Composite Inelastic Dark Matter

Jay WackerSLAC

June 6, 2009

WithPhilip SchusterSiavosh BehabaniDaniele Alves

arXiv:0903.3945

11 Years of Oscillation

A distinctive recoil spectrum

Inelastic Dark MatterTucker-Smith & Weiner (2001)

Large modulation fraction

Large recoil energy

Scatters off of heavier nuclei

!1

!2

!m ! O(100 keV)

Dark matter has 2 nearly degenerate states

!1

!2 N

N

Scattering off the SM is!1 ! !2

3 Consequences:(CDMS ineffective)

(Xenon10 didn’t look)

A new number to explain:

10!6!m

m!

Breaking of an approximate global symmetry

Sign of dark sector dynamics

Inelastic Dark Matter

Like YukawasRadiatively stable

Hard to discover origin

First of many splittingsNew interactions to discover

Changes what questions are interesting

Composite Dark MatterA new SU(Nc) gauge sector

Confines at !Dark

A pair of quarks:qL

qH

mL ! !dark

mH ! !dark

mH

mL

!dark

Composite Dark MatterA new SU(Nc) gauge sector

Confines at !Dark

A cosmological asymmetry(nH ! nH̄) = !(nL ! nL̄) "= 0

At T ! !Dark DM is in qH q̄L bound states

Dark Mesons

A pair of quarks:qL

qH

mL ! !dark

mH ! !dark

mH

mL

!dark

Degeneracy of the Ground State

Dark Chromomagnetic interaction breaks spin symmetry

Spin 1

Dark Rho

!d

Spin 0

Dark Pion

!dm!d !m"d

!2Dark

mH!

!d

!dqH q̄Lm !H ! "# · "B

mH

Heavy quark spin preserved in electric interactions

Doesn’t require adding new symmetry and breaking itAccidental global symmetry from Lorentz Invariance

Coupling to the SMKinetically Mix U(1)darkU(1)Y with

Lmix = ! Fµ!darkFY µ!

At low energy Lint = ! Aµdark jEM µ

Higgs U(1)dark near EW scale

SM DMU(1)Y U(1)dark

!GUT

LHiggs = |Dµ!d|2 ! V (!d) !" m2dA2

d

Charging the Dark QuarksTwo Choices Anomaly-Free Charges

jµdark = gd(q̄H!µqH ! q̄L!µqL)

Vector coupling

Doesn’t forbid dark quark massesHas both elastic and inelastic scattering channels

Charging the Dark QuarksTwo Choices Anomaly-Free Charges

jµdark = gd(q̄H!µqH ! q̄L!µqL)

Vector coupling

Doesn’t forbid dark quark massesHas both elastic and inelastic scattering channels

jµdark = gd(q̄H!µ!5qH ! q̄L!µ!5qL)

Axial Vector coupling

Forbids dark quark masses until U(1)dark HiggsingOnly inelastic scattering channels

Inelastic Axial TransitionsMust compute couplings to dark mesons

Lint =gd

!darkFµ!

dark !†d ! "µ #d

!d ! "dDim 5

1 2 3 4 5 6 7 8

!0.005

0.000

0.005

0.010

0.015

0.020

0.025

0.030

ER!KeVee

"cpd!kg!keV#

MDM"200 GeV, #"125 keV, MA"1 GeV

Figure 2: Nuclear recoil spectrum (red line) for inelastic scattering as compared to the

DAMA annual modulation signal (blue data points). At low recoil energy, only the high

velocity tail of the halo can scatter (see equation (1), thereby suppressing low energy events.

At higher energy, recoil rates are suppressed by both the nuclear form factor and the falling

halo profile as a function of relative velocity. Consequently, a peak in the recoil spectrum

scaling with ! is characteristic of inelastic dark matter.

4

1 2 3 4 5 6 7 8

All !d ! !d!d ! !d

transitions forbidden

RecoilSpectrum

µ = 0 ! = iuse

Vector Couplings

Lint =gd

!2dark

!µFµ!dark "†

d !! "d

Lint =gd

!dark!µ!"#Fdark µ! "†d " ## $d

parity!

Different low energy interactions

velocity suppressed

Elastic transition

Inelastic transition

Dim 6 elastic Charge Radius scattering

10!6 smaller

20 40 60 80 1000.000

0.005

0.010

0.015

0.020

0.025

0.030

ER!KeVee

CountRate"arbitratyunits#

MDM!200 GeV, MA!1 GeV

Charged Radius Elastic Scattering

Charged Elastic Scattering

1 2 3 4 5 6 7 8

"0.005

0.000

0.005

0.010

0.015

0.020

0.025

0.030

ER!KeVee

"cpd!kg!keV#

MDM!200 GeV, #!125 keV, MA!1 GeV

Figure 4: Nuclear recoil spectra characteristic of composite dark matter. In addition to

scattering inelastically, composite dark matter may also scatter elastically through charged

radius scattering, but with a suppressed rate. Left: For a dark matter mass of MDM =

200 GeV and mediator mass MA = 1 GeV, the charged radius recoil spectrum (blue) is

shown alongside the charged scattering spectrum (red). The finite size of the dark matter

suppresses low recoil energy events, thereby pushing the entire recoil spectrum to higher

energies. Consequently, direct detection experiments need to include large nuclear recoil

energies to maximize sensitivity to this kind of elastic scattering. Right: Charged inelastic

scattering (orange) and electric-dipole inelastic scattering (red) are shown alongside the

DAMA recoil spectrum (blue data points), again for MDM = 200 GeV and mediator mass

MA = 1 GeV. The finite dark matter size suppresses low energy events, thereby pushing the

spectrum to slightly higher energies.

11

Erecoil

Suppressed at lowErecoil

Vector Couplings

Lint =gd

!2dark

!µFµ!dark "†

d !! "d

Lint =gd

!dark!µ!"#Fdark µ! "†d " ## $d

parity!

Different low energy interactions

velocity suppressed

Elastic transition

Inelastic transition

Dim 6 elastic Charge Radius scattering

10!6 smaller

CP-Violation Add term to dark QCD sector!

LCPV = !Gµ!G̃µ!

Mixes states of opposite CP!d a1 d& mixi.e.

Lint =gd

!darkFµ!

dark !†d ! "µ #dAllows

Both inelastic & form-factor suppressed elastic interactions

Nearly the same Recoil SpectraHow to measure?

Spin 1 sector

!dark

l = 0, s = 1

l = 1, s = 0

Directional Detection Finkbeiner, Lin,Weiner (2009)

!vearth

!

w/ Lisanti (in Progress)

0 20 40 60 80 1000.000

0.005

0.010

0.015

0.020

0.025

Recoil Energy !keV"

Rate

!1.0 !0.8 !0.6 !0.4 !0.2 0.0

10!4

0.001

0.01

0.1

1

Cos!""

Rate

Recoil Spectrum Recoil Direction

iDM

iDM

eDM w/FFeDM w/FF

ERecoil cos !

Outlook

Composite inelastic DM givesexplanation to 100 keV scale

Lots of variants with different scattering New experiments needed to understand DM dynamics

Collider signatures of DM could have showering

Lots of models to exploreSusy & Dark Flavor