An April 13, 2010 presentation on composite inelastic dark matter

1. Composite Inelastic Dark Matter
Jay Wacker
SLAC
Caltech
April 13, 2010
with P. Schuster, D. Alves, S. Behbahbani, M. Lisanti, A. Hook, E. Izaguirre
arXiv: 0903.3945, 0911.1997, 0911.4483, 1003.4729....

2. Dark Matter
Discovering its nature is a great open question
80% of the Universe’s mass is unknown
What we know:
Cold/Massive
Suppressed EM & Strong interactions
Isn’t strongly self-interacting
WIMP Miracle drives a lot of the thinking
DM is a thermal relic for 1000 GeV weakly interacting particle
Most DM model building links
weak scale/hierarchy problem

3. Status of Dark Matter
Not your grandfather’s DM Candidate
DAMA
PAMELA
ATIC
FERMI Electrons
WMAP Haze
INTEGRAL
CoGeNT
Hints at non-trivial mass scales & interactions

4. Secluded Sectors
“Hidden Valleys”
Standard Secluded
Model Weak Connection Sector
L = φsecluded Oportal
Oportal = FY , |h|2, hL , jB−L ,
µν µ
λY , etc

5. Secluded Sectors
“Hidden Valleys”
High Energy/Intensity
Standard Secluded
Model Weak Connection Sector
Slow decays back to SM
L = φsecluded Oportal
Oportal = FY , |h|2, hL , jB−L ,
µν µ
λY , etc

6. Secluded Sectors
“Hidden Valleys”
High Energy/Intensity
Standard Secluded
Model Weak Connection Sector
Slow decays back to SM
L = φsecluded Oportal
Oportal = FY , |h|2, hL , jB−L ,
µν µ
λY , etc
Ubiquitous in Top-Down Models
Hard part is getting rid of additional gauge groups & matter
Dark Matter might be a secluded sector

7. Dark Matter Model Building
Occam’s Razor vs. Principle of Plentitude
“Plurality should not be posited “No possibilities which remain eternally
without necessity” possible will go unrealized”
When searching in the dark, Occam’s Razor can lead to blind spots!

8. Dark Matter Model Building
Occam’s Razor vs. Principle of Plentitude
“Plurality should not be posited “No possibilities which remain eternally
without necessity” possible will go unrealized”
When searching in the dark, Occam’s Razor can lead to blind spots!
Minimality may not be best guide to
Dark Matter’s existence
Why should 20% of the mass, have all the fun?
Gauge theories appear in SM & many BSM constructions
Models illustrate new mechanisms and new experiments

9. Plan of Talk
DAMA & Inelastic Dark Matter
Composite dark matter models
Experimental Prospects
Discussion

10. Direct Detection
χ
N
χ N
Dark matter scatters off nuclei in detectors
Measure nuclear recoil spectrum
[Counts/kg day/keV]
dR ρDM dσ
= v
dER mDM mN dER average over initial DM velocities
Multiply by exposure [kg day]

11. Spectrum of Recoils
Minimum DM velocity to scatter cause ER recoil
mN E R
vmin =
2µ2
Boltzmann Distribution
vesc
dR dσ
3 −v 2 /v0
2
−ER /E0
dER
∝ d v
dER
ve ∼e
vmin
Average over initial DM velocities in the galactic halo
2µ2 v0
2
Falling spectrum ∼ 25 keV E0 =
mN
Push to lower energy thresholds

12. DAMA
Residuals
NaI Experiment running for 13 years
Time (day)
Galactic Dark Matter 2-5 keV
Annual modulationkg intonyr) WIMP signal
Residuals (cpd/kg/keV)
DAMA/LIBRA ! 250 (0.87
⊙
v Φdm = ndm v
summer
winter
E
v E
v
Amod = RSum − RWin
Modulation amplitude ~2.5% for
v ≤ vesc + |vE − v⊙ |
v ≤ vesc + |vE + v⊙ |
elastic scattering
Time (day)
2-6 keV
Residuals (cpd/kg/keV)
DAMA/LIBRA =250 kg (0.87 (0.87 ton yr)
DAMA/LIBRA ! 250kg tonyr)
Time (day)

13. Current Limits
-5
10 http://dmtools.brown.edu/
Cross-section [pb] (normalised to nucleon)
DAMA Gaitskell,Mandic,Filippini
2 Excluded
LIN
ZEP by a factor
-6
RE
SS
T of 30
10 C
ZE
PL
IN 3
-5
XE
10
-7 S
http://dmtools.brown.edu/
DM
[pb] (normalised to nucleon)
10
NO
C
Gaitskell,Mandic,Filippini
N
-6
10
-8 090913122401 spin-independent
10 1 2 3
10 10 10
WIMP Mass [GeV/c2]
-7
10

14. Inelastic Dark Matter
Dark matter has two nearly degenerate states
δm ∼ (100 keV)
Tucker-Smith and Weiner, hep-ph/0101138.
Scattering off SM transitions between states
χ2 q
χ1 q
Higher threshold velocity necessary to scatter,
Higher typical recoil energies
1 mN ER
vmin = √ + δm
2mN ER µ
Lighter nuclei, higher threshold

15. Inelastic Dark Matter
Threshold behavior
Rate
Recoil Energy (keV)
3 Consequences
(1) Scatters off of heavier nuclei -- CDMS ineffective
(2) Large recoil energy -- ZEP3 Xe10 didn’t initialy look
(3) Large modulation fraction -- absolute signal is smaller
3 Coincidences
XENON10, CRESST II, ZEPLIN2 all had events

16. Larger Modulation Fraction
Smaller rate
One reason for apparent tension
3.5
3.0
Summer scattering
v 2 f (v)/10−4
2.5
2.0
Winter scattering
1.5
v0
1.0 Boost f(v) into Earth’s frame
0.5
vesc
0.0
0 100 200 300 400 500 600
0 100 200 300 400 500 600
1.2 velocity
1.0
elastic
0.8 2.5% modulation
# of Events
0.6
0.4
0.2 inelastic
100% modulation
0.0 0.2 0.4 0.6 0.8 1.0
June 2 Dec 2 June 2
Factor of 40 difference in translating
modulated to unmodulated rate!

17. Recent Experiments
Inelastic DM has a lot in common with Mark Twain
“The report of my death was
an exaggeration”
XENON100 reported 0 events
... but ran in late Oct through early Nov.
CRESST reported exclusion
... but had 40 keV upper threshold
... and won’t release their raw results
CoGeNT reported anomalous low energy events
... points to low mass dark matter (not iDM)

18. Inelastic Dark Matter
A new number to explain:
δm
∼ 10−6
m
Sign of dark sector dynamics?
First of many splittings
New interactions to discover
Changes which questions are interesting
Will be confirmed/refuted in 2010!
XENON100

19. Hyperfine Splittings
Magnetic moment splitting
Can give very small energy differences
HHF ∼ µ1 · µ2 δ (r)
3
g
µ S
m
Occurs in all bound state systems
Fermions + Gauge interactions

20. Hyperfine Splittings
Weakly Coupled:
Hydrogen
s=1
m2
∆E ∼ α 4
mp
e
1s s=0 1 µeV
Strongly Coupled:
Heavy Flavor Mesons (B, B*)
Λ2 s=1
1s
QCD
∆E ∼ s=0 45 MeV
mb

21. Open Questions
Can engineer systems with 100 keV mass splittings
Coupling to Standard Model?
Inelastic transitions dominate over elastic?
Cosmology constraints?
How will we know?

22. Plan of Talk
DAMA Inelastic Dark Matter
Composite dark matter models
Experimental Prospects
Discussion

23. Anatomy of Composite Inelastic Dark Matter
Simple Setup, Rich Dynamics
dark quarks kinetic mixing
qH Fd µν FY µν
SU(N) U(1)d SM
qL
Start with left and move right

24. Composite Inelastic Dark Matter
Alves, Behbahani, Schuster, JW, 0903.3945.
1
Ldark = − Tr G2 + q iD q + m¯q
¯ q
2 µν
New SU(Nc) gauge sector confines at scale Λd
2π
Λdark ∼ exp −
b0 αdark
Two dark quarks qH qL
mH Λdark , mL
No flavor changing effects: stabilizes DM

25. Cosmology of CiDM
Alves, Behbahani, Schuster, JW: 0903.3945 + 1003.4729
A primordial cosmological dark quark asymmetry
(nH − nH ) = −(nL − nL ) = 0
¯ ¯
More heavy quarks than antiquarks More light antiquarks than quarks
Given up Wimp Miracle for asymmetric DM
Driven off of SM’s baryon asymmetry?
nDM 5 GeV
nbaryon mDM

26. Cosmology of CiDM
Alves, Behbahani, Schuster, JW: 0903.3945 + 1003.4729
A primordial cosmological dark quark asymmetry
(nH − nH ) = −(nL − nL ) = 0
¯ ¯
More heavy quarks than antiquarks More light antiquarks than quarks
Given up Wimp Miracle for asymmetric DM
Driven off of SM’s baryon asymmetry?
nDM 5 GeV
nbaryon mDM
¯
When T Λd , dark matter is in qH qL bound state
qH
¯
qL

27. States of CiDM
Alves, Behbahani, Schuster, JW, 1003.4729.
Heavy quarks can bind together
2
EBind ∼ αdark mH
Heavy
Quarks 0 1 2 3 4
Mesons
Baryons
More deeply bound
Dark Matter Synthesis occurs

28. (1)
number density of dark matter is the πd state and there are other com
Dark Matter Synthesis
of the dark matter to discover.
A chainIV:, Arrested The completeexothermic a few percent in the form
Region
reaction, increasingly densities, with unsynthesized compon
and πd share comparable mass
synthesized and
pions, πd and π1 → 2 + 0 step of Q = 2EB − mlightπd → πd π
1 + d . The first
(2) (3) (1) (1) (2)
the synthesis chain, πd
bottleneck much like deuterium formation slows BBN in the Standard M
2+1→3+0 Q = 10E has mlight
−
only occurs for a brief period, but once the πd B formed, it processe
(2)
into BH . 2 + 2 → 4 + 0 Q = 32EB
Region V: Inhibited The3 + 1 Q = 8EB
2 + 2 → first step of the synthesis chain is strongly supre
(1)
the CiDM 3 + 1 → 4 is dominatedQ = d24E
composition + 0 by π . Region V is the cosmolo
B
in [7]. The heavy baryon component mostly arises through the primor
First reaction is potential bottleneck
formation described in Sec. 3.2.
A quantitative description lightest dark hadron one of these regions is sum
Depends on mass of of the abundances in each
in Table 3.
!m=95keV
Region ρπ(1) /ρDM ρπ(2) /ρDM ρπ(3) /ρDM ρBH /ρDM
d d d
III
mH (GeV)
10−4 − 0.1% 10−4 − 0.2% 10−3 − 0.9%
d (MeV)
I 99%
II 0.1% − 4% 0.2% − 5% 0.9% − 11% 80% − 99%
IV III 4% − 57% 5% − 24% 11% − 17% 9% − 80%
II IV 57% − 99% 5% 5% 1% − 30%
V V 99% 10−5 10−5 1%
I
Table 3: The relations on the fractional mass densities that define the region
mlight /d matter synthesis in Fig. 1.

29. Splitting of Ground State
Mass difference in meson states arises from hyperfine splitting
Coulombic limit
mH
mL qH α4 m2
¯ δm ∼ d L
Energy
Λd qL mH
For U(1): Atomic Dark Matter
D. E. Kaplan, et al (2009)
(Susy version in progress )
spin 0 spin 1
dark pion dark rho
πd ρd

30. Splitting of Ground State
Mass difference in meson states arises from hyperfine splitting
Coulombic limit
mH
mL qH α4 m2
¯ δm ∼ d L
Energy
Λd qL mH
mL For U(1): Atomic Dark Matter
D. E. Kaplan, et al (2009)
(Susy version in progress )
spin 0 spin 1 Confined
qH Λ2
d
dark pion dark rho ¯
qL δm ∼
πd ρd mH

31. Spin Temperature
Need to explain why iDM is in ground state
Self interaction keeps DM in equilibrium
ρ d ρ d → πd πd
Solves de-excitation problem
nρd
= exp(−δm/Tspin )
n πd
Kinetically decouple late, smaller spin temperature
Tspin 10 keV
∼
Still Satisfy Self-Interaction Limits
σ −2 cm2 1 bn
m ∼ 10 g
∼
100 GeV

32. Dark Matter Couplings
Couples to a secluded U(1)
Axial-Vector Coupling
µ
Jd = qH γ µ γ 5 qH − qL γ µ γ 5 qL
¯ ¯
Forbids quark masses until U(1)d Higgsed
How does the U(1) couple to mesons?
Dark Matter Scattering
¯
qH qL ρµ
d
elastic inelastic
mass
πd πd→πd πd→ρd
spin 0 meson spin 1 meson
πd → −πd ρdµ → (−1)µ ρdµ

33. Axial Coupling to Mesons
Elastic
πd→πd
Forbidden
†
πd ∂µ πd Aµ
Parity
d
1 † µν
πd ∂µ πd ∂ν Fd
Λ2
d
1 †
Vanishes
˜ µν
2 πd ∂µ πd ∂ν Fd
Λd

34. Axial Coupling to Mesons
Elastic Inelastic
πd→πd πd→ρd
Suppressed
Velocity
Forbidden
†
πd ∂µ πd Aµ mπd †
πd ρ µ d µ
Ad
Parity
d
1 † µν
πd ∂µ πd ∂ν Fd
Λ2
d
Dominant
1 † 1 † µ ν
Vanishes
˜ µν
2 πd ∂µ πd ∂ν Fd
Λd Λd
πd ∂ ρd Fdµν
Near purely Inelastic

35. Coupling to Standard Model
Kinetically mix U(1)d with U(1)Y
U (1)d U (1)Y
DM SM
ψgut
1 µν 1 µν µν 1
LU(1) = − Fd Fdµν − B Bµν − Fd Bµν → − F
4 4 2 4

36. Coupling to Standard Model
Kinetically mix U(1)d with U(1)Y
U (1)d U (1)Y
DM SM
ψgut
1 µν 1 µν µν 1
LU(1) = − Fd Fdµν − B Bµν − Fd Bµν → − F
4 4 2 4
Higgs U(1)d near the electroweak scale
LHiggs = |Dµ φd |2 − V (φd ) → m2 A2
d d
md = 2gd vφ

37. Coupling to Standard Model
Kinetically mix U(1)d with U(1)Y
U (1)d U (1)Y
DM SM
ψgut
1 µν 1 µν µν 1
LU(1) = − Fd Fdµν − B Bµν − Fd Bµν → − F
4 4 2 4
Higgs U(1)d near the electroweak scale
LHiggs = |Dµ φd |2 − V (φd ) → m2 A2
d d
md = 2gd vφ
Gives mass to fermions
LYuk = +c
yL q L q L φ c †
yH q H qH φ
mf = yf vφ

38. Coupling to Standard Model
Holdom 1985
Kinetically mix U(1)d with U(1)Y
U (1)d U (1)Y
DM SM
ψgut
After EWSB:
L = −Fd − FEM − Fd FEM + m2 A2 + JEM AEM + Jd Ad
2 2
A d
kinetic mixing
redefine SM photon AEM → AEM − Ad

39. Coupling to Standard Model
Holdom 1985
Kinetically mix U(1)d with U(1)Y
U (1)d U (1)Y
DM SM
ψgut
After EWSB:
L = −Fd − FEM − Fd FEM + m2 A2 + JEM AEM + Jd Ad
2 2
A d
kinetic mixing
redefine SM photon AEM → AEM − Ad
L = −Fd − FEM + m2 A2 + JEM (AEM − Ad ) + Jd Ad
2 2
A d
µ
Lint ∝ Jem Adµ
SM is milli-charged under dark U(1), DM is neutral under EM

40. Current Limits on ε
10-1
(g − 2)µ
Υ decays
10-2
10-3 E774
M
D
Ci
10-4 E141
10-5 E137
10 MeV 100 MeV 1 GeV 10 GeV 100 GeV
mAd
Model independent limits not known for 1 GeV to 200 GeV
Precision EW + High energy Bounds
2
2 2
(w/ A. Hook E. Izaguirre)
e q
α(q ) =
2
1+ 2
4π q + mAd

41. CP-Violation
˜
Θ term in dark QCD sector Lcpv = Θd TrGd Gd
Not necessarily small
Leads to mixing between states of different parity
e.g. πd ↔ a0d
In limit mL → 0 chiral rotation removes Θ term
Parity violating mixing sin θp
Scalar states neutral under U(1)d
sin θp † µν
Leads to πd ∂µ πd ∂ν Fd
Λd
2

42. ansition Charge Radius Scattering
parity!
gd µνσρ sin θp † † µν
int = πd ∂µ πd ∂ν Fd
Fdark µν2 ρd σ ∂ρ πd
Λd
Λdark Neutral composite states with charged constituents
velocity suppressed
−6 smaller (ER )
Fdm
Form-factor suppression from 10 πd
sition interaction with background field
q
gd µν †
Lint = 2 Lcr∂µFdm (ER )¯ieAdν πd
F π ∂
= dark q d q
Λdark γd
Fdm (0) = 0 + rc ER
2 q
MDMπ200 GeV,
im 6 elastic Charge Radius scattering
M 200 GeV, M 1 GeV
0.030
DM A d 125 keV, MA 1 GeV
Count Rate arbitraty units
0.030
0.025
Charged Elastic Scattering
Charged Radius Elastic Scattering
elastic
0.025
w cpd kg keV
0.020
0.020
Rate
0.015 charge-radius Charge-radius scattering difficult to
0.015
0.010
distinguish from inelastic scattering
0.010
0.005
0.005
0.000
0.000
20 40 60 80 100
ER recoil
E 0.005
1 2 3 4 5 6 7 8
ER KeVee ER KeVee

43. Plan of Talk
DAMA Inelastic Dark Matter
Composite dark matter models
Experimental Prospects
Discussion

44. Standard Halo Model
N-body simulations indicate that density falls off more
steeply at larger radii
3.5
3
3.0 isothermal, isotropic, Gaussian
v 2 f (v)/10−4
2.5 2 2
f (v) ∝ e−(v/v0 ) − e−(vesc /v0 ) Θ(vesc − v)
2
2.0 v0
1.5
1
1.0
0.5
vesc
0
0.0
0 100 200 300 400 500 600
0 100 200 300 400 500 600
velocity

45. Modified SHM
Will use modified ansatz
2α 2α
f (v) ∝ e−(v/v0 ) − e−(vesc /v0 ) Θ(vesc − v)
3.5
α parameterizes variation in the
3
3.0 α=1.1 tail of the distribution
)
v 2 f (v)/10−4
2.5
α=0.8 captures qualitative behavior of
2
2.0 v0 ) N-body simulations
1.5
1
1.0
0.5 600
vesc
0
0.0
0 100 200 300 400 500 600
0 100 200 300 400 500 600
velocity

46. Marginalizing over Uncertainties
How do current experiments constrain parameters?
Usually astrophysical parameters are benchmarked
0.8 ≤ α ≤ 1.25
particle physics astrophysics
200 ≤ v0 ≤ 300
mπd , δm, σ v0 , vesc , α 500 ≤ vesc ≤ 600
2
pred
Xi obs
− Xi
χ (m, δ, σ, v0 , ve , α) =
2
σi
Minimize χ2 over 6 parameters using results from direct detection experiments
Fit to DAMA recoil spectrum
No experiment rules out point at 95% CL

47. Parameter Space
θp = 0, 4%, 6%, 8%
Best fit
mπd ∼ 70 GeV
δm ∼ 95 keV
Slow halos
v0 ∼ 200 km/s
α 1.0
∼

48. Global Fit
gd2 2
gd gd mπd
mAd gd vφ
4
→ 4 yH
q mAd
0.010
0.005
0.001
5 104 DAMA Regions
Ε
1 104
5 105
θp = 0, 6%, 8%
1 105
Dark Photon Mass GeV
0.01 0.1 1 10 100

49. DAMA
Best fits
Modulation Amplitude
0.03 θp =c0%, 8%
el/cin=0
cel/cin=0.15
countskgdaykeVee
0.02
0.01
0.00
Recoil Energy keVee
0 2 4 6 8
Difficult to distinguish from DAMA
mixed elastic-inelastic scattering

50. Xenon100
100 kg Liquid Xe detectors (upgrade for Xenon10)
Will see a large number of events
DAMA rate: 0.02/kg d/keV
Nevents 0.5 Nevents 40
0.25
0.25
0.20
0.20
Frequency
Frequency
0.15
0.15
0.10 0.10
0.05 0.05
0.00 0.00
0 20 40 60 80 100 120 0 20 40 60 80 100 120
Events Observed Events Observed
(1000 kg-day exposure ~ 1 month!)
Tail down to small 5 events

51. Xenon100
Recoil Spectrum
5.00
1000 kg· day
: summer
1.00
: winter
0.50
countskeV
0.10
0.05
Recoil Energy keV
0 20 40 60 80
Elastic subcomponent apparent but distorts spectrum,
inelastic kinematics get washed out
Directional detection experiments key

52. Plan of Talk
DAMA Inelastic Dark Matter
Composite dark matter models
Experimental Prospects
Discussion

53. Future Work
Susy: New Hierarchy Problem
SM might be mediator of DM SSB
Nearly Susy bound states
Possible DM forming MACHOS
Discovering other components
Light Baryons
Heavy Baryons Multicore Mesons
Generating Asymmetry
Decays Annihilations
Cosmic Ray Signals
Collider Signatures
Lepton Jets

54. Collider Signatures
+
−
+
Light mesons
ωD ηD − √
ωD s ΛD
23-4/5-))'
0/-(*5506)'!-7')
!#$%'()*#
+*,'#-. qD
+!#*/01)0*/
√
s ΛD
p
e− p+
e #*89+5:-;+'#0(5-
''/)
¯
qD
γ
mA ΛD
ωD
ωD Lepton Jets
=**)'!-;#*!8()-
+
−
ωD #'(*05-*-;+*)*/
− ηD
+ − + ωD

55. Signal Simulation
(w/ A. Haas Y. Gershtein)
Need Hadron
Spectrum + Decays Dark Showering
Sherpa Herwig
Dark Hadronization
Sherpa Herwig
Cascading to SM

56. DarkSpecGen (w/ S. Behbehani)
An interface to produce semi-realistic
hadronic final spectra and decay tables
and interface to Sherpa Herwig
Gauge
SU(N), Sp(2N), SO(N) Partons
Reps (Fund, Adj)
Nf, Masses, Spins
Strong Decays
Weak Decays Flavor/CP
SM Neutral Portals

57. Conclusions
Inelastic DM is an elegant explanation for
DAMA vs the Rest of the World
New scale to explain: New Dynamics
Discovery or Refutation Imminent
Within the year
iDM sensitive to halo:
Need to go beyond SHM
New measurements are important
Directional Detection
Finding DM subcomponents
Measuring Halo properties