Cosmological Probes of Cosmological Probes of Dark Matter - PowerPoint PPT Presentation

Cosmological Probes of Cosmological Probes of Dark Matter Interactions Dark Matter Interactions Vera Gluscevic Vera Gluscevic Princeton / USC New Directions in the Search for Light Dark Matter Particles Fermilab/KICP (Jun 7, 2019) 1

Cosmological direct detection Cosmological direct detection Production (colliders) SM DM ? Cosmology Direct detection SM DM Indirect detection 2

Observables VG et al, Astro2020 (2019) 3

~370 k yrs ~200 M yrs ~14 G yrs (today) VG et al, Astro2020 (2019) 4

~370 k yrs ~200 M yrs ~14 G yrs (today) VG et al, Astro2020 (2019) 5

CMB power spectrum CMB power spectrum [ μK ] Variance 2 TT ℓ ∼ C Planck Collaboration 2015 6

CMB with DM-baryon scattering CMB with DM-baryon scattering fluids + gravity = baryonic acoustic oscillations 7

CMB with DM-baryon scattering CMB with DM-baryon scattering fluids + gravity + drag = damped baryonic acoustic oscillations 8

CMB with DM-baryon scattering CMB with DM-baryon scattering fluids + gravity + drag = damped baryonic acoustic oscillations angular scale Variance 9

Planck limits on DM- Planck limits on DM-proton proton scattering scattering [velocity-independent spin-independent interaction] VG and Boddy, PRL (2018) See also: Boehm+ (2002), Chen+ (2002), Dubovsky+ (2004), Sigurdson+ (2004), Dvorkin+ (2014). 10

And beyond... And beyond... momentum-transfer rate momentum-transfer momentum-transfer cross section rate ( v ) n σ R MT χ momentum time dependance of the Boddy and VG (2018) interaction operator 11

Interaction physics in cosmological context Interaction physics in cosmological context signal shape operator signal ( m , c ) C O ℓ χ i i angular scale Fan et al, 2010; Fitzpatrick et al, 2012; Anand et al, 2013 Boddy and VG (2018) 12

CMB limits on DM EFT CMB limits on DM EFT Boddy and VG (2018) 13

CMB limits on DM EFT CMB limits on DM EFT Age of the Universe ~1000 years: Boddy and VG (2018) less than 1 in 100 000 scatterings is with DM. 13

Planck limits on DM- Planck limits on DM-electron electron scattering scattering PRELIMINARY Boddy and VG, in prep. (2019) 14

Next-generation ground-based CMB observatories => high resolution measurements. 15

Next-generation ground-based CMB observatories => high resolution measurements. Proposed: CMB-S4 15

Next-generation ground-based CMB observatories => high resolution measurements. Proposed: CMB-S4 Funded: Simons Observatory 15

[2016] 16

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Forecasts Forecasts velocity-independent scattering DM interactions do NOT look like other science targets, given well-measured CMB lensing. Li, VG, + (2018) See also: SO collaboration science goals [1808.07445] 18

today 19

Dark matter interactions suppress structure on small scales. scale Variance 20

Dark matter interactions suppress structure on small scales. scale Variance 20

Near-field cosmology Near-field cosmology Galaxy surveys: SDSS, DES; Upcoming: LSST,DESI,... Bullock and Boylan-Kolchin (2017) 21

Near-field cosmology Near-field cosmology Galaxy surveys: SDSS, DES; Upcoming: LSST,DESI,... Big Question : Can we use small-scale structure to study fundamental physics? Bullock and Boylan-Kolchin (2017) 21

Near-field cosmology Near-field cosmology Galaxy surveys: SDSS, DES; Upcoming: LSST,DESI,... Big Question : Can we use small-scale structure to study fundamental physics? Challenges: Bullock and Boylan-Kolchin (2017) 21

Near-field cosmology Near-field cosmology Galaxy surveys: SDSS, DES; Upcoming: LSST,DESI,... Big Question : Can we use small-scale structure to study fundamental physics? Challenges: Observational: smaller halos host fainter galaxies [completeness correction] Bullock and Boylan-Kolchin (2017) 21

Near-field cosmology Near-field cosmology Galaxy surveys: SDSS, DES; Upcoming: LSST,DESI,... Big Question : Can we use small-scale structure to study fundamental physics? Challenges: Observational: smaller halos host fainter galaxies [completeness correction] Theoretical: baryonic physics and non-linear evolution [galaxy-halo connection] Bullock and Boylan-Kolchin (2017) 21

Near-field cosmology: Analytic estimate Near-field cosmology: Analytic estimate ( σ , m ) z decoupling redshift: 0 crit χ Horizon size ( σ , m ) proxy for halo mass k 0 crit χ 8 ∼ 10 M sun Nadler, VG,+ (ApJ Letters 2019; ) 22

Near-field cosmology: Analytic estimate Near-field cosmology: Analytic estimate ( σ , m ) z decoupling redshift: 0 crit χ Horizon size ( σ , m ) proxy for halo mass k 0 crit χ 8 ∼ 10 M sun Population of Milky Way satellite galaxies => no lack of structure => limits on DM scattering. Nadler, VG,+ (ApJ Letters 2019; ) 22

Near-field cosmology: Probabilistic inference Near-field cosmology: Probabilistic inference Population of smallest galaxies in Milky Way's orbit => no lack of structure on corresponding scales => limits on DM scattering. Nadler, VG,+ (ApJ Letters 2019; ) Promise: 3 orders of magnitude better than Planck. 23

Broader scope Broader scope 24

Broader scope Broader scope Lots of data coming: Simons Observatory, CMB-S4, LSST, DESI, HERA, SKA, EDGES, SARAS, DD experiments, ... 24

Towards the future Towards the future 25

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~200 M yrs 27

21-cm cosmology 21-cm cosmology time 28

Case study: EDGES Case study: EDGES [Experiment to Detect the Global Epoch of reionization Signature] Bowman, + (2018). 29

Case study: EDGES Case study: EDGES [Experiment to Detect the Global Epoch of reionization Signature] Bowman, + (2018). NB: Is it in the sky? Is it cosmological? 29

Case study: EDGES Case study: EDGES [Experiment to Detect the Global Epoch of reionization Signature] Bowman, + (2018). NB: Is it in the sky? Is it cosmological? 29

Case study: EDGES Case study: EDGES [Experiment to Detect the Global Epoch of reionization Signature] Bowman, + (2018). NB: Is it in the sky? Is it cosmological? 29

Case study: EDGES Case study: EDGES Bowman, + (2018) and Barkana (2018); see also: Munoz, + (2016) Baryons are cold! Dark matter-baryon interactions?! σ ∼ v −4 Millicharge: 30

What does CMB have to say? What does CMB have to say? 31

Planck limits on millicharge Planck limits on millicharge σ ( v ) ∼ v −4 Excluded Fractional charge Boddy, VG, + (2018) Kovetz, Poulin, VG, + (2018) Dark matter mass [MeV] See also: Xu, + (2018); Slatyer, + (2018); Wu, + (2018); Dvorkin, + (2014). 32

Limits on interacting DM sub-component Limits on interacting DM sub-component Boddy, VG, + (2018). 33

Limits on interacting DM sub-component Limits on interacting DM sub-component EDGES signal is inconsistent with Planck, if more than 0.5% of DM is millicharged. Boddy, VG, + (2018). 33

Cosmological probes are already very sensitive. Comprehensive analyses are essential to establish a discovery. 34