Dark Matter I · 10 Sept. 28, 2015 G. Drexlin –DM1 KIT-IEKP dark matter –galactic halo flat rotation curves imply extended dark matter halos (V. Rubin) : - DM halos contain 80-90%

KIT – University of the State of Baden-Württemberg and

National Research Center of the Helmholtz Association

Guido Drexlin, Institut für Experimentelle Kernphysik

www.kit.edu

Guido Drexlin, Institut für Experimentelle Kernphysik

Dark Matter – I

GRK 1694: Elementarteilchenphysik bei höchster Energie und höchster Präzision

Workshop Freudenstadt 2015

KIT-IEKP2 Sept. 28, 2015 G. Drexlin – DM1

dark matter –

30-50 t Lxe

TPC Ø > 2 m


outline of lectures

Dark Matter – 1

- introduction

- astrophysical evidences for DM

- thermal relics & freeze-out

- non-thermal relics: sterile n´s

- WIMP candidates

- experimental searches

Dark Matter – 2

- indirect searches: principles & (selected) results

Dark Matter – 3

- direct detection: experiments & (selected) results


introduction - a brief history of dark matter


a buzz of excitement or the final round?

see 2014 lectures by

I. Melzer-Pellmann, DESY Hamburg :

„SUSY Searches at the LHC“

LHC searches

not covered here



Sept. 10, 2015: XMASS - new results

Sept. 15, 2015: MiniCLEAN – starting up

Nov. 11, 2015:

XENON1T

inauguration



(too?) many astrophysical evidences for dark matter keV – MeV – GeV …

c0~1

nR

a


dark matter – galactic halo

flat rotation curves imply extended dark matter halos (V. Rubin) :

- DM halos contain 80-90% of entire mass of a galaxy

- detailed modelling gives úniversal´ NFW-profile

M(r) ~ r

r(r) ~ 1/r2

DM halo

2

0

1

)(

SS

DM

R

r

R

rr

rr






- clumpy sub-structure (DM simulations)

2

0

1

)(

SS

DM

R

r

R

rr

rr






- clumpy sub-structure (DM simulations)

- DM halos from virialization of dissipation-less WIMPs

& tidal disruption of ´primoridal´ DM halos

2

0

1

)(

SS

DM

R

r

R

rr

rr

DM: WIMP interactions

spherical halo

virialization

dissipation-less

angular momentum

conservation

only gravitation


dark matter – rotation curve of Milky Way

distance to galactic centre (kpc)

3 5 10 20

vro

t(k

m s

-1kpc

-1) observation

baryonic models

resid

.

reference

100

50

20

R0 = 8 kpc v0 = 230 km s-1

NFW model

c2/n

df

60

0

-6010

10.1

F. Iocco et al.,

2015

Nature Physics

inner

cuto

ff

r =

2.5

kpc

KIT-IEKP12 Sept. 28, 2015

rWIMP = 50 GeV/150 cm3

local DM density

local DM density much higher than cosmological mean DM density

halo density profile r(r)~1/r2

milky way

r(r)

vrot = 230 km/s

r = 8 kpc

r

estimate: from solar rotation speed vrot to rlocal

local DM-density r:

important parameter

for directe WIMP

searches

DMlokalDM rr 5

, 10

≈ rbaryonic

rDM,local ~ 0.3 GeV/cm3

r 3

3

4rMrwith2

2v

r

GM

r

rrot

Gr

rotlocal 2

2

4

v3

r

mass?

G. Drexlin – DM1

http://www.cosmographica.com/gallery/portfolio2007/content/index_27.html

http://www.cosmographica.com/gallery/portfolio2007/content/index_27.html


dark matter – galaxy clusters

first postulation of dark matter (F. Zwicky, 1933) :

- DM: non-luminous matter, interacts only via gravitational forces

explains the very high peculiar velocities of single galaxies

in the Coma galaxy cluster

Coma Cluster: 1000 galaxies in d = 120 Mpc

F. Zwicky

Helv. Phys. Acta 6

110-127 (1933)

´Die Rotverschiebung

von extragalaktischen

Nebeln´

virial theorem: potkin UE2

1

C153 in Abell 2125

non-luminous matter

~ 90% of the mass

in Coma cluster…


Dark matter – galaxy cluster 1E 0657-556

M~1015M

M~1014M

Bullet

Cluster

d =1 Gpc

z = 0.296


mapping of dark matter - Abell 901/902

distribution of dark matter (weak lensing) & baryonic matter


2015 update: DM map from DE survey

Dark Energy Survey:

- large-scale weak lensing studies

520 Megapixel

CCD

4 m Blanco

telescope

at Cerro Tololo


2015 update: DM map from DE survey

Dark Energy Survey:

- large-scale weak lensing studies

DM forms large filaments


dark matter – cosmological scalesT-f

luctu

ationsD

T2

(µK

2)

angular scale Q

multipole moment ℓ

- overall fraction of dark matter

WDM h2 = 0.1199 ± 0.0027

baryon acoustic

oscillations

LCDM concordance

model


Lee-Weinberg curve for HDM & CDM

ho

td

ark

matt

er

10-1 100 101 102 103 104 105 106 107 108 109 1010

dominant DM part

WIMP-

mass M (eV)

HDM: relativistic free-streaming after decoupling, no annihilation processes

thus: WHDM ~ M, result: HDM particle density not reduced

HDM:

M << Tfr

energ

ydensityW

DM

105

104

103

102

101

100

10-1

M = Tfr

이휘소 Wein-

berg

http://www.quantumdiaries.org/wp-content/uploads/2012/03/neutrino.png

http://www.quantumdiaries.org/wp-content/uploads/2012/03/neutrino.png

http://en.wikipedia.org/wiki/File:PortraitBen.jpg

http://en.wikipedia.org/wiki/File:PortraitBen.jpg


co

ldd

ark

matt

er

10-1 100 101 102 103 104 105 106 107 108 109 1010

WIMP-

mass M (eV)

CDM: non-relativistic before decoupling, strong annihilation processes

with sAnn ~ M2, result: CDM particle density extremely reduced

M = Tfr

M >> Tfr

HDM:

M << Tfr

105

104

103

102

101

100

10-1

WDM = 0.27

energ

ydensityW

DM


ho

td

ark

matt

er

dominant DM part


co

ldd

ark

matt

er

10-1 100 101 102 103 104 105 106 107 108 109 1010

WIMP-

mass M (eV)

CDM/HDM: only two narrow regions remain for thermal relics from Big Bang

very light neutrals (meV-eV neutrinos), heavy neutralinos (TeV)

105

104

103

102

101

100

10-1

WDM = 0.27

energ

ydensityW

DM


ho

td

ark

matt

er

dominant DM part

meV-

eV

GeV-

TeV


WIMPs – thermal relics of the early universe

10-8 s:

WIMPs

propagate

freely

10-9 s:

final WIMPs

annihilate

Hubble-

expansion

freeze-out

of WIMPs

Big Bang

thermo-

dynamic

equilibrium

ttT 1~)(


WIMPs in radiation-dominated universe

time t (ns)

10 1

100 101 102 103

mc = 100 GeV10-4

10-8

10-12

10-16

annihilation and

production of WIMPs

ćo

-mo

vin

g´

pa

rtic

led

en

sity

nc(T

)

temperature T (GeV)

thermal

equilibrium

)(tH

exponential

decrease of

WIMP density

TkM BWIMPetn/

~)(

c


thermal

equilibrium

ćo

-mo

vin

g´

pa

rtic

led

en

sity

nc(T

)

temperature T (GeV)10 1

time t (ns)100 101 102 103

mc = 100 GeV10-4

10-8

10-12

10-16

108

104

100

10-4

WDM

moment of WIMP

decoupling:

WIMP-density

WDM = 100

WIMP-density

WDM = 0.001

WDM = 0.27

)()( tHti

G. Drexlin – DM1

WIMP decoupling and WDM

1(t) 2(t) 3(t)


WIMP decoupling to WDM = 0.27

thermal

equilibrium

ćo

-mo

vin

g´

pa

rtic

led

en

sity

nc(T

)


time t (ns)100 101 102 103

10-4

10-8

10-12

10-16

108

104

100

10-4

WDM

moment of WIMP

decoupling:

)()( tHti

1(t) 2(t) 3(t)

n~

sneutrinos (LH)

Interact too strong


WIMP decoupling to WDM = 0.27

mc = 100 GeV

G. Drexlin – DM1

WDM = 0.27

thermal

equilibrium

ćo

-mo

vin

g´

pa

rtic

led

en

sity

nc(T

)


time t (ns)100 101 102 103

10-4

10-8

10-12

10-16

108

104

100

10-4

WDM

moment of WIMP

decoupling:

)()( tHti


WIMP ´miracle´ & annihilation rate

T (GeV)10

100 101

10-4

10-8

10-12

10-16

)()( frfri tHt

132510

~)0(

W scmvAnns

c

for v ~ 0.3 c at WIMP decoupling

one obtains for Wc ~ 0.27

the WIMP ´miracle´:

WIMP density Wc(0) today & sAnn:

sAnn ~ 10-36 cm2

G. Drexlin – DM1

weak interaction

ćo

-mo

vin

g´

pa

rtic

led

en

sity

nc(T

)

time t (ns)


T (GeV)10

100 101

10-4

10-8

10-12

10-16

)()( frfri tHt

mc = 100 GeV

time of WIMP-freeze-out: t ~ few ns

non-relativisitic propagation

20~fr

frT

Mx

c

20~

cMT fr

CDM: Mcc2 >> kBTfreeze out

WIMPs after freeze-out act as

CDM (cold dark matter)

Tfr = 5 GeV

G. Drexlin – DM1

ćo

-mo

vin

g´

pa

rtic

led

en

sity

nc(T

)

time t (ns)

WIMP decoupling – non-relativistic


structure formation with CMD, WDM, HDM

CMB

LSS

z =

1100z =

0

structure evolution

top-

down

scenario

ne,µ,t

WDMnsterile

bottom-

up

scenario

c0


comparison of DM-models with observations (<rDM> ~ 1 keV/cm³):

wash-out on different length scales (lfree-streaming)

Hot Dark Matter HDM

particles:

active neutrinos ne,µ,t

m ~ 0.05 – 2 eV

WarmDarkMatter WDM

particles:

sterile neutrinos ns

m ~ 1 – 20 keV

Cold Dark Matter CDM

particles:

SUSY neutralinos c0

m ~ 10 – 1000 GeV

number density:

N(active): 339/cm3

decoupling:

T = 2 – 3 MeV

T/m ~ 106 – 107

number density:

N(sterile): ~0.1-1/cm3

decoupling:

none, produced via

n-oscillations

Number density:

N(c0): 10-7-10-9/cm3

decoupling:

T = 0.5 – 50 GeV

T/m ~ 1/20

LSS implication:

wash-out on scales

l < 1 Gpc

LSS implication:

wash-out on scales

l < 100 kpc

LSS implication:

wash-out on scales

l < 0.1 pc

dark matter: hot, warm or cold?


comparison of DM-models with observations (<rDM> ~ 1 keV/cm³):

wash-out on different length scales (lfree-streaming)

Hot Dark Matter HDM

particles:

active neutrinos ne,µ,t

m ~ 0.05 – 2 eV

WarmDarkMatter WDM

particles:


m ~ 1 – 20 keV

Cold Dark Matter CDM

particles:

SUSY neutralinos c0

m ~ 10 – 1000 GeV

LSS implication:

wash-out on scales

l < 1 Gpc

LSS implication:

wash-out on scales

l < 100 kpc

LSS implication:

wash-out on scales

l < 0.1 pc

dark matter: hot, warm or cold?


keV-scale sterile neutrinos would be produced via non-thermal processes

and act as CDM/WDM in evolustion of LSS

intermission: keV-scale sterile neutrinos

WarmDarkMatter WDM

particles:


m ~ 1 – 20 keV

LSS implication:

wash-out on scales

l < 100 kpc

particle physicsastrophysics

nMSM – a SM extension

(Shaposhnikov et al 2013)

a faint X-ray line at

3.5 keV in clusters?

(Bulbul et al 2014)


KATRIN – a novel detector system for ns

Cover entire phase-space of T2 ß-decay

search for kink-like structure well

below E0 = 18.6 keV

shape modification by keV-mass

sterile neutrino with mass ms


KATRIN – a novel detector system for WDM

Cover entire phase-space of T2 ß-decay

search for kink-like structure well

below E0 = 18.6 keV

- main spectrometer operated at

variable retarding potential (0-18.6 keV)huge signal rates O (1010 cps)

- need detectors with energy resolution

of DE ~ 300 eV for kink identification


TRISTAN – R&D on detector technology

TRISTAN – TRitium beta decay Investigation on Sterile To Active Neutrino mixing

(S. Mertens et al.)

- promising differential read-out

technology:

p-type point contact detectors

array with 104 pixels


KATRIN – sensitivity to keV-scale sterile n´s

sensitivity estimates for 3 full KATRIN years

- investigation of systematics (detector,

weak interactions)

wavelet approach

Documents

Dark Matter I · 10 Sept. 28, 2015 G. Drexlin –DM1 KIT-IEKP dark matter –galactic halo flat rotation curves imply extended dark matter halos (V. Rubin) : - DM halos contain 80-90%