Dwarf Spheroidal J-factors with Self-interacting Dark Matter
Self-Interacting Asymmetric Dark Matter Coupled to a Light Massive Dark Photon
Transcript of Self-Interacting Asymmetric Dark Matter Coupled to a Light Massive Dark Photon
Self-Interacting Asymmetric Dark Matter Coupled to aLight Massive Dark Photon
Lauren Pearce
University of Minnesota
September 17th, 2014
Collaborators: Kalliopi Petraki and Alex Kusenko
JCAP 1407, 039 (2014)
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 1 / 19
Motivation
The Standard Model
In the Standard Model:
Interactions are mediated by spin-1 gauge bosons.
The only spin-0 boson is the Higgs boson, which is involved inelectroweak symmetry breaking.
Matter is made of spin-1/2 fermions.
Global U(1) symmetries: baryon and lepton number.
What would a “similar” dark matter model look like?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 2 / 19
Motivation
The Standard Model
In the Standard Model:
Interactions are mediated by spin-1 gauge bosons.
The only spin-0 boson is the Higgs boson, which is involved inelectroweak symmetry breaking.
Matter is made of spin-1/2 fermions.
Global U(1) symmetries: baryon and lepton number.
What would a “similar” dark matter model look like?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 2 / 19
Motivation
The Standard Model
In the Standard Model:
Interactions are mediated by spin-1 gauge bosons.
The only spin-0 boson is the Higgs boson, which is involved inelectroweak symmetry breaking.
Matter is made of spin-1/2 fermions.
Global U(1) symmetries: baryon and lepton number.
What would a “similar” dark matter model look like?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 2 / 19
Motivation
The Standard Model
In the Standard Model:
Interactions are mediated by spin-1 gauge bosons.
The only spin-0 boson is the Higgs boson, which is involved inelectroweak symmetry breaking.
Matter is made of spin-1/2 fermions.
Global U(1) symmetries: baryon and lepton number.
What would a “similar” dark matter model look like?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 2 / 19
Motivation
The Standard Model
In the Standard Model:
Interactions are mediated by spin-1 gauge bosons.
The only spin-0 boson is the Higgs boson, which is involved inelectroweak symmetry breaking.
Matter is made of spin-1/2 fermions.
Global U(1) symmetries: baryon and lepton number.
What would a “similar” dark matter model look like?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 2 / 19
Minimal “Similar” Dark Sector
Self-Interacting Dark Matter Model
Assume dark matter is also spin-1/2 fermions.
Has a self-interaction which is described by a UD(1) gauge group.
Carries a global quantum number: dark baryon number.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 3 / 19
Minimal “Similar” Dark Sector
Self-Interacting Dark Matter Model
Assume dark matter is also spin-1/2 fermions.
Has a self-interaction which is described by a UD(1) gauge group.
Carries a global quantum number: dark baryon number.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 3 / 19
Minimal “Similar” Dark Sector
Self-Interacting Dark Matter Model
Assume dark matter is also spin-1/2 fermions.
Has a self-interaction which is described by a UD(1) gauge group.
Carries a global quantum number: dark baryon number.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 3 / 19
Further Motivations: Asymmetric Dark Matter
Asymmetric DM
Matter in the universe today carries a net baryon number.
We further assume that DM today has a nonzero dark baryon number.
The production of these asymmetries may be related.(Review: Petraki & Volkas, 2013)
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 4 / 19
Further Motivations: Asymmetric Dark Matter
Asymmetric DM
Matter in the universe today carries a net baryon number.
We further assume that DM today has a nonzero dark baryon number.
The production of these asymmetries may be related.(Review: Petraki & Volkas, 2013)
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 4 / 19
Further Motivations: Asymmetric Dark Matter
Asymmetric DM
Matter in the universe today carries a net baryon number.
We further assume that DM today has a nonzero dark baryon number.
The production of these asymmetries may be related.(Review: Petraki & Volkas, 2013)
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 4 / 19
Further Motivations: Self-Interaction
U(1) Gauge Self-Interaction
Long-range interaction, but strength ↓ as velocity ↑:
Can satisfy astrophysical bounds (Vogelsberger & Zavala, MNRAS 430(2013) 1722)......while being large enough for DM symmetric component to annihilatein early universe.
Eliminates cuspy profiles.
One way to resolve “Too-big-to-fail problem” (Boylan-Kolchin,Bullock, & M. Kaplinghat, 2011 & 2012)
Others: baryon effects, warm dark matter...
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 5 / 19
Further Motivations: Self-Interaction
U(1) Gauge Self-Interaction
Long-range interaction, but strength ↓ as velocity ↑:Can satisfy astrophysical bounds (Vogelsberger & Zavala, MNRAS 430(2013) 1722)...
...while being large enough for DM symmetric component to annihilatein early universe.
Eliminates cuspy profiles.
One way to resolve “Too-big-to-fail problem” (Boylan-Kolchin,Bullock, & M. Kaplinghat, 2011 & 2012)
Others: baryon effects, warm dark matter...
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 5 / 19
Further Motivations: Self-Interaction
U(1) Gauge Self-Interaction
Long-range interaction, but strength ↓ as velocity ↑:Can satisfy astrophysical bounds (Vogelsberger & Zavala, MNRAS 430(2013) 1722)......while being large enough for DM symmetric component to annihilatein early universe.
Eliminates cuspy profiles.
One way to resolve “Too-big-to-fail problem” (Boylan-Kolchin,Bullock, & M. Kaplinghat, 2011 & 2012)
Others: baryon effects, warm dark matter...
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 5 / 19
Further Motivations: Self-Interaction
U(1) Gauge Self-Interaction
Long-range interaction, but strength ↓ as velocity ↑:Can satisfy astrophysical bounds (Vogelsberger & Zavala, MNRAS 430(2013) 1722)......while being large enough for DM symmetric component to annihilatein early universe.
Eliminates cuspy profiles.
One way to resolve “Too-big-to-fail problem” (Boylan-Kolchin,Bullock, & M. Kaplinghat, 2011 & 2012)
Others: baryon effects, warm dark matter...
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 5 / 19
Further Motivations: Self-Interaction
U(1) Gauge Self-Interaction
Long-range interaction, but strength ↓ as velocity ↑:Can satisfy astrophysical bounds (Vogelsberger & Zavala, MNRAS 430(2013) 1722)......while being large enough for DM symmetric component to annihilatein early universe.
Eliminates cuspy profiles.
One way to resolve “Too-big-to-fail problem” (Boylan-Kolchin,Bullock, & M. Kaplinghat, 2011 & 2012)
Others: baryon effects, warm dark matter...
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 5 / 19
Further Motivations: Self-Interaction
U(1) Gauge Self-Interaction
Long-range interaction, but strength ↓ as velocity ↑:Can satisfy astrophysical bounds (Vogelsberger & Zavala, MNRAS 430(2013) 1722)......while being large enough for DM symmetric component to annihilatein early universe.
Eliminates cuspy profiles.
One way to resolve “Too-big-to-fail problem” (Boylan-Kolchin,Bullock, & M. Kaplinghat, 2011 & 2012)
Others: baryon effects, warm dark matter...
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 5 / 19
If UD(1) is unbroken...
Dark Baryon Number
At high energies an asymmetry in dark baryon number is produced.
The particles that carry the dark baryon number also carry chargeunder the UD(1) gauge interaction (assume positive charge).
This asymmetry must be produced via UD(1) gauge-invariantoperators...
Hence an equal asymmetry is produced in some negatively-chargedparticle!
This negatively charged particle can’t be the antiparicle; otherwisethere’s no net asymmetry in dark baryon number.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 6 / 19
If UD(1) is unbroken...
Dark Baryon Number
At high energies an asymmetry in dark baryon number is produced.
The particles that carry the dark baryon number also carry chargeunder the UD(1) gauge interaction (assume positive charge).
This asymmetry must be produced via UD(1) gauge-invariantoperators...
Hence an equal asymmetry is produced in some negatively-chargedparticle!
This negatively charged particle can’t be the antiparicle; otherwisethere’s no net asymmetry in dark baryon number.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 6 / 19
If UD(1) is unbroken...
Dark Baryon Number
At high energies an asymmetry in dark baryon number is produced.
The particles that carry the dark baryon number also carry chargeunder the UD(1) gauge interaction (assume positive charge).
This asymmetry must be produced via UD(1) gauge-invariantoperators...
Hence an equal asymmetry is produced in some negatively-chargedparticle!
This negatively charged particle can’t be the antiparicle; otherwisethere’s no net asymmetry in dark baryon number.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 6 / 19
If UD(1) is unbroken...
Dark Baryon Number
At high energies an asymmetry in dark baryon number is produced.
The particles that carry the dark baryon number also carry chargeunder the UD(1) gauge interaction (assume positive charge).
This asymmetry must be produced via UD(1) gauge-invariantoperators...
Hence an equal asymmetry is produced in some negatively-chargedparticle!
This negatively charged particle can’t be the antiparicle; otherwisethere’s no net asymmetry in dark baryon number.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 6 / 19
If UD(1) is unbroken...
Dark Baryon Number
At high energies an asymmetry in dark baryon number is produced.
The particles that carry the dark baryon number also carry chargeunder the UD(1) gauge interaction (assume positive charge).
This asymmetry must be produced via UD(1) gauge-invariantoperators...
Hence an equal asymmetry is produced in some negatively-chargedparticle!
This negatively charged particle can’t be the antiparicle; otherwisethere’s no net asymmetry in dark baryon number.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 6 / 19
If UD(1) is unbroken...
Multiple Species
Need two species:
Positively charged dark protons which carry dark baryon number.
Negatively charged dark electrons.
An asymmetry of particles over antiparticles is produced in both species.
Like the Standard Model:
Somehow we have a baryon asymmetry, which corresponds to somenumber of positively charged protons.
Since electromagnetism is a good symmetry, this same process alsomade an equal number of negatively charged electrons.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 7 / 19
If UD(1) is unbroken...
Multiple Species
Need two species:
Positively charged dark protons which carry dark baryon number.
Negatively charged dark electrons.
An asymmetry of particles over antiparticles is produced in both species.
Like the Standard Model:
Somehow we have a baryon asymmetry, which corresponds to somenumber of positively charged protons.
Since electromagnetism is a good symmetry, this same process alsomade an equal number of negatively charged electrons.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 7 / 19
If UD(1) is unbroken...
Multiple Species
Need two species:
Positively charged dark protons which carry dark baryon number.
Negatively charged dark electrons.
An asymmetry of particles over antiparticles is produced in both species.
Like the Standard Model:
Somehow we have a baryon asymmetry, which corresponds to somenumber of positively charged protons.
Since electromagnetism is a good symmetry, this same process alsomade an equal number of negatively charged electrons.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 7 / 19
If UD(1) is unbroken...
Multiple Species
Need two species:
Positively charged dark protons which carry dark baryon number.
Negatively charged dark electrons.
An asymmetry of particles over antiparticles is produced in both species.
Like the Standard Model:
Somehow we have a baryon asymmetry, which corresponds to somenumber of positively charged protons.
Since electromagnetism is a good symmetry, this same process alsomade an equal number of negatively charged electrons.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 7 / 19
If UD(1) is unbroken...
Multiple Species
Need two species:
Positively charged dark protons which carry dark baryon number.
Negatively charged dark electrons.
An asymmetry of particles over antiparticles is produced in both species.
Like the Standard Model:
Somehow we have a baryon asymmetry, which corresponds to somenumber of positively charged protons.
Since electromagnetism is a good symmetry, this same process alsomade an equal number of negatively charged electrons.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 7 / 19
If UD(1) is unbroken...
Multiple Species
Need two species:
Positively charged dark protons which carry dark baryon number.
Negatively charged dark electrons.
An asymmetry of particles over antiparticles is produced in both species.
Like the Standard Model:
Somehow we have a baryon asymmetry, which corresponds to somenumber of positively charged protons.
Since electromagnetism is a good symmetry, this same process alsomade an equal number of negatively charged electrons.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 7 / 19
What About a Broken UD(1)?
Motiation to Break UD(1) Symmetry
Dark interactions cannot be infinitely long-ranged (e.g., would affectclustering at large scales).
One way to screen the interactions by giving the dark gauge mediatora nonzero mass through a dark Higgs mechanism.
This means that there is a phase transition above which the UD(1)symmetry is restored, and below which it is broken.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 8 / 19
What About a Broken UD(1)?
Motiation to Break UD(1) Symmetry
Dark interactions cannot be infinitely long-ranged (e.g., would affectclustering at large scales).
One way to screen the interactions by giving the dark gauge mediatora nonzero mass through a dark Higgs mechanism.
This means that there is a phase transition above which the UD(1)symmetry is restored, and below which it is broken.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 8 / 19
What About a Broken UD(1)?
Motiation to Break UD(1) Symmetry
Dark interactions cannot be infinitely long-ranged (e.g., would affectclustering at large scales).
One way to screen the interactions by giving the dark gauge mediatora nonzero mass through a dark Higgs mechanism.
This means that there is a phase transition above which the UD(1)symmetry is restored, and below which it is broken.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 8 / 19
Multiple Species
As long as the asymmetry is generated before the dark phase transition inwhich the above argument still holds.
DM is multi-component in much of parameter space.
Ξ�ann =.5
Α D=Α D
,min
Α D=10
Α D,m
in
Below solid lines:Asymmetry generation
in pD and eD
Above solid lines:Asymmetry generationin pD only possible
Short-range scatte
ring Hv ~ 10 km�sL
Long-range scatterin
g Hv t10 km�sL
10-1 1 101 10210-6
10-5
10-4
10-3
10-2
10-1
mp @GeVD
MD
@GeV
D
ΑD > 4Π
ΑD> 4Π
Below solid lines:Asymmetry generation
in pD and eD
Above solidlines: Asymmetrygenerationin pD onlypossible
ΑD>Α
D, m
in
ΑD<Α
D, m
in
10-1 1 101 102 103 10410-6
10-5
10-4
10-3
10-2
10-1
mp @GeVD
MD@G
eVD
Σpp�mp = 1 cm2�g at v = 220 km�s
Σpp�mp = 0.5 cm2�g at v = 10 km�s
αD,min: minimum for sufficient annihilation of the thermal dark protons in the early universe.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 9 / 19
Multiple Species
As long as the asymmetry is generated before the dark phase transition inwhich the above argument still holds.
DM is multi-component in much of parameter space.
Ξ�ann =.5
Α D=Α D
,min
Α D=10
Α D,m
in
Below solid lines:Asymmetry generation
in pD and eD
Above solid lines:Asymmetry generationin pD only possible
Short-range scatte
ring Hv ~ 10 km�sL
Long-range scatterin
g Hv t10 km�sL
10-1 1 101 10210-6
10-5
10-4
10-3
10-2
10-1
mp @GeVD
MD
@GeV
D
ΑD > 4Π
ΑD> 4Π
Below solid lines:Asymmetry generation
in pD and eD
Above solidlines: Asymmetrygenerationin pD onlypossible
ΑD>Α
D, m
in
ΑD<Α
D, m
in
10-1 1 101 102 103 10410-6
10-5
10-4
10-3
10-2
10-1
mp @GeVD
MD@G
eVD
Σpp�mp = 1 cm2�g at v = 220 km�s
Σpp�mp = 0.5 cm2�g at v = 10 km�s
αD,min: minimum for sufficient annihilation of the thermal dark protons in the early universe.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 9 / 19
Dark Atoms
pD + eD → HD
Generically expect an asymmetric population of dark electrons anddark protons.
These can then form dark atoms (as long as dark photon massMD < αDµD).
Even in this simplistic model, we end up with multi-component darkmatter: dark protons, dark electrons, and dark atoms.
What Does This Mean?
What does the multicomponent nature of DM mean for:
Cosmology?
Halo shapes?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 10 / 19
Dark Atoms
pD + eD → HD
Generically expect an asymmetric population of dark electrons anddark protons.
These can then form dark atoms (as long as dark photon massMD < αDµD).
Even in this simplistic model, we end up with multi-component darkmatter: dark protons, dark electrons, and dark atoms.
What Does This Mean?
What does the multicomponent nature of DM mean for:
Cosmology?
Halo shapes?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 10 / 19
Dark Atoms
pD + eD → HD
Generically expect an asymmetric population of dark electrons anddark protons.
These can then form dark atoms (as long as dark photon massMD < αDµD).
Even in this simplistic model, we end up with multi-component darkmatter: dark protons, dark electrons, and dark atoms.
What Does This Mean?
What does the multicomponent nature of DM mean for:
Cosmology?
Halo shapes?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 10 / 19
Dark Atoms
pD + eD → HD
Generically expect an asymmetric population of dark electrons anddark protons.
These can then form dark atoms (as long as dark photon massMD < αDµD).
Even in this simplistic model, we end up with multi-component darkmatter: dark protons, dark electrons, and dark atoms.
What Does This Mean?
What does the multicomponent nature of DM mean for:
Cosmology?
Halo shapes?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 10 / 19
Dark Atoms
pD + eD → HD
Generically expect an asymmetric population of dark electrons anddark protons.
These can then form dark atoms (as long as dark photon massMD < αDµD).
Even in this simplistic model, we end up with multi-component darkmatter: dark protons, dark electrons, and dark atoms.
What Does This Mean?
What does the multicomponent nature of DM mean for:
Cosmology?
Halo shapes?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 10 / 19
Dark Atoms
pD + eD → HD
Generically expect an asymmetric population of dark electrons anddark protons.
These can then form dark atoms (as long as dark photon massMD < αDµD).
Even in this simplistic model, we end up with multi-component darkmatter: dark protons, dark electrons, and dark atoms.
What Does This Mean?
What does the multicomponent nature of DM mean for:
Cosmology?
Halo shapes?
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 10 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30
Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30
Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
These events change number of d.o.f. in dark sector.Ratio of dark to SM d.o.f. ξ is time-dependent and may be > 1 or < 1.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 11 / 19
Implications for Cosmology...
Sample Sequence of Events
More involved cosmology due to multi-component nature:
Event Temperature ScaleDark asymmetry generation Tasy
Thermal decoupling of dark and SM sectors Tdec
Freeze-out of pD pD annihilations TD,p,fo ≈ mp/30Freeze-out of eD eD annihilations TD,e,fo ≈ me/30Dark recombination ∆ & TD,DR & ∆/50
UD(1)-breaking phase transition TD,PT ∼ MD/(8πq2φαD)1/2
Freeze-out of dark Higgs annihilations TD,φD ,fo ≈ mϕ/41
Dark photon chemical decoupling TD,γD ∼ MD/[40(8πq2φαD)1/2]
Big Bang Nucleosynthesis TV ,BBN ≈ 1 MeV
The UD(1)-breaking phase transition can occur before dark recombinationor freeze-out of dark proton and/or dark electron annihilations
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 12 / 19
Implications for Cosmology...
Cosmological Constraints
Different cosmological histories lead to different constraints.
Time-dependence of ξ can affect constraints.
Several examples given in JCAP 1407, 039 (2014).
One example of constraints on dark photon mass:
qΦ 2Α
D»
0.1
qΦ 2
ΑD »
0.01
qΦ 2
ΑD »
10 -3
qΦ 2
ΑD »
10 -4
De
ca
yΓ
D®
e +e -
po
ssible
ifΕ
¹0
extra radiation at BBN
10-8 10-6 10-4 10-2 1
10-3
10-2
10-1
1
MD @GeVD
Ξ=
TD
�TV
Red: relic abundance of the dark photons may alterthe time of matter-radiation equality or dominate theDM density
Blue: Too much radiation at BBN
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 13 / 19
Implications for Cosmology...
Cosmological Constraints
Different cosmological histories lead to different constraints.
Time-dependence of ξ can affect constraints.
Several examples given in JCAP 1407, 039 (2014).
One example of constraints on dark photon mass:
qΦ 2Α
D»
0.1
qΦ 2
ΑD »
0.01
qΦ 2
ΑD »
10 -3
qΦ 2
ΑD »
10 -4
De
ca
yΓ
D®
e +e -
po
ssible
ifΕ
¹0
extra radiation at BBN
10-8 10-6 10-4 10-2 1
10-3
10-2
10-1
1
MD @GeVD
Ξ=
TD
�TV
Red: relic abundance of the dark photons may alterthe time of matter-radiation equality or dominate theDM density
Blue: Too much radiation at BBN
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 13 / 19
Implications for Cosmology...
Cosmological Constraints
Different cosmological histories lead to different constraints.
Time-dependence of ξ can affect constraints.
Several examples given in JCAP 1407, 039 (2014).
One example of constraints on dark photon mass:
qΦ 2Α
D»
0.1
qΦ 2
ΑD »
0.01
qΦ 2
ΑD »
10 -3
qΦ 2
ΑD »
10 -4
De
ca
yΓ
D®
e +e -
po
ssible
ifΕ
¹0
extra radiation at BBN
10-8 10-6 10-4 10-2 1
10-3
10-2
10-1
1
MD @GeVD
Ξ=
TD
�TV
Red: relic abundance of the dark photons may alterthe time of matter-radiation equality or dominate theDM density
Blue: Too much radiation at BBN
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 13 / 19
Implications for Cosmology...
Cosmological Constraints
Different cosmological histories lead to different constraints.
Time-dependence of ξ can affect constraints.
Several examples given in JCAP 1407, 039 (2014).
One example of constraints on dark photon mass:
qΦ 2Α
D»
0.1
qΦ 2
ΑD »
0.01
qΦ 2
ΑD »
10 -3
qΦ 2
ΑD »
10 -4
De
ca
yΓ
D®
e +e -
po
ssible
ifΕ
¹0
extra radiation at BBN
10-8 10-6 10-4 10-2 1
10-3
10-2
10-1
1
MD @GeVD
Ξ=
TD
�TV
Red: relic abundance of the dark photons may alterthe time of matter-radiation equality or dominate theDM density
Blue: Too much radiation at BBN
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 13 / 19
Implications for Cosmology...
Cosmological Constraints
Different cosmological histories lead to different constraints.
Time-dependence of ξ can affect constraints.
Several examples given in JCAP 1407, 039 (2014).
One example of constraints on dark photon mass:
qΦ 2Α
D»
0.1
qΦ 2
ΑD »
0.01
qΦ 2
ΑD »
10 -3
qΦ 2
ΑD »
10 -4
De
ca
yΓ
D®
e +e -
po
ssible
ifΕ
¹0
extra radiation at BBN
10-8 10-6 10-4 10-2 1
10-3
10-2
10-1
1
MD @GeVD
Ξ=
TD
�TV
Red: relic abundance of the dark photons may alterthe time of matter-radiation equality or dominate theDM density
Blue: Too much radiation at BBN
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 13 / 19
Implications for Halos
Self-Interaction and Dark Matter Halos
One motivation for introducing dark matter self-interaction is:
Interactions can modify the shape of small dark matter halos,potentially alleviating the disagreement between dark mattersimulations and observations.
However, if self-interactions are too large, than large halos may notbe elliptical.
Both of these questions must be revisited if dark matter ismulti-component, with different intra- and inter-species interactions.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 14 / 19
Implications for Halos
Self-Interaction and Dark Matter Halos
One motivation for introducing dark matter self-interaction is:
Interactions can modify the shape of small dark matter halos,potentially alleviating the disagreement between dark mattersimulations and observations.
However, if self-interactions are too large, than large halos may notbe elliptical.
Both of these questions must be revisited if dark matter ismulti-component, with different intra- and inter-species interactions.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 14 / 19
Implications for Halos
Self-Interaction and Dark Matter Halos
One motivation for introducing dark matter self-interaction is:
Interactions can modify the shape of small dark matter halos,potentially alleviating the disagreement between dark mattersimulations and observations.
However, if self-interactions are too large, than large halos may notbe elliptical.
Both of these questions must be revisited if dark matter ismulti-component, with different intra- and inter-species interactions.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 14 / 19
Implications for Halos
Self-Interaction and Dark Matter Halos
One motivation for introducing dark matter self-interaction is:
Interactions can modify the shape of small dark matter halos,potentially alleviating the disagreement between dark mattersimulations and observations.
However, if self-interactions are too large, than large halos may notbe elliptical.
Both of these questions must be revisited if dark matter ismulti-component, with different intra- and inter-species interactions.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 14 / 19
Momentum-Transfer in Halos
Momentum-Transfer Rate
Define effective momentum transfer rate:
Γeff = hpΓp + heΓe + hHΓH
hi : mass fraction of species iΓi : momentum scattering rate of species i
Impose a cut-off on the contribution of each species:If the momentum-transfer rate for a given species is very large but this
species carries only a tiny fraction of the mass of the halo, the effect of the
momentum loss by this species on the halo dynamics is negligible.
Atom-atom interaction: Cline, Liu, Moore, & Xue (2014), Cyr-Racine & Sigurdson(2013)Atom-ion interactions: Cyr-Racine & Sigurdson (2013)
Ion-ion interactions: Khrapak, Ivlev & Morfill (2004)
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 15 / 19
Momentum-Transfer in Halos
Momentum-Transfer Rate
Define effective momentum transfer rate:
Γeff = hpΓp + heΓe + hHΓH
hi : mass fraction of species iΓi : momentum scattering rate of species i
Impose a cut-off on the contribution of each species:
If the momentum-transfer rate for a given species is very large but this
species carries only a tiny fraction of the mass of the halo, the effect of the
momentum loss by this species on the halo dynamics is negligible.
Atom-atom interaction: Cline, Liu, Moore, & Xue (2014), Cyr-Racine & Sigurdson(2013)Atom-ion interactions: Cyr-Racine & Sigurdson (2013)
Ion-ion interactions: Khrapak, Ivlev & Morfill (2004)
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 15 / 19
Momentum-Transfer in Halos
Momentum-Transfer Rate
Define effective momentum transfer rate:
Γeff = hpΓp + heΓe + hHΓH
hi : mass fraction of species iΓi : momentum scattering rate of species i
Impose a cut-off on the contribution of each species:If the momentum-transfer rate for a given species is very large but this
species carries only a tiny fraction of the mass of the halo, the effect of the
momentum loss by this species on the halo dynamics is negligible.
Atom-atom interaction: Cline, Liu, Moore, & Xue (2014), Cyr-Racine & Sigurdson(2013)Atom-ion interactions: Cyr-Racine & Sigurdson (2013)
Ion-ion interactions: Khrapak, Ivlev & Morfill (2004)
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 15 / 19
Momentum-Transfer in Halos
Momentum-Transfer Rate
Define effective momentum transfer rate:
Γeff = hpΓp + heΓe + hHΓH
hi : mass fraction of species iΓi : momentum scattering rate of species i
Impose a cut-off on the contribution of each species:If the momentum-transfer rate for a given species is very large but this
species carries only a tiny fraction of the mass of the halo, the effect of the
momentum loss by this species on the halo dynamics is negligible.
Atom-atom interaction: Cline, Liu, Moore, & Xue (2014), Cyr-Racine & Sigurdson(2013)Atom-ion interactions: Cyr-Racine & Sigurdson (2013)
Ion-ion interactions: Khrapak, Ivlev & Morfill (2004)
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 15 / 19
Constraints on Momentum-Transfer Rate
Constraints on Momentum-Transfer Rate
To preserve ellipticity of large halos:
Γeff less than ∼ 17H0 at v ∼ 220 km/s, ρ ∼ 1 GeV/cm3.(σ/m . 1 cm2/g; Rocha, Bullock, & Kaplinghat (2012))
To modify smaller dwarf halos:
Γeff greater than ∼ 0.2H0 at v ∼ 10 km/s, ρ ∼ 0.5 GeV/cm3 .(σ/m & 0.5 cm2/g; Battaglia, Helmi, & Breddels (2013))
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 16 / 19
Constraints on Momentum-Transfer Rate
Constraints on Momentum-Transfer Rate
To preserve ellipticity of large halos:
Γeff less than ∼ 17H0 at v ∼ 220 km/s, ρ ∼ 1 GeV/cm3.
(σ/m . 1 cm2/g; Rocha, Bullock, & Kaplinghat (2012))
To modify smaller dwarf halos:
Γeff greater than ∼ 0.2H0 at v ∼ 10 km/s, ρ ∼ 0.5 GeV/cm3 .(σ/m & 0.5 cm2/g; Battaglia, Helmi, & Breddels (2013))
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 16 / 19
Constraints on Momentum-Transfer Rate
Constraints on Momentum-Transfer Rate
To preserve ellipticity of large halos:
Γeff less than ∼ 17H0 at v ∼ 220 km/s, ρ ∼ 1 GeV/cm3.(σ/m . 1 cm2/g; Rocha, Bullock, & Kaplinghat (2012))
To modify smaller dwarf halos:
Γeff greater than ∼ 0.2H0 at v ∼ 10 km/s, ρ ∼ 0.5 GeV/cm3 .(σ/m & 0.5 cm2/g; Battaglia, Helmi, & Breddels (2013))
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 16 / 19
Constraints on Momentum-Transfer Rate
Constraints on Momentum-Transfer Rate
To preserve ellipticity of large halos:
Γeff less than ∼ 17H0 at v ∼ 220 km/s, ρ ∼ 1 GeV/cm3.(σ/m . 1 cm2/g; Rocha, Bullock, & Kaplinghat (2012))
To modify smaller dwarf halos:
Γeff greater than ∼ 0.2H0 at v ∼ 10 km/s, ρ ∼ 0.5 GeV/cm3 .(σ/m & 0.5 cm2/g; Battaglia, Helmi, & Breddels (2013))
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 16 / 19
Constraints on Momentum-Transfer Rate
Constraints on Momentum-Transfer Rate
To preserve ellipticity of large halos:
Γeff less than ∼ 17H0 at v ∼ 220 km/s, ρ ∼ 1 GeV/cm3.(σ/m . 1 cm2/g; Rocha, Bullock, & Kaplinghat (2012))
To modify smaller dwarf halos:
Γeff greater than ∼ 0.2H0 at v ∼ 10 km/s, ρ ∼ 0.5 GeV/cm3 .
(σ/m & 0.5 cm2/g; Battaglia, Helmi, & Breddels (2013))
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 16 / 19
Constraints on Momentum-Transfer Rate
Constraints on Momentum-Transfer Rate
To preserve ellipticity of large halos:
Γeff less than ∼ 17H0 at v ∼ 220 km/s, ρ ∼ 1 GeV/cm3.(σ/m . 1 cm2/g; Rocha, Bullock, & Kaplinghat (2012))
To modify smaller dwarf halos:
Γeff greater than ∼ 0.2H0 at v ∼ 10 km/s, ρ ∼ 0.5 GeV/cm3 .(σ/m & 0.5 cm2/g; Battaglia, Helmi, & Breddels (2013))
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 16 / 19
Sample Plots
Disfavored by ellipticityof large halos
Favored bygalactic
substructure
4ΜD > m H + D
Insufficientannihilation inearly universe
xD = 0.01
xD =0.99
1 101 102 103 104
10-2
10-1
mH @GeVD
ΑD
D = 500 keV, MD = 1 eV, ΞDR = 0.5
Favored by galactic substructure
Disfavored by ellipticity of large halos
xD =0.07
xD =0.01
D<
MD
<Μ
DΑ
D
MD
>Μ
DΑ
D
4ΜD >mH +D
10-11 10-9 10-7 10-5 10-3 10-110-1
1
101
102
MD @GeVD
ΜD
@GeV
D
m H = 250 GeV, ΑD = 0.05, ΞDR = 0.3
Regions where self-interaction can modify small halos withoutdestroying the ellipticity of large halos: due to velocity-dependence ofcross sections.
Can take mass of dark photon → 0; screening provided by boundstate formation.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 17 / 19
Sample Plots
Disfavored by ellipticityof large halos
Favored bygalactic
substructure
4ΜD > m H + D
Insufficientannihilation inearly universe
xD = 0.01
xD =0.99
1 101 102 103 104
10-2
10-1
mH @GeVD
ΑD
D = 500 keV, MD = 1 eV, ΞDR = 0.5
Favored by galactic substructure
Disfavored by ellipticity of large halos
xD =0.07
xD =0.01
D<
MD
<Μ
DΑ
D
MD
>Μ
DΑ
D
4ΜD >mH +D
10-11 10-9 10-7 10-5 10-3 10-110-1
1
101
102
MD @GeVD
ΜD
@GeV
D
m H = 250 GeV, ΑD = 0.05, ΞDR = 0.3
Regions where self-interaction can modify small halos withoutdestroying the ellipticity of large halos: due to velocity-dependence ofcross sections.
Can take mass of dark photon → 0; screening provided by boundstate formation.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 17 / 19
Sample Plots
Disfavored by ellipticityof large halos
Favored bygalactic
substructure
4ΜD > m H + D
Insufficientannihilation inearly universe
xD = 0.01
xD =0.99
1 101 102 103 104
10-2
10-1
mH @GeVD
ΑD
D = 500 keV, MD = 1 eV, ΞDR = 0.5
Favored by galactic substructure
Disfavored by ellipticity of large halos
xD =0.07
xD =0.01
D<
MD
<Μ
DΑ
D
MD
>Μ
DΑ
D
4ΜD >mH +D
10-11 10-9 10-7 10-5 10-3 10-110-1
1
101
102
MD @GeVD
ΜD
@GeV
D
m H = 250 GeV, ΑD = 0.05, ΞDR = 0.3
Regions where self-interaction can modify small halos withoutdestroying the ellipticity of large halos: due to velocity-dependence ofcross sections.
Can take mass of dark photon → 0; screening provided by boundstate formation.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 17 / 19
Sample Plots
Disfavored by ellipticityof large halos
Favored bygalactic
substructure
4ΜD > m H + D
Insufficientannihilation inearly universe
xD = 0.01
xD =0.99
1 101 102 103 104
10-2
10-1
mH @GeVD
ΑD
D = 500 keV, MD = 1 eV, ΞDR = 0.5
Favored by galactic substructure
Disfavored by ellipticity of large halos
xD =0.07
xD =0.01
D<
MD
<Μ
DΑ
D
MD
>Μ
DΑ
D
4ΜD >mH +D
10-11 10-9 10-7 10-5 10-3 10-110-1
1
101
102
MD @GeVD
ΜD
@GeV
D
m H = 250 GeV, ΑD = 0.05, ΞDR = 0.3
Regions where self-interaction can modify small halos withoutdestroying the ellipticity of large halos: due to velocity-dependence ofcross sections.
Can take mass of dark photon → 0; screening provided by boundstate formation.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 17 / 19
Effect of Dark Atom Formation
Dark Atom Formation
Scattering rate in halos varies non-monotonically with αD and mH .
Very small αD : DM mostly ions, negligible DM self-interaction.Smaller αD : DM mostly ions, but more scattering. May affect smallhalos and eventually affect Milky-Way sized halos.Increasing αD : Dark recombination becomes more efficient; dark atomsform and scattering rate decreases.Large αD : atom-atom scattering cross section increases, may affectsmall halos and eventually larger halos.
Large mH suppresses the recomination rate in early universe (andscattering rate today).
This is the reason for the “wedge” shape.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 18 / 19
Effect of Dark Atom Formation
Dark Atom Formation
Scattering rate in halos varies non-monotonically with αD and mH .
Very small αD : DM mostly ions, negligible DM self-interaction.
Smaller αD : DM mostly ions, but more scattering. May affect smallhalos and eventually affect Milky-Way sized halos.Increasing αD : Dark recombination becomes more efficient; dark atomsform and scattering rate decreases.Large αD : atom-atom scattering cross section increases, may affectsmall halos and eventually larger halos.
Large mH suppresses the recomination rate in early universe (andscattering rate today).
This is the reason for the “wedge” shape.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 18 / 19
Effect of Dark Atom Formation
Dark Atom Formation
Scattering rate in halos varies non-monotonically with αD and mH .
Very small αD : DM mostly ions, negligible DM self-interaction.Smaller αD : DM mostly ions, but more scattering. May affect smallhalos and eventually affect Milky-Way sized halos.
Increasing αD : Dark recombination becomes more efficient; dark atomsform and scattering rate decreases.Large αD : atom-atom scattering cross section increases, may affectsmall halos and eventually larger halos.
Large mH suppresses the recomination rate in early universe (andscattering rate today).
This is the reason for the “wedge” shape.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 18 / 19
Effect of Dark Atom Formation
Dark Atom Formation
Scattering rate in halos varies non-monotonically with αD and mH .
Very small αD : DM mostly ions, negligible DM self-interaction.Smaller αD : DM mostly ions, but more scattering. May affect smallhalos and eventually affect Milky-Way sized halos.Increasing αD : Dark recombination becomes more efficient; dark atomsform and scattering rate decreases.
Large αD : atom-atom scattering cross section increases, may affectsmall halos and eventually larger halos.
Large mH suppresses the recomination rate in early universe (andscattering rate today).
This is the reason for the “wedge” shape.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 18 / 19
Effect of Dark Atom Formation
Dark Atom Formation
Scattering rate in halos varies non-monotonically with αD and mH .
Very small αD : DM mostly ions, negligible DM self-interaction.Smaller αD : DM mostly ions, but more scattering. May affect smallhalos and eventually affect Milky-Way sized halos.Increasing αD : Dark recombination becomes more efficient; dark atomsform and scattering rate decreases.Large αD : atom-atom scattering cross section increases, may affectsmall halos and eventually larger halos.
Large mH suppresses the recomination rate in early universe (andscattering rate today).
This is the reason for the “wedge” shape.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 18 / 19
Effect of Dark Atom Formation
Dark Atom Formation
Scattering rate in halos varies non-monotonically with αD and mH .
Very small αD : DM mostly ions, negligible DM self-interaction.Smaller αD : DM mostly ions, but more scattering. May affect smallhalos and eventually affect Milky-Way sized halos.Increasing αD : Dark recombination becomes more efficient; dark atomsform and scattering rate decreases.Large αD : atom-atom scattering cross section increases, may affectsmall halos and eventually larger halos.
Large mH suppresses the recomination rate in early universe (andscattering rate today).
This is the reason for the “wedge” shape.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 18 / 19
Effect of Dark Atom Formation
Dark Atom Formation
Scattering rate in halos varies non-monotonically with αD and mH .
Very small αD : DM mostly ions, negligible DM self-interaction.Smaller αD : DM mostly ions, but more scattering. May affect smallhalos and eventually affect Milky-Way sized halos.Increasing αD : Dark recombination becomes more efficient; dark atomsform and scattering rate decreases.Large αD : atom-atom scattering cross section increases, may affectsmall halos and eventually larger halos.
Large mH suppresses the recomination rate in early universe (andscattering rate today).
This is the reason for the “wedge” shape.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 18 / 19
Conclusions
Conclusions
Even with rather minimal assumptions, self-interacting asymmetricdark matter models generally have multi-component dark matter,with two species of ions and dark atoms.
This remains true for a light but not necessarily massless mediatorgauge boson.
Cosmological constraints may take very different forms depending onthe sequence of cosmological events.
There exist regions of parameter space in which DM self-scatteringcan affect clustering in small halos without endangering the ellipticityof larger halos.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 19 / 19
Conclusions
Conclusions
Even with rather minimal assumptions, self-interacting asymmetricdark matter models generally have multi-component dark matter,with two species of ions and dark atoms.
This remains true for a light but not necessarily massless mediatorgauge boson.
Cosmological constraints may take very different forms depending onthe sequence of cosmological events.
There exist regions of parameter space in which DM self-scatteringcan affect clustering in small halos without endangering the ellipticityof larger halos.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 19 / 19
Conclusions
Conclusions
Even with rather minimal assumptions, self-interacting asymmetricdark matter models generally have multi-component dark matter,with two species of ions and dark atoms.
This remains true for a light but not necessarily massless mediatorgauge boson.
Cosmological constraints may take very different forms depending onthe sequence of cosmological events.
There exist regions of parameter space in which DM self-scatteringcan affect clustering in small halos without endangering the ellipticityof larger halos.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 19 / 19
Conclusions
Conclusions
Even with rather minimal assumptions, self-interacting asymmetricdark matter models generally have multi-component dark matter,with two species of ions and dark atoms.
This remains true for a light but not necessarily massless mediatorgauge boson.
Cosmological constraints may take very different forms depending onthe sequence of cosmological events.
There exist regions of parameter space in which DM self-scatteringcan affect clustering in small halos without endangering the ellipticityof larger halos.
Lauren Pearce (University of Minnesota) Self-Interacting Asymmetric DM September 17th, 2014 19 / 19