1. Prospect after discoveries of Higgs/SUSY
Yasuhiro Okada (KEK)
“Discoveries of Higgs and Supersymmetry to Pioneer Particle Physics in the 21st century” November 25, 2005, Univ. of Tokyo

2. (1) Higgs Physics
Finding the mass-generation mechanism for gauge bosons, quarks and leptons the most urgent question of the present particle physics.
Discovery of the Higgs boson is the first step.
The answer is most probably related to what is physics beyond the standard model. The electroweak symmetry breaking requires dynamics beyond the SU(3)xSU(2)xU(1) gauge interactions.

3. How we have come to understand the strong interaction.
Structure of
a nucleus
(proton / neutron)
Discovery of
Yukawa
meson
Quark model
QCD
Discovery of the Higgs boson is similar to discovery of the Yukawa meson
in understanding the weak interaction.
Weak interaction
Higgs mechanism
Dynamics behind
the EW symmetry
breaking

4. A Higgs sector is unknown : How many Higgs bosons? (is there any?)
What is the mass ?
What is SU(2) representation?
Even if one Higgs doublet model is a good description,
What is f?
What physics determines –m^2?
What physics determines l?
Different scenarios provides different answers.
SUSY, String Theory
Composite model, Little Higgs model
TeV scale extra dimension

5. Composite model
~10 TeV a
SUSY GUT
Gravity
Gauge force
Extr dimension
Various new physics signals
are expected in the TeV
region, depending on different
signals.

6. Higgs mass Large Higgs mass  Large self-coupling  Strong dynamics
If we require that the SM is valid
up to 10^19 GeV,

7. Higgs potential is generated at low energy scale (< 0(10) TeV )
Two interesting cases
(1) Low mass Higgs boson (< 130 GeV)
(2) High mass Higgs boson (>300 GeV)
M.Peskin and J.Wells
mh=100 GeV
200
300
500
1000
SUSY
(mh< 135 GeV for MSSM) or
Higgs potential is generated at
low energy scale (< 0(10) TeV )
Ex. Pseudo Nambu-Goldstone boson
Something is needed to be consistent
with the EW precision data.

8. Higgs coupling LHC 0(10)% for ratio of the coupling constants ILC
A few % for absolute values
of various coupling

9. Indirect constraint on the heavy Higgs boson mass in MSSM
Direct search
at LHC
Direct search
at 1TeV LC
ACFA Higgs WG
S. Kiyoura, et al
ACFA report

10. SUSY loop contributions to the hbb Yukawa coupling
B(h->bb)/B(h->tt) is sensitive to
the SUSY loop correction to the
bottom Yukawa coupling for a
large tanb region.
B(h->bb)/B(h->tt) nomalized by SM value LC
LHC
K.S.Babu, C.Kolda:
M.Carena, D.Garcia, U.Nierste, C.E.M.Wagner
J.Guasch, W.Hollik,S.Penaranda

11. Higgs self-coupling measurement
Access to the Higgs potential.
Precision at 1/ab for 120 GeV Higgs boson
~20% for 500GeV ILC
~10% for 1 TeV ILC
Y.Yasui, et al, LCWS 02

12. Electroweak baryogenesis and Higgs potential
First order phase transition
Extension of the Higgs sector
The Higgs potential at zero temperature is also modified.
=> Self coupling measurement
Model with dim 6 potential
2HDM
S.Kaenmura, Y. Okada, E.Senaha
C.Grojean,G.Servant, J.D.Wells

13. (2) Supersymmetry
Supersymmetry is a revolution of physics similar to relativity, if it is found.
SUSY provides a coherent picture of particle physics and cosmology
SUSY + GUT => Gauge coupling unification
SUSY + R parity => Dark matter
SUSY + Seesaw neutrino => Leptogenesis
(Baryon number of the Universe)
After we confirm the supersymmetry, whether these ideas are realized
could be central issues.

14. SUSY breaking scenario
SUSY and GUT
LHC/LC combined
analysis
SUSY breaking scenario

15. Dark matter SUSY mass and coupling measurements
ALCPG cosmology subgroup
SUSY mass and coupling measurements
=> Identification of dark matter
PLANCK
WMAP

16. SUSY Seesaw model
Large Lepton flavor violation processes are expected.
m->eg in SU(5) SUSY GUT
with seesaw neutrino
Slepton flavor mixing
J.Hisano, M.M.Nojiri, Y.Shimizu, M.Tanaka
T.Goto,Y.Shimizu,T.Shindo,M.Tanaka and Y.Okada.

17. Conclusions
Discovery of the Higgs boson is the first step to understand the dynamics of the electroweak symmetry breaking.
Measurements of the Higgs coupling constants can provide hints to new physics.
SUSY, if it exists, has far-reaching consequences in particle physics and cosmology.