Review of mssm higgs boson searches at lep
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Review of MSSM Higgs boson searches at LEP. MSSM with CP conservation MSSM with CP violation Conclusions. 3 neutral Higgs bosons: h, H, A CP-eigenstates at tree level, 2 parameters : tan , m A. CP-conserving MSSM scenarios. hZ: low tan  large tan & m A

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Review of MSSM Higgs boson searches at LEP

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Review of mssm higgs boson searches at lep

Review of MSSM Higgs boson searches at LEP

MSSM with CP conservation

MSSM with CP violation

Conclusions

3 July 2006


Cp conserving mssm scenarios

3 neutral Higgs bosons: h, H, A CP-eigenstates

at tree level, 2 parameters : tan, mA

CP-conserving MSSM scenarios

hZ: low tan

large tan & mA

HZ: large tan & low mA

hA: interm./large tan & low mA

Higgsdecays: invisible, , ee, , , KK, cc, , bb, AA, hadrons

3 July 2006


The mssm underlying parameters at higher order

The MSSM underlying parameters at higher order

mtopand the SUSY breaking parameters, assumed to be unified at some scale :

SU(2), U(1) gaugino mass terms unified at MGUT  M2 at MEW

sfermion mass terms : unified at MEW  Msusyat MEW

squark trilinear couplings : unified at MEW  A at MEW

 mixing parameter in the stop sector :  X = A -  cot

gluino mass and Higgs mixing parameter  Mğand

Total: 8 parameters

mtop is measured ; M2, Msusy, Mğ,  et X are chosen to define a “scenario”; tan and mA are free to vary (tan[0.4, 50] and mA[0.02, 1000] GeV).

NB: radiative corrections in the Feynman-diagrammatic approach (the most complete at two-loop order)

3 July 2006


The scenarios 3 lep 5 lhc scenarios

  • mhmax: sparticules at high mass (M2, Msusy, Mğ large),  et X such that mh range is maximal (mtop=174.3 GeV: mh < 132.9 GeV).

    LHC variants: 1)   -, 2)   - & X  -X

  • No mixing: counterpart of mhmax with X=0;mh range reduced (mtop=174.3 GeV: mh < 115.5 GeV).

    LHC variant: 1)   -, Msusy  2 Msusy

  • Large : at least one Higgs (h, A or H) kinematically accessible (mtop=174.3 GeV: mh < 108.0 GeV) but Br(bb, ) vanish at large tan.

  • Gluophobicscenario:ggh (strongly) suppressed  tan, mA

  • Small eff: Brh(bb, ) suppressedat large tan, moderate mA

The scenarios : 3 LEP / 5 LHC scenarios

3 July 2006


The m h max scenario s

mtop

95%CL

99.7%CL

The mhmax scenario(s)

mtop=174.3 GeV,95% CL limits:

mh > 92.8 GeV, mA > 93.4 GeV

insensitive to mtop

tan exclusion : 0.7 – 2.0

sensitive to mtop

LHC variants:~identical mass limits, looser tan constraints

3 July 2006


The no mixing scenario s

unexcluded holes:

hAA, mA<3GeV, mh~80GeV

lack of searches at LEP2

The no mixing scenario(s)

mtop=174.3 GeV,95% CL limits:

mh, mA > 93.6 GeV (tan>0.7)tan exclusion : 0.4 – 10.2 (mA>3GeV)

very sensitive to mtop: scenario fully excluded at mtop=169.3 GeV (H within reach)

LHC variant: tighter mass and tan limits

3 July 2006


The large scenario

The large  scenario

  • excluded at 95% CL, not at 99.7% CL:

  • hZ only remaining process

  • BR(hbb) suppressed

  • mh~108GeV close to the sensitivity of the flavour-blind searches

    This strip grows with increasing mtop

theoretically forbidden

mtop=174.3 GeV or smaller:

scenario fully excluded at 95%CL

thanks to: H searches and flavour-blind analyses

3 July 2006


The gluophobic and small scenarios

The gluophobic and small  scenarios

mtop=174.3 GeV , 95% CL limits:

mh > 90.5 GeV, mA > 96.3 GeV mh > 87.3 GeV, mA > 98.8 GeV

tan exclusion : 0.4 – 5.4 tan exclusion : 0.4 – 4.2

moderately sensitive to mtop

NB: h, A not degenerate in mass at large tan

3 July 2006


Cp conserving mssm scenarios conclusions

CP-conserving MSSM scenarios, conclusions:

  • 8 representative scenarios scanned with ADLO results on neutral Higgs boson searches at LEP1 & LEP2 ;

  • improved sensivitivity thanks to H searches and flavour-blind analyses (esp. for low mtop)

  • mass limits are set atlarge tan and ~ O(90) GeV in mh,mA

  • tan limits are set by the LEP mhmax scenario :

    tan exclusion (95%CL) : 0.7 – 2.0 for mtop=174.3 GeV

3 July 2006


Cp violating mssm scenarios

3 neutral Higgs bosons: H1,H2,H3mixtures ofCP-eigenstates

at tree level, 2 parameters : tan, mH

CP-violating MSSM scenarios

H1H2: interm./large tan & low mH1

H1Z: low tan,

large tan & mH1

H2Z: low/interm. tan & low mH1

wrt CPC case:

more processes a priori, but some ZZHi couplings can be suppressed

similar decays, but Hj HiHi is enhanced

3 July 2006


Review of mssm higgs boson searches at lep

The MSSM underlying parameters

  • The usual eight MSSM underlying parameters:

    • at tree level: tan, mH±

    • through radiative corrections : mtop and the SUSY breaking parameters: M2, Msusy, Mğ,  andAt,b

  • Additional CPV parameters :

    • two CPV phases : arg(At,b) and arg(Mğ)

  • Dominant CPV effects scale as: mtop4 Im(At,b)/(v12+v22)322Msusy2

     low Msusy, large  and arg(At,b)~90o

     the CPX scenario:

    Msusy=500GeV, =4Msusy=2TeV, |At,b|=Mğ=2Msusy=1TeV,M2=200GeV andarg(At,b)=arg(Mğ)=90o

    + 10 variants to study the dependence with arg(At,b),  and Msusy.

  • NB: radiative corrections in the renormalization group and Feynman-diagrammaticapproaches(presently at the same stage of developpement)

    3 July 2006


    Dependence with the cp violating phases

    60°

    CPC !

    90°

    slight excess of data

    lack of sensitivity

    Dependence with the CP-violating phases

    Phases ~90°:H1Z suppressed

    large tan: H1H2

    interm.tan: H2Z, esp. H2 H1H1

    3 July 2006


    Dependence with

    2TeV

    1TeV

    4TeV

    Dependence with 

    At intermediate tan:

    =1TeV: two processes left

    =2TeV: one process left

    =4TeV: no process left

    3 July 2006


    Dependence with m top

    174.3GeV

    169.2GeV

    179.4GeV

    Dependence with mtop

    At intermediate tan:

    H1Z, H2Z and H1H2 suppression gets stronger with increasing mtop

    3 July 2006


    Review of mssm higgs boson searches at lep

    CP-violating MSSM scenarios, conclusions:

    • 11 representative scenarios scanned with ADLO results on neutral Higgs boson searches at LEP1 & LEP2 ;

    • Significant effects require arg(At,b)=90°,135°, mtop174GeV, and |At,b|/ Msusy2 8 ;

    • CPV = redundancy lost reduced sensitivity of LEP at intermediate tan down to the lowest massesNo absolute mass limits!

    • tan limits are set by the CPX scenario :

      tan > 2.9 (95% CL) for mtop=174.3 GeV

    • Results are qualitatively the same in the renormalization group and Feynman-diagrammatic approaches.

    3 July 2006


    Conclusions

    Conclusions

    From the neutral Higgs boson searches at LEP applied to a set of representative MSSM scenarios :

    • If CP is conserved in the Higgs sector:

      • absolute mass limits around 90 GeV in mh,mA;

      • low tan region not favoured (0.7 – 2.0 excluded in theLEP mhmax scenariofor mtop=174.3 GeV).

    • If CP is not conserved in the Higgs sector:

      • No absolute mass limits (at intermediate tan) !

      • low tan region still not favoured (tan<2.9 excluded in theCPX scenariofor mtop=174.3 GeV);

      • Calculations of radiative corrections not yet as complete as in the CP-conserving case.

    3 July 2006


    Introduction

    Higgsstrahlung

    Pair-production

    (+ WW, ZZ fusion)

    Yukawa production

    Introduction

    Higgs boson searches at LEP:

    • Direct searches :

      • Only 3 production processes

      • Almost all decays can be exploited

      • model-independentconstraints on  x Br

      • model scans : SM, MSSM, 2HDM

    • Indirect constraints through EW precision measurements

    In this talk: SM + MSSM neutral Higgs boson direct searches

    published in April 2006

    3 July 2006


    Current summary about the sm higgs boson

    Current summary about the SM Higgs boson:

    EW precise measurements:

    MH ≤ 175 GeV (95% CL)

    Direct searches :

    MH ≥ 114.4 GeV (95% CL)

    MH [115,118] GeV ?

    (status as of spring 2006)

    3 July 2006


    The standard model after lep

    The Standard Model after LEP

    LEP results:

    New physics scale

    3 July 2006


    95 cl upper bounds on x br

    95% CL upper bounds on  x Br

    dominant decays : direct decays in bb or 

    H1Z

    H2H1

    3 July 2006


    95 cl upper bounds on x br1

    95% CL upper bounds on  x Br

    non dominant decays : the example of the H2H1H1 cascade

    H2Z

    H2H1

    3 July 2006


    Review of mssm higgs boson searches at lep

    The gluophobic and small  scenarios

    gluo. scen.

    small 

     Br(MSSM)/ Br(SM) predictions

    NB: tthttbb and WW fusion channels enhanced

    NB: h channel unsuppressed

    3 July 2006


    Cph vs feynhiggs

    weaker exclusion

    weaker exclusion

    CPH

    FeynHiggs

    CPH vs FeynHiggs

    more one-loop and two-loop order corrections in FeynHiggs

    phase dependence more complete in CPH than in FeynHiggs

    3 July 2006


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