Radiative B-L symmetry Radiative B-L symmetry breaking and the Z' mediated breaking and the Z' mediated

SUSY breakingSUSY breaking

Takayuki Kubo (KEK)Takayuki Kubo (KEK)arXiv:0804.3933 [hep-ph]

work in collaboration with Tatsuru Kikuchi (KEK)

SUSY 08, Korea June 17, 20081

Outline

June 17, 2008SUSY 08, Korea2

Introduction Review of the U(1)B-L extended MSSM Review of the Z’-mediated SUSY

breaking Results Summary

Introduction (1)

June 17, 2008SUSY 08, Korea3

The U(1)B-L extended MSSM has fascinating features.

Right-handed neutrinos are naturally introduced in order to cancel the anomalies.

B and L violating interactions are forbidden. Discrete symmetries (e.g. R-parity) are not

needed !

Seesaw scale can be understood as a breaking scale of the U(1)B-L symmetry.

Introduction (2)

June 17, 2008SUSY 08, Korea4

Z’-mediated SUSY breaking need only an extra U(1)’ gauge multiplet. P. Langacker et.al., Phys. Rev. Lett. 100 (2008)

041802 We can identify U(1)B-L as U(1)’

We treat the U(1)B-L extended MSSM in a framework of the Z’-mediated SUSY breaking. Radiative B-L symmetry breaking is achieved. Obtained mass spectra are much different from

mSUGRA.

Review of the U(1)B-L extended MSSM (1)

June 17, 2008SUSY 08, Korea5

SM and MSSM have a global U(1)B-L symmetry.

But it can not be a local one, since Tr(B-L)3≠0. Q : -1/3, Uc : 1/3, Dc : 1/3, L : -1, Ec : +1, H1 : 0, H2

: 0

Now, add the right-handed neutrinos Nc : +1 .

Tr(B-L)3=0 and U(1)B-L can be a local symmetry !

Right-handed neutrinos are naturally introduced.

Review of the U(1)B-L extended MSSM (2)

June 17, 2008SUSY 08, Korea6

U(1)B-L symmetry forbids B and L violating terms! UcDcDc : -1/3-1/3-1/3≠0, LQDc : -1+1/3-1/3≠0, LLEc : -1-1+1≠0, 　　　　　 etc.

U(1)B-L symmetry forbids B and L violating terms! Discrete symmetries (e.g. R-parity) are not

needed !

Review of the U(1)B-L extended MSSM (3)

June 17, 2008SUSY 08, Korea7

Superpotential

∆1 and ∆2 are MSSM siglets with B-L charges ∆1 : -2 and ∆2 : +2.

(∆2 is necessary to cancel the anomaly produced by the fermionic component of ∆1.)

U(1)B-L symmetry forbids MNNcNc term !

Instead, ‹∆1› gives the seesaw scale.

Seesaw scale can be understood as the breaking scale of the U(1)B-L symmetry.

2112 ')( cj

ciij

cjiij NNfNLHYWW MSSM

new comers

Review of the Z’-mediated SUSY breaking (1)

June 17, 2008SUSY 08, Korea8

Extra gauge multiplet U(1)’ couples to both visible and hidden sectors.

U(1)’ gaugino acquires its mass at a scale Λs by a dynamics in the hidden sector.

All the soft-terms are induced by the U(1)’ gaugino mass through the RGE.

VisibleDynamicalSUSYBreaking'

~Z

Review of the Z’-mediated SUSY breaking (2)

June 17, 2008SUSY 08, Korea9

At the scale Λs, only the U(1)’ gaugino acquires its mass. MSSM gauginos and scalars acquire their masses through

the RGE.

Taking Ma≈100GeV, we have the U(1)’ gaugino mass≈106GeV.

Scalar masses ≈105GeV. At low energy, all the scalars decouple (split SUSY). There is no SUSY flavor & CP problems in this model.

LB

LB

LB

ZZ

sZLBa

a MM

MggM

~

4

~22

~22

10log)16(

LBZ ~

2~

2

~2

2~

2

2~ 10log

16 LB

LB

LB

ZZ

sZLB

fM

M

Mgm

LBZ ~

Setup

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Superpotential (I have already shown):

SUSY breaking terms: We adopt the “Z’-mediated SUSY breaking”. Z’ is identified as ZB-L in this work. Only four input parameters !

2112 ')( cj

ciij

cjiij NNfNLHYWW MSSM

ssLBsZs fgMLB

at , at , at , ~

=106GeV

Radiative B-L breaking

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Running behavior for the soft-mass of the ∆1 is shown below.

m2△ 1 goes into the negative region and develops a VEV.

Seesaw scale MN≈‹∆1› are generated dynamically.

≈ 105GeV~106GeV

221 /

1 LBN gmM

Only the B-L gaugino acquires its mass≈106GeV at Λs=109GeVf=5

f=4

f=6f=7

∆1 scalar acquire its mass through the RGE.

Gaugino Masses

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Running behavior is shown below, where Λs=109GeV and gB-

L=0.5 at μ=Λs.

Mass spectra are much different from mSUGRA (1:2:7) !

The signals at the LHC experiments are rather exotic and interesting.

Only the B-L gaugino acquires its mass≈106GeV at Λs=109GeV

gluinowino

bino

B-L gaugino and all scalars decouples here!

Summary

June 17, 2008SUSY 08, Korea13

Radiative B-L symmetry breaking works in a framework of Z’-mediation.

The mass spectra for gauginos are much different from mSUGRA.

U(1)B-L extension is fascinating.

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Back up

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Gaugino Masses

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Running behavior is shown below, where Λs=109GeV and gB-L=0.5 at μ=Λs.

Mass spectra are much different from mSUGRA (1:2:7) !

The signals at the LHC experiments are rather exotic and interesting.

Only the B-L gaugino acquires its mass≈106GeV at Λs=109GeV

gluinowino

bino

B-L gaugino and all scalars decouples here!

Gaugino Masses (2)

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Gaugino masses as a function of the boundary value of gB-L.

Gaugino masses as a function of Λs.

gluinowino

bino

gB-L is set to 0.5 at μ=Λs.

gluinowino

bino

Λs is set to109GeV.

Summary

SUSY 08, Korea

U(1)B-L extension is fascinating. Existence of RH neutrinos makes U(1)B-L gaugeable. U(1)B-L symmetry forbids B and L violating terms. Seesaw scale can be understood as the breaking

scale of U(1)B-L.

U(1)B-L extended MSSM with Z’-mediation gives characteristic mass spectra. All the sfermion masses become very heavy (~105

GeV). The mass spectra for gauginos are much different

from mSUGRA.

Radiative B-L symmetry breaking works in a framework of Z’-mediation.

June 17, 200818

Brief Review of the U(1)B-L extended MSSM(4)

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Three features which I have shown Existence of RH neutrinos makes U(1)B-L gaugeable.

U(1)B-L symmetry forbids B and L violating terms. Seesaw scale can be understood as the breaking

scale of U(1)B-L

are enough reason to study the gauged U(1)B-L.

I will show the radiative U(1)B-L symmetry breaking works and the mass spectra is characteristic in a framework of “Z’-mediated SUSY breaking”.