Higgs Portal WS 14 MRM...symmetry-breaking in particle physics driven by a fundamental scalar likely correct • Supersymmetry as an illustration • Theoretical progress & challenges

1

Higgs Portal & Cosmology: Theory Overview

Higgs Portal WS May 2014!

M.J. Ramsey-Musolf U Mass Amherst

http://www.physics.umass.edu/acfi/

The Origin of Matter

Cosmic Energy Budget

Dark Matter

Dark Energy

68 %

27 %

5 %

Baryons Baryons

The Origin of Matter

Explaining the origin, identity, and relative fractions of the cosmic energy budget is one of the most compelling motivations for physics beyond the Standard Model

Cosmic Energy Budget

Dark Matter

Dark Energy

68 %

27 %

5 %

Baryons Baryons

Symmetries & Cosmic History


Standard Model Universe

EW Symmetry Breaking: Higgs

QCD: n+p! nuclei

QCD: q+g! n,p…

Astro: stars, galaxies,..




QCD: n+p! nuclei

QCD: q+g! n,p…





QCD: n+p! nuclei

QCD: q+g! n,p…


What is the nature of the EW phase transition ?




QCD: n+p! nuclei

QCD: q+g! n,p…


What is the nature of the EW phase transition ? ! Origin of matter ?




New Forces ?

QCD: n+p! nuclei

QCD: q+g! n,p…


What is the Origin of Matter Baryogenesis: When? CPV? SUSY? Neutrinos?

What is the Origin of Matter

?

Baryogenesis: When? CPV? SUSY? Neutrinos?


?


EW Baryogenesis: testable w/ EDMs + colliders

Leptogenesis: less testable, look for ingredients w/ νs


?




Other Scenarios: •  GUT baryogenesis •  Affleck-Dine •  Asymmetric DM •  Post sphaleron…


?




Other Scenarios: •  GUT baryogenesis •  Affleck-Dine •  Asymmetric DM •  Post sphaleron…

Symmetries & the Origin of Matter

?




Can new TeV scale physics explain the abundance of matter ?

If so, how will we know ?

Questions for This Workshop

•  What happened ~ 10ps after the Big Bang?



•  Single step (cross over) transition ?

•  More d.o.f. with a richer pattern of EWSB?

•  Single or multiple steps ? •  First or second order ? •  Coupled to origin of matter ?






•  What are collider signatures that could provide clues?

•  Modified Higgs properties (production, decays)

•  New states

Recent Developments:

•  Discovery of BEH-like boson ! Paradigm of symmetry-breaking in particle physics driven by a fundamental scalar likely correct

•  Supersymmetry as an illustration

•  Theoretical progress & challenges

•  Our work

•  Non-observation (so far) of physics beyond the Standard Model at the LHC

•  BICEP2 CMB B-mode observation ! Evidence for primordial gravitational radiation associated with inflation

Recent Results

•  Discovery of BEH-like scalar at the LHC

•  Non-observation (so far) of sub-TeV particles at LHC

Recent Results


•  Non-observation (so far) of sub-TeV particles at LHC

•  Idea of φ-driven spontaneous EW symmetry breaking is likely correct

Recent Results


•  Non-observation (so far) of sub-TeV particles at LHC •  Sub-TeV BSM spectrum is compressed •  Sub-TeV BSM is purely EW or Higgs portal •  BSM physics lies at very different mass scale

•  Idea of φ-driven spontaneous EW symmetry breaking is likely correct

Outline

•  Portals & the Early Universe

•  Why the Higgs Portal

•  Scalar Fields in Particle Physics & Cosmology

•  General Considerations

•  Illustrative Higgs Portals: Simplest Extensions

I. Portals & Early Universe

Standard Model “Hidden Sector” : DM, early universe dynamics (EWPT)…

Portals Two approaches:

•  Specific model (MSSM….)

•  “Model independent”

Model Independent Portals

•  Vector portal (“dark photons”…)

•  Neutrino portal

•  Axion portal

•  Higgs portal

•  Higher dimensional op’s portal




•  Axion portal

•  Higgs portal





•  Axion portal

•  Higgs portal


Higgs Portal: DM

•  Renormalizable

•  Z2 symmetric

•  Dimensionless coupling

•  φ (DM): singlet or charged under SU(2)L x U(1)Y

Higgs Portal: Phase Transitions

•  Renormalizable ✔

•  Z2 symmetric ✖

•  Dimensionless coupling ✖

•  φ (DM): singlet or charged under SU(2)L x U(1)Y

+…

Higgs Portal: Higher Dim Op’s

•  Renormalizable ✖

•  Z2 symmetric ✔

•  Dimensionless coupling ✖

•  χ (DM): singlet or charged under SU(2)L x U(1)Y

+…

II. Why the Higgs Portal ?

Stable EW Vacuum ? Preserving EW Min

top loops sets mH

VEFF

ϕ

top loops EW vacuum

Stable EW Vacuum ? Preserving EW Min “Funnel plot”

top loops sets mH

VEFF

ϕ

perturbativity top loops EW vacuum


top loops sets mH

VEFF

ϕ

perturbativity top loops

naïve stability scale Λ

EW vacuum

SM stability & pert’vity


top loops sets mH

VEFF

ϕ

perturbativity

mH

top loops


EW vacuum

SM unstable above ~ 108 - 1015 TeV



top loops sets mH

VEFF

ϕ

perturbativity

mH

top loops


EW vacuum

SM unstable above ~ 108 - 1013 TeV


Higgs portal interactions ! more robust stability ?

What is the BSM Energy Scale Λ ?

~ 10-3 agreement with EWPO

EWPO: data favor a “light” SM-like Higgs scalar

BSM: OBSM = c / Λ2 !

Λ ~ 10 TeV

Barbieri & Strumia ‘99

LHC: so far no sub-TeV BSM physics

Higgs Portal: new low scale d.o.f. ?

III. Scalar Fields in Particle Physics & Cosmology

ϕ ?

Scalar Fields in Cosmology

What role do scalar fields play (if any) in the physics of the early universe ?


Problem Theory Exp’t

•  Inflation

•  Dark Energy

•  Dark Matter

•  Phase transitions


•  Inflation

•  Dark Energy

•  Dark Matter



✔

✔

✔

✔


•  Inflation

•  Dark Energy

•  Dark Matter



✔

✔

✔

✔

?

?

?

?


•  Inflation

•  Dark Energy

•  Dark Matter



✔

✔

✔

✔

?

?

?

?

•  Could experimental discovery of additional scalars point to early universe scalar field dynamics?

•  Are there signatures in modified Higgs properties, new states, or EW precision tests ?


•  Inflation

•  Dark Energy

•  Dark Matter



✔

✔

✔

✔

?

?

?

?

Focus of this talk, but perhaps part of larger role of scalar fields in early universe

IV. General Considerations

Thermal DM: ΩCDM & σSI

Thermal DM: WIMP

χ

χ SM

SM

Direct detection: Spin-indep DM-nucleus scattering

χ

χ A

A

LUX

1310.8214

XENON 100

Thermal DM: ΩCDM & σSI

Thermal DM: WIMP

χ

χ SM

SM

Direct detection: Spin-indep DM-nucleus scattering

χ

χ A

A

?

CDMS 2013

K McCarthy APS ‘13

EWPT & EW Baryogenesis

EW Phase Transition: New Scalars & CPV

?

φ

?

φ

?

F

?

F1st order 2nd order


?

φ

?

φ

?

F

?


Increasing mh


?

φ

?

φ

?

F

?


Increasing mh

New scalars

?

φ

?

φ

?

F

?


Increasing mh

New scalars

Baryogenesis Gravity Waves Scalar DM LHC Searches

“Strong” 1st order EWPT


?

φ

?

φ

?

F

?


Increasing mh

New scalars



Bubble nucleation

EWSB


?

φ

?

φ

?

F

?


Increasing mh

New scalars



Bubble nucleation

EWSB YB : CPV & EW sphalerons

€

Aλ


?

φ

?

φ

?

F

?


Increasing mh

New scalars



Bubble nucleation

EWSB YB : CPV & EW sphalerons

€

Aλ

BSM


?

φ

?

φ

?

F

?


Increasing mh

New scalars



Bubble nucleation

EWSB YB : diffuses into interiors

€

Aλ


?

φ

?

φ

?

F

?


Increasing mh

New scalars



Bubble nucleation


Preserve YB

initial

Quench EW sph


?

φ

?

φ

?

F

?


Increasing mh

New scalars



Bubble nucleation


Preserve YB

initial

Quench EW sph


EW Phase Transition: Gravity waves

?

φ

?

φ

?

F

?


Increasing mh

New scalars



Bubble nucleation

EWSB

GW Spectra: ΔQ & ΔtEW F(φ)

Detonation & turbulence

nMSSM

ΔQ

ΔtEW

?

φ

?

φ

?

F

?


Increasing mh

New scalars



Bubble nucleation


Preserve YB

initial

Quench EW sph


Electroweak Phase Transition

EW Phase Transition: St’d Model

v ?

φ

?

φ

?

F

?


Increasing mh

Lattice: Endpoint

S’td Model: 1st order EWPT requires light Higgs

EW Phase Transition: New Scalars

?

φ

?

φ

?

F

?


Increasing mh

New scalars 1st order EWPT

Decreasing RH stop mass

CCB Vac

Lattice: Laine, Rummukainen

MSSM: Light RH stops

PT: Carena et al,…

EW Phase Transition: MSSM

?

φ

?

φ

?

F

?


Increasing mh

New scalars


CCB vac

Carena et al 2008: Higgs phase metastable


?

φ

?

φ

?

F

?


Increasing mh

New scalars


CCB vac



?

φ

?

φ

?

F

?


Increasing mh

New scalars


CCB vac


CMS PAS SUS-13-009

EW Phase Transition: Higgs Portal

?

φ

?

φ

?

F

?


Increasing mh

New scalars

< φ >

+…


?

φ

?

φ

?

F

?


Increasing mh

New scalars

< φ >

+…


•  φ : singlet or charged under SU(2)L x U(1)Y

•  Generic features of full theory (NMSSM, GUTS…)

•  More robust vacuum stability

•  Novel patterns of SSB


?

φ

?

φ

?

F

?


Increasing mh

New scalars

< φ >

+…


•  φ : singlet or charged under SU(2)L x U(1)Y

•  Generic features of full theory (NMSSM, GUTS…)

•  More robust vacuum stability

•  Novel patterns of SSB

Higgs Portal: Simple Scalar Extensions

Extension EWPT DM DOF

May be low-energy remnants of UV complete theory & illustrative of generic features

Real singlet

Real singlet

Complex Singlet

Real Triplet

1

1

2

3

✔

✖

✔

✔

✖

✔

✔

✔



May be low-energy remnants of UV complete theory & illustrative of generic features (NMSSM, GUTs, Hidden Valley….)

Real singlet

Real singlet

Complex Singlet

Real Triplet

1

1

2

3

✔

✖

✔

✔

✖

✔

✔

✔



May be low-energy remnants of UV complete theory & illustrative of generic features (NMSSM, GUTs, Hidden Valley….)

Real singlet

Real singlet

Complex Singlet

Real Triplet

1

1

2

3

✔

✖

✔

✔

✖

✔

✔

✔

The Simplest Extension

Model

Independent Parameters:

v0, x0, λ0, a1, a2, b3, b4

H-S Mixing H1 ! H2H2

€

M 2 =µh2 µhs

2 2µhs2 2 µs

2

"

# $

%

& '

Mass matrix

€

h1h2

"

# $

%

& ' =

sinθ cosθcosθ −sinθ"

# $

%

& ' hs"

# $ %

& '

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 xSM EWPT: ✖

Signal Reduction Factor

Production Decay

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

EWPT: a1,2 = 0 & <S> = 0

DM: a1 = 0 & <S> = 0

/ /

O’Connel, R-M, Wise; Profumo, R-M, Shaugnessy; Barger, Langacker, McCaskey, R-M Shaugnessy; He, Li, Li, Tandean, Tsai; Petraki & Kusenko; Gonderinger, Li, Patel, R-M; Cline, Laporte, Yamashita; Ham, Jeong, Oh; Espinosa, Quiros; Konstandin & Ashoorioon…

The Simplest Extension, Cont’d

€

M 2 =µh2 µhs

2 2µhs2 2 µs

2

"

# $

%

& '

Mass matrix

€

h1h2

"

# $

%

& ' =


# $

%

& ' hs"

# $ %

& '

x0 = <S>


€

M 2 =µh2 µhs

2 2µhs2 2 µs

2

"

# $

%

& '

Mass matrix

€

h1h2

"

# $

%

& ' =


# $

%

& ' hs"

# $ %

& '

x0 = <S>

€

γ

€

γ h1,2

€

b

€

b

€

γ

€

γ

hj

hk

hk

New topologies


€

M 2 =µh2 µhs

2 2µhs2 2 µs

2

"

# $

%

& '

Mass matrix

€

h1h2

"

# $

%

& ' =


# $

%

& ' hs"

# $ %

& '

Stable S (dark matter) •  Tree-level Z2 symmetry: a1=0 to


•  x0 =0 to prevent h-s mixing & s ! hh

x0 = <S>

€

γ

€

γ h1,2

€

b

€

b

€

γ

€

γ

hj hk

hk


Model H-S Mixing

H1 ! H2H2

€

M 2 =µh2 µhs

2 2µhs2 2 µs

2

"

# $

%

& '

Mass matrix

€

h1h2

"

# $

%

& ' =


# $

%

& ' hs"

# $ %

& '





Production Decay

DM Scenario


Model


v0, x0, λ0, a1, a2, b3, b4


€

M 2 =µh2 µhs

2 2µhs2 2 µs

2

"

# $

%

& '

Mass matrix

€

h1h2

"

# $

%

& ' =


# $

%

& ' hs"

# $ %

& '





Production Decay

DM Scenario

ΩDM & σSI

+ +…

DM Phenomenology Relic Density

He, Li, Li, Tandean, Tsai

Direct Detection


Barger, Langacker, McCaskey, R-M, Shaugnessy

New Scalars EW Vacuum Stability Preserving EW Min “Funnel plot”

VEFF

ϕ

perturbativity

mH

top loops


EW vacuum

top loops

Gonderinger, Li, Patel, R-M; Gonderinger, Lim, R-M


DM-H coupling

New Scalars EW Vacuum Stability Preserving EW Min “Funnel plot”

VEFF

ϕ

perturbativity

mH

top loops


EW vacuum

top loops

Gonderinger, Li, Patel, R-M; Gonderinger, Lim, R-M


SM + singlet: stable but non-pertur’tive

DM-H coupling

LHC & Higgs Phenomenology LHC discovery potential


Production Decay



Production Decay

V1j < 1: mixed states hj New decays: h2 ! h1 h1



Production Decay

V1j < 1: mixed states hj New decays: h2 ! h1 h1

Dark matter: no mixing ! states are h,S

New decays h! SS (invisible!) possible

LHC & Higgs Phenomenology Invisible decays


Look for azimuthal shape change of primary jets (Eboli & Zeppenfeld ‘00)

Dijet azimuthal distribution

€

h j

€

A

€

A

Γ (h!SS)=0 Invis search

LHC discovery potential


Production Decay





€

h j

€

A

€

A



Production Decay

Jets + ET





€

h j

€

A

€

A



Production Decay

ATLAS

Real Singlet: EWPT

Model H-S Mixing

H1 ! H2H2

€

M 2 =µh2 µhs

2 2µhs2 2 µs

2

"

# $

%

& '

Mass matrix

€

h1h2

"

# $

%

& ' =


# $

%

& ' hs"

# $ %

& '





Production Decay

Real Singlet: EWPT

Model H-S Mixing

H1 ! H2H2

€

M 2 =µh2 µhs

2 2µhs2 2 µs

2

"

# $

%

& '

Mass matrix

€

h1h2

"

# $

%

& ' =


# $

%

& ' hs"

# $ %

& '





Production Decay

Raise barrier Lower TC

Real Singlet: EWPT

Model


v0, x0, λ0, a1, a2, b3, b4


€

M 2 =µh2 µhs

2 2µhs2 2 µs

2

"

# $

%

& '

Mass matrix

€

h1h2

"

# $

%

& ' =


# $

%

& ' hs"

# $ %

& '





Production Decay

Low energy phenomenology

Mixing

Raise barrier Lower TC

Modified BRs

Two mixed (singlet-doublet) states w/ reduced SM branching ratios

EWPT & LHC Phenomenology Signatures m2 > 2 m1

m1 > 2 m2

Light: all models Black: LEP allowed

Profumo, R-M, Shaugnessy ‘07

Scan: EWPT-viable model parameters


m1 > 2 m2



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

€

h2

€

h1

€

h2


€

h1

€

h2

€

h1€

b

€

b

€

γ

€

γ


LHC: reduced BR(h SM)

Mixed States: Precision $ ILC


m1 > 2 m2




€

h2

€

h1

€

h2


€

h1

€

h2

€

h1€

b

€

b

€

γ

€

γ


LHC: reduced BR(h SM) Signal Reduction Factor

Production Decay

Mixed States: Precision $ ILC

EWPT: Resonant Di-Higgs Production Signatures m2 > 2 m1

m1 > 2 m2




R-M & No, arXiv:1310.6035

€

h1

€

h2

€

h1€

b

€

b

Scan: EWPT-viable model parameters Mixed States:

Precision $ ILC

τ+ τ-

bbτ+τ- : discovery with ~ 100 fb-1 in “τlep τhad” channel

m2 = 270 GeV “un-boosted” m2 = 370 GeV “boosted”

EWPT: Resonant Di-Higgs Production Signatures m2 > 2 m1

m1 > 2 m2




R-M & No, arXiv:1310.6035

€

h1

€

h2

€

h1€

b

€

b


Precision $ ILC

τ+ τ-

8

h2 → h1h1 tt̄ Z bb̄ Z jj

bb̄τlepτhad bb̄ℓτhad bb̄τlepτhad bb̄τlepτhad jjτlepτhadEvent selection (see section V.C) 19.17 5249 762 601 98∆Rbb > 2.1, PT,b1 > 45 GeV, PT,b2 > 30 GeV 11.45 2639 384 188 10.8h1-mass: 90 GeV < mbb < 140 GeV 8.00 531 80 69 3.68Collinear x1, x2 Cuts 4.81 209 36.4 41.6 2.41∆Rℓτ > 2 4.10 129 23.1 26.5 2.03mℓ

T < 30 GeV 3.44 30.9 11.1 24.4 1.90h1-mass: 110 GeV < mcoll

ττ < 150 GeV 1.56 4.97 2.05 4.92 0.38Emiss


bbττ < 300 GeV 1.29 0.39 0.17 1.21 0.13

TABLE IV: Event selection and background reduction for the bb̄τlepτhad channel in the un-boosted benchmark scenario. Weshow the NLO cross section (in fb) for the signal h2 → h1h1 → bb̄τlepτhad and the relevant backgrounds tt̄ → bb̄τlepτhad, bb̄ℓτhad,Z bb̄ → bb̄τlepτhad and Z jj → jjτlepτhad after successive cuts (same efficiency and face rate assumptions as in Table II).

h2 → h1h1 tt̄ Z bb̄ Z jj

bb̄τlepτhad bb̄ℓτhad bb̄τlepτhad bb̄τlepτhad jjτlepτhadEvent selection (see section V.C) 10.73 5249 762 601 98∆Rbb < 2.2, PT,b1 > 50 GeV, PT,b2 > 30 GeV 6.02 1576 223 85 2.46h1-mass: 90 GeV < mbb < 140 GeV 4.77 672 94 31.5 0.84|P⃗ bb

T | > 110 GeV 3.42 345 49 13.9 0.33Collinear x1, x2 Cuts 2.31 136 22.3 8.38 0.22∆Rℓτ < 2.3 1.71 68 11.1 4.31 0.055mℓ


ττ < 150 GeV 1.05 4.2 1.26 0.30 0.00325 GeV < Emiss


bbττ < 400 GeV 0.63 0.60 0.15 0.026 < 0.001

TABLE V: Event selection and background reduction for the bb̄τlepτhad channel in the boosted benchmark scenario (sameefficiency and face rate assumptions as in Table II).

(GeV)TmissE

0 20 40 60 80 100 120 140 160 180 200

mis

s/d

Eσ

) dσ

(1/

-210

-110

= 270 GeV)2

Signal (m

= 370 GeV)2

Signal (m

b Z b

t t Z jj

FIG. 7: Normalized EmissT distribution after event selection

(before cuts) for signal and background (“τlepτlep”)

events (largely dominated by tt̄ production), we cut onthe transverse mass of the lepton (see Fig. 8)

mℓT =

!

2pℓTEmissT (1 − cosφℓ,miss) < 30 GeV (13)

with φℓ,miss being the azimuthal angle between the di-rection of missing energy and the lepton transverse mo-mentum.

The corresponding impact of the cut-flow on signaland background cross sections are given in Tables IVand V for the unboosted and boosted scenarios. As forthe τlepτlep channel, the various cuts allow one to greatlysuppress the backgrounds and increase the signal signifi-cance. For the τlepτhad channel, since it is not possible toimpose a Z-peak veto through a cut in the invariant massof the lepton pair, we increase the lower end of the mcoll

ττ

invariant mass signal window (from 100 GeV to 110 GeV)in order to suppress Zbb̄ and Zjj backgrounds. The dis-tributions for mcoll

ττ and mcollbbττ in this channel are shown

in Figs. 9 and 10.

From the results from Tables IV and V, we find thatfor the semileptonic channel a S/

√S +B ∼ 5 for the

unboosted benchmark scenario can be obtained with ∼50 fb−1, while for the boosted benchmark scenario the re-quired integrated luminosity is slightly higher, ∼ 90 fb−1.This channel therefore appears to be promising both forthe boosted and unboosted regimes.

9

(GeV)Tlm

0 20 40 60 80 100 120

T/d

mσ

) dσ

(1/

-210

-110

= 270 GeV)2

Signal (m

= 370 GeV)2

Signal (m

b Z bτ t t~ -> l τ τ t t~ ->

Z jj

FIG. 8: Normalized mℓT distribution for signal and back-

ground (“τlepτhad”).

(GeV)ττcollm

50 100 150 200 250

/dm

σ) dσ

(1/

-210

-110

= 270 GeV)2

Signal (m

= 370 GeV)2

Signal (m

b Z b

t t Z jj

FIG. 9: Normalized mcollττ distribution for τ+τ− system in

signal and background (“τlepτhad”).

D. Hadronic (τhadτhad) final states.

The selection criteria for this channel are given by twohadronically-decaying τ -leptons (Nτh = 2), exactly zeroleptons ( Nℓ = 0), and a similar set of kinematic require-ments on the τ leptons and b-jets as in the other chan-nels: pτT > 10 GeV, |yb| < 2.5, ∆Rbb > 0.5, pbT > 10. Ascompared to the semileptonic and leptonic channels, thebackgrounds for the purely hadronic channel are smaller.The cut flows for the unboosted and boosted scenariosare given in Tables VI and VII, respectively.In light of the results from Tables VI and VII, we ob-

tain S/√S +B ∼ 5 with ∼ 100 fb−1 in the hadronic

channel for both the unboosted and boosted benchmark

(GeV)ττbbcollm

100 200 300 400 500 600

/dm

σ) d

σ(1

/

-210

-110

= 270 GeV)2

Signal (m

= 370 GeV)2

Signal (m

b Z b

t t Z jj

FIG. 10: Normalized mcollbbττ distribution for signal and back-


scenarios. While this channel appears to be promisingboth for both scenarios, we caution that we have notconsidered other pure QCD backgrounds, such as multi-jet or bb̄jj production, where the jets fake a hadronicallydecaying τ lepton. The reason is the difficulty of reli-ably quantifying the jet fake rate for these events, whichwhile being under 5%, depends strongly on the character-istics of the jet [40]. While we do not expect this class ofbackground contamination to be an impediment to signalobservation in the τhadτhad channel, we are less confidentin our quantitative statements here than for the otherfinal states.

V. DISCUSSION AND OUTLOOK

Uncovering the full structure of the SM scalar sectorand its possible extensions will be a central task for theLHC in the coming years. The results will have impor-tant implications not only for our understanding of themechanism of electroweak symmetry-breaking but alsofor the origin of visible matter and the nature of darkmatter. Extensions of the SM scalar sector that addressone or both of these open questions may yield distinc-tive signatures at the LHC associated with either mod-ifications of the SM Higgs boson properties and/or theexistence of new states.In this study, we have considered one class of Higgs

portal scalar sector extensions containing a singlet scalarthat can mix with the neutral component of the SU(2)Ldoublet leading to two neutral states h1,2. This xSMscenario can give rise to a strong first order electroweakphase transition as needed for electroweak baryogenesis;it maps direction onto the NMSSM in the decouplinglimit; and it serves as a simple paradigm for mixed statesignatures in Higgs portal scenarios that contain other

9

(GeV)Tlm

0 20 40 60 80 100 120

T/d

mσ

) dσ

(1/

-210

-110

= 270 GeV)2

Signal (m

= 370 GeV)2

Signal (m

b Z bτ t t~ -> l τ τ t t~ ->

Z jj

FIG. 8: Normalized mℓT distribution for signal and back-


(GeV)ττcollm

50 100 150 200 250

/dm

σ) dσ

(1/

-210

-110

= 270 GeV)2

Signal (m

= 370 GeV)2

Signal (m

b Z b

t t Z jj

FIG. 9: Normalized mcollττ distribution for τ+τ− system in

signal and background (“τlepτhad”).

D. Hadronic (τhadτhad) final states.

The selection criteria for this channel are given by twohadronically-decaying τ -leptons (Nτh = 2), exactly zeroleptons ( Nℓ = 0), and a similar set of kinematic require-ments on the τ leptons and b-jets as in the other chan-nels: pτT > 10 GeV, |yb| < 2.5, ∆Rbb > 0.5, pbT > 10. Ascompared to the semileptonic and leptonic channels, thebackgrounds for the purely hadronic channel are smaller.The cut flows for the unboosted and boosted scenariosare given in Tables VI and VII, respectively.In light of the results from Tables VI and VII, we ob-

tain S/√S +B ∼ 5 with ∼ 100 fb−1 in the hadronic

channel for both the unboosted and boosted benchmark

(GeV)ττbbcollm

100 200 300 400 500 600/d

mσ

) dσ

(1/

-210

-110

= 270 GeV)2

Signal (m

= 370 GeV)2

Signal (m

b Z b

t t Z jj

FIG. 10: Normalized mcollbbττ distribution for signal and back-


scenarios. While this channel appears to be promisingboth for both scenarios, we caution that we have notconsidered other pure QCD backgrounds, such as multi-jet or bb̄jj production, where the jets fake a hadronicallydecaying τ lepton. The reason is the difficulty of reli-ably quantifying the jet fake rate for these events, whichwhile being under 5%, depends strongly on the character-istics of the jet [40]. While we do not expect this class ofbackground contamination to be an impediment to signalobservation in the τhadτhad channel, we are less confidentin our quantitative statements here than for the otherfinal states.

V. DISCUSSION AND OUTLOOK

Uncovering the full structure of the SM scalar sectorand its possible extensions will be a central task for theLHC in the coming years. The results will have impor-tant implications not only for our understanding of themechanism of electroweak symmetry-breaking but alsofor the origin of visible matter and the nature of darkmatter. Extensions of the SM scalar sector that addressone or both of these open questions may yield distinc-tive signatures at the LHC associated with either mod-ifications of the SM Higgs boson properties and/or theexistence of new states.In this study, we have considered one class of Higgs

portal scalar sector extensions containing a singlet scalarthat can mix with the neutral component of the SU(2)Ldoublet leading to two neutral states h1,2. This xSMscenario can give rise to a strong first order electroweakphase transition as needed for electroweak baryogenesis;it maps direction onto the NMSSM in the decouplinglimit; and it serves as a simple paradigm for mixed statesignatures in Higgs portal scenarios that contain other

bbτ+τ- : discovery with ~ 100 fb-1 in “τlep τhad” channel

m2 = 270 GeV “un-boosted” m2 = 370 GeV “boosted”


m1 > 2 m2




Precision $ ILC



May be low-energy remnants of UV complete theory & illustrative of generic features

Real singlet

Real singlet

Complex Singlet

Real Triplet

1

1

2

3

✔

✖

✔

✔

✖

✔

✔

✔

Back up slides

Complex Singlet: EWB & DM? Barger, Langacker, McCaskey, R-M Shaugnessy

Spontaneously & softly broken global U(1)

Controls ΩCDM , TC , & H-S mixing

Gives non-zero MA

< S > = 0

Complex Singlet: EWB & DM? Barger, Langacker, McCaskey, R-M Shaugnessy

Consequences:

Three scalars: h1 , h2 : mixtures of h & S

A : dark matter

Phenomenology: •  Produce h1 , h2 w/ reduced σ •  Reduce BR (hj ! SM)

•  Observation of BR (invis)

•  Possible obs of σSI



Simplest non-trivial EW multiplet

Real singlet

Real singlet

Complex Singlet

Real Triplet

1

1

2

3

✔

✖

✔

✔

✖

✔

✔

✔

Real Triplet

Σ0 , Σ+, Σ- ~ ( 1, 3, 0 ) Fileviez-Perez, Patel, Wang, R-M: PRD 79: 055024 (2009); 0811.3957 [hep-ph]

EWPT: a1,2 = 0 & <Σ0> = 0

DM & EWPT: a1 = 0 & <Σ0> = 0

/ /

Real Triplet

Σ0 , Σ+, Σ- ~ ( 1, 3, 0 ) Fileviez-Perez, Patel, Wang, R-M: PRD 79: 055024 (2009); 0811.3957 [hep-ph]

EWPT: a1,2 = 0 & <Σ0> = 0

DM & EWPT: a1 = 0 & <Σ0> = 0

/ /

Small: ρ-param

Real Triplet: DM

Σ0 , Σ+, Σ- ~ ( 1, 3, 0 )

EWPT: a1,2 = 0 & <Σ0> = 0

DM & EWPT: a1 = 0 & <Σ0> = 0

/ /

Small: ρ-param

Fileviez-Perez, Patel, Wang, R-M: PRD 79: 055024 (2009); 0811.3957 [hep-ph]


?

φ

?

φ

?

F

?


Increasing mh

New scalars

Real Triplet

Two-step EWPT & dark matter

Patel, R-M: arXiv 1212.5652 ; Fileviez-Perez, Patel, RM, Wang

<Σ0 >

Σ ~ (1,3,0)

Baryogenesis

Quench sphalerons

Small entropy dilution

Σ dark matter

Higgs Diphoton Decays •  SM “background” well below new CPV expectations

•  New expts: 102 to 103 more sensitive

•  CPV needed for BAU?

LHC: H ! γγ

D

D

€

h j

€

h jD

D

€

h j γ

γ

Σ+

Post –Moriond 2013


Real Triplet: EWPT

Σ0 , Σ+, Σ- ~ ( 1, 3, 0 ) H. Patel & R-M, 1212.5652/hep-ph (2012)

Two-step EWSB

1.  Break SU(2)L x U(1)Y w/ Σ vev

2.  Transition to Higgs phase w/ small or zero Σ vev

EWB favorable

Real Triplet: EWPT


Two-step EWSB



EWB favorable

Real Triplet : DM Search

Mass splitting due to EW symmetry breaking: O5 =

��H

⇤

�̄� H†H (25)

M⌃± �M⌃0 ⇠ ↵

4⇡MW (26)

3

Σ+ ! Σ0 + π+ (soft)

Generalizes to higher dim EW multiplets


Basic signature: Charged track disappearing after ~ 5 cm

SM Background: QCD jZ and jW w/ Z !νν & W!lν

Trigger: Monojet (ISR) + large ET €

qq →W ±* → H ±H2

€

qq → Z*,γ * → H +H−



Basic signature: Charged track disappearing after ~ 5 cm

SM Background: QCD jZ and jW w/ Z !νν & W!lν

Trigger: Monojet (ISR) + large ET €

qq →W ±* → H ±H2

€

qq → Z*,γ * → H +H−

Cuts: large ET

hard jet

One 5cm track



?

φ

?

φ

?

F

?


Increasing mh

New scalars

Patel, R-M, Wise: PRD 88 (2013) 015003

Do good symmetries today need to be good symmetries in the early Universe ?

Symmetry Breaking & Restoration

?

φ

?

φ

?

F

?


Increasing mh

New scalars

Do good symmetries today need to be good symmetries in the early Universe ?

Increasing T !

Pie

zoel

ectri

city

Rochelle salt: KNaC4H4O6 4H20

J. Valasek


?

φ

?

φ

?

F

?


Increasing mh

New scalars

Patel, R-M, Wise: PRD 88 (2013) 015003

Do good symmetries today need to be good symmetries in the early Universe ? No

• O(n) x O(n): Weinberg (1974)

•  SU(5), CP…: Dvali, Mohapatra, Senjanovic (‘79, 80’s, 90’s)

•  Cline, Moore, Servant et al (1999)

•  EM: Langacker & Pi (1980)

•  SU(3)C : Patel, R-M, Wise: PRD 88 (2013) 015003


?

φ

?

φ

?

F

?


Increasing mh

New scalars

Colored Scalars

Color breaking & restoration

Patel, R-M, Wise: PRD 88 (2013) 015003

Do good symmetries today need to be good symmetries in the early Universe ? No

• O(n) x O(n): Weinberg (1974)

•  SU(5), CP…: Dvali, Mohapatra, Senjanovic (‘79, 80’s, 90’s)

•  Cline, Moore, Servant et al (1999)

•  EM: Langacker & Pi (1980)

•  SU(3)C : Patel, R-M, Wise: PRD 88 (2013) 015003

Color Breaking & Restoration

H. Patel, R-M, Wise 1303.1140 (2013) Two illustrative cases:


Color triplet scalar

Color triplet + singlet

…..

6

7

✔

✔

✖

✖






…..

6

7

✔

✔

✖

✖

Spontaneous B violation


?

φ

?

φ

?

F

?


Increasing mh

New scalars

Colored Scalars (triplet)

Color breaking & restoration

Patel, R-M, Wise: PRD 88 (2013) 015003

1. Break SU(3)C

2. Restore SU(3)C

1. Break SU(3)C

2. Restore SU(3)C

Summary: Workshop Questions





•  What are collider signatures that could provide clues?

•  Modified Higgs properties (production, decays)

•  New states

Back Up Slides

Ingredients for Baryogenesis

•  B violation (sphalerons)

•  C & CP violation

•  Out-of-equilibrium or CPT violation

Standard Model BSM

✔

✖

✖

✔

✔

✔





Standard Model BSM

✔

✖

✖

✔

✔

✔

Scenarios: leptogenesis, EW baryogenesis, Afflek-Dine, asymmetric DM, cold baryogenesis, post-sphaleron baryogenesis…





Standard Model BSM

✔

✖

✖

✔

✔

✔

Scenarios: leptogenesis, EW baryogenesis, Afflek-Dine, asymmetric DM, cold baryogenesis, post-sphaleron baryogenesis…

Testable

Baryon Number Preservation “Washout factor”

ζ = F(ϕ)

ln S ~ A(TC) e ζ

Two qtys of interest:

•  TC from Veff

•  Esph from Γeff

Daisy Resummation Convergence of PT: going beyond expansion

Patel & R-M ‘11 Light stop scenario

Increased ΔV ! Lowered TC

For given T, increasingly negative increases difference between two minima

Csikor ‘00

DM Phenomenology Relic Density


Direct Detection


Barger, Langacker, McCaskey, R-M, Shaugnessy

H S

S

f

f

-

Higgs pole

Real Triplet: EWPT


Two-step EWSB



Real Triplet: EWPT


Two-step EWSB

Real Triplet: EWPT


Two-step EWSB








…..

6

7

✔

✔

✖

✖

Spontaneous B violation “Light”: special flavor structure






…..

6

7

✔

✔

✖

✖

Spontaneous B violation heavy: generic flavor structure

SM + Color Triplet

H. Patel, R-M, Wise 1303.1140 (2013)

Decays: C ! <C> = υC : B violation

SM + Color Triplet

Upper bound on mC:

H. Patel, R-M, Wise 1303.1140 (2013)

SM + Color Triplet + Singlet

H. Patel, R-M, Wise 1303.1140 (2013)

Heavier colored scalar

Higgs Decays: All Channels

)µSignal strength ( -1 0 +1

Combined

4l→ (*) ZZ→H

γγ →H

νlν l→ (*) WW→H

ττ →H

bb→W,Z H

-1Ldt = 4.6 - 4.8 fb∫ = 7 TeV: s-1Ldt = 13 - 20.7 fb∫ = 8 TeV: s

-1Ldt = 4.6 fb∫ = 7 TeV: s-1Ldt = 20.7 fb∫ = 8 TeV: s



-1Ldt = 4.6 fb∫ = 7 TeV: s-1Ldt = 13 fb∫ = 8 TeV: s

-1Ldt = 4.7 fb∫ = 7 TeV: s-1Ldt = 13 fb∫ = 8 TeV: s

= 125.5 GeVHm

0.20± = 1.30 µ

ATLAS Preliminary

Theoretical Issues

Gauge-dependence in VEFF (ϕ , T )

VEFF (ϕ , T ) ! VEFF (ϕ , T ; ξ )

Ongoing research: approaches for carrying out tractable, GI computations

•  H. Patel & MRM, JHEP 1107 (2011) 029

•  C. Wainwright, S. Profumo, MRM Phys Rev. D84 (2011) 023521

•  H. Gonderinger, H. Lim, & MRM, arXiv:1202.1316

Origin of Gauge Dependence Effective Action

Effective Potential

Source term:

Not GI

Nielsen Identities Identity:

Extremal configurations:

Effective potential:

Baryon Number Preservation “Washout factor”

ζ = F(ϕ)

ln S ~ A(TC) e ζ

Two qtys of interest:

•  TC from Veff

•  Esph from Γeff

Baryon Number Preservation: Pert Theory

~

ζ = F(ϕ)

Conventional treatments

Gauge Dep

H. Patel & MRM, JHEP 1107 (2011) 029 “Baryon number preservation criterion” (BNPC)

Baryon Number Preservation: Pert Theory

~

ζ = F(ϕ)

Conventional treatments

Gauge Dep

•  GI TC from hbar exp, Veff (φ+φ), or Hamiltonian formulation

•  Use GI scale in Esph computation

H. Patel & MRM, JHEP 1107 (2011) 029 “Baryon number preservation criterion” (BNPC)

Nielsen Identities: Application to TC Critical Temperature

Veff (ϕmin , TC) = Veff (0 , TC)

Apply consistently order-by-order in

Implement minimization order-by-order (defines φn )

Fukuda & Kugo ‘74: T=0 VEFF Laine ‘95 : 3D high-T Eff Theory Patel & R-M ‘11: Full high T Theory

Obtaining a GI TC Track evolution of minima with T using expansion

Track evolution of different minima with T using

n=1

n=2 n=3

Patel & R-M ‘11

Illustrative results in SM:

Full φ

Documents

Higgs Portal WS 14 MRM...symmetry-breaking in particle physics driven by a fundamental scalar likely correct • Supersymmetry as an illustration • Theoretical progress & challenges