Prospects for Inelastic Dark Matter Daniele Alves Stanford / SLAC - - PowerPoint PPT Presentation

Prospects for Inelastic Dark Matter

Daniele Alves

Stanford / SLAC In collaboration with M. Lisanti and J. Wacker PHENO ’10

DM interpretation due to Sun and Earth’s motion

DAMA’s 8.9σ annual modulation in single hit rate

Bernabei et.al.

Eur.Phys.J. C56(2008)

Elastic heavy WIMP interpretation excluded by other searches

DAMA

Aprile et.al.

arXiv: 1005.0380

Inelastic Dark Matter (iDM)

Tucker-Smith & Weiner

Phys.Rev. D64 (2001) 043502

m

I

127

m+δm

127I

ER

δm ~ 100 keV

v

min =

√ 2m E

N R

1 (δm + m E

N R

µ )

72Ge 127I

Heavy elements are favored

100 200 300 400 500 600 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 vkms DM Local Velocity Distribution

v

min =

√ 2m E

N R

1 (δm + m E

N R

µ ) Summer

100 200 300 400 500 600 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 vkms DM Local Velocity Distribution

v

min =

√ 2m E

N R

1 (δm + m E

N R

µ )

100 200 300 400 500 600 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 vkms DM Local Velocity Distribution

Winter

v

min =

√ 2m E

N R

1 (δm + m E

N R

µ ) inelastic elastic

100 200 300 400 500 600 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 vkms DM Local Velocity Distribution

0.0 0.5 1.0 1.5 2.0 2.5 3.0 time years Rate

High modulation fraction

CRESST experiment

might have seen less events than typically predicted by iDM in the 10 - 40 keV region preliminary

• W. Seidel - WONDER 2010 Workshop

XENON100

• nly 11 live days of exposure for calibration run

strongest current limits on DM

XENON100 collaboration

arXiv: 1005.0380

XENON100

• nly 11 live days of exposure for calibration run

strongest current limits on DM

Decisively CONFIRM

• r

REFUTE iDM hypothesis

XENON100 collaboration

arXiv: 1005.0380

What affects predictions for Dark Matter Direct Detection ? Astrophysical uncertainties

Local DM velocity distribution

Particle physics uncertainties

DM interactions & scattering kinematics

Detector uncertainties

Target nucleus form factor & quenching factor

scattering rate in iDM is highly sensitive to velocity distribution

dR dt ∝ vesc

vmin

d v f( v + vearth) v

standard assumption: Maxwell-Boltzmann distribution

f( v) ∝ (e

− v2

v2 0 − e

−

v2 esc v2 0 )Θ(|

vesc − v|)

standard procedure: benchmark velocity parameters and

narrows the parameter space and limits the predictions

broader and more sensible procedure:

marginalize over unknown velocity parameters

Astrophysical uncertainties

v0

vesc

Astrophysical uncertainties

numerical simulations of galactic DM structure:

significant departure from Maxwell-Boltzmann distribution

• bservations of Saggitarius stellar tidal steam

triaxial Milky Way halo?

Law & Majewski

Ap.J. 714 (2010) 229-254

substructures and streams? symmetry axes of halo and disk unrelated?

Astrophysical uncertainties Investigate 3 scenarios:

Standard Maxwell-Boltzmann marginalize over and

v0 vesc

Local stream

f( v) = δ3( v − vstream)

marginalize over magnitude and direction of

vstream

Axisymmetric halo

f( v) ∝ e−αL2

ye

− v2

v2 0 Θ(|

vesc − v|)

f( v) ∝ e

− v2

v2 0 Θ(|

vesc − v|)

marginalize over , and

v0 vesc α

Astrophysical uncertainties

0.0 0.1 0.2 0.3 0.4 0.5 0.0 0.2 0.4 0.6 0.8 1.0 Mod Fraction

Typical range when benchmarking

DM Stream Maxwellian Axisymmetric

# CRESST events / 100kg-d (10-40 keV)

10 20 30 40 50

Modulation Fraction

Uncertainties in iDM particle properties

Cross-Section dependence on momentum transfer

σ ∝ σ0

(e.g. sneutrino)

Dark Matter Form Factor (sign of compositeness)

(e.g. CiDM)

σ ∝ σ0q2

σ ∝ σ0q4

Uncertainties in iDM particle properties

σ0

• 20

40 60 80 0.00 0.01 0.02 0.03 Recoil Energy keV Modulation Amplitude cpdkgkeVee

σ0q2

σ0q4

DAMA

M

• d

u l a t e d R a t e ( c p d / k g / k e V e e )

Uncertainties in iDM particle properties

• 20

40 60 80 0.00 0.01 0.02 0.03 Recoil Energy keV Modulation Amplitude cpdkgkeVee

20 40 60 80 0.00 0.02 0.04 0.06 0.08 0.10 Recoil Energy keV Rate cpdkgkeV

CRESST

σ0

σ0q2

σ0q4

Uncertainties in iDM particle properties

0.0 0.1 0.2 0.3 0.4 0.5 0.0 0.2 0.4 0.6 0.8 1.0 Eventskgday Mod Fraction

σ0

σ0q2

σ0q4

# CRESST events / 100kg-d (10-40 keV) 10 20 30 40 50

Modulation Fraction

Typical range when benchmarking

Detector uncertainties

Quenching Factor for 127I

Recoil Energy (keV) QI Reference 22-330 0.09± 0.01 40-100 0.08± 0.02 10-71 0.086± 0.007 40-300 0.05± 0.02

Several independent measurements found 0.05 ≤ qI ≤ 0.09

Bernabei et.al. PLB389 (1996) Pecourt et.al. ApJ11 (1999) Tovey et.al. PLB433 (1998) Fushimi et.al. PRC47 (1993)

qI

q = Escintillation Enuclear recoil

Detector uncertainties

• 20

40 60 80 100 120 0.00 0.01 0.02 0.03 Recoil Energy keV Modulation Amplitude cpdkgkeVee

q=0.085 DAMA

M

• d

u l a t e d R a t e ( c p d / k g / k e V e e )

Detector uncertainties

• 20

40 60 80 100 120 0.00 0.01 0.02 0.03 Recoil Energy keV Modulation Amplitude cpdkgkeVee

• 20

40 60 80 100 120 0.00 0.01 0.02 0.03 Recoil Energy keV Modulation Amplitude cpdkgkeVee

q=0.070 DAMA

M

• d

u l a t e d R a t e ( c p d / k g / k e V e e )

Detector uncertainties

• 20

40 60 80 100 120 0.00 0.01 0.02 0.03 Recoil Energy keV Modulation Amplitude cpdkgkeVee

• 20

40 60 80 100 120 0.00 0.01 0.02 0.03 Recoil Energy keV Modulation Amplitude cpdkgkeVee

• 20

40 60 80 100 120 0.00 0.01 0.02 0.03 Recoil Energy keV Modulation Amplitude cpdkgkeVee

q=0.060 DAMA

M

• d

u l a t e d R a t e ( c p d / k g / k e V e e )

Detector uncertainties

50 100 150 0.00 0.02 0.04 0.06 0.08 0.10 Recoil Energy keV Rate cpdkgkeV

q=0.085 q=0.060 q=0.070

CRESST

Detector uncertainties

0.0 0.1 0.2 0.3 0.4 0.00 0.05 0.10 0.15 0.20 0.25 Neventskgday 1040 keV Neventskgday 40100 keV

q=0.060 q=0.070 q=0.085 10-40 keV window 10 20 30 40 5 10 15 20 25 40-100 keV window # CRESST events / 100kg-d

Typical range when benchmarking

Summary and Conclusions

Uncertainties on the DM velocity distribution, DM form factor and 127I quenching factor have a dramatic impact on predictions for direct detection In light of that, it is unlikely that the next CRESST data release will rule out iDM in a completely model independent way. XENON100 data from this summer will decisively exclude of confirm iDM. In case it confirms iDM, it might tell us a lot about properties

• f the dark matter particle and our Milky Way halo.

THANK YOU