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Licia Verde ICREA & ICC-UB BARCELONA Licia Verde ICREA & ICC-UB BARCELONA Challenges of par.cle physics: the cosmology connecon http://icc.ub.edu/~liciaverde Context and overview • Cosmology over the past 20 years has made the transition to precision cosmology • Cosmology has moved from a data-starved science to a data-driven science • Cosmology has now a standard model. The standard cosmological model only needs few parameters to describe origin composition and evolution of the Universe • Big difference between modeling and understanding • Implies Challenges and opportunities Precision cosmology ΛCDM: The standard cosmological model Just 6 numbers….. describe the Universe composition and evolution Homogenous background Perturbations connecons • Inflaon • Dark maer (some 80% of all the maer) • Dark energy (some 80% of all there is) • Origin of (the rest of) the maer • Neutrinos (~0.5% of maer, but sll) • … Primary CMB temperature informaon content has been saturated. The near future is large-scale structure. SDSS LRG galaxies power spectrum (Reid et al. 2010) 13 billion years of gravita2onal evolu2on Longer-term .mescale: CMB polarizaon Can now do (precision) tests of fundamental physics with cosmological data “We can’t live in a state of perpetual doubt, so we make up the best story possible and we live as if the story were true.” Daniel Kahneman about theories GR, big bang, choice of metric, nucelosynthesis, etc etc… Cosmology tends to rely heavily on models (both for “signal” and “noise”) Essen.ally, all models are wrong , but some are useful (Box and Draper 1987) With ~1% precision, systemacs become the name of the game Systemacs in the data Systemacs in the model (analysis) outline • The trouble with H0 (Bernal, verde, Riess, JCAP, 2016) • Lesgourgues and Verde, Neutrinos in cosmology new secon in Review of Par.cle physics 2017 (out in 2018) • Neutrino mass limits: robust informa2on from the power spectrum of galaxy surveys; Cuesta, Niro, Verde, 2016 • Neutrino footprint in Large Scale Structure; Jimenez, Penya-Garay, Verde, 2016 • Strong Bayesian Evidence for the Normal Neutrino Hierarchy; Simpson, Jimenez, Penya-Garay, Verde, JCAP 2017, arXiv:1703.03425 • (Primordial) Black Holes ….....as dark maer (?) (Scelfo et al 2018 JCAP in press) The trouble with H0 JL Bernal, LV,.A Riess, JACP 2016 • Direct measurement: 73.24 ± 1.74 km/s/Mpc (Riess et al 2016; verified with GAIA parallaxes)* • Planck-2018- (ΛCDM): 67.4± 0.5 km/s/Mpc • Formally 3.6 σ, maybe we should pay aen.on • Possibly worst with new data since. The landscape Birrer et al 18 (4 lenses) Planck 2015 E2E test.. of the Universe!!! The trouble with H0 Three avenues Without invoking systemacs (beside those declared by the authors themselves) • Allow early cosmology to deviate from ΛCDM (unaltered late-.me cosmology) • Give freedom to late cosmology (unaltered early me physics*) • Model-independent The trouble with H0 Data • CMB (2015): Planck TT, lowP, TEEE*, Lensing (even l>1000 or l<1000 for TT)# • BAO: compilaon 6dF, SDSS MGS, LOWZ, CMASS, WiggleZ • SNe: JLA compilaon • Riess 2016 H0 measurement # Addison et al. 2016, response of Planck team (Planck 2016) * Planck high l polarizaon “ok for LCDM not ok beyond LCDM” The trouble with H0 SNe : standard candles DA: funcon of Since L is poorly known this is “uncalibrated”, geometry and usually calibrated using measurements of H0 integral of 1/H BAOs Baryon acoustic oscillations Observe photons “See” dark matter AS baryons are ~1/6 of the dark Photons coupled to baryons matter these baryonic oscillations leave some imprint in the dark matter distribution (gravity is the coupling) large Cuesta et al (2015) The Cosmic Distance Ladder At glance: direct and inverse distance ladder Direct cosmic distance ladder (Cuesta et al 2015) Inverse cosmic distance ladder H0: Direct measurement: 73.24 ± 1.74 km/s/Mpc (Riess et al 2016) rd, high z anchor Low z anchor Cuesta et al 2014, Bernal et al 2016 Modify Early Universe physics: early me expansion history, Neff With Planck polarizaon Without Planck polarizaon Need ΔN eff~0.4 The trouble with H0 Changing late-.me cosmology • Spline reconstruc.on of the expansion history H(z) with 4 (5 with SNe) knots. Direct and inverse cosmic distance ladder Direct cosmic distance ladder rs Inverse cosmic distance ladder Here is where in LCDM or its simple variaons the two ladders do not match The trouble with H0 Good ladders need 2 good anchor points I gotcha! model-independent reconstruc.on Ho+BAO+ SNe +rs H(z) reconstruc.on BAO SNe Ho+BAO+ Sne The trouble with H0 The SHAPE of expansion history is well constrained The issue is with the normalizaon The trouble with H0 The H0 problem as a rs problem Model-independent The trouble with H0 In a nutshell The H0 problem is an anchor problem (either at z=0 or at z=1100), which cannot be solved by tweaking (or bending) the expansion history It can be solved by changing rs (thus early me physics) but polarizaon data impose some ght limits. Standard sirens to the rescue (with some paence) LIGO Nature paper last fall 70(+12-8) Km/s/Mpc 14% error In summary • The ``Ho trouble”: It is a mis-match of anchors no evidence for strange expansion history. • Can shi H0 or rs. (keep this in mind if looking for new physics) • ΔNeff~0.4 would do (if no Planck polarizaon) • More beer data are (coming) in Watch this space Gaia parallaxes (recalibrate distance ladder) Carnegie SN project, Carnegie-Chicago Hubble program (arxiv:1809.06381 et al) H0=72.7 ± 2.1 km/s/Mpc But there is more to come (distance ladder, etc.) Cosmic Neutrino Background A relict of the big bang, similar to the CMB except that the CvB decouples from matter after 2s (~ MeV) not 380,000 years At decoupling they are still relativistic (mν << Τν) è large velocity dispersions (1eV ~ 100 Km/s) Recall: T~1eV Matter-radiation equality, T=0.26eV Recombination 60Billion nu/s/cm2 from the sun ~100nu/cm3 from CvB What is a neutrino? (for cosmology) • Behaves like radiation at T~ eV (recombination/decoupling) • Eventually (possibly) becomes non-relativistic, behaves like matter • Small interactions (not perfect fluid) • Has a high velocity dispersion (is “HOT”) Planck 2018 has spoken Planck + polarization+BAO “…the presence of a light thermalized sterile neutrino is in strong contradiction with cosmological data, and (..) the production of sterile neutrinos possibly explaining the SBL anomaly would need to be suppressed by some non-standard interactions (….)or another special mechanism. “ Planck 2018 parameters paper Cosmology is key in determining the absolute mass scale forecasted Katrin (detection vs 90% limit) degenerate CMB(Planck) +BAO 95% limit Inverted 2018+ lensing +BAO+pol Forecasts The problem is live here systematic errors normal This means that neutrinos contribute at least to ~0.5% of the total matter density Neutrino mass: Physical effects Total mass >~1 eV become non relativistic before recombination CMB Total mass <~1 eV become non relativistic after recombination: alters matter-radn equality, da, but effect can be “cancelled” CMB by other parameters Degeneracy After recombination This if you keep fixed ωm ωb Λ =0) FINITE NEUTRINO MASSES ν Σm = 0 eV SUPPRESS THE MATTER POWER k,m ( SPECTRUM ON SCALES SMALLER P Σm = 0.3 eV )/ THAN THE FREE-STREAMING k ( LENGTH P m = 1 eV linear theory Σ Different masses become non-relativistic a slightly different times Cosmology can yield information about neutrino mass hierarchy Neutrino mass: Physical effects Move along CMB parameters degeneracy H0 is everywhere! i.e. play with h again… keep fixed ωc ωb, θs Suppression BAO linear theory Different masses become non-relativistic a slightly different times Cosmology can yield information about neutrino mass hierarchy Including large-scale structure clustering Pros: see the “signature” scale-dependent clustering suppression Cons: astrophysics, bias,non-linearities Possible approach & useful exercise: use completely different tracers and see if there is agreement Cuesta, Niro, LV, 2016 Ly α from BOSS survey Neutrino mass limits: robust information from the power spectrum of galaxy surveys Palanque-Delabrouille et al. 2015 Use galaxy clustering (red and blue galaxies) Limits on the sum of the masses M⌫ < 0.14 eV (95%C.L.) Robust to choice of galaxies CMB+BAO+LRG limit M⌫ < 0.13 eV (95%C.L.) Competitive with CMB+BAO+Lyman alpha M⌫ < 0.12 eV(95%C.L.) Planck 2018 full incl. Lensing and BAO M⌫ < 0.12 eV(95%C.L.) Completely different tracers Confirmed see also other works: e.g., Giusarma et al 2016, Vagnozzi et al 2017 NB in the past: various claims of detection 0.3-0.4eV mass….not with solely AAA ratings data sets The Cosmology limits Katrin (detection vs 90% limit) degenerate CMB(Planck) +BAO Inverted +LSS Forecasts 5% or less effects on P(k) live here normal +H0? Implications I Katrin (detection vs 90% limit) degenerate Inverted L If we add H0 then HI L J Σ<0.11eV @95% normal This means that neutrinos contribute at least to ~0.5% of the total matter density Hierarchy effect on the shape of the linear matter power spectrum Δ Neutrinos of different masses have different transition NH IH redshifts from relativistic to non-relativistic behavior, and their individual masses and their mass splitting change the details m Δ sol of the radiation-domination to matter- domination regime. Δmatmo Δm atmo approx Δmsol Jimenez, Penya-Garay, Verde, 2016 Hierarchy effect on the shape of the linear matter power spectrum Δ Neutrinos of different masses have different transition NH IH redshifts from relativistic to non-relativistic behavior, and their individual masses and their mass splitting change the details m Δ sol of the radiation-domination to matter- domination regime.
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