Mar. 29, 2008 LHC 研究会

Axionic Mirage Mediation

Tohoku Univ.

Shuntaro Nakamura

Collaborated with K. Okumura and M. Yamaguchi

This talk is based on arXiv:0803.3725

Mar. 29, 2008 LHC 研究会

Contents

1. Introduction

2. The model

3. The problem

4. Cosmology

5. Summary

Mar. 29, 2008 LHC 研究会

1. Introduction

SUSY is the good candidate for new physics beyond SM

• solve the hierarchy problem

• has DM candidates

However, sparticles have not been discovered yet

It has to be broken

Phenomenological aspects depend on how SUSY is broken

To understand the SUSY mechanism is important !

Mar. 29, 2008 LHC 研究会

The moduli mediation The anomaly mediation

In KKLT set-up, the modulus is stabilized with the relatively heavy mass

: modulus mass

Thus, the anomaly mediation is comparable to the modulus one

This is known as the mirage mediation Choi et. al. ’05

Endo, Yamaguchi, Yoshioka ’05

The mirage mediation is one of most plausible mediation mechanisms

Mar. 29, 2008 LHC 研究会

The mirage mediation is very attractive mechanism

However, it has two crucial problems

In general, B parameter becomes TeV

Too large !

2. moduli problem

The modulus decay produces too many gravitinos

Neutralinos, if they are stable, overclose the Universe !

Endo, Hamaguchi, Takahashi ’06 SN, Yamaguchi ’06

Choi, Jeong, Okumura ’05

1. problem

Mar. 29, 2008 LHC 研究会

We showed to introduce the axion superfield into the mirage mediation can solve

moduli problem

as well as

DM

strong CP problem

SUSY CP problem

axino MeV

problem

Mar. 29, 2008 LHC 研究会

2. The model

Let us consider the following superpotential

: axion superfield : messenger

The scalar potential of S is

From RGE of , S is stabilized at some scale

Mar. 29, 2008 LHC 研究会

The PQ scale in axionic mirage mediation

In what follows, we consider the case

Mar. 29, 2008 LHC 研究会

The axino mass is

: anomalous dimension of S

This is two-loop order in contrast with the other soft masses being one-loop

The axino becomes LSP

Mar. 29, 2008 LHC 研究会

Let us consider the following superpotential and Kahler potential

are singlets

When gets VEV, we can integrate out

3. The problem

Mar. 29, 2008 LHC 研究会

4. Cosmology

We assume both and have Planck scale amp., and their coherent oscillations start before the reheating is completed

for

The modulus decay dilutes unwanted particles

saxion mainly decays into axions

for

modulus mainly decays into gauge multiplet

Mar. 29, 2008 LHC 研究会

Axino are produced by non-thermally from the modulus

This process gives the

dominant contribution

Table of the abundance of the axino in the 4th. process

Mar. 29, 2008 LHC 研究会

Contours of the density parameter of the axino

Case A Case B

Mar. 29, 2008 LHC 研究会

Especially, the higgsino NLSP case is very interesting !

The higgsino can decay into the Higgs and the axino through the term

also decay into the Z boson through the higgsino-axino mixing

The lifetime of the higgsino is

for

Mar. 29, 2008 LHC 研究会

5. Summary

We discussed the axionic extended mirage mediation, axionic mirage mediation

In this model, the axino is LSP, which is much lighter than the neutralinos

no moduli problem

also SUSY CP problem

axino with MeV can explain DM

The problem can be solved

Its collider signature is very interesting