Implications of cosmological observables for particle physics: an overview

Implications of cosmological observables for particle physics: an overview Yvonne Y. Y. Wong The University of New South Wales Sydney, Australia TAUP 2015, Torino, September 7 11, 2015

The concordance flat ΛCDM model... The simplest model consistent with present observations. (Nearly) Massless Neutrinos (3 families) 5% 69% 26% Composition today Plus flat spatial geometry+initial conditions from single-field inflation 13.4 billion years ago (at photon decoupling)

Particle content of the concordance ΛCDM model... Interacting Protons, He4 nuclei Cold dark matter Observables Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Spacetime metric Hot DM light neutrinos (3 families) Compton Photons Cosmic microwave background SM interaction Gravity

Particle content of the concordance ΛCDM model... Interacting In a standard ΛCDM fit only the CDM energy density and the baryon density are free parameters. Cold dark matter Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Spacetime metric mν=0.06ev Minimum value from oscillations experiments Protons, He4 nuclei Observables Hot DM light neutrinos (3 families) Fixed ν-to-γ number density ratio assuming SM physics Compton Photons Energy density fixed by COBE FIRAS Cosmic microwave background SM interaction Gravity

Beyond ΛCDM and the standard model... Interacting Many good reasons why we might want to modify this picture and test the modifications against cosmological observables. Theoretical motivations (BSM physics) Complementarity to laboratory and other astrophysical searches Protons, He4 nuclei Cold dark matter Observables Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Spacetime metric Hot DM light neutrinos (3 families) Compton Photons Cosmic microwave background SM interaction Gravity

Hot dark matter sector... Interacting See talk of Lattanzi Planck TT+TE+EE+lowP +lensing+ BAO mν <0.23 ev (95 % C. L.) Ade et al. [Planck collaboration] 2015 Neutrino masses + Dark radiation Neff Protons, He4 nuclei Cold dark matter Observables Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Spacetime metric Hot DM light neutrinos (3 families?) Compton Photons Cosmic microwave background SM interaction Gravity

Hot dark matter sector > neutrino masses... KATRIN projected sensitivity mν <0.6 ev See talk of Mertens Planck TT+TE+EE+lowP +lensing+ BAO mν <0.23 ev (95 % C. L.) Ade et al. [Planck collaboration] 2015 Planck + Lyman-alpha mν <0.12 ev (95 % C. L.) Palanque-Delabrouille et al. 2015

Hot dark matter sector > dark radiation... Interacting Total relativistic energy density at early times ρ R=(3.046+Δ N eff )ρ(0) ν Energy density in one thermalised species of neutrinos at early times Neutrino masses + Dark radiation ΔNeff Protons, He4 nuclei Cold dark matter Observables Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Spacetime metric Hot DM light neutrinos (3 families?) Compton Photons Cosmic microwave background SM interaction Gravity

Hot dark matter sector > dark radiation... See talk of Lattanzi Ade et al. [Planck collaboration] 2015 Planck-inferred Neff compatible with 3.046 at better than 2σ. ΛCDM+Neff (7 parameters) Planck TT+lowP +BAO 68% C.L. +TE+EE +TE+EE+BAO ΛCDM+neutrino mass+neff (8 parameters)

Hot dark matter sector > dark radiation There is no shortage of particle physics candidates for dark radiation... Here I discuss two scenarios: ev-mass sterile neutrinos (short baseline neutrino oscillations anomalies) Hot axions (solar axion searches)

Hot dark matter sector > ev sterile neutrinos... See talks of Link and Palazzo Anomalies in short baseline neutrino oscillation experiments: LSND and MiniBooNE electron (anti)neutrino appearance Reactor anti electron neutrino disappearance Combined best fit : 2 2 Δ m SBL 1 ev sin 2 2 θsbl 3 10 3 clearly at odds with the standard 3-neutrino interpretation of the global oscillation results. Can be explained with a sterile neutrino. Kopp, Maltoni & Schwetz 2011

Hot dark matter sector > ev sterile neutrinos... See talks of Link and Palazzo Anomalies in short baseline neutrino oscillation experiments: LSND and MiniBooNE electron (anti)neutrino appearance Reactor anti electron neutrino disappearance Combined best fit : 2 2 Δ m SBL 1 ev sin 2 2 θsbl 3 10 3 clearly at odds with the standard 3-neutrino interpretation of the global oscillation results. Can be explained with a sterile neutrino. min (m s ) Δ msbl 1 ev 2

Δ N eff SBL-preferred mixing parameters full thermalisation can be expected. msbl 1 ev Δ N eff 1 Looks to be at odds with the Planck constraints: But there are ways (involving new physics) around these constraints... See talk of Archidiacono SBL-preferred Hannestad, Hansen, Tram & Y3W 2015 also Hannestad, Tamborra & Tram 2012 and older works of Abazajian, Di Bari, Foot, Kainulainen, etc. from 1990s-early 2000s

Hot dark matter sector > Axions... Thermal production Axion mass Radiating axion strings π+π π+a Cold dark matter Hot dark matter Present-day energy density Re-alignment mechanism Peccei-Quinn scale Figure adapted from J. Redondo

Hot dark matter sector > Axions... See talks of Rosenberg and Pivovaroff The hot dark matter axion parameter space overlaps with the search range for solar axions. Tokyo Axion Helioscope Sumico CERN Axion Solar Telescope

Axion-photon coupling Axion model space Tokyo axion helioscope exclusion limit (h ad ro ni c CAST exclusion limit ax io n) Inoue et al. 2008 Hot dark matter exclusion limit Axion mass Aune et al. [CAST] arxiv:1106.3919

Axion-photon coupling arxiv:1401.3233 Axion model space CAST exclusion limit IAXO expected sensitivity Hot dark matter exclusion limit Next generation: The International AXion Observatory (IAXO) Axion mass See talk of Pivovaroff

Cold dark matter sector... Small-scale See talk of Steinmetz structures Interacting kev sterile neutrino warm DM (X-ray searches of radiative decay) See talk of Zandanel Observables Protons, He4 nuclei Cold (warm?) dark matter Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Spacetime metric Hot DM light neutrinos (3 families?) Compton Photons Cosmic microwave background SM interaction Gravity BSM interaction?

Cold dark matter sector... Fraction of energy kev absorbed by neutrino sterile the talk medium See of (X-ray Galli searches warm DM of(model-dependent) radiative decay) WIMP annihilation/decay (indirect detection) Annihilation/ Interacting decay? Protons, He4 nuclei Cold (warm?) dark matter Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Rate of energy release Spacetime metric de 2 2 6 =ρcrit Ωχ (1+ z) pann dt dv Annihilation cross-section σ v p ann f ( z) mχ Fraction of energy absorbed Observables Hot DM light neutrinos (3 families?) WIMP mass Compton Photons Cosmic microwave background SM interaction Gravity BSM interaction?

Cold dark matter sector > WIMP annihilation... Annilihiation cross section x Efficiency factor Ade et al. [Planck collaboration] 2015 See talk of Galli AMS-02/ Fermi/Pamela Disfavoured by Planck Fermi GC WIMP mass See talks of Ando and Cirelli + many more in the DM indirect searches session

Dark sector interactions... Interacting Protons, He4 nuclei Cold (warm?) dark matter Dark sector interactions (DM models, neutrino mass models) Observables Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Spacetime metric Hot DM light neutrinos (3 families?) Compton Photons Cosmic microwave background SM interaction Gravity BSM interaction?

Dark sector interactions... Interacting Protons, He4 nuclei Cold (warm?) dark matter See talks of Archidiacono and Oldengott Galaxies, Hydrogen clouds, etc. Electrons Dark sector interactions (DM models, neutrino mass models) Are neutrinos free-streaming? Have we really detected the CνB (indirectly)? Ionisation & recombination Coulomb Self interaction from e.g., neutrino mass models Observables Spacetime metric Hot DM light neutrinos (3 families?) Self? Compton Photons Cosmic microwave background SM interaction Gravity BSM interaction?

Dark sector interactions... Self interaction from e.g., mirror matter, hidden sectors,... Small-scale structures Interacting Self? Protons, He4 nuclei Cold (warm?) dark matter Observables Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Dark sector interactions (DM models, neutrino mass models) Spacetime metric Hot DM light neutrinos (3 families?) Self? Compton Photons Cosmic microwave background SM interaction Gravity BSM interaction?

Dark sector interactions... Small-scale structures Interacting Self? Protons, He4 nuclei Cold (warm?) dark matter Dark sector interactions (DM models, neutrino mass models) Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons DM-neutrino interaction from, e.g., a common origin for DM and neutrino mass Observables DM-neutrino? Spacetime metric Hot DM light neutrinos (3 families?) Self? Compton Photons Cosmic microwave background SM interaction Gravity BSM interaction?

Dark sector interactions... Small-scale structures Interacting Self? Protons, He4 nuclei Cold (warm?) dark matter Dark sector interactions (DM models, neutrino mass models) How dark is dark? How far can we push the envelope? Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Observables DM-neutrino? Spacetime metric Compton DM-photon? Hot DM light neutrinos (3 families?) Self? Photons Cosmic microwave background SM interaction Gravity BSM interaction?

DM-photon/neutrino elastic scattering... Acoustic oscillations from DM-photon elastic scattering Suppress growth of density perturbations on length scales below the collisional damping scale (cf Jeans' instability). DM-photon elastic scattering: also delays photon decoupling. Planck constraints: Massless mediator 28 DM-neutrino σ DM ν <3 10 DM-photon 31 σ DM γ <8 10 ( ) cm ( ) cm m DM GeV m DM GeV 4-fermion 2 <4 10 2 <6 10 40 40 ( ) cm ( ) cm mdm GeV m DM GeV 2 2 Wilkinson et al. 2013

Beyond ΛCDM and the standard model... kev sterile neutrino warm DM (X-ray searches of radiative decay) WIMP annihilation/decay (indirect detection) Dark sector interactions (DM models, neutrino mass models) Annihilation/ Interacting decay? Self? Protons, He4 nuclei Cold (warm?) dark matter How dark is dark? Ionisation & recombination Coulomb Galaxies, Hydrogen clouds, etc. Electrons Observables DM-neutrino? Spacetime metric Compton DM-photon? Neutrino masses + Dark radiation Neff ev-mass sterile neutrino (Short-baseline oscillations) Hot axions (solar axion searches) Hot DM light neutrinos (3 families?) Self? Photons Cosmic microwave background SM interaction Gravity BSM interaction?