Takehiro Nabeshima University 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. B703:66-70 S. Kanemura, T.N., H. Sugiyama, Phys. Rev. D85, 033004
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Takehiro Nabeshima University of Toyama ILC physics general meeting 9 jun. 2012 Phenomenology at a linear collider in a radiative seesaw model from TeV.
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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 νR
M ~ 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
Aoki,Kanemura,Seto (2008)
Φ
νLνR
Φ Φ
νL
νR
νL
νL νL
ΦΦ
νR νR νR
M ~ 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)
Kanemura, T.N., Sugiyama (2012)
M ~ O(1) TeV → c ~ O(10-2-10-1)
νR are not stable.
Neutrino masses
1.Introduction
Aoki,Kanemura,Seto (2008)
Φ
νLνR
Φ Φ
νL
νR
νL
νL νL
ΦΦ
νR νR νR
M ~ 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)
Kanemura, T.N., Sugiyama (2012)
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 (1-at O10) ,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 (1-at O10) ,TeV MDM is given by this vevthrough yDM .Y Y s coupling
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 L yh 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
e, gZ
h-
Y1
m
Y1
Electron efficiency
4. Physics at the ILC
1. In the signal processes, Electron tend to be emitted forward region.
2. 30 We assume detectable area of electron 20 350 500 mrad and mrad for GeV and
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 ILC
The 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 √ = 500 5 . .s GeV collider at s C L
10
1
0.1Cr
oss
secti
on (fb
)0.1
0.01
0.001
0.0001
1
Cros
s se
ction
(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 pprocesses
4. Physics at the ILC
f
f
1. In our model, f tj coupling can take larger value than f mj .coupling
2. 100 Signal cross section increase about times , more than e E → , , e m p processes in our
.parameter set3. , → , , Background are same value to e E e m
.p processes
E
e
E
e, gZ
h-
Y1
t
Y1
Y1 would be tested by invisible decay of h at √ =350 s GeV with
500fb-1 3 . ..at s C L
10-3
10-5
10-4
10-1
100010010
XENON100
4. Physics at the ILC
Parameter set
10-2
S.Kanemura, S.Matsumoto, TN, H.Taniguchi (2011).
Y2
Physics of nR
4. Physics at the ILC
1. In our parameter set, nR→W±, l∓ is main . decay mode
2. → , .We consider W jet jet process3. , → ( ), , Background are e E e or m W p
.processes
f
fhij
E
e
h- nR
Y1
S1, S2
l-
W+
L yh coupling constant f
0
4. Physics at the ILC
The 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 3 s. . C L at the √ = 1 s TeV collider with
3ab-1 .data
0.1
10
1
Cros
s se
ction
(fb)
0.1
Back ground
signal
3 s with1ab-1
3 s with3ab-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 missingmomentum → 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-
1 :data at √ = 350 s GeV linear collider withMDM 64 3 . ..≲ GeV at s C L
at √ = 500 s GeV linear collider 5 at s. . .C L
⑤ Right handed neutrino could be tested 3 . . at s C L at √ = 1 s TeV linear collider
with 3 ab-1 .data⑥ 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
tree
tree
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 .
3.Neutrino mass and dark matter
Okada and Seto (2010)Kanemura, Seto and Shimomura (2011)
yY yf
LFV constraint
e
η±
μΨ
γ
BR(μ→e,γ) < 2.4×10-12
Experimental 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)
3.Neutrino mass and dark matter
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)
3.Neutrino mass and dark matter
yY
yf
4.Phenomenology
Physics 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.