itp seminar - max planck society

ITP seminarRecent results from Dark Matter direct detection

experiments and their interpretation

Thomas Schwetz

T. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 1

Outline

• introduction to Dark Matter direct detection

• recent hints for low-mass WIMPsCDMS, CoGeNT, CRESST, DAMA

and their (in)compatibility with boundsCDMS, XENON

• focus on spin-independent elastic scattering

• brief comments on spin-dependent scattering andmore exotic scenarios


Dark Matter in a Milkyway-like Galaxy

Via Lactea N-body DM simulation Diemand, Kuhlen, Madau, astro-ph/0611370

you are here


Dark Matter distribution

“standard halo model”:

local DM densityρχ ≈ 0.389 ± 0.025 GeV cm−3

Catena, Ullio, 0907.0018

⇒ nχ ≈ 4000 m−3

(

100 GeV

mχ

)


Dark Matter distribution

“standard halo model”:

local DM densityρχ ≈ 0.389 ± 0.025 GeV cm−3

Catena, Ullio, 0907.0018

⇒ nχ ≈ 4000 m−3

(

100 GeV

mχ

)

Maxwellian velocity distribution (in halo rest frame)

fgal(~v) ≈

N exp(

−v2/v2)

v < vesc

0 v > vesc

with v ≃ 220 km/s and vesc ≃ 600 km/sT. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 4

DM direct detection

. . . assuming DM has non-gravitational interactions (“WIMP”):

DM direct detection M. Goodman, E. Witten, PRD 1985

Look for recoil of DM-nucleus scattering:

χ+N → χ+N

cnts / keV recoil energy ER:

dN

dER

(t) ∝ ρχ

mχ

∫

v>vmin

d3vdσ

dER

v f⊕(~v, t)

vmin: minimal DM velocity required to produce recoil energy ER


DM nucleon scattering cross section

in general the interaction between χ and a nucleus can bespin-independent (SI) and/or spin-dependent (SD):



in general the interaction between χ and a nucleus can bespin-independent (SI) and/or spin-dependent (SD):

Example: fermionic DM Leff = 1Λ2 (χqΓdarkχq) (ψΓvisψ)

S P V A T AT

Γdark,vis γ0 γ0γ5 γµ γµγ5 σµν σµνγ5

⇒ in the non-relativistic limit:• (S ⊗ S), (V ⊗ V ): spin-independent interaction• (A⊗A), (T ⊗ T ): spin-dependent interaction• other combinations are suppressed by O(v2) ∼ 10−6

e.g., A. Kurylov, M. Kamionkowski, hep-ph/0307185T. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 6


σSI = σp

µ2χN

µ2χp

[Zfp + (A− Z)fn]2

f 2p

|F (q)|2 ∝ A2 for fn ≈ fp

σSD =32µ2

χNG2F

2J + 1

[

a2pSpp(q) + apanSpn(q) + a2

nSnn(q)]

µχN (µχp): DM-nucleus(proton) reduced mass

fp, fn, ap, an: couplings to proton and neutron

F (q), Spp(q), Spn(q), Snn(q): nuclear structure functions

SI: A2 enhancement → (heavy nuclei)

SD: coupling mainly to unpaired n or p


DM velocity distribution

f⊕(~v, t) = fgal(~v + ~v⊙ + ~v⊕(t)) fgal(~v) ∝ exp(v2/v)

sun velocity: ~v⊙ = (0, 220, 0) + (10, 13, 7) km/searth velocity: ~v⊕(t) with v⊕ ≈ 30 km/s


Direct detection: where do we stand?

• many exps. running and setting relevant limits:

CDMS (Ge, Si), CoGeNT (Ge), COUPP (CF3I), CRESST(CaWO4), DAMA (NaI), Edelweiss (Ge), KIMS (CsI),PICASSO (F), SIMPLE (C2ClF5), TEXONO (Ge), XENON(Xe), ZEPLIN (Xe),. . .

• a few of them report “hints” for WIMP interactions:

CDMS?, CoGeNT?, CRESST?, DAMA?

which might point to WIMPs (SI) in the low-mass(∼10 GeV) region, or something more exotic. . .


Hints for low-mass WIMPs andelastic spin-independent scattering


Event spectrum

dN

dER

(t) =ρχ

mχ

σp|F (q)|2A2

2µ2p

∫

v>vmin(ER)

d3vf⊕(~v, t)

v

vmin : minimal DM velocity required to produce recoil energy ER

vmin =mχ +M

mχ

√

ER

2M⇒ mχ ≪M : vmin ≈

√

MER/2

mχ

need light target and/or low threshold on ER to see light WIMPs


Event spectrum

0 10 20 30 40 50E

nr [keV]

even

ts o

n G

e / k

eV [

arb.

Uni

ts] 5

1020304050

mχ [GeV]

spectrum gets shifted to low energies for low WIMPmasses ⇒energy threshold is crucial


SI elastic scattering exclusion curve

10 100mχ [GeV]

10-44

10-43

10-42

10-41

10-40

σ p [cm

2 ]

10 100

energy threshold

mχ ~ mN

exposure


low-mass WIMP hints

CDMS-IICoGeNT

CRESST-IIDAMA


CDMS-II

Germanium detector, recoil energy range 10–100 keV

• 0912.3592 July 2007-Sep 2008, 612 kg day: 2 candidate ev.

electron and nucl. recoilregions for two differentdetectors

candidates:12.3 keV and 15.5 keV

background: 0.8 ± 0.1 ± 0.2

probablitly for >= 2 ev: 23%


CDMS-II

10 100 1000mχ [GeV]

10-44

10-43

10-42

10-41

10-40

10-39

σ p [cm

2 ]

10 100 1000

CDMS 08+09 max-gap limitCDMS 09 max-likelihood fit

vesc

= 550 km/s

90% CL68% CL

90% CL

assuming a shape forthe distribution of the 0.8background events basedon the event distr. shownin fig. 3 of 0802.3530and performing a maxi-mum likelihood fit to thetwo observed events(no uncert. on bckg num-ber and shape included)


low-mass WIMP hints

CDMS-IICoGeNT

CRESST-IIDAMA


CoGeNT

Germanium detector with extremely low threshold of 0.4 keVee

exponential rise of eventsat low energiesclaim that it cannot beelectronic noise

Aalseth et al., 1002.4703


CoGeNT

3 10 100mχ [GeV]

10-44

10-43

10-42

10-41

10-40

10-39

σ p [cm

2 ]

10 100

CDMS 08+09 limit 90% CLCDMS 09 fit, 68% CLCoGeNT 90, 99.73% CL, no bgCoGeNT 90% CL, exp bkg

vesc

= 550 km/s


low-mass WIMP hints

CDMS-IICoGeNT

CRESST-IIDAMA


DAMA/LIBRA annual modulation signal

Scinitillation light in NaI detector, 1.17 t yr exposure (13 yrs)∼ 1 cnts/d/kg/keV → ∼ 4 × 105 events/keV in DAMA/LIBRA∼ 8.9σ evidence for an annual modulation of the count rate withmaximum at day 146 ± 7 (June 2nd: 152) Bernabei et al., 1002.1028

2-6 keV

Time (day)

Res

idua

ls (

cpd/

kg/k

eV) DAMA/NaI (0.29 ton×yr)

(target mass = 87.3 kg)DAMA/LIBRA (0.53 ton×yr)

(target mass = 232.8 kg)

Bernabei et al., 0804.2741




Bernabei et al., 1002.1028




Energy (keV)

S m (

cpd/

kg/k

eV)

-0.05

-0.025

0

0.025

0.05

0 2 4 6 8 10 12 14 16 18 20

energy shape of modulation is important for constraining paramsChang, Pierce, Weiner, 0808.0196; Fairbairn, TS, 0808.0704


Quenching

DAMA measures energy in“electron equivalent” (keVee)

only a fraction q of nuclear recoil energy ER isobservable as scintillation signal in DAMA:

Eobs = q × ER

with qNa ≈ 0.3, qI ≈ 0.09

⇒ the energy threshold of 2 keVee implies athreshold in ER of 6.7 keV for Na and 22 keV for I.


Channeling

Drobyshevski, 0706.3095; Bernabei et al., 0710.0288

with a certain probability a recoiling nucleus will not interact withthe crystal but loose its energy only electro-magnetically: q ≈ 1

no measurments available at relevant energies

Bozorgnia, Gelmini, Gondolo, 1006.3110 channeling negligible in NaIT. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 24

Fitting DAMA

3 10 100mχ [GeV]

10-44

10-43

10-42

10-41

10-40

10-39

σ p [cm

2 ]

10 100

CDMS 08+09 limit 90% CLCDMS 09 fit, 68% CLDAMA 90, 99.73% CL no chanDAMA 90, 99.73% CL with chan CoGeNT 90, 99.73% CL, no bgCoGeNT 90% CL, exp bkg

vesc

= 550 km/s

region with channeling assumes fraction of chan. according to Bernabei et al., 0710.0288


DAMA vs CoGeNT

can we make CoGeNT and DAMA consistent?Hooper, Collar, Hall, McKinsey, 1007.1005

How well do we know the quenching factor of Na?

3 10mχ [GeV]

10-41

10-40

10-39

σ p [cm

2 ]

10

vesc

= 550 km/s

qNa

= 0.3qNa

= 0.6

90% CL, 3σ


DAMA vs CoGeNT



3 10mχ [GeV]

10-41

10-40

10-39

σ p [cm

2 ]

10

vesc

= 550 km/s

solid: qNa

= 0.3 +/- 0.03dashed: q

Na = 0.3 +/- 0.1

DAMA

CoGeNT

90%, 99.73% CL (2 dof)

χ2DAMA = 8.2/(12 − 2) (61%)χ2

CoG = 46/(56 − 4) (71%)

χ2glb,0.1 = 75/(68 − 4) (1.6%)χ2

glb,0.03 = 95/(68 − 4) (0.7%)


DAMA vs CoGeNT



3 10mχ [GeV]

10-41

10-40

10-39

σ p [cm

2 ]

10

vesc

= 550 km/s

solid: qNa

= 0.3 +/- 0.03dashed: q

Na = 0.3 +/- 0.1

DAMA

CoGeNT

90%, 99.73% CL (2 dof)0 50 100 150 200 250

Enr

[keV]

0

0.1

0.2

0.3

0.4

0.5

quen

chin

g fa

ctor

Tovey et al., PLB 1998Chagani et al., JINST, 0806.1916


DAMA vs CoGeNT



3 10mχ [GeV]

10-41

10-40

10-39

σ p [cm

2 ]

10

vesc

= 550 km/s

solid: qNa

= 0.3 +/- 0.03dashed: q

Na = 0.3 +/- 0.1

DAMA

CoGeNT

90%, 99.73% CL (2 dof)0 50 100 150 200 250

Enr

[keV]

0

0.1

0.2

0.3

0.4

0.5

quen

chin

g fa

ctor

Tovey et al., PLB 1998Chagani et al., JINST, 0806.1916

semi-empirical fitTretyak 0911.3041

Iodine


low-mass WIMP hints

CDMS-IICoGeNT

CRESST-IIDAMA


CRESST-II

Talk by W. Seidel @ WONDER 2010, March 22 to 23

CaWO4 target, 9 detectors, about 400 kg d

excess of single-scatter events in O-band (magenta)

10 15 20 25 30 35 40E

nr [keV]

0

1

2

3

4

even

ts p

er k

eV

m = 12 GeV

shape agrees with ∼ 10 GeV WIMPT. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 29

CRESST-II

Talk by W. Seidel @ IDM10: CaWO4 target, about 400 kg d


Attempt CRESST O band fit

3 10 100mχ [GeV]

10-44

10-43

10-42

10-41

10-40

10-39

σ p [cm

2 ]

10 100

CDMS 08+09 limit 90% CLCDMS 09 fit, 68% CLDAMA 90, 99.73% CL no chanDAMA 90, 99.73% CL with chan CoGeNT 90, 99.73% CL, no bgCoGeNT 90% CL, exp bkgCRESST O+W bandsCRESST O-band

vesc

= 550 km/s

WARNING:Do not take too serious - very speculative! ⇒ regions willshift/shrink/go away (?) when detailed information on CRESSTevents and background becomes available (publ. Sept. 2010?)T. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 31

Constraints from CDMS and XENON


CDMS Si constraints

3 10 100mχ [GeV]

10-44

10-43

10-42

10-41

10-40

10-39

σ p [cm

2 ]

10 100

CDMS Si 2005

vesc

= 550 km/s

CDMS data on Si (astro-ph/0509259): 12 kg day, 7 keV thresholdmore data on tape ⇒ new paper expected very soon


XENON-10

2 phase (gas/liquid) Xenon detector @ Gran SassoOct 2006 - Feb 2007, 316 kg day exposure

0706.0039: original blind analysis: 10 events0910.3698: revised cuts: 13 events, extended energy window

0 10 20 30 40 50 60 70 80nuclear recoil energy [keV]

2007 analysis (10 events / exp. backgr.: ~7.0)

2009 analysis (13 events / exp. backgr.: ~7.4)


XENON-100

11.7 days, 40 kg fid., ∼ 230 kg day effective exp.

XENON100, 1005.0380

S1: prompt signal from scintillationS2: delayed signal from ionization


Leff

translate S1 signal [PE] into Enr [keV]: Enr = S1Leff (Enr)

1Ly

Se

Sn

1 10 100E

nr [keV]

0

0.1

0.2

0.3

0.4

Lef

f

AkimovEtAlAprileEtAl05AprileEtAl08ArneodoEtAlChepelEtAlManzurEtAlSorensenEtAl


Leff

translate S1 signal [PE] into Enr [keV]: Enr = S1Leff (Enr)

1Ly

Se

Sn

1 10 100E

nr [keV]

0

0.1

0.2

0.3

0.4

Lef

f


all except Sorensen Et Al

Manzur Et Al + Arneodo Et Al

Sorensen Et Al + Aprile Et Al 08

3 exemplary fits, extrapolating with straight lines at low energiesT. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 36

Acceptance window in XENON100

acceptance window is defined by cuts on S1 and S2 # of PEs:

4 < S1 < 20 , 300 < S2 < 〈S2〉S1

• this translates into window in Enr according to Leff

• Poisson statistics of PEs implies smearing of the thresholds

0 10 20 30 40E

nr [keV]

0

0.1

0.2

0.3

0.4

0.5

acce

ptan

ce d

ue to

Poi

sson

dis

trib

utio

n of

PE

s

10 GeV WIMP [arb. units]

1 10 100E

nr [keV]

0

0.1

0.2

0.3

0.4

Lef

f





same color codingT. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 37

Leff and the XENON bounds

3 10 100mχ [GeV]

10-44

10-43

10-42

10-41

10-40

10-39

σ p [cm

2 ]

10 100

solid: XENON100dashed: XENON10 1 10 100

Enr

[keV]

0

0.1

0.2

0.3

0.4

Lef

f





same color coding


Leff and the XENON bounds

3 10 100mχ [GeV]

10-44

10-43

10-42

10-41

10-40

10-39

σ p [cm

2 ]

10 100

solid: XENON100dashed: XENON10

1 10 100E

nr [keV]

0

0.1

0.2

0.3

0.4

Lef

f





heated discussion: Collar, McKinsey, 1005.0838; XENON100, 1005.2615;Collar, McKinsey, 1005.2615; Savage et al., 1006.0972; Collar, 1006.2031

Bezrukov, Kahlhöfer, Lindner


XENON S2 analysis

3 10 100mχ [GeV]

10-44

10-43

10-42

10-41

10-40

10-39

σ p [cm

2 ]

10 100

solid: XENON100dashed: XENON10

XENON10 S2 analysis

P. Sorensen, talk @ IDM10XENON10 analysisusing only S2 signal(ionization)Talk by P. Sorensen,

IDM conference, Montpellier 2010


XENON-100 exposure

Talk by E. Aprile, GGI conference, 19 May 2010


Summary elastic SI scattering

3 10mχ [GeV]

10-41

10-40

10-39

σ pSI [

cm2 ]

10

DAMA + CoGeNTCoGeNTDAMACRESSTCDMS Si (2005)CDMS GeXENON100 (mean L

eff)

XENON10 S2 analysisP. Sorensen, talk @ IDM2010

solid: qNa

= 0.3 +/- 0.03dashed: q

Na = 0.3 +/- 0.1


How to obtain ∼ 10 GeV WIMPs?


Scalar singlet DM

the most simple WIMP model:add a scalar singlet to the SM with a Z2 symmetry S → −SSilveira, Zee, 85; McDonald 94; Burgess, Pospelov, Veldhuis, 00; . . .

L = LSM +1

2∂νS∂

νS − 1

2µ2S2 − 1

2λ1S

4 − λ2S2φ†φ

communication with the SM via the “Higgs portal” λ2

for a given DM mass m2S = µ2 + λ2v

2 the requirement of acorrect thermal abundance fixes λ2 and all phenomenology(including Higgs searches at LHC)


Scalar singlet DM

the most simple WIMP model:add a scalar singlet to the SM with a Z2 symmetry S → −SSilveira, Zee, 85; McDonald 94; Burgess, Pospelov, Veldhuis, 00; . . .

He, Li, Li, Tandean, Tsai, 0912.4722 Andreas, Arina, Hambye,Ling, Tytgat, 1003.2595


light SUSY DM

MSSM neutralino: LEP Z0 invis width OK by making it mostlybino, but have to depart from CMSSM to make it light ⇒non-universal gaugino massese.g., Bottino, Donato, Fornengo, Scopel, 02,03,07,08,09; Hooper, Plehn, 02; Belanger,Boudjema, Cottrant, Pukhov, Rosier-Lees, 03; Asano, Matsumoto, Senami, Sugiyama, 09;Hisano, Nakayama, Yamanaka, 09 Kuflik, Pierce, Zurek, 1003.0682

Bs → µ+µ− and Tevatron light Higgs searches: mχ > 28 GeVFeldman, Liu, Nath, 1003.0437; Albornoz, Belanger, Boehm, Pukhov, Silk, 1009.4380


light SUSY DM



NMSSM (singlino component): e.g., Gunion, Hooper, McElrath, hep-ph/0509024;Bae, Kim, Shin, 1005.5131; Das, Ellwanger, 1007.1151; Belikov, Gunion, Hooper, Tait,1009.0549; Gunion, Belikov, Hooper, 1009.2555; Draper, Liu, Wagner, Wang, Zhang, 1009.3963;Albornoz, Belanger, Boehm, Pukhov, Silk, 1009.4380; Kappl, Ratz, Winkler, 1010.0553


light SUSY DM



NMSSM (singlino component): e.g., Gunion, Hooper, McElrath, hep-ph/0509024;Bae, Kim, Shin, 1005.5131; Das, Ellwanger, 1007.1151; Belikov, Gunion, Hooper, Tait,1009.0549; Gunion, Belikov, Hooper, 1009.2555; Draper, Liu, Wagner, Wang, Zhang, 1009.3963;Albornoz, Belanger, Boehm, Pukhov, Silk, 1009.4380; Kappl, Ratz, Winkler, 1010.0553

sneutrino: MSSM + νR Arkani-Hamed, Hall, Murayama, Tucker-Smith, Weiner, 00;Belanger, Kakizaki, Park, Kraml, Pukhov, 1008.0580


Asymmetric Dark Matter

Nussinov, 1985; Barr, Chivukula, Farhi, 1990; Barr, 1991; Kaplan, 1992; Kaplan, Luty, Zurek,

0901.4117; Shelton, Zurek, 1008.1997; Davoudiasl, Morrissey, Sigurdson, Tulin, 1008.2399;

Haba, Matsumoto, 1008.2487; McDonald, 1009.3227; Chun, 1009.0983; Buckley, Randall,

1009.0270; Gu, Lindner, Sarkar, Zhang, 1009.2690; Blennow, Dasgupta, Fernandez-Martinez,

Rius, 1009.3159

DM carries some quantum number

ΩDM ∼ ΩB ⇒ mDM ∼ mp

often predict DM in the several GeV range,direct detection scattering is model dependent


How to reconcile?

3 10mχ [GeV]

10-41

10-40

10-39

σ pSI [

cm2 ]

10

DAMA + CoGeNTCoGeNTDAMACRESSTCDMS Si (2005)CDMS GeXENON100 (mean L

eff)

XENON10 S2 analysisP. Sorensen, talk @ IDM2010

solid: qNa

= 0.3 +/- 0.03dashed: q

Na = 0.3 +/- 0.1


How to reconcile?

• experimental issues?∼ 10 GeV region is experimentally challengingsystematic uncertainties on quenching factors, energy scale,threshold effects, backgrounds. . . have to be understoodand taken into account before making strong statements


How to reconcile?

• experimental issues?∼ 10 GeV region is experimentally challengingsystematic uncertainties on quenching factors, energy scale,threshold effects, backgrounds. . . have to be understoodand taken into account before making strong statements

• modify astrophysics?changing v, vesc has little impact on consistencynon-standard halos (asymmetric, streams, dark disc) requireextreem params Fairbairn, Schwetz, 0808.0704, and others


How to reconcile?

• more exotic particle physics?spin-dependent interactioninelastic DM Tucker-Smith, Weiner, hep-ph/0101138

mirror DM R. Foot

leptophilic DM Fox, Poppitz, 0811.0399; Kopp, Niro, Schwetz, Zupan, 0907.3159

Form Factor DM Feldstein, Fitzpatrick, Katz, 0908.2991

Momentum dep. DM Scattering Chang, Pierce, Weiner, 0908.3192

Resonant Dark Matter Bai, Fox, 0909.2900

electro-magnetic DM interactions Masso, Mohanty, Rao, 0906.1979;

Chang, Weiner, Yavin, 1007.4200; Barger, Keung, Marfatia, 1007.4345; Fitzpatrick, Zurek,

1007.5325; Banks, Fortin, Thomas, 1007.5515


elastic spin-dependent (eSD) scattering


Spin-dependent scattering

coupling mainly to an un-paired nucleon:

neutron proton

DAMA 23

11Na even odd

DAMA, KIMS, COUPP 127

53I even odd

SIMPLE 35

17Cl, 37

17Cl even odd

XENON, ZEPLIN 129

54Xe, 131

54Xe odd even

CDMS, CoGeNT 73

32Ge odd even

PICASSO, COUPP, SIMPLE 19

9F even odd

CRESST A74

W, 16

8O, 40

20Ca even even

coupling with proton promising for DAMA vs CDMS/XENON

BUT: severe bounds from COUPP, KIMS, PICASSO, SIMPLE


eSD

Kopp, Schwetz, Zupan, 0912.4264


Constraints from Tevatron

assume effective quark DM interaction:

g

Λ2(qγ5γµq)(χγ5γ

µχ)

⇒ pp→ χχ+ j

constraints from mono-jet searches at Tevatronassume EFT is still valid at ∼TeV momentum transfer

e.g., Feng, Su, Takayama, hep-ph/0503117;

Beltran et al., 1002.4137; Goodman et al., 1005.1286; Bai, Fox, Harnik, 1005.3797;. . .


SD and constraints from Tevatron

Bai, Fox, Harnik, 1005.3797 T. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 54

SD and constraints from Tevatron and neutrinos


SD and constraints from Tevatron and neutrinos

Interplay of direct det. / indirect det. / collider very powe rful


inelastic scattering (DAMA)Tucker-Smith, Weiner, hep-ph/0101138


Inelastic DM scattering

0 20 40 60 80 100E

recoil [keV]

even

t spe

ctru

m [

arb.

uni

ts]

δ = 0

δ = 50 keV

δ = 100 keV

δ = 150 keV

δ = 200 keV

mχ = 100 GeV scattering off Xenon

σ increased by factor 10 in each step for δ

mχ∗−mχ = δ ≃ 100 keV ∼ 10−6mχ

vinelmin =

1√2MER

(

MER

µχ

+ δ

)

• sampling only high-velocity tail of velocity distribution

• no events at low recoil energies

• high mass targets favoured ⇒ use iodine in DAMA butno explanation for GoGeNT, CRESST-O


iSI

talk by W. Seidel @ IDM 2010

mχ ≃ 50 GeV, δ ≃ 130 GeV

disfavored by CRESST (tungsten)


iSD on protons

inelastic spin-dependent scatteringKopp, Schwetz, Zupan, 0912.4264

0 5 10 15 20

-0.04

-0.02

0.00

0.02

0.04

0.06

E @keVD

S m@d-

1kg-

1ke

V-

1 D

DAMA annual modulation vs. iSD fit

Analysis window

mΧ = 44.7 GeV

Σp = 1.´10-32 cm2

∆ = 133 keVΧ2 = 5.24058

mχ ≃ 50 GeV, δ ≃ 130 GeVT. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 58

iSD on protons

• no tuning wrt to vesc needed

• SD coupling to proton gets rid of XENON/CDMS/CRESSTbounds (no unpaired proton)

• inelastic scatt. gets rid of PICASSO/COUPP (light target)


iSD on protons

• no tuning wrt to vesc needed

• SD coupling to proton gets rid of XENON/CDMS/CRESSTbounds (no unpaired proton)

• inelastic scatt. gets rid of PICASSO/COUPP (light target)

BUT:

• cannot explain CoGeNT/CRESST-O

• neutrino constraints from annihilations in the sundepend on annihilations channels (light quarks, µ, e still OK)Shu, Yin, Zhu, 1001.1076

• probably mono-jet bounds from Tevatron applyT. Schwetz, ITP Heidelberg, 14 Oct 2010 – p. 59

iSD - toy model

Kopp, Schwetz, Zupan, 09: generalize idea of Tucker-Smith, Weiner, 01 to SD int.:assume 4-Fermi interaction with T ⊗ T structure:

Lint =CT

Λ2

[

ψΣµνψ][

qΣµνq]

, Σµν = i[γµ, γν ]/2

ψ = (η, ξ†) with Dirac mψψ and Majorana mass (δηηη + δξξξ)/2

⇒ two Majorana fermions with masses m± δ (δη = δξ = δ ≪ m):

χ1 = i(η − ξ)/√

2, χ2 = (η + ξ)/√

2

⇒ ψΣµνψ = −2i(χ2σµνχ1 + χ†2σµνχ

†1) ,

• inelastic scattering for δ 6= 0• T ⊗ T leads to spin dependent scattering in the non-rel. limit


magnetic inelastic DM

observe that I, Cs, Na, F nuclei have very large effective MMassume DM has MM: L = µχ

2χ∗σµνχF

µν + h.c.

Chang, Weiner, Yavin, 1007.4200

• use large MM of iodine to enhance rate in DAMA• inelast kinematics avoids florine constraints (light target)• no explanation for CoGeNT/CRESST-O


Conclusions


Conclusions

There are a few hints in the low mass region, BUT:• mostly not consistent with each other• region(s) strongly constrained (excluded?) by

various bounds

⇒ we are speaking about a challenging region on theedge of the capabilities of detectors

⇒ experimental issues like quenching factors andthreshold effects are not yet well enough understood


Conclusions

maybe we are not seeing DM now,. . .

but this situation is typical for the DM field:any claimed signal has to be cross checked /re-discovered / excluded by several complementaryexperiments

similar situation as recent cosmic ray “DM signals”

at some point “hints” will converge (hopefully)!


Additional slides


iSI

vmin relevant for the DAMA signal is tuned exactly tothe galactic escape velocity:

0 100 200 300day

0

0.01

0.02

0.03

0.04

0.05

cnts

/ kg

/ d

/ keV

δ = 37.65 keVδ = 39 keV

mχ = 10.92 GeV, σ = 1.66e-38 cm2


iSD on protons - neutrino constraints

δ = 40 keV δ = 130 keV

Shu, Yin, Zhu, 1001.1076

constraints from SuperK on high-energy neutrinosfrom DM annihilations inside the sun


itp seminar - max planck society

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