Supersymmetric Models with 125 GeV Higgs Masahiro Yamaguchi (Tohoku University) 17 th Lomonosov Conference on Elementary Particle Physics Moscow State.

Supersymmetric Models with 125 GeV Higgs

Masahiro Yamaguchi(Tohoku University)

17th Lomonosov Conference on Elementary Particle Physics

Moscow State University, 20-26 August, 2015

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Higgs BosonHiggs Boson Mass

LHC combined 125.09±0.21(stat. )±0.11(syst. ) GeV

Signal Strength for Decay Modes CMS combined 1.00±0.14 ATLAS combined 1.18±0.15 consistent with SM prediction still some room to play with (room for BSM)

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Motivations for Supersymmetry• Unnaturalness of Higgs Sector: – gauge hierarchy problem/naturalness problem

• Unification of forces: Grand unification

• Muon g-2: possible deviation from SM

• Call for Beyond SM– Neutrino masses and mixings– Cosmology Connection

• Dark Matter, Baryogenesis, Dark Energy, Inflation

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SUSY Search

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Higgs Mass in MSSMIn MSSM SUSY Higgs Self Coupling = gauge coupling mh < mZ @tree level (SUSY relation)

Large SUSY breaking loop effect can raise the Higgs mass stop-top loops 1) large log mstop/mtop

2) finite A-term(stop-stop-Higgs coupling) contribution

Inoue et al ‘85

Okada, MY, Yanagida ’91Haber, HempflingEllis, Ridolfi, Zwirner

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Higgs Mass @3-loop

Hahn, Heinemeyer,Hollik, Rzehak, Weiglein,2014

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Challenge to Low Energy SUSY?To achieve the observed Higgs mass (125 GeV), we need either1)Heavy stop ( ～ 7TeV) and/or large stop mixing　　　 in MSSMor2) Addition of new source of Higgs mass at TeV scale e.g. Vector-like Generation (T+Tbar) Additional Gauge Sym. (eg. U(1)B-Lsym.)

Singlet Extension 7

Singlet Extensions

New Sources to increase Higgs Mass1)tree-level coupling (significant only for small tan )

2)Higgs/Higgsino loop (>0, for heavy singlet boson)

3) Doublet-Singlet Mixing (>0, for light singlet boson) If singlet boson is light, mixing increases doublet Higgs mass.

Jeong, Shoji & MY ‘11, ‘12, ’14Choi, Im, Jeong & MY ‘12

2 |HuHd|2 : new contribution to the Higgs potential

superpotential

New coupling: Higgs-Higgsino-Singlino

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Doublet-Singlet Mixingin CP even Higgs sector

Mixing terms in Scalar Sector

Mass^2 matirx for doublet and singlet Higgses

Mass eigenstates: three mixing angles

θ2: mixing between h and s9

Relations

Constraint on mixing upperbound on higgsino mass parameter (see below.)

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Coupling of SM-like Higgs boson

with from top-stop sector

Chargino loop

Mixings with singlet and with heavier doublet Change of SM-like Higgs coupling

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LHC Constraints on Higgs mixing

• Signal Strength (relative to SM expectation)

• With Singlet Experimental Constraints

2014 Summer

Mainly ggF Mainly VBF

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Experimental ConstraintsMixings compatible with LHC data within 1sigma(2 sigma)

ATLAS

CMS

tan =5 10 15

θ2: mixing between h and sCb 1 ̴� Cb -1 ̴�

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LEP Constraint on Singlet-like Higgs s

e+e- Z s Z bb

LEP constaint is not severe if singlet is heavier than 90 GeV.

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Contours of Higgsino mass parameter tan =5 tan = 10

Approximate Higgsino mass parameter: obtained from the previous relations

yellow: no solution to 125 GeV HiggsWhite: λ >1 (Landau pole)Cyan: μ ̴ <100 GeV (excluded)

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Summary so far:

Doublet-Singlet Mixing in NMSSM

1) realizes m_h=125 GeV by the mixing 2) satisfies LEP constraint on singlet s 3) is compatible with LHC Higgs data 4) favors Relatively Light Higgsino

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Comment on heavy stop case in MSSMCase of Non Universal Higgs Model (NUHM)

A slice of allowed parameter regions (at GUT scale)

In the bulk, all superparticles are heavy >> LHC reachBut near boundary, some of superparticles become light, accessible at LHCPrice: severe fine tuning of parameters

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Case of NUHM

Interesting cases light stop (only one of two stops) light first two generation squarks light Higgsinos light pseudoscalar A light sleptons with muon g-2 within 1 sigma

MY & Yin, in preparation

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Conclusions• 125GeV Higgs appears a challenge to low energy SUSY.

• MSSM: Heavy Stop (>>LHC bound)– Possible to have some light superparticles even in this case (explicit demonstration in NUHM)

• Alternatives to MSSM– New vector-like generation– Gauge symmetry– Singlet richer Higgs sector & neutralino sector

Rich phenomenology expected at LHC RUN2 in either caseStay tuned!

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Thank you very much!

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