1. Mitsuru Kakizaki (University of Toyama)
Indirect reach of the heavy MSSM Higgs boson mass scale by precise measurements of Higgs boson decay branching ratios at future linear colliders
Mitsuru Kakizaki (University of Toyama)
Asian Linear Colliders Workshop (ALCW2015), April KEK
In collaboration with Shinya Kanemura, Mariko Kikuchi, Toshinori Matsui, Hiroyuki Taniguchi and Hiroshi Yokoya (U. of Toyama)
Work in progress
April 20, 2015
Mitsuru KAKIZAKI

2. This is not the end of the story
Motivation
Discovery of a Higgs boson at the CERN LHC
The Standard Model (SM) is established as a low-energy effective theory below GeV
This is not the end of the story
Unsolved questions include:
Hierarchy problem
Is the Higgs boson elementary or composite?
Dynamics behind the EW sym. breaking?
Origin of the Higgs coupling?
Is the Higgs boson solitary?
Higgs boson = Window to New Physics
An SM-like Higgs boson The SM Higgs boson
Hints of new physics are obtained by investigating properties of the discovered Higgs boson
April 20, 2015
Mitsuru KAKIZAKI

3. Strategy New physics effects are left in the Higgs couplings
Fingerprinting of the Higgs couplings:
New phys
New physics scale can be determined
New models can be distinguished
：SM particle
ILC accuracy of : percent level
[ILC Higgs White Paper]
Precise prediction of the Higgs couplings is important
[See Prof. Kanemura’s talk]
This talk:
In the Minimal Supersymmetric Standard Model (MSSM) , we evaluate Higgs boson branching ratios at 1-loop level
The indirect heavy Higgs mass reach is obtained through the ratio of the Higgs decay rates measured at the ILC
The indirect heavy Higgs mass reach at the ILC can be higher than the direct reach at the LHC
[See also Prof. Endo’s talk]
[For 2HDM, see Ms. Kikuchi’s talk; for composite models, see Dr. Kaneta’s talk]
April 20, 2015
Mitsuru KAKIZAKI

4. Loop corrections to the MSSM Bottom Yukawa coupling
MSSM Higgs sector:
：SM-like Higgs boson
：MSSM heavy Higgs bosons
Bottom Yukawa interaction:
[ILC Technical Design Report; ILC Higgs White Paper]
- SUSY breaking
“Wrong Higgs coupling”
[Hall,Rattazzi,Sarid(1994);Hempfling(1994); Eberl,Hidaka,Kraml,Majerotto,Yamada(2000); Haber,Mason(2008);Endo,Moroi,Nojiri(2015), ...]
Bottom quark mass:
Bottom Yukawa coupling to the SM-like Higgs boson:
April 20, 2015
Mitsuru KAKIZAKI

5. Properties of the Bottom Yukawa coupling
There are two new mass scales in the MSSM:
In the limit of large with fixed
- SUSY loop corrections do not decouple for small and are enhanced for large , (in sharp contrast to the type-II two-Higgs-doublet model)
In the limit of a large heavy Higgs boson mass
- SUSY radiative corrections decouple
April 20, 2015
Mitsuru KAKIZAKI

6. Numerical Analysis FeynHiggs2.10.3 is used
[ Hahn,Heinemeyer,Hollik, Rzehak,Weiglein,Williams]
FeynHiggs is used
The Higgs boson masses and mixing angle are computed at 2-loop level in the on-shell scheme
Higgs boson decay rates are computed at 1-loop level
[Williams,Weiglein(2008)]
Imposed conditions：
CP conservation; No color or charge breaking
No negative sfermion mass squared
Superparticle mass bounds obtained at the LHC
1st Neutralino is the lightest supersymmetric particle
Simplifying assumptions：
Mass universality for the 1st and 2nd generation sfermions
Universal A-parameters:
April 20, 2015
Mitsuru KAKIZAKI

7. MSSM Parameters and Constraints
Input parameters:
Constraints:
Reference point:
(Common)
(Common)
Scanned parameters:
April 20, 2015
Mitsuru KAKIZAKI

8. Heavy MSSM Higgs Mass Reach at ILC 500
To cancel uncertainties of the production and total decay rate, we consider the ratio of branching fractions:
ILC 500
ILC sensitivity:
[ILC Higgs White Paper(2013)]
[ATLAS (2014)]
April 20, 2015
Mitsuru KAKIZAKI

9. Heavy MSSM Higgs Mass Reach at ILC 500
To cancel uncertainties of the production and total decay rate, we consider the ratio of branching fractions:
ILC 500
ILC sensitivity:
[ILC Higgs White Paper(2013)]
[ATLAS (2014)]
[Morinaga, JPS 70th Annual Meeting (2015)]
April 20, 2015
Mitsuru KAKIZAKI

10. Heavy Higgs Mass Reach (Luminosity Upgrades)
ILC 500 LumiUp:
ILC 1000 LumiUp:
[ILC Higgs White Paper; ATLAS (2014)]
The indirect reach through the Higgs coupling measurements can be higher than the LHC direct observation limits
The indirect reach of the MSSM heavy Higgs boson mass can be significantly extended, compared to the tree-level results
April 20, 2015
Mitsuru KAKIZAKI

11. Heavy MSSM Higgs Mass Reach (Luminosity Upgrades)
ILC 500 LumiUp:
ILC 1000 LumiUp:
[ILC Higgs White Paper; ATLAS (2014); Morinaga, JPS 70th Annual Meeting (2015)]
The indirect reach through the Higgs coupling measurements can be higher than the LHC direct observation limits
The indirect reach of the MSSM heavy Higgs boson mass can be significantly extended, compared to the tree-level results
April 20, 2015
Mitsuru KAKIZAKI

12. Summary
We have evaluated SM-like Higgs boson branching fractions including loop corrections in the MSSM
Due to the non-decoupling effects, of the Higgs couplings significantly deviate from the tree-level predictions
The indirect heavy MSSM Higgs mass reach through the ratio of the SM-like Higgs decay branching ratios is shown at each ILC stage
The indirect heavy MSSM Higgs reach at the ILC can be higher than the direct limit at the LHC
Fingerprinting of Higgs boson couplings is a powerful tool to explore and distinguish models explaining dynamics of the EWSB (MSSM, NMSSM, Composite models, ...) and should be encouraged
April 20, 2015
Mitsuru KAKIZAKI

13. Backup slides
April 20, 2015
Mitsuru KAKIZAKI

14. Determination of the Higgs Boson Branching ratios at the ILC
Expected accuracies for cross section times branching ratio for the 125 GeV Higgs boson:
[ILC Higgs White paper (2013)]
April 20, 2015
Mitsuru KAKIZAKI

15. Determination of the Higgs Boson Couplings at the ILC
Expected accuracies for model independent determination of the 125 GeV Higgs boson couplings:
[ILC Higgs White paper (2013)]
April 20, 2015
Mitsuru KAKIZAKI

16. Heavy MSSM Higgs boson search at the LHC
Exclusion limit at the LHC through
[arXiv: ]
[arXiv: ]
April 20, 2015
Mitsuru KAKIZAKI

17. Expected Heavy MSSM Higgs Boson Mass Reach at the LHC
5 sigma direct discovery potential of the MSSM heavy Higgs bosons at the LHC through:
[ATLAS-PHYS-PUB ]
April 20, 2015
Mitsuru KAKIZAKI

18. Expected Heavy MSSM Higgs Boson Mass Reach at the LHC
Expected 95% CL exclusion limit at the LHC ATLAS
[From Morinaga, JPS 70th Annual Meeting (2015)]
April 20, 2015
Mitsuru KAKIZAKI

19. Wrong-Higgs Yukawa interactions
1-loop diagrams contributing to the wrong-Higgs Yukawa interactions:
3-point scalar interactions:
[Haber,Mason(2008)]
April 20, 2015
Mitsuru KAKIZAKI

20. Yukawa couplings in the MSSM
Radiative corrections to the bottom Yukawa coupling：
April 20, 2015
Mitsuru KAKIZAKI