dark matter direct and indirect detection martti raidal nicpb, tallinn, estonia 07.01.2015nordita...

1

Dark Matter direct and indirect detection

Martti Raidal

NICPB, Tallinn, Estonia

07.01.2015 NORDITA Winer School 2015

07.01.2015 NORDITA Winer School 2015 2

We are experiencing very interesting period in fundamental physics

–

there are paradigm shifts in several fields

Instead of introduction:

A lesson from the LHC


LHC discovered the Higgs boson

17.12.2014 Frascati, 2014 4

All LHC + Tevatron data - 10σ signal

17.12.2014 Frascati, 2014 5

P. Giardino, K. Kannike, I. Masina, M. Raidal, A. Strumia,arXiv:1303.3570

Tests of Higgs couplings

17.12.2014 Frascati, 2014 6

New physics enters only in loops

17.12.2014 Frascati, 2014 7

At the same time ….

• LHC:– No SUSY discovered yet – No signals of compositness, no new resonances – No extra dimensions– No unexpected results

• Precision physics and flavour physics:– No new sources of flavour and CP violation– No higher dim. operators below 10-100 TeV

17.12.2014 Frascati, 2014 8

This is exactly opposite to the expectations by naturalness:

• All scalar masses must be at cutoff scale …

• … unless there exists a stabilizing mechanism at EW scale

• … or Nature is fine tuned

17.12.2014 Frascati, 2014 9

17.12.2014 Frascati, 2014 10

The hierarchy problem is properly named: it is not the "quadratic divergence problem”

It concerns the physical hierarchy of physical particles

Naturalness is a real, physical principle for NP

The lesson

Physics is experimental science!

• No SUSY seems to be around the corner

• Higgs indicates no GUTs

• Community is polarized in rethinking naturalness


Dark Matter comes to rescue!


Outline of my lectures

• Dark Matter – the evidence

• Dark Matter candidates

• Ways to detect Dark Matter – direct, indirect, colliders, dark matter self-interactions


History of DM Jan Oort (1932) Fritz Zwicky (1933)


Movement of starsin the Galaxy

Movement of galaxiesin clusters

Evidences for DM

• Small scale (galactic sizes/distances)

• Medium scale (galaxy clusters)

• Large scale (observable Universe)

• DM is dark because it is seen only through its gravitational interaction. No interaction with SM seen so far!


Small scale - rotation curves of galaxies


Medium scale – galaxy clusters• Velocity dispersion of galaxies in clusters• Gravitational lensing


Medium scale – bullet clusters

• Kills MOND, constrains DM self-interactions07.01.2015 NORDITA Winer School 2015 18

Large scale

• Cosmic Microwave Background (CMB) anisotropies

• Large Scale Structure (LSS)

• Baryon Acoustic Oscillations (BAO)


The history of Universe


Anisotropies in the Cosmic Microwave Background


The ESA Planck satellite

Fluctuations 10-5

CMB tells the content of the Universe


• The first peak – overall mass-energy content Ω• The second peak – baryonic matter Ωb

• The third peak – cold Dark Matter ΩDM

• The Universe can be described with ΛCDM

Energy budget of the Universe


Also SN observations confirm the accelerated expansion of the Universe

CMB polarization

• Induced by Thomson scattering at the end of recombination – very small effect

• Consistency check for inflation

• Planck Mission polarization data must come out these days!

• The rumor is …..


Two types of polarization – E-modes and B-modes!

• BICEP2 claims to measure primordial B-modes– Fluctuations of gravity– Gravitational lensing (excluded)

• Can also be induced by dust• Assuming the first, the measured tensor-to-

scalar ratio r=0.2 implies the scale of inflation to be 1016GeV

• This is our only realistic exp. test of quantum nature of gravity

17.12.2014 Frascati, 2014 25

Tension with Planck data

17.12.2014 Frascati, 2014 26

Implications for inflation and gravity?

• V=(1016)4 GeV4 is sub-Planckian – particle physics is under control

• But Lyth bound implies trans-Planckian field excursions

• What about operators likeϕ6, ϕ48, ϕ234567 which all must be there according to standard paradigm?• Inflation data shows no trans-Planckian operators!

17.12.2014 Frascati, 2014 27

Planck published first dust data

17.12.2014 Frascati, 2014 28

The BICEP2 signal strength can be explained with• r=0.2 and no dust• R=0 and dust only

One needs to study correlations between the BICEP2 and dust maps

17.12.2014 Frascati, 2014 29

• Done by theorists• Small but significant correlation found

• r=0.1±0.04

This analyses must be repeated by experiments

Large scale - BAO

Matter distributionhas a preferred scale


Acoustic peak dependson DM and baryon content

Large Scale Structure

• Primordial fluctuations are seeds of structure

• Structure formation happens dimension by dimension

• Structure has fractal properties – it repeats itself in different scales


DM in galaxies - where is it?• DM halos are believed to

be spherical (cannot loose energy)

• N-body simulations suggest rich sub-halo content (satellite and dwarf galaxies observed)

• Detection of DM depends on mass distribution and minimal mass of subhalos

• Detection of DM depends on DM halo properties around Sun


DM density profiles in galaxies


Non-relativistic DM velocity distribution


Problems/challenges/future work

• Core vs. cusp problem - N-body simulations prefer cuspy profiles (NFW, Einasto)

• “Missing” satellites compared to N-body sim.• “Too big to fail” – satellites less massive than sim.

• DM self-interactions?

• Planes of satellites in the Galaxy• Bulge-less disc galaxies • Voids too empty?


Example – core vs cusp problem• Density profile in dwarfs seems to have a core• Problem of physics or obs./sim.?• Baryonic matter dominatesin the Galactic centre• DM self-interactions, warm DM?

• Solutions:• GAIA satellite will measure movement of stars in our

Galaxy and in dwarf satellite galaxies!• N-body simulations become realistic (baryons, DM self)


What is the Dark Matter?


What is the DM mass scale?


• The SM does not haveviable cold DM candidate!• The SM neutrinos with Σ mi=0.1 eV contribute 0.2% of DM• The SM neutrinos arewarm DM

Whatever is DM, it couples to gravity via Tμν

Supermassive objects - MACHOs


Dead stars, planets etc., must be non-baryonic or created before BBN

Microlensing: MACHO fraction <20% for M=M

Primordial Black Holes (PBH)


Not predicted by standard cosmology because of small primordial perturbations

DM as elementary particles


DM as a thermal relic


The WIMP miracle


This mass scale has nothing to do with EWSB

Warning – many alternatives possible

• DM stabilized by Z3 not Z2

semi-annihilations

• Freeze-in of very weakly coupled particle

very heavy DM possible


Asymmetric DM


• DM may be like proton

• The asymmetries in the baryon and DM sectors may be related

Scenarios contain dark forces and selfinteractions

Paradigm shift in WIMP DM physics

• Instead of Z2-stabilized one thermal relic (SUSY)– Dark sector can be as complicated as visible sector– Multi-component DM– Dark sector can contain dark forces• Dark photons• Dark Yukawa sector• Strong interactions in the dark sector – Dark Techicolor

– Dark Matter can form dark discs (10% of DM in our Galaxy) and/or affect large scale structure


DM mass scale


Ultralight scalars: axion-like particles (ALPs)

• If scalar is light, its phase space density is high

Such a DM should be described as a field• To be viable DM, particles must be created at rest


Initial misalignment mechanism

The QCD axion Pseudo-Goldstone boson of axial symmetry


Invented to explain the absence of strong CP violation

Axions solve the strong CP problem

QCD axion couplingsCouples to gluons and photons due to mixing with the pion

where

Other possible interactions

1 MHz ≈ 4×10-9 eV

nucleon dipole moment d = gda

Detection principle


Look for axion-photon conversion• From cosmological sources• Create your own - laser

CAST

ADMXRes. microwave cavity

Experiments: light-through a wall

• Photons „tunnel“ through a barrier via conversion to axions in a strong magnetic field

Nucleon electric dipole moment• Given that

– DM is a classical field a– that couples to nucleons as

• then all (local) nucleons will have a time dependent EDM (current bound |dn| < 2.9×10−26 e·cm)

• In the case of the QCD axion

(Molecular EDMs are about 28 orders of magnitude larger.)

Expected CASPER sensitivity

The message

New experiments are being planned to test light dark sector properties (APLs, dark photons etc.)


dark matter direct and indirect detection martti raidal nicpb, tallinn, estonia 07.01.2015nordita...

Documents

nordita winer school

ew scale

cutoff scale

peak cold dark matter

dark matter selfinteractions

new physics

history of universe

peak baryonic matter