Dark Matter and Baryogenesis Through the Higgs Portal

Robert Hogan

King’s College London

Malcolm Fairbairn and RH - 1305.3453 (JHEP)

Dark MatterWe need it!

I. Baryon Number Violation

II. C- and CP-Violation

III. Non-equilibrium dynamics

2 most popular mechanisms are: Electroweak Baryogenesis and Leptogenesis

Baryon Asymmetry

CPT Theorem suspect equal amounts of matter and anti-matter should annihilate to form thermal bath of radiation need to establish asymmetry dynamicallyMatter observed

Baryogenesis theories must satisfy the

Sakharov ConditionsSakharov (1967)

I. Baryon Number Violation

II. C- and CP-Violation

III. Non-equilibrium dynamics

2 most popular mechanisms are: Electroweak Baryogenesis and Leptogenesis

Baryon Asymmetry

CPT Theorem suspect equal amounts of matter and anti-matter should annihilate to form thermal bath of radiation need to establish asymmetry dynamicallyMatter observed

Baryogenesis theories must satisfy the

Sakharov ConditionsSakharov (1967)

Possibility of separate islands of matter and antimatter now highly constrained!

I. Baryon Number Violation

II. C- and CP-Violation

III. Non-equilibrium dynamics

2 most popular mechanisms are: Electroweak Baryogenesis and Leptogenesis

Baryon Asymmetry

CPT Theorem suspect equal amounts of matter and anti-matter should annihilate to form thermal bath of radiation need to establish asymmetry dynamicallyMatter observed

Baryogenesis theories must satisfy the

Sakharov ConditionsSakharov (1967)

I. Baryon Number Violation

II. C- and CP-Violation

III. Non-equilibrium dynamics

2 most popular mechanisms are: Electroweak Baryogenesis and Leptogenesis

Baryon Asymmetry

CPT Theorem suspect equal amounts of matter and anti-matter should annihilate to form thermal bath of radiation need to establish asymmetry dynamicallyMatter observed

Baryogenesis theories must satisfy the

Sakharov ConditionsSakharov (1967)

Electroweak BaryogenesisI. Baryon Number Violation

Electroweak BaryogenesisI. Baryon Number Violation

B+L violated by non-perturbative processes in SM - Sphalerons

Sphaleron transitions highly suppressed at T=0 but become efficient at High T

Image stolen from - hep-ph/0609145 (Cline)

Kuzmin, Rubakov, and Shaposhnikov (1985)

Electroweak BaryogenesisII. C- and CP-Violation

Needed to ensure baryon production not matched by anti-baryon production

Turns out that this is not enough - Need additional CP violating source

CKM matrix of the SM provides source CP violation

Gavela et al. (hep-ph/9312215 ), Gavela et al. (hep-ph/9406289), Huet and Sather (hep-ph/9404302)

Electroweak BaryogenesisIII. Non-equilibrium Dynamics

Electroweak BaryogenesisIII. Non-equilibrium Dynamics

A first order electroweak phase transition could satisfy this condition

Images stolen from - 1206.2942 (Morrissey and Ramsey-Musolf)

It turns out that at first order transition requires Mh < 70 GeV

125 GeV Higgs gives a crossover transition -> No bubble nucleation in SM!

To prevent sphaleron washout require:

Bochkarev and Shaposhnikov (’87)

How do we make it 1st Order?

1-loop thermal corrections to V

High-T expansion

Yields order parameter:Enhance with larger thermal loops, add more

bosonic dofs (e.g. MSSM)

Corrections to ϕc are T dependent - largely cancelled by Tc

NOTE: Also have gauge invariance issues with T term

Must create a potential barrier

How do we make it 1st Order?

1-loop thermal corrections to V

High-T expansion

Yields order parameter:Enhance with larger thermal loops, add more

bosonic dofs (e.g. MSSM)

Corrections to ϕc are T dependent - largely cancelled by Tc

NOTE: Also have gauge invariance issues with T term

Need to create barrier at tree level!

Must create a potential barrier

Buttazzo et al. (1307.3536)

Scalar to the Rescue?

Stability of EW VacuumIn-

Meta- }Hint?

Buttazzo et al. (1307.3536)

Scalar to the Rescue?

Stability of EW VacuumIn-

Meta- }Hint?

Buttazzo et al. (1307.3536)

Scalar to the Rescue?

Stability of EW VacuumIn-

Meta- }Hint?

Who Cares?

I do - and so should you!

1) Neutrino masses only make matters worse

2) How did we end up in our vacuum after

inflation? Why did fluctuations not bump us into the true vacuum and leading to a BIG CRUNCH?

Buttazzo et al. (1307.3536)

Scalar to the Rescue?

Stability of EW VacuumIn-

Meta- } Add scalar to stabilize vacuum:

But what else can we gain?

Hint?

Buttazzo et al. (1307.3536)

Scalar to the Rescue?

Stability of EW VacuumIn-

Meta- } Add scalar to stabilize vacuum:

But what else can we gain?

Minimal Dark Matter - A Singlet Scalar?

Cline et al.

(1306.4710)

Stability guaranteed by Z2 (S -S) symmetry

Hint?

Buttazzo et al. (1307.3536)

Scalar to the Rescue?

Stability of EW VacuumIn-

Meta- } Add scalar to stabilize vacuum:

But what else can we gain?

Minimal Dark Matter - A Singlet Scalar?

Cline et al.

(1306.4710)

Stability guaranteed by Z2 (S -S) symmetry

1st Order Phase Transition?

Tree level barrier in 2D potential makes this easily achievable

Espinosa et al.

(1107.5441)

Hint?

Buttazzo et al. (1307.3536)

Scalar to the Rescue?

Stability of EW VacuumIn-

Meta- } Add scalar to stabilize vacuum:

But what else can we gain?

Minimal Dark Matter - A Singlet Scalar?

Cline et al.

(1306.4710)

Stability guaranteed by Z2 (S -S) symmetry

1st Order Phase Transition?

Tree level barrier in 2D potential makes this easily achievable

Espinosa et al.

(1107.5441)

Can we combine these two?

No - Can’t account for all DM if we require 1st order phase transition

Cline and Kainulainen

(1210.4196)

Hint?

Buttazzo et al. (1307.3536)

Scalar to the Rescue?

Stability of EW VacuumIn-

Meta- } Add scalar to stabilize vacuum:

But what else can we gain?

Minimal Dark Matter - A Singlet Scalar?

Cline et al.

(1306.4710)

Stability guaranteed by Z2 (S -S) symmetry

1st Order Phase Transition?

Tree level barrier in 2D potential makes this easily achievable

Espinosa et al.

(1107.5441)

Can we combine these two?

No - Can’t account for all DM if we require 1st order phase transition

Cline and Kainulainen

(1210.4196)

Hint?

Singlet Fermionic Dark Matter

Reconcile minimal solutions of DM and EWBG Relax Z2 Symmetry

s is no longer stable introduce additional singlet to play role of DM

“Next to Minimally extended SM”

DM must carry global U(1) ‘fermion number’ charge to avoid decaying like right-handed neutrino

Kim et al. (0803.2932)

Lopez-Honorez et al. (1203.2064)

Baek et al. (1209.4163)

Farina et al. (1303.7244)

Singlet Fermionic Dark Matter

Reconcile minimal solutions of DM and EWBG Relax Z2 Symmetry

s is no longer stable introduce additional singlet to play role of DM

“Next to Minimally extended SM”

DM must carry global U(1) ‘fermion number’ charge to avoid decaying like right-handed neutrino

Kim et al. (0803.2932)

Lopez-Honorez et al. (1203.2064)

Baek et al. (1209.4163)

Farina et al. (1303.7244)

Higgs Physics modifications

In general both s and h will obtain vevs They will mix

Mass eigenstates:

For small mixing we have h1∼h and h2∼s

Measurement of Higgs signal strengths

Non-discovery of 2nd Higgs

a’ > 0.9 b’2 < 0.1 for Mh2 < 400 GeVe.g. Ellis and You (1303.3879) CMS (1304.0213)

Higgs-Like

Singlet-Like

Higgs Physics modifications

In general both s and h will obtain vevs They will mix

Mass eigenstates:

For small mixing we have h1∼h and h2∼s

Measurement of Higgs signal strengths

Non-discovery of 2nd Higgs

a’ > 0.9 b’2 < 0.1 for Mh2 < 400 GeVe.g. Ellis and You (1303.3879) CMS (1304.0213)

Higgs-Like

Singlet-Like

Higgs Physics modifications

In general both s and h will obtain vevs They will mix

Mass eigenstates:

For small mixing we have h1∼h and h2∼s

Measurement of Higgs signal strengths

Non-discovery of 2nd Higgs

a’ > 0.9 b’2 < 0.1 for Mh2 < 400 GeVe.g. Ellis and You (1303.3879) CMS (1304.0213)

Higgs-Like

Singlet-Like

Higgs Physics modifications

In general both s and h will obtain vevs They will mix

Mass eigenstates:

For small mixing we have h1∼h and h2∼s

Measurement of Higgs signal strengths

Non-discovery of 2nd Higgs

a’ > 0.9 b’2 < 0.1 for Mh2 < 400 GeVe.g. Ellis and You (1303.3879) CMS (1304.0213)

Higgs-Like

Singlet-Like

Higgs Physics modifications

In general both s and h will obtain vevs They will mix

Mass eigenstates:

For small mixing we have h1∼h and h2∼s

Measurement of Higgs signal strengths

Non-discovery of 2nd Higgs

a’ > 0.9 b’2 < 0.1 for Mh2 < 400 GeVe.g. Ellis and You (1303.3879) CMS (1304.0213)

Higgs-Like

Singlet-Like

Higgs Physics modifications

In general both s and h will obtain vevs They will mix

Mass eigenstates:

For small mixing we have h1∼h and h2∼s

Measurement of Higgs signal strengths

Non-discovery of 2nd Higgs

a’ > 0.9 b’2 < 0.1 for Mh2 < 400 GeV

Easily Satisfied

in this Model

e.g. Ellis and You (1303.3879) CMS (1304.0213)

Higgs-Like

Singlet-Like

Relic Densityh1,2

h1,2

h1,2

DM

DM h1,2

h1,2

h1,2

DM

DM

h1,2

DM

DM h1,2

h1,2

SM

SM

h1,2

DM

DM

(from thermal freeze-out)

Relic Densityh1,2

h1,2

h1,2

DM

DM h1,2

h1,2

h1,2

DM

DM

h1,2

DM

DM h1,2

h1,2

SM

SM

h1,2

DM

DM

(from thermal freeze-out)

Relic Densityh1,2

h1,2

h1,2

DM

DM h1,2

h1,2

h1,2

DM

DM

h1,2

DM

DM h1,2

h1,2

Mh2 =250 GeVMh2 =500 GeV

SM

SM

h1,2

DM

DM

(from thermal freeze-out)

Direct Detection

Effective WIMP-Nucleon coupling

Mh2 =500 GeV Mh2 =250 GeV

Some regions are quite resilient to direct detection

Direct Detection

Effective WIMP-Nucleon coupling

Mh2 =500 GeV Mh2 =250 GeV

Some regions are quite resilient to direct detection

Annihilation processes with mixing unconstrained

Tiny mixing = Tiny Signal

DM

DM h2

h2

independent of sinα

EW Phase Transition

Find that general (non-Z2) potential offers freedom needed to create 1st

order phase transitions

Add Temperature corrections to potential and search for well behaved

1st order phase transitions

Conclusions

DM and Baryogenesis require physics Beyond the Standard Model

The absence of signals for conventional BSM models (e.g. SUSY) motivates considering a more minimal approach

Models with singlets can provide simple and economical solutions to Vacuum Stability, Dark Matter, and EW Baryogenesis

Conclusions

DM and Baryogenesis require physics Beyond the Standard Model

The absence of signals for conventional BSM models (e.g. SUSY) motivates considering a more minimal approach

Models with singlets can provide simple and economical solutions to Vacuum Stability, Dark Matter, and EW Baryogenesis

Thank You!