Comprehensive Analysis on the Light Higgs Scenario in the Framework of Non-Universal Higgs

Mass Model

M. Asano (Tohoku Univ.)M. Senami (Kyoto Univ.)H. Sugiyama (Ritsumeikan Univ.)

Shigeki Matsumoto

Collaborators

New Physics @ Tera-scale

The Standard Model (SM) is one of the most successful models

describing physics below O(100) GeV. There are, however, some

problems that can not be explained in this framework.～ Hierarchy Problem ～

O(102 GeV)2 O(10-2)L2

mh2 = Tree level

mass (m02) + Quantum

Corrections

The cutoff scale L should be smaller than O(1) TeV. ～ Dark Matter Problem ～

1. No candidate for dark matter in the SM.

2. WIMP seems to be natural for the DM.

New particle (dark matter) will be at O(1) TeV.

Neutral & Stable particle with O(1) TeV mass Cold DM & Correct Relic Density of

DM!

New Physics @ Tera-scale

New Physics @ 1 TeV Scale

E (GeV)

102

103

(10-16cm)

(10-15cm) Standard Model

1. The Standard Model should be regarded as an effective field theory describing physics below 100 GeV.

2. New Physics appears at O(1) TeV, and it will solve the problems.

New Physics scenarios!

1. Supersymmetric Scenario

2. Little Higgs Scenario3. Extra-dimension Scenario4. Gauge Higgs Scenario,

etc.

SUSY scenario gives the solution to the both problems!Which SUSY model we consider?

MSSM

Gauge sym: SU(3)×SU(2)×U(1)Part. cont: Li, Ei, Qi, Di, Ui, H1, H2

The Light Higgs Scenario (LHS)

CP-odd Scalars Charged Scalars

In the MSSM, there are two Higgs doublets: H1 & H2

For down-type quarks For up-type quarks

We focus on the parameter region of the LHS!1. Explaining the LEP anomaly [M. Drees, PRD71 (2005)]2. Collider signals at the LHC [A. Belyaev, et.al., PRL100, (2008)]3. Relaxing the little hierarchy Problem [S. G. Kim, et.al., PRD74,

(2006)]

The Light Higgs Scenario (LHS)

Ｋ

CP-even Scalars

We focus on the parameter region of the LHS!1. Explaining the LEP anomaly [M. Drees, PRD71 (2005)]2. Collider signals at the LHC [A. Belyaev, et.al., PRL100, (2008)]3. Relaxing the little hierarchy Problem [S. G. Kim, et.al., PRD74,

(2006)]In the MSSM, there are two Higgs doublets: H1 & H2

For down-type quarks For up-type quarks

The Light Higgs Scenario (LHS)

+ DWhen Radiative

correction

ee

SM-like Higgs boson!

&Usual case

mZ D

H ～ η1 h ～ η2

mA sin&

LHS case

mZ D

H ～ η2 h ～ η1

All Higgs bosons are light!

Constraints on the Higgs sector of LHS

gZZh

(gZZh)MSSM << (gZZh)SM

LHS case (mA ～ mZ) h ～ η1

No LEP bound!

LEP bound on mh > 114.4 GeV

(gZZh)MSSM ～ (gZZh)SM

Usual case (mA >> mZ) h ～ η2

～ Bound on mh ～

Possible to explain the LEP Anomaly

Constraints on the Higgs sector of LHS

, H

The LEP limit is avoided for the Lightest Higgs boson (h)The LEP limit is applied to the Heavy Higgs boson (H).

This mode is suppressed due to the P-wave production as long as mA ～ mZ (mA is not too small.)

Realization of the Light Higgs Boson Scenario

1. MSSM has many parameters, so that it is difficult to handle with the model to explore the region realizing the LHS.

2. We have considered the NUHM (Non-universal Higgs Mass) model, which can realize the LHS. In this model, GUT relation on gaugino masses is assumed.

Purpose: Dark Matter phenomenology in the LHS

m0, mH1, mH2, m1/2, A0, B, m

E (GeV)

GUT

1 TeVMasses of SUSY particles, Higgs masses, v, tanb, …

Through RGEsParameters

m0, m1/2, A0, tanb, m, mA

Purpose: Dark Matter phenomenology in the LHS

Realization of the Light Higgs Boson Scenario

Constraints on NUHM

With the use of MCMC method, we have generated about

3.0 x 107 sample points which satisfy above constraints.

Realization of the Light Higgs Boson Scenario

Contour of Maximal Likelihood P = exp(-c2/2)

The NUHM model realize the LHS region of the MSSM!

The LHS Region

Realization of the Light Higgs Boson Scenario

100 GeV < m1/2 < 600 GeV

100 GeV < m0 < 1.9 TeV 7 < tan b < 19 93 GeV < mA < 113 GeV200 GeV < m < 850 GeV-3.5 TeV < A0 < 100 GeV

Allowed Region on the input parameter space

DM in the LHS

1. What is the Dark Matter? (Ans.) The Lightest neutralino!2. Composition of the DM? (Ans.) Almost Bino-like!3. Mass of the DM? (Ans.) 50 GeV < mDM < 300 GeV

(Bound on Chargino mass)I. Chargino mass > LEP search II. Chargino mass < Br(bsγ)

Contamination of higgsino components in the DM

100 GeV < m1/2 < 600 GeV

• M. Asano, S. M., M. Senami, and H. Sugiyama, PLB663 (2008)• S.-G. Kim, N. Maekawa, K. I. Nagao, K. Sakurai, T. Yoshikawa, PRD78

(2008)• M. Asano, S.M., M. Senami, and H. Sugiyama, JHEP 1007 (2010)

DM in the LHS

90% C.L. on SI cross section arXiv:1005.0380

CDMSII XENON100 XMASS SuperCDMS

DM in the LHS

All higgs bosons are light. sDM N > 7 x 10-45 cm2

Lower Bound!

DM in the LHS

～ SUSY Little Hierarchy Problem ～

How severe fine-tuning is needed for the EW scale?

A few % fine-tuning is needed. (In CMSSM, typically 0.1%)

Implication to the LHC

LHS spectrum

Mas

s (G

eV)

Spectrum is very similar to that of SPS1a’ except the Higgs sector. 1. Confirmation of the LHS by measuring a ～ p/2. 2. Confirmation of the WIMP by measuring WDMh2.

Summary & Discussions

• The Standard Model is the successful model to describe physics below the scale of O(100) GeV. However, there are some problems which can not been explained in this framework, and the existence of "New Physics” is expected to solve these problems naturally.

• Many scenarios of the New Physics have been proposed so far, and supersymmetric scenario is one of the most attractive scenarios. In this talk, we have focused on the Light Higgs Boson Scenario (LHS) of the MSSM. It is shown that the NUHM model realizes the LHS.

• One of interesting predictions of the LHS is coming from dark matter phenomenology. In this model, the mass of the dark matter is expected to be about 100 GeV, and its scattering cross section with a nucleon is about 10-44cm2. As a result, the dark matter in the LHS can be easily discovered in near future direct detection experiments.

• Since almost all new particles are predicted to be light, it is interesting to consider signals of new physics at the LHC. It is also interesting to consider signals at the ILC, because higgs sector of the scenario can be explored carefully.

Current Status of Higgs BosonCurrent Status of Higgs Boson

~ MSSM Higgs ~

Status of MSSM HiggsMSSM Higgs Interactions

MSSM contains 2 Higgs doublets Higgs interactions can be different!

tanb = ratio of vevs, a: mixing

The LEP limit may not be applied to the MSSM Higgs bosons

LEP collaboration have also analyzedconstraints on MSSM Higgs bosons

However, analysis have been performed in some MSSM benchmark scenarios,but not in all MSSM parameter space! (The parameter space is too large!!)

~ some details of benchmarks ~ 1. m and At term are fixed in some specific values 2. mA & tanb are scanned within specific ranges

Current Status of Higgs BosonCurrent Status of Higgs Boson

MSSM Benchmarks

For example, No Mixing case.

We can find the LHS region.

However, the LHS region isonly a part of the benchmark,The choice of the parameter space is not useful.