UCLA Dark Matter, 18 Feb 2016 Models of · 2016-02-19 · dw.1 dw 1 dw 10 MW.1 MW 1 cl.1 cl 1 10-4...
Transcript of UCLA Dark Matter, 18 Feb 2016 Models of · 2016-02-19 · dw.1 dw 1 dw 10 MW.1 MW 1 cl.1 cl 1 10-4...
UCLA Dark Matter, 18 Feb 2016
Models of Self-Interacting Dark Matter
Kimberly BoddyUniversity of HawaiiDepartment of Physics & Astronomy
Motivation for SIDM
SIDM helps alleviate small-scale structure issues from dwarf to cluster scales
(see earlier talks by J. Bullock and H.B. Yu)
Think beyond WIMPs
�
m⇠ cm2
g⇠ 2
barn
GeV
Simple Hidden Sectors1. SU(N)
❖ Pure gauge SU(N)
❖ With adjoint fermion
2. U(1) — massless mediator
❖ Atomic dark matter
3. U(1) — massive mediator
❖ Attractive/Repulsive Yukawa potential
This list is not exhaustive!
Aim is to cover a few models and some phenomenology.
Case 1: SU(N)
Minimal Model
❖ Hidden SU(N) gauge
❖ Confinement scale 𝚲
❖ Particle content:❖ Massless gluons❖ Composite glueballs
with mass ~𝚲
❖ Massless gluon sets relic density❖ Geometric scattering cross section
(velocity-independent)
� ⇠ 4⇡
⇤2N2
target SIDM (at small N)
0.1 cm2êg1 cm2êg
N=2
N=10
N=100
10-5 10-4 0.001 0.010.01
0.1
1
10
100
xL
L@Ge
VD
Glueball-only dark matter
KB, Feng, Kaplinghat, Tait, PRD 89, 115017 (2014).
fixed N
Include Adjoint Fermion
Excluded by LEP2
Wgbino = 0.1 WDMWgb = 0.9 WDM
N=2
N=10
N=100
x f=4.5¥10-3
x f=1.4¥10-3
x f=3.0¥10-4
0.01 0.1 1 10 1000.01
0.1
1
10
100
mX @TeVD
L@Ge
VD
Mostly-Glueball Dark Matter HNo ConnectorsL
❖ Include SU(N) adjoint fermion with mass mX — “gluino”
❖ At confinement, form both glueballs (gluon+gluon) and glueballinos (gluino+gluon)
fixed N
fixed ξf
KB, Feng, Kaplinghat, Tait, PRD 89, 115017 (2014).
Scattering via Yukawa
Tulin, et al., PRD 87, 115007 (2013).
Wide range of velocitiesfor which the
cross section ~ constant
Scattering via Yukawa
Excluded by LEP2
Wgbino = 0.9 WDMWgb = 0.1 WDM
N=2
N=10N=100
x f=2.0¥10-2
x f=5.0¥10-3
x f=7.0¥10-4
0.01 0.1 1 10 1000.01
0.1
1
10
100
1000
mX @TeVD
L@Me
VD
Mostly-Glueballino Dark Matter HNo ConnectorsL
fixed N
fixed ξf
dwarfs
LSBs
mX = 14 TeV𝚲 = 0.35 MeV
KB, Feng, Kaplinghat, Tait, PRD 89, 115017 (2014).
3.5 keV LineChromomagnetic interactions give hyperfine splittings:
∆E ~ Λ2/mX
KB, Feng, Kaplinghat, Shadmi, Tait, PRD 90, 095016 (2014).
sêm=0.1 cm 2êg10 cm2êg
35.6 keV
DE=0.356 keV
x=1
N=30 10 3
N=3
10
Flux
DwarfLSB
0.01 0.1 1 10 1000.01
0.1
1
10
100
1000
mX @TeVD
L@Me
VD
Case 2: Unbroken U(1)
Atomic Dark Matter❖ Particle content and model
parameters:
❖ Dark proton (mp)
❖ Dark electron (me)
❖ Dark photon
❖ Dark fine structure constant αD
❖ Temperature ratio ξ=TD/T
❖ Consider scattering of dark hydrogen with mass mD
KB, Kaplinghat, Kwa, Peter (in prep).
(All quantities in atomic units)
Preliminary
Wide range of energies (velocities)for which the cross section ~ constant
R =
mp / m
e
Dark Recombination
Cyr-Racine and Sigurdson, PRD 87, 103515 (2013).
BD = mD H8êaD 2-1L -1BD = 10 keVx = 0.37
Ionized DM
Neutral DM
10 102 103 104 105
10-4
10-3
10-2
10-1
10 102 103 104 105
10-4
10-3
10-2
10-1
mD @GeVD
a D
10-12
10-10
10-8
10-6
10-4
10-2
1
xDionization fraction
↵6D
⇠
✓⌦DMh2
0.11
◆⇣ mD
GeV
⌘�1✓BD
keV
◆�1
& 1.5⇥ 10�16
Binding energy
Matching to SIDM
Cline et al., PRD 89, 043514 (2014).
f i = 1 →
= 0.01α
= 0.02α
= 0.03α f i = 1 →
allowed →
excluded
→
0.01
0.03
0.1
0.3
1
1e−5
1e−4
0.001
Lines of constant α for which
σV/mH = 0.5 cm2/g
R=mp/me
Lines of constant α for which
ionization fraction = 1
Effects on Cosmology
⌃DAO ⌘ ↵D
✓BD
eV
◆�1 ⇣ mD
GeV
⌘�1/6
Cyr-Racine et al., PRD 89, 063517 (2014).
Case 3: Broken U(1)
Yukawa Scattering
Vogelsberger and Zavala, MNRAS 430, 1722 (2013).
V (r) = ��
rexp(��r)
Matching to SIDM
dw0.1
dw1
dw10
MW 0.1
MW 1cl 0.1
cl 1
10-4 0.001 0.01 0.1 10.1
1
10
100
1000
104
mf HGeVL
mXHGe
VL
Dark matter with relic density Hs-waveLdw0.1
dw1
dw10
MW 0.1MW 1
cl 0.1
cl 1
0.001 0.01 0.1 10.1
1
10
100
1000
104
mf HGeVL
mXHGe
VL
Dark matter with relic density Hp-waveLscalar mediator
α fixed to obtain correctrelic density
Tulin, et al., PRD 87, 115007 (2013).
vector mediator
mediator mass DM mass
Include U(1) Kinetic Mixing
Kaplinghat, et al., PRD 89, 035009 (2013).
Summary❖ SIDM helps solve small-scale problems, while preserving large-scale structure
❖ Rich phenomenology from very simple models
❖ SU(N) dark matter:
❖ confinement separates early- and late-universe physics
❖ keV line from connectors to SM
❖ U(1) atomic dark matter:
❖ dark recombination forms neutral dark hydrogen
❖ dissipative dark matter can affect cosmology
❖ U(1) Yukawa interactions:
❖ light mediator gives velocity-dependent cross sections
❖ kinetic mixing with SM photon can produce direct detection signal