comprehensive analysis on the light higgs scenario in the framework of non-universal higgs mass...
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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
~ 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