ψ

γ

J. Adam et al.(2011)

f f

Direct detection of Ψ1

N

Ψ1 Ψ1

Z’

N

Experimental bound(XENON100): < 8×10-45cm2E. Aprile et al. (2011)Consistent with current experimental

bound.

2.Model

Parameter set

Normal Hierarchy, Tri-bi maximal(Our results are not sensitive to value of q13 ) 　 0.0757 0.0445fij = 0.01 -0.0123 -0.141 -0.0723MR = 250 GeV , MY1 = 57.0 GeV , MY2 = 800 GeVMS1 = 200 GeV, MS2 = 300 GeV , Mh = 120 GeV, MH = 140 GeV, Mh±= 280 GeV, cosq= 0.05, cosa=1/√2,gB-L=0.2, MZ’=2000GeV, vj=246 GeV, vs= 5 TeV

・ neutrino oscillation ・ LFV ・ LEP・ DM abundance ・ DM direct detection

hij = -0.131 0.1 0.1 0.1

100 GeV

1TeV

S2

η±

S1

Ψ2

hHνR

1,2

Z’

Ψ1

(DM)

2.Model

All coupling constant are O(0.01-0.1) and all masses are O(100-1000) GeV.

Physics of Z’

3. Physics at the LHC

Z’ decay into invisible about 30%Z’ production cross section is 70 ｆ b at the LHC for √s = 14 TeV , MZ’= 2000 GeV and gB-L= 0.2

L. Basso, A. Belyaev, S.Moretti and C. H. Shepherd-Themistocleous (2009);L.Basso 　 (2011)

G(Z’→XX) ∝ (B-L charge)2Z’ mass: O(1-10)TeV

Our model could be tested by measuring decay of the Z’ at the LHC.

However, if Z’ mass is heavy, our model would be difficult to be tested at the LHC.

Physics of Y1

4. Physics at the ILC

f

f

1. In our model, dark matter and electron are coupled via the Lyh coupling

2. The energy momentum conservation is used to detect the dark matter.

3. Background are e, E → e, m, p processes.

E

e

E

eg, Z

h-

Y1

m

Y1

Electron efficiency


1. In the signal processes, Electron tend to be emitted forward region.

2. We assume detectable area of electron 30 mrad and 20 mrad for 350 GeV and 500 GeV collider respectively

● ： 250GeV■ ： 150GeV▲ ： 75GeV

effici

ency

(%)

Identical efficiency of electron

Detect area (mrad)302010 40

60

20

80

100

40

0

I.Bozovic-Jelisavcic [on behalf of the FCAL Collaboration], (2011)

55 60 65 70 75 8050

4. Physics at the ILCThe cross section of the signal is very low in this case. The kinematical cuts to reduce B.G.

Dark matter can be tested with 1ab-1 data: at the √s = 350GeV collider for MDM 64 GeV at 3≲ s C.L. at the √s = 500GeV collider at 5s C.L.

10

1

0.1Cros

s sec

tion

(fb)0.1

0.01

0.001

0.0001

1

Cros

s sec

tion

(fb)

55 60 65 70 75 8050Dark matter mass (GeV) Dark matter mass (GeV)

√ ｓ = 500 GeV

√ ｓ = 350 GeV Back ground Back ground

signal

signal3s

3s

e, E → e, t, p processes


f

f

1. In our model, ftj coupling can take larger value than fmj coupling.

2. Signal cross section increase about 100 times more than e, E → e, m, p processes in our parameter set.

3. Background are same value to e, E → e, m, p processes.

E

e

E

eg, Z

h-

Y1

t

Y1

Y1 would be tested by invisible decay of h at √s=350 GeV with 500fb-1 at 3s C.L..

10-3

10-5

10-4

10-1

100010010

XENON100


Parameter set

10-2

S.Kanemura, S.Matsumoto, TN, H.Taniguchi (2011).

Y2

Physics of nR


1. In our parameter set, nR→W±, 　 l∓ is main decay mode.

2. We consider W→jet, jet process.3. Background are e, E → e (or m), W, p

processes.

f

fhij

E

e

h- nR

Y1

S1, S2

l-

W+

Lyh coupling constant f

0

4. Physics at the ILCThe cross section of the signal is very low in this case. The kinematical cuts to reduce B.G.

Right handed neutrino can be tested at 3s C.L. at the √s = 1 TeV collider with 3ab-1 data.

0.1

10

1

Cros

s sec

tion

(fb)

0.1

Back ground

signal

3s with 1ab-1

3s with 3ab-1

0.15 0.2 0.25 0.3

Parameter set

√ ｓ = 1 TeV

0.01

0.0010.05

LHC

e, W with Missing momentum → O(100) GeV right handed neutrino

ILCe, m with missing momentum → Dark matter which is directly coupled to charged lepton.

・ 350 GeV – 500 GeV (also 1 TeV)

・ 1 TeV

Radiative seesaw model with B-L gauge symmetry which include non stable right handed neutrino exist at TeV scale

Z’B-L is detected at the LHC

Most optimistic case

① We consider possibility of testing the TeV-scale seesaw model in which U(1)B−L gauge symmetry is the common origin of neutrino masses, the dark matter mass, and stability of the dark matter.

② Z’ boson could be tested at the LHC.③ Dark matter Y1 can be tested with 1 ab-

1data: at √s = 350 GeV linear collider with

MDM 64 GeV at 3s C.L..≲ at √s = 500 GeV linear collider at 5s

C.L. .⑤ Right handed neutrino could be tested at

3s C.L. at √s = 1 TeV linear collider with 3 ab-1data.

⑥ ILC have potential which distinguish between around U(1)B-L models.

5.Conclusion

Back up

0.1eV

1TeV

S2

η±

S1Ψ1

(DM)

Ψ2

νL

Z’ U(1)B-LU(1)DM

hH

EWSB νR

1,2

Type I like 2-loop seesaw

100 GeV

≈

Maximal mixing

1-loop neutrino Dirac Yukawa

treetree

charge assign

Wh2=0.1

U(1)B-L anomaly would be resolved by some heavy singlet fermions with appropriate B-L charge.

Our model focus to explain TeV scale physics.

Right hand: 1×9, -1/2×14, 1/3×9left hand: 3/2×14, -5/3×9

For example;

2.ModelU(1)B-L

anomaly

U(1)B-L anomaly is not serious

Remnant global U(1)DM remains on half unit of U(1)B-L charged particles after SSB of U(1)B-L.U(1)DM guarantee stability of dark matter.We consider that the Ψ1 is lightest U(1)DM particle case.

U(1)B-L

U(1)B-L breaking

-

ラグランジアン

e

eΨ1

Ψ1

η+

Relic abundance of Ψ1

LΨη coupling is small due to LFV constraint

f

fΨ1

Ψ1

σ φ ΨΨσ coupling ～ O(0.01) but resonance can be used.

Mixing between B-L Higgs σ and SM Higgs Φ is essentially important.

3.Neutrino mass and dark matter

f

f

yY yf

f

fΨ1

Ψ1

σ φ

Relic abundance of Ψ1

Mh=120GeVMH=140GeVcosα ～ 1/√2

Ψ1 is consistent with WMAP data at the MΨ1 = 57.0 GeV .


Okada and Seto (2010)Kanemura, Seto and Shimomura (2011)

yY yf

LFV constraint

e

η±

μ Ψ

γ

BR(μ→e,γ) < 2.4×10-12Experimental upper bound:

For our parameter set, it is evaluated asBR(μ→e,γ) = 5.1×10-13

Our parameter set safety current experimental upper bound but could be within future experimental reach.

J. Adam et al.(2011)


f f

Our parameter set safety current experimental bound but could be within future experimental reach.

NN

Ψ1 Ψ1σ

φ

Direct detection of Ψ1

N

Ψ1 Ψ1

Z’

Experimental bound (XENON100):

For our parameter set, it is evaluated as=8×10-45cm2

=2.7×10-45cm2

N

E. Aprile et al. (2011)


yY

yf

4.PhenomenologyPhysics of νR

・ νR are produced about 1200 pair from decay of 7000 Z’ at the LHC for √s = 14 TeV with 100 fb-1 data.

・ νR are light (O(100) GeV) 　 and are not stable.

W+

νR

l

j

j

νL

・ The mass of νR

can be reconstructed by jjl±

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Takehiro Nabeshima University of Toyama