Transcript Baryogenesis and Higgs Phenomenology

Baryogenesis and Higgs
Phenomenology
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M.J. Ramsey-Musolf
Wisconsin-Madison
Baryogenesis
V. Cirigliano
C. Lee
S. Tulin
S. Profumo
G. Shaugnessy
Higgs Phenomenology
LANL
LBL
Caltech
UC Santa Cruz
Wisconsin
PRD 71: 075010 (2005)
PRD 73: 115009 (2006)
JHEP 0607:002 (2006 )
JHEP 0807:010 (2007)
V. Barger
P. Langacker
M. McCaskey
D. O’Connell
S. Profumo
G. Shaugnessy
M. Wise
Wisconsin
IAS
Wisconsin
IAS
UC Santa Cruz
Wisconsin
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 No need for light RH stop
•
EWPT viable xSM can allow for heavier SMlike 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
Outline
I.
EWB & Higgs: Brief Review
II.
Extending the Higgs Sector: the
simplest xSM
III. Phenomenology: EWPO &
Colliders
EW Baryogenesis: Testability
Unbroken phase
Weak Scale Baryogenesis
• B violation
Topological transitions
new
• C & CP violation
• Nonequilibrium
dynamics
(x)
Broken phase

1st order phase transition

CP Violation
Sakharov, 1967
new

• gIs it viable? 
e

• Can experiment
constrain it?

e
g
  can we compute it?
• How reliably



0
Z
Z0




new


new
e


Baryogenesis: New Electroweak Physics
90’s:
Weak Scale Baryogenesis
• B violation
Cohen, Kaplan, Nelson
Joyce, Prokopec, Turok
Unbroken phase
Topological transitions
• C & CP violation
• Nonequilibrium
dynamics
Broken phase
1st order phase transition

(x)
new
More Higgs?
CP Violation
Barger,Langacker,

McCaskey,O.Connell,
Profumo, R-M,
Shaugnessy, Tulin,
Wise
new
Sakharov, 1967
Theoretical
Issues:
Strength of phase transition (Higgs
new
sector) •Bubble
dynamics (expansion rate)
Is it viable?
Transport
at phase
boundary
(non-eq
• Can
experiment
constrain
it? QFT)
 
EDMs: many-body
physics
& QCD
• How reliably
can we
compute it?
e


new

Electroweak Phase Transition & Higgs
F
F
1st order
2nd order

Need


Increasing mh

Stop loops
in VEff
LEP EWWG

t˜



EMSSM ~ 10
 ESM ! mH< 120 GeV

Light RH stop w/ special

So that Gsphaleron is not too fast
mh>114.4 GeV
ComputedorESM
! mGeV
~ 90
H < 40 GeV
(SUSY)
S


Electroweak Phase Transition & Higgs
e
e



Z0


F
sin2q
Z0


F
1st order

2nd order

LEP EWWG
Need


Increasing mH


Non-SU(2) Higgs (w / wo SUSY)
S


S
S


Decay


So that Gsphaleron is not too fast
mh>114.4 GeV
Mixing

ComputedorESM
! mGeV
~ 90
H < 40 GeV
(SUSY)
Reduced SM Higgs branching ratios
Electroweak Phase Transition & Higgs
B.R.
reduction
F
F
1st order
2nd order
LEP EWWG
mH
Unusual final states


S


b

S






Increasing
m
H


Need
b

O’Connell,
 R-M, Wise
 (w / wo SUSY)
Non-SU(2) Higgs
S


S
S


Decay


So that Gsphaleron is not too fast
mh>114.4 GeV
Mixing

ComputedorESM
! mGeV
~ 90
H < 40 GeV
(SUSY)
Extending the Higgs Sector
SUSY Beyond the MSSM
+L
Ando, Barger, Langacker, Profumo,
R-M, Shaugnessy, Tulin
soft
GUTs: SU(5) example
S0 ,S,S
Fileviez Perez, Patel, R-M
The Simplest Extension
Model
Simplest extension of the SM scalar
sector: add one real scalar S
H-S Mixing • Goal: identify generic features of
H1!H2H2
models with extended
scalar sectors that give a
strong, 1st order EWPT
• Determine low-energy
phenomenology (Higgs
studies, precisionIndependent
ewk)
Parameters:
v 0 , x 0 , l 0 , a1 , a2 , b3 , b4
• Address CPV with a different
mechanism
The Simplest Extension, Cont’d
Mass matrix
2
2




2
h
hs 2
M   2
2 
hs 2 s 


h1  sin q cosq h 
  
 
h
cos
q
sin
q
 2  
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
F
F• What is the pattern of
symmetry breaking ?


H
0




Cylindrical Co-ordinates


• What are conditions on the
couplings in V(H,S) so that
<H0>/T > 1 at TC ?
S

• Compute Veff ( ,,T )
• Minimize w.r.t ,
 T
• Find
C
• Evaluate v(TC )/TC ~
cos (TC) (TC )/TC
Electroweak Symmetry Breaking
Strong first order EWPT
Potential
Conditions
Analytic
Numerical
Analytic
Symmetry Breaking
F
F

H

0

S




Two Cases for
 high T:
<S>at
Vmin = 0
Vmin = V0 < 0

Electroweak Symmetry Breaking
Strong first order EWPT
Increase e
Large e < 0
Reduce l
S
e
Potential parameters
e





Small c limit
h2
h1
h2





Z0


Z0
Nonzero V0
Electroweak Symmetry Breaking
S
Strong first order EWPT
e
e




Z0



Z0


h2
h1
h2



Light: all models
Black: LEP allowed
a1<0, a2 either sign
a1=b3= 0, a2 < 0
x0 > 0
occurs
readily
Electroweak Symmetry Breaking
Critical Temperature
LEP allowed models: TC ~ 100 GeV
|V0| / TC4 << 1
Phenomenology
Electroweak Precision Observables (EWPO)
SM: global fit
favors light scalar
(mh~ 85 GeV)
Oblique parameters
Similar for S,U…
Phenomenology
Electroweak Precision Observables (EWPO)
Oblique parameters
Global fit (GAPP)
Phenomenology
ILC: H’strahlung
Colliders
m2 > 2 m1
LHC exotic final
states: 4b-jets,
 + 2 b-jets…
b
h
LHC:
reduced
h
h
BR(h
SM)
1
2
1






EWPO: favors
light SM-like
scalar
b


m1 > 2 m2
EWPO
compatible

Phenomenology
Colliders
Z2 Symmetry
m1 > 2 m2
LHC: reduced
BR(h
SM)
h2
h1
h2

Small q:
LHC Phenomenology
Discovery Potential
Barger, Langacker, McCaskey,
R-M, Shaughnessy
LHC Higgs Searches
CMS & ATLAS: gg!H,
H!,H!ZZ!llll
H!WW!lnln
CMS :
WW!H,
H!,H!tt!l + j
H!WW!lnjj
ATLAS :
gg!H,
H!ZZ!ll nn,
Higgstrahlung
CMS 30 fb-1
LHC Phenomenology
Barger, Langacker, McCaskey,
R-M, Shaughnessy
Discovery Potential
SM-like
SM-like
Singlet-like
SM-like w/
H2!H1H1 or
Singlet-like
~ EWB Viable
Could discovery
heavy H2
CMS 30 fb-1
LHC Phenomenology, cont’d
Determining x
Barger, Langacker, McKaskey, RM, Shaughnessy
Enhanced gHVV coupling
needed for 5sobservation
SM-like
~ EWB Viable
SM-like w/
H2!H1H1 or
Singlet-like
ILC Phenomenology
Colliders: e+e-
Z*h
S
e



e



Z0

(also WWF, ZZF)
sin2q
Z0
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 No need for light RH stop
•
EWPT viable xSM can allow for heavier SMlike 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
Back Matter