Dark Matter direct and indirect detection Martti Raidal NICPB, Tallinn, Estonia 07.01.2015 NORDITA Winer School 2015

We are experiencing very interesting period in fundamental physics – there are paradigm shifts in several fields 07.01.2015 NORDITA Winer School 2015

Instead of introduction: A lesson from the LHC 07.01.2015 NORDITA Winer School 2015

LHC discovered the Higgs boson 17.12.2014 Frascati, 2014

All LHC + Tevatron data - 10σ signal P. Giardino, K. Kannike, I. Masina, M. Raidal, A. Strumia, arXiv:1303.3570 17.12.2014 Frascati, 2014

Tests of Higgs couplings 17.12.2014 Frascati, 2014

New physics enters only in loops 17.12.2014 Frascati, 2014

At the same time …. LHC: Precision physics and flavour physics: 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

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

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 17.12.2014 Frascati, 2014

Physics is experimental science! The lesson Physics is experimental science! No SUSY seems to be around the corner Higgs indicates no GUTs Community is polarized in rethinking naturalness 07.01.2015 NORDITA Winer School 2015

Dark Matter comes to rescue! 07.01.2015 NORDITA Winer School 2015

Outline of my lectures Dark Matter – the evidence Dark Matter candidates Ways to detect Dark Matter – direct, indirect, colliders, dark matter self-interactions 07.01.2015 NORDITA Winer School 2015

History of DM Movement of stars in the Galaxy Movement of galaxies Jan Oort (1932) Fritz Zwicky (1933) Movement of stars in the Galaxy Movement of galaxies in clusters 07.01.2015 NORDITA Winer School 2015

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! 07.01.2015 NORDITA Winer School 2015

Small scale - rotation curves of galaxies 07.01.2015 NORDITA Winer School 2015

Medium scale – galaxy clusters Velocity dispersion of galaxies in clusters Gravitational lensing 07.01.2015 NORDITA Winer School 2015

Medium scale – bullet clusters Kills MOND, constrains DM self-interactions 07.01.2015 NORDITA Winer School 2015

Large scale Cosmic Microwave Background (CMB) anisotropies Large Scale Structure (LSS) Baryon Acoustic Oscillations (BAO) 07.01.2015 NORDITA Winer School 2015

The history of Universe 07.01.2015 NORDITA Winer School 2015

Anisotropies in the Cosmic Microwave Background The ESA Planck satellite Fluctuations 10-5 07.01.2015 NORDITA Winer School 2015

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 07.01.2015 NORDITA Winer School 2015

Energy budget of the Universe Also SN observations confirm the accelerated expansion of the Universe 07.01.2015 NORDITA Winer School 2015

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 ….. 07.01.2015 NORDITA Winer School 2015

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

Tension with Planck data 17.12.2014 Frascati, 2014

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 like ϕ6, ϕ48, ϕ234567 which all must be there according to standard paradigm? Inflation data shows no trans-Planckian operators! 17.12.2014 Frascati, 2014

Planck published first dust data The BICEP2 signal strength can be explained with r=0.2 and no dust R=0 and dust only 17.12.2014 Frascati, 2014

One needs to study correlations between the BICEP2 and dust maps Done by theorists Small but significant correlation found r=0.1±0.04 This analyses must be repeated by experiments 17.12.2014 Frascati, 2014

Large scale - BAO Matter distribution has a preferred scale Acoustic peak depends on DM and baryon content 07.01.2015 NORDITA Winer School 2015

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 07.01.2015 NORDITA Winer School 2015

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 07.01.2015 NORDITA Winer School 2015

DM density profiles in galaxies 07.01.2015 NORDITA Winer School 2015

Non-relativistic DM velocity distribution 07.01.2015 NORDITA Winer School 2015

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? 07.01.2015 NORDITA Winer School 2015

Example – core vs cusp problem Density profile in dwarfs seems to have a core Problem of physics or obs./sim.? Baryonic matter dominates in 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) 07.01.2015 NORDITA Winer School 2015

What is the Dark Matter? 07.01.2015 NORDITA Winer School 2015

What is the DM mass scale? Whatever is DM, it couples to gravity via Tμν The SM does not have viable cold DM candidate! The SM neutrinos with Σ mi=0.1 eV contribute 0.2% of DM The SM neutrinos are warm DM 07.01.2015 NORDITA Winer School 2015

Supermassive objects - MACHOs Dead stars, planets etc., must be non-baryonic or created before BBN Microlensing: MACHO fraction <20% for M=M 07.01.2015 NORDITA Winer School 2015

Primordial Black Holes (PBH) Not predicted by standard cosmology because of small primordial perturbations 07.01.2015 NORDITA Winer School 2015

DM as elementary particles 07.01.2015 NORDITA Winer School 2015

DM as a thermal relic 07.01.2015 NORDITA Winer School 2015

The WIMP miracle This mass scale has nothing to do with EWSB 07.01.2015 NORDITA Winer School 2015

Warning – many alternatives possible DM stabilized by Z3 not Z2 semi-annihilations Freeze-in of very weakly coupled particle very heavy DM possible 07.01.2015 NORDITA Winer School 2015

Asymmetric DM DM may be like proton The asymmetries in the baryon and DM sectors may be related Scenarios contain dark forces and selfinteractions 07.01.2015 NORDITA Winer School 2015

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 07.01.2015 NORDITA Winer School 2015

DM mass scale 07.01.2015 NORDITA Winer School 2015

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 07.01.2015 NORDITA Winer School 2015

The QCD axion Pseudo-Goldstone boson of axial symmetry Invented to explain the absence of strong CP violation Axions solve the strong CP problem 07.01.2015 NORDITA Winer School 2015

QCD axion couplings Couples 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 ADMX Res. microwave cavity CAST 07.01.2015 NORDITA Winer School 2015

07.01.2015 NORDITA Winer School 2015

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.) 07.01.2015 NORDITA Winer School 2015