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)

April 20, 2015 Mitsuru KAKIZAKI 1

Asian Linear Colliders Workshop (ALCW2015), 20-24 April 2015 @ KEK

In collaboration with Shinya Kanemura, Mariko Kikuchi, Toshinori Matsui, Hiroyuki Taniguchi and Hiroshi Yokoya (U. of Toyama)

Work in progress

Motivation

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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

Hints of new physics are obtained by investigatingproperties of the discovered Higgs boson

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

An SM-like Higgs boson The SM Higgs boson

Strategy

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This talk:

The indirect heavy Higgs mass reach at the ILC can be higher than the direct reach at the LHC

Precise prediction of the Higgs couplings is important

New physics effects are left in the Higgs couplings

New physics scale can be determined New models can be distinguished

The indirect heavy Higgs mass reach is obtained through the ratio of the Higgs decay rates measured at the ILC

In the Minimal Supersymmetric Standard Model (MSSM) ,we evaluate Higgs boson branching ratios at 1-loop level

Fingerprinting of the Higgs couplings:

： SM particle

New phys

ILC accuracy of : percent level [ILC Higgs White Paper]

[See Prof. Kanemura’s talk]

[For 2HDM, see Ms. Kikuchi’s talk; for composite models, see Dr. Kaneta’s talk][See also Prof. Endo’s talk]

Loop corrections to the MSSM Bottom Yukawa coupling

Bottom quark mass:

Bottom Yukawa coupling to the SM-like Higgs boson:

“Wrong Higgs coupling”

Bottom Yukawa interaction:

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[ILC Technical Design Report;ILC Higgs White Paper]

[Hall,Rattazzi,Sarid(1994);Hempfling(1994);Eberl,Hidaka,Kraml,Majerotto,Yamada(2000);Haber,Mason(2008);Endo,Moroi,Nojiri(2015), ...]

- SUSY breaking

MSSM Higgs sector:： SM-like Higgs boson

： MSSM heavy Higgs bosons

Properties of the Bottom Yukawa coupling

There are two new mass scales in the MSSM:

- SUSY radiative corrections decouple

In the limit of large with fixed

In the limit of a large heavy Higgs boson mass

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- SUSY loop corrections do not decouple for small and are enhanced for large , (in sharp contrast to the type-II two-Higgs-doublet model)

Numerical Analysis

Imposed conditions ：

Superparticle mass bounds obtained at the LHC

FeynHiggs2.10.3 is used [www.feynhiggs.de: Hahn,Heinemeyer,Hollik, Rzehak,Weiglein,Williams]

1st Neutralino is the lightest supersymmetric particle

Mass universality for the 1st and 2nd generation sfermions

Simplifying assumptions ：

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)]

CP conservation; No color or charge breaking

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No negative sfermion mass squared

Universal A-parameters:

MSSM Parameters and Constraints

Reference point:

Scanned parameters:

Constraints:

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Input parameters:

(Common)(Common)

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

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ILC sensitivity:

[ILC Higgs White Paper(2013)]

[ATLAS (2014)]

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

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ILC sensitivity:

[Morinaga, JPS 70th

Annual Meeting (2015)]

[ATLAS (2014)]

[ILC Higgs White Paper(2013)]

Heavy Higgs Mass Reach (Luminosity Upgrades)

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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

ILC 1000 LumiUp:

[ILC Higgs White Paper; ATLAS (2014)]

ILC 500 LumiUp:

Heavy MSSM Higgs Mass Reach (Luminosity Upgrades)

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[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

ILC 1000 LumiUp: ILC 500 LumiUp:

We have evaluated SM-like Higgs boson branching fractionsincluding loop corrections in the MSSM

Summary

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The indirect heavy MSSM Higgs reach at the ILCcan be higher than the direct limit at the LHC

Due to the non-decoupling effects, of the Higgs couplings significantly deviate from the tree-level predictions

Fingerprinting of Higgs boson couplings is a powerful tool toexplore and distinguish models explaining dynamics ofthe EWSB (MSSM, NMSSM, Composite models, ...) and should be encouraged

The indirect heavy MSSM Higgs mass reach through the ratio of the SM-like Higgs decay branching ratios is shownat each ILC stage

Backup slides

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Determination of the Higgs Boson Branching ratios at the ILC

April 20, 2015 Mitsuru KAKIZAKI 14[ILC Higgs White paper (2013)]

Expected accuracies for cross section times branching ratiofor the 125 GeV Higgs boson:

Determination of the Higgs Boson Couplings at the ILC

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[ILC Higgs White paper (2013)]

Expected accuracies for model independent determinationof the 125 GeV Higgs boson couplings:

Heavy MSSM Higgs boson search at the LHC

[arXiv:1409.6064] [arXiv:1408.3316]

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Exclusion limit at the LHC through

Expected Heavy MSSM Higgs Boson Mass Reach at the LHC

[ATLAS-PHYS-PUB-2013-016]

5 sigma direct discovery potential of the MSSM heavy Higgs bosons at the LHC through:

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Expected Heavy MSSM Higgs Boson Mass Reach at the LHC

[From Morinaga, JPS 70th Annual Meeting (2015)]

Expected 95% CL exclusion limit at the LHC ATLAS

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Wrong-Higgs Yukawa interactions

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[Haber,Mason(2008)]

1-loop diagrams contributing to the wrong-Higgs Yukawa interactions:

3-point scalar interactions:

Yukawa couplings in the MSSM

Radiative corrections to the bottom Yukawa coupling ：

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