Baryogenesis and Higgs Phenomenology

V. Cirigliano LANLC. Lee LBLS. Tulin CaltechS. Profumo UC Santa CruzG. Shaugnessy Wisconsin

PRD 71: 075010 (2005) PRD 73: 115009 (2006) JHEP 0607:002 (2006 ) JHEP 0807:010 (2007)

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M.J. Ramsey-MusolfWisconsin-Madison

Baryogenesis Higgs Phenomenology

V. Barger WisconsinP. Langacker IASM. McCaskey WisconsinD. O’Connell IASS. Profumo UC Santa CruzG. Shaugnessy WisconsinM. Wise Caltech

PRD 75: 037701 (2007) arXiv: 0706.4311 hep-ph

Key Ideas & Results

• Simple extensions of the SM scalar sector (xSM) w/ small number of d.o.f. can readily lead to a strong, 1st order EWPT as needed for EW baryogenesis

• EWPT viable xSM can allow for heavier SM-like Higgs consistent with EWPO

• EWPT xSM can readily probed at the LHC and ILC using Higgs boson searches

• One can obtain an analytic criteria for parameters of xSM needed for 1st order EWPT that provides guidance for specific model realizations

No need for light RH stop

Outline

I. EWB & Higgs: Brief Review

II. Extending the Higgs Sector: the simplest xSM

III. Phenomenology: EWPO & Colliders

EW Baryogenesis: Testability

Weak Scale Baryogenesis

• B violation

• C & CP violation

• Nonequilibrium dynamics

Sakharov, 1967

?

ϕ new

?

φ(x)

Unbroken phase

Broken phaseCP Violation

Topological transitions

1st order phase transition

?

γ

?

e -?

ψnew

?

ϕ new

?

ϕ new

€

g

€

ϕ

€

g€

γ

€

γ€

e+

€

e−

€

Z 0

€

Z 0€

ϕ• Is it viable?• Can experiment constrain it?• How reliably can we compute it?

Baryogenesis: New Electroweak Physics

Weak Scale Baryogenesis

• B violation

• C & CP violation

• Nonequilibrium dynamics

Sakharov, 1967

?

ϕ new

?

φ(x)

Unbroken phase

Broken phaseCP Violation

Topological transitions

1st order phase transition

• Is it viable?• Can experiment constrain it?• How reliably can we compute it?

90’s: Cohen, Kaplan, Nelson Joyce, Prokopec, Turok

Theoretical Issues:Strength of phase transition (Higgs sector) Bubble dynamics (expansion rate)Transport at phase boundary (non-eq QFT)EDMs: many-body physics & QCD

?

γ

?

e -?

ψnew

?

ϕ new

?

ϕ new

More Higgs? Barger,Langacker, McCaskey,O.Connell,Profumo, R-M, Shaugnessy, Tulin, Wise

Electroweak Phase Transition & Higgs

?

φ

?

φ

?

F

?

F1st order 2nd orderLEP EWWG

Increasing mh

mh>114.4 GeV

or ~ 90 GeV (SUSY)

Computed ESM ! mH < 40 GeV

Need

So that sphaleron is not too fast

EMSSM ~ 10 ESM ! mH < 120 GeV€

ϕ

€

ϕ

€

˜ t

€

+LStop loops in VEff

Light RH stop w/ special

Electroweak Phase Transition & Higgs

?

φ

?

φ

?

F

?

F

Increasing mH

1st order 2nd orderLEP EWWG

mh>114.4 GeV

or ~ 90 GeV (SUSY)

Computed ESM ! mH < 40 GeV

Need

So that sphaleron is not too fastNon-SU(2) Higgs (w / wo SUSY)

€

S

€

ϕ

Mixing€

S

€

ϕ

€

S

Decay

€

e+

€

e−

€

Z 0

€

Z 0

€

ϕ

€

S

sin2

Electroweak Phase Transition & Higgs

?

φ

?

φ

?

F

?

F

Increasing mH

1st order 2nd orderLEP EWWG

mh>114.4 GeV

or ~ 90 GeV (SUSY)

Computed ESM ! mH < 40 GeV

Need

So that sphaleron is not too fastNon-SU(2) Higgs (w / wo SUSY)

€

S

€

ϕ

Mixing€

S

€

ϕ

€

S

Decay

B.R. reduction

Reduced SM Higgs branching ratios

Unusual final states

€

S

€

ϕ

€

S€

b

€

b

€

μ+

€

μ−

mH

O’Connell, R-M, Wise

Extending the Higgs Sector

GUTs: SU(5) example

+ L soft

SUSY Beyond the MSSM

Fileviez Perez, Patel, R-M

Ando, Barger, Langacker, Profumo, R-M, Shaugnessy, Tulin

The Simplest Extension

Model

Independent Parameters:

v0, x0, 0, a1, a2, b3, b4

H-S Mixing H1!H2H2

Simplest extension of the SM scalar sector: add one real scalar S

• Goal: identify generic features of models with extended scalar sectors that give a strong, 1st order EWPT

• Determine low-energy phenomenology (Higgs studies, precision ewk)

• Address CPV with a different mechanism

The Simplest Extension, Cont’d

€

M 2 =μh

2 μhs2 2

μhs2 2 μ s

2

⎛

⎝ ⎜

⎞

⎠ ⎟

Mass matrix

€

h1

h2

⎛

⎝ ⎜

⎞

⎠ ⎟=

sinθ cosθ

cosθ −sinθ

⎛

⎝ ⎜

⎞

⎠ ⎟h

s

⎛

⎝ ⎜

⎞

⎠ ⎟

Stable S (dark matter?)

• Tree-level Z2 symmetry: a1=b3=0 to prevent s-h mixing and one-loop s

hh

• x0 =0 to prevent h-s mixing

Finite Temperature Potential

?

φ

?

φ

?

F

?

F

€

H 0

€

S

• What is the pattern of symmetry breaking ?

• What are conditions on the couplings in V(H,S) so that <H0>/T > 1 at TC ?

Cylindrical Co-ordinates

€

ϕ

€

α • Compute Veff ( ϕ α T )

• Minimize w.r.t ϕ α

• Find TC

• Evaluate v(TC )/TC ~

cos α(TC) ϕ(TC )/TC

Electroweak Symmetry Breaking

Strong first order EWPT

Potential

ConditionsAnalytic

Analytic

Numerical

Symmetry Breaking

Two Cases for <S>at high T:

?

φ

?

φ

?

F

?

F

€

H 0

€

S

€

ϕ

€

α

Vmin = 0

Vmin = V0 < 0

Electroweak Symmetry Breaking

Strong first order EWPT

Potential parameters

Small αc limit

Increase

Large e < 0

Reduce

Nonzero V0

€

e+

€

e−

€

Z 0

€

Z 0

€

ϕ

€

S

€

h2

€

h1

€

h2

Electroweak Symmetry Breaking

Strong first order EWPT

a1<0, a2 either sign a1=b3= 0, a2 < 0

x0 > 0 occurs readily

Light: all models Black: LEP allowed

€

e+

€

e−

€

Z 0

€

Z 0

€

ϕ

€

S

€

h2

€

h1

€

h2

Electroweak Symmetry Breaking

Critical Temperature

LEP allowed models: TC ~ 100 GeV

|V0| / TC4 << 1

Phenomenology

Electroweak Precision Observables (EWPO)

Oblique parameters

Similar for S,U…

SM: global fit favors light scalar (mh~ 85 GeV)

Phenomenology

Electroweak Precision Observables (EWPO)

Oblique parameters

Global fit (GAPP)

Phenomenology

Colliders

EWPO: favors light SM-like scalar

EWPO compatible

m2 > 2 m1

m1 > 2 m2

LHC exotic final states: 4b-jets, γγ + 2 b-jets…

LHC: reduced BR(h SM)

ILC: H’strahlung

€

h1

€

h2

€

h1€

b

€

b

€

γ

€

γ

Phenomenology

Colliders

Z2 Symmetry

m1 > 2 m2

LHC: reduced BR(h SM)

€

h2

€

h1

€

h2Small :

LHC Phenomenology

Discovery PotentialBarger, Langacker, McCaskey, R-M, Shaughnessy

LHC Higgs Searches

CMS & ATLAS: gg!H, H!γγ H!ZZ!llll H!WW!l l

CMS : WW!H, H!γγ H!!l + jH!WW!l jj

ATLAS : gg!H, H!ZZ!ll Higgstrahlung

CMS 30 fb-1

LHC Phenomenology

Discovery Potential

SM-like

Singlet-like

~ EWB Viable

Barger, Langacker, McCaskey, R-M, Shaughnessy

SM-like

SM-like w/ H2!H1H1 or Singlet-like

CMS 30 fb-1Could discovery heavy H2

LHC Phenomenology, cont’d

Determining Barger, Langacker, McKaskey, R-M, Shaughnessy

SM-like

SM-like w/ H2!H1H1 or Singlet-like

~ EWB Viable

Enhanced gHVV coupling needed for 5 observation

ILC Phenomenology

Colliders: e+e- Z * h

€

e+

€

e−

€

Z 0

€

Z 0

€

ϕ

€

S

(also WWF, ZZF)

sin2

Key Ideas & Results

• Simple extensions of the SM scalar sector (xSM) w/ small number of d.o.f. can readily lead to a strong, 1st order EWPT as needed for EW baryogenesis

• EWPT viable xSM can allow for heavier SM-like Higgs consistent with EWPO

• EWPT xSM can readily probed at the LHC and ILC using Higgs boson searches

• One can obtain an analytic criteria for parameters of xSM needed for 1st order EWPT that provides guidance for specific model realizations

No need for light RH stop

Back Matter