Neutrino Cosmology in 2020: Where do we Stand? · 2020. 1. 28. · Choudhury & Hannestad 19'...

Neutrino Cosmology in 2020:Where do we Stand?

LCDM23-01-2020

Miguel Escudero [email protected]

mailto:[email protected]

Neutrino Cosmology in 2020 LCDM 23-01-20Miguel Escudero (KCL)

New Laboratory Neutrino Mass Bound

2

3H ! 3He+ + e� + ⌫̄eKATRIN experiment



2


Mainz and Troitsk (2001) : m⌫e < 2.2 eV (95 % CL)



2



(90 % CL)(PRL 2019, 1909.06048)

m⌫e < 1.1 eVCurrent laboratory bound:



2



(90 % CL)(PRL 2019, 1909.06048)


(95 % CL)X

m⌫ < 3.9 eV



2


KATRIN expected reach Xm⌫ < 0.6 eV

(90 % CL)m⌫e < 0.2 eV(in ~3-years)


(90 % CL)(PRL 2019, 1909.06048)


(95 % CL)X

m⌫ < 3.9 eV


Planck Legacy Data is now Public

3

Planck Likelihoods 1907.12875

CLASS/CAMB MontePython/CosmoMC


The Hubble Tension Increases

4

From Verde et. al. 1907.10625


Outline

5

1) Neutrinos and ΛCDM2) Neutrino Masses

Cosmological Constraints within ΛCDM Non-standard Cosmologies

3) NeffBBN and the CMB Constraints on BSM Physics

4) Neutrinos and the Hubble Tension

5) Conclusions and Outlook


Neutrino Decoupling

6

e+e� $ ⌫̄i⌫ie±⌫i $ e±⌫i

ElectronsNeutrinos Z-W (off-shell)Photons


Neutrino Decoupling

7

Ne↵ ⌘ 8

7

✓11

4

◆4/3 ✓⇢rad � ⇢�⇢�

◆


Neutrino Decoupling

7

Ne↵ ⌘ 8

7

✓11

4

◆4/3 ✓⇢rad � ⇢�⇢�

◆Ne↵ = 3

✓1.4T⌫

T�

◆4


Neutrino Decoupling

7

Ne↵ ⌘ 8

7

✓11

4

◆4/3 ✓⇢rad � ⇢�⇢�

◆

de Salas & Pastor 1606.06986Escudero 2001.04466NSM

e↵ = 3.045

Ne↵ = 3

✓1.4T⌫

T�

◆4


Neutrino Decoupling

7

Ne↵ ⌘ 8

7

✓11

4

◆4/3 ✓⇢rad � ⇢�⇢�

◆

de Salas & Pastor 1606.06986Escudero 2001.04466NSM

e↵ = 3.045

Why is it not 3?Some e+e- heatingNon-instantaneous decouplingQED thermal correctionsNeutrino Oscillations

Excellent reviewby Dolgov 0202122

T⌫µ/⌫⌧⇠ 3.5MeV

T⌫e ⇠ 2MeV

Relic Neutrino Decouplingt ⇠ 0.1 s

Ne↵ = 3

✓1.4T⌫

T�

◆4


Neutrino Evolution

8

Xm⌫ = 1 eV

Neutrinos are always a relevant species in the Universe evolution

γ ν

Hot DM: ⌦⌫h2 ' 0.01

Xm⌫/eVNon-Rel: znon�rel

⌫ ' 600m⌫

0.3 eV


q�m2

sol

q�m2

atm

q�m2

sol

' 0.01 eV

q�m2

atm ' 0.05 eV

Neutrino Properties

9

InvertedNormal

Figure from de Salas et. al. 1806.11051


q�m2

sol

q�m2

atm

q�m2

sol

' 0.01 eV

q�m2

atm ' 0.05 eV

Neutrino Properties

9

InvertedNormal


Xm⌫ & 0.06 eV

Xm⌫ & 0.10 eV


q�m2

sol

q�m2

atm

q�m2

sol

' 0.01 eV

q�m2

atm ' 0.05 eV

Neutrino Properties

9

InvertedNormal


Xm⌫ & 0.06 eV

Xm⌫ & 0.10 eV

Mass differences and mixings measured with high precision


q�m2

sol

q�m2

atm

q�m2

sol

' 0.01 eV

q�m2

atm ' 0.05 eV

Neutrino Properties

9

InvertedNormal


Xm⌫ & 0.06 eV

Xm⌫ & 0.10 eV


What is Delta CP and what is the mass ordering?(see Sophie's talk)


q�m2

sol

q�m2

atm

q�m2

sol

' 0.01 eV

q�m2

atm ' 0.05 eV

Neutrino Properties

9

InvertedNormal


Xm⌫ & 0.06 eV

Xm⌫ & 0.10 eV


What is mmin? The lightest neutrino could still be massless!

What is Delta CP and what is the mass ordering?(see Sophie's talk)


Neutrino Masses from Cosmology

10

Planck 2018 (1807.06209)X

m⌫ < 0.54 eVX

m⌫ < 0.26 eV

Xm⌫ < 0.12 eV

(95 % CL, TT+lowE)

(95 % CL, TTTEEE+lowE)

(95 % CL, TTTEEE+lowE+lensing+BAO)

(95 % CL, TTTEEE+lowE+lensing)X

m⌫ < 0.24 eV



10

Planck 2018 (1807.06209)X

m⌫ < 0.54 eVX

m⌫ < 0.26 eV

Xm⌫ < 0.12 eV

(95 % CL, TT+lowE)

(95 % CL, TTTEEE+lowE)

(95 % CL, TTTEEE+lowE+lensing+BAO)

(95 % CL, TTTEEE+lowE+lensing)X

m⌫ < 0.24 eV

1) Prior dependent bounds (see next talk by Constance)

2) Dependence upon the Cosmological Model

3) Other not that linear data sets?

Very robust bounds from linear Cosmology



11

Cosmological Model DependencePlanck+BAO and 3 degenerate neutrinosX

m⌫ < 0.12 eV ΛCDM+mνPlanck 1807.06209

Standard Case



11

Cosmological Model DependencePlanck+BAO and 3 degenerate neutrinos

Choudhury & Hannestad 19'CDM+mν+ωa+ω

Xm⌫ < 0.25 eV Dark Energy dynamics

Xm⌫ < 0.12 eV ΛCDM+mν

Planck 1807.06209Standard Case



11




Varying CurvatureX

m⌫ < 0.15 eV ΛCDM+mν+Ωk Choudhury & Hannestad 19'





11




Varying CurvatureX


Varying Neff ΛCDM+mν+Neff

Xm⌫ < 0.23 eV

Planck 1807.06209





11




Varying CurvatureX



Xm⌫ < 0.23 eV

Planck 1807.06209



Varying Neff+ω+αs+mνdi Valentino et al. 1908.01391

Xm⌫ < 0.17 eV CDM+mν+Neff+ω+αs+mν



11




Varying CurvatureX



Xm⌫ < 0.23 eV

Planck 1807.06209



Varying Neff+ω+αs+mνdi Valentino et al. 1908.01391

Xm⌫ < 0.17 eV CDM+mν+Neff+ω+αs+mν

Constraints are robust upon standard modifications of ΛCDM



12

Cosmological Model DependenceMore exotic scenarios:



12


⌫i

⌫j

�

relaxed by 0.1 eVEscudero & Fairbairn 1907.05425

Xm⌫

Invisible Neutrino Decay



12


⌫i

⌫j

�


Xm⌫


Xm⌫ . 1 eV

⌫i

⌫4

�

Chacko et. al. 1909.05275




12


⌫i

⌫j

�


Xm⌫


Lorenz et. al. 1811.01991

Time dependent Neutrino Masses

Xm⌫ < 4.8 eV

m⌫(t)

Xm⌫ . 1 eV

⌫i

⌫4

�





12


⌫i

⌫j

�


Xm⌫


Lorenz et. al. 1811.01991

Time dependent Neutrino Masses

Xm⌫ < 4.8 eV

m⌫(t)

Xm⌫ . 1 eV

⌫i

⌫4

�



Bounds can be significantly loosen in some extensions of ΛCDM. They typically require modifications to the neutrino sector.



13

Data beyond Planck and BAO within ΛCDMPlanck Planck 1807.06209

Xm⌫ < 0.26 eV



13

Data beyond Planck and BAO within ΛCDMPlanck Planck 1807.06209X

m⌫ < 0.12 eV Planck 1807.06209Planck+BAO

Xm⌫ < 0.26 eV



13



Xm⌫ < 0.26 eV

Ivanov et. al. 1909.05277BOSS P(k)X

m⌫ < 0.86 eV



13



Xm⌫ < 0.26 eV

Ivanov et. al. 1912.08208Planck+BOSS P(k)X

m⌫ < 0.16 eV


m⌫ < 0.86 eV



13



Xm⌫ < 0.26 eV


m⌫ < 0.16 eV

Palanque-Delabrouilleet. al. 1911.09073

Lyman-α+H0prior X

m⌫ < 0.58 eV


m⌫ < 0.86 eV



13



Xm⌫ < 0.26 eV


m⌫ < 0.16 eV

Planck+Lyman-α X

m⌫ < 0.10 eVPalanque-Delabrouilleet. al. 1911.09073

Lyman-α+H0prior X

m⌫ < 0.58 eV


m⌫ < 0.86 eV



13



Xm⌫ < 0.26 eV


m⌫ < 0.16 eV

Planck+Lyman-α X

m⌫ < 0.10 eV

Choudhury & Hannestad 19'Planck+BAO+H0X

m⌫ < 0.08 eV


Lyman-α+H0prior X

m⌫ < 0.58 eV


m⌫ < 0.86 eV



13



Xm⌫ < 0.26 eV


m⌫ < 0.16 eV

Planck+Lyman-α X

m⌫ < 0.10 eV

Choudhury & Hannestad 19'Planck+BAO+H0X

m⌫ < 0.08 eV


Lyman-α+H0prior X

m⌫ < 0.58 eV


m⌫ < 0.86 eV

Planck is driving current cosmological constraints

Non-linear or mildly non-linear data sets break degeneracies in the fit

The larger H0 is, the stronger the constraint on areX

m⌫


Current Constraints on Neff

14

Ne↵ = 2.99± 0.17 Planck 2018, 1807.06209

Current Constraints

Fields et. al. 1912.01132Ne↵ = 2.88± 0.28

Ne↵ = 3.27± 0.15

BBN

Planck+BAO

Planck+BAO+H0 Planck 2018, 1807.06209


Current Constraints on Neff

14

Ne↵ = 2.99± 0.17 Planck 2018, 1807.06209

Current Constraints

Fields et. al. 1912.01132Ne↵ = 2.88± 0.28

Ne↵ = 3.27± 0.15

BBN

Planck+BAO

Planck+BAO+H0 Planck 2018, 1807.06209

Data is in excellent agreement with the Standard Model prediction

Standard Model Prediction: NSMe↵ = 3.045


Constraints from Neff

15

Sterile NeutrinoGoldstone BosonsOther sterile long-lived particles Gravitino, axino, hidden sector particles ...

mN ⇠ eV �Ne↵ = 1

Weinberg 1305.1971

(e.g. Gariazzo, de Salas, Pastor 1905.11290)

http://arxiv.org/abs/arXiv:1305.1971


Constraints from Neff

15

Sterile NeutrinoGoldstone BosonsOther sterile long-lived particles Gravitino, axino, hidden sector particles ...

mN ⇠ eV �Ne↵ = 1

Weinberg 1305.1971

(e.g. Gariazzo, de Salas, Pastor 1905.11290)

Constraints are relevant in many other BSM settings (see James' talk)

http://arxiv.org/abs/arXiv:1305.1971


The Hubble Tension

16

The Hubble Tension:

H0 = 67.36± 0.54 km s�1 Mpc�1

4.4 σ tension within ΛCDM! Planck 2018 1807.06209

Riess et. al. 1903.07603H0 = 74.03± 1.42 km s�1 Mpc�1


The Hubble Tension

16

The Hubble Tension:

H0 = 67.36± 0.54 km s�1 Mpc�1



Possible resolutions:1) Systematics in the CMB data very unlikely2) Systematics in local measurements none so far3) New feature of ΛCDM


The Hubble Tension

16

The Hubble Tension:

H0 = 67.36± 0.54 km s�1 Mpc�1



Possible resolutions:1) Systematics in the CMB data very unlikely2) Systematics in local measurements none so far3) New feature of ΛCDM

Possibilities Beyond ΛCDM (Knox and Millea 1908.03663):1) Late Universe Modifications very unlikely2) Early Universe Modifications hard but doable


The Hubble Tension: Theory

17

Way to Resolve the Hubble Tension (Knox and Millea 1908.03663):



17


Enhance the expansion history of the Universe prior and close to recombination!



17

Most Popular Scenario: Early Dark EnergyPoulin, Smith, Karwal, Kamionkowski 1811.04083. Smith, Poulin, Amin 1908.06995 Agrawal, Cyr-Racine, Pinner, Randall 1904.01016.

V (�) ⇠ �2n

M2n�4Pl

n = 2� 3 z� ⇠ 3000 f� ⇠ 10%





17

Most Popular Scenario: Early Dark EnergyPoulin, Smith, Karwal, Kamionkowski 1811.04083. Smith, Poulin, Amin 1908.06995 Agrawal, Cyr-Racine, Pinner, Randall 1904.01016.

V (�) ⇠ �2n

M2n�4Pl

n = 2� 3 z� ⇠ 3000 f� ⇠ 10%



Resolve the tension 4.4σ to ~1σ

Theoretical Interpretation is not simple ... m� ⇠ 10�27 eV

So far, only Planck 2015 analysesThere are some discrepancies between these analyses

f� ⇠ 10% z� ⇠ 3000


Neutrinos and the Hubble Tension

18

Why Neutrinos?



18

1) Neutrinos are always a relevant species in the Universe evolution

Why Neutrinos?



18

1) Neutrinos are always a relevant species in the Universe evolution

2) Neutrino masses are the only Laboratory evidence of Physics Beyond the Standard Model

Why Neutrinos?



19

Dark Radiation

(68 % CL, Planck+BAO+H0)

�Ne↵ = 0.23± 0.15



19

Dark Radiation


�Ne↵ = 0.23± 0.15 H0 tension from 4.4σ to 3σCMB fit is degraded

Clear Interpretation 😃😐☹



19

Dark Radiation




Strong Neutrino Scattering + Dark Radiation Kreisch, Cyr-Racine, Doré 1902.00543

⌫

⌫

⌫

⌫



19

Dark Radiation





⌫

⌫

⌫

⌫

H0 tension solved if TEEE data is ignored 😃

Almost excluded by Lab data (Blinov++1905.02727)☹If pol data is included no solution for H0 😐



19

Dark Radiation




Light Neutrinophilic Scalar + Dark Radiation Escudero & Witte 1909.04044

⌫̄

⌫

�


⌫

⌫

⌫

⌫





19

Dark Radiation





⌫̄

⌫

�H0 tension from 4.4σ to 2.5σ 😐CMB fit is not degraded 😃Direct connection with Seesaw 😃


⌫

⌫

⌫

⌫





19

Dark Radiation




Early Dark Energy sourced by neutrinos Sakstein & Trodden 1911.11760


⌫̄

⌫



⌫

⌫

⌫

⌫





19

Dark Radiation




Early Dark Energy sourced by neutrinos Sakstein & Trodden 1911.11760

Use which is excluded at 3σ by KATRIN! m⌫ = 2 eVGood attempt to solve the coincidence problem 😃

☹


⌫̄

⌫



⌫

⌫

⌫

⌫




Conclusions

20

Neutrino Masses:New lab bound from KATRIN: (95 % CL)

Bounds from Planck+BAO:X

m⌫ < 0.12 eV (95 % CL)

Xm⌫ < 3.9 eV


Conclusions

20



m⌫ < 0.12 eV (95 % CL)

Xm⌫ < 3.9 eV

Neff:Planck Constraints:BBN Constraints:

Ne↵ = 2.99± 0.17

Ne↵ = 2.88± 0.28


Conclusions

20



m⌫ < 0.12 eV (95 % CL)

Xm⌫ < 3.9 eV

Neff:Planck Constraints:BBN Constraints:

Ne↵ = 2.99± 0.17

Ne↵ = 2.88± 0.28

The Hubble Tension:Many neutrino related approaches


Outlook

21

Neutrino Masses:KATRIN reach: (90% CL)

Next Galaxy Surveys+CMB should detect neutrino masses

Xm⌫ < 0.6 eV

e.g.: 1308.4164 Font-Ribera et. al., 1408.7052 Kitching et. al.

DESI/EUCLID+Planck: �⇣X

m⌫

⌘' 0.02 eV (1�)


Outlook

21



Xm⌫ < 0.6 eV



m⌫

⌘' 0.02 eV (1�)

Neff:Stage-IV experiments will reach 1% precision, e.g. CMB-S4Strong constraints on new physics


Outlook

21



Xm⌫ < 0.6 eV



m⌫

⌘' 0.02 eV (1�)

Neff:Stage-IV experiments will reach 1% precision, e.g. CMB-S4Strong constraints on new physics

The Hubble Tension:Further data on the way: Gaia, Strong Lensing, GW, DESI ...More models will appear and neutrinos will play a leading role


Time for Questions and Comments

22

Upcoming years are going to be exciting!

Thank you for your attention!

⌫


Back Up

23


KATRIN

24

a)

18535 18555 18575 18595 18615

100

101

Count

rate

(cp

s)

KATRIN data with 1 errorbars 50 Fit result

b)

18535 18555 18575 18595 18615-2

0

2

Res

idual

s (

)

Stat. Stat. and syst.

c)

18535 18555 18575 18595 18615

Retarding energy (eV)

0

20

40

Tim

e (h

)

m⌫̄e = 0

m⌫̄e = 1 eV

Ch. Weinheimer hep-ex/0210050

1909.06048


Neutrino Mass Models

25

Asai et. al. 1811.07571

U(1)Lµ�L⌧

Particle Physicists take very seriously neutrino mass constraints:


ΛCDM in 2020

26

Weak lensing

BAOs

SNIa

Lyman-α forest

BBN CMBΛCDM model tested on very different time/length scales


CMB constraints on Neff

27

Planck Results

2.0 2.5 3.0 3.5 4.0

Ne↵

60

65

70

75

H0[k

ms�

1M

pc�

1]

Riess et al. (2018)

0.77

0.78

0.79

0.80

0.81

0.82

0.83

0.84

�8

Ne↵ = 2.92± 0.18 (68 % CL, TTTEEE+lowE)

(68 % CL, TTTEEE+lowE+len+BAO)Ne↵ = 2.99± 0.17Ne↵ = 3.27± 0.15 (68 % CL, TTTEEE+lowE+len+BAO+H0)

ΔNeff ~ 0.2-0.5 can ameliorate the Hubble tension

But values ΔNeff ~ 0.2-0.5 are not favoured by Planck Observations within ΛCDM

Beyond ΛCDM : ΔNeff ~ 0.5 can occur: e.g. Escudero & Witte 1909.04044


Neutrino Interactions

28

Neutrino Perturbations have a strong effect on the CMB spectra.

Gµ⌫ = 8⇡GTµ⌫ �Gµ⌫ = 8⇡G �Tµ⌫

Bashinsky & Seljak astro-ph/0310198

CMB: Follin, Knox, Millea & Pan, PRL 1503.07863BAO: Baumann et. al., Nature Phys. 1803.10741

Free Streaming effect detection:

This can be used to test relevant particle physics models:Annihilations Decays Scatterings Light Species



29

Parametrization mattersVagnozzi et. al. 1701.08172 Mahony et. al. 1907.04331

Choudhury & Hannestad 1907.12598 Gariazzo et. al. 1801.04946 Loureiro et. al. 1811.02578

⌫1⌫2

⌫3

Degenerate

⌫1 ⌫2 ⌫3

Normal

⌫1⌫2

⌫3Inverted



29

Parametrization mattersVagnozzi et. al. 1701.08172

Xm⌫ < 0.12 eVPlanck+BAO Degenerate

Planck+BAO Normal Hierarchy (vary mlight)X

m⌫ < 0.15 eV

bounds from Choudhury & Hannestad 1907.12598

Planck+BAO Inverted Hierarchy (vary mlight)X

m⌫ < 0.17 eV

Mahony et. al. 1907.04331Choudhury & Hannestad 1907.12598

Gariazzo et. al. 1801.04946 Loureiro et. al. 1811.02578

⌫1⌫2

⌫3

Degenerate

⌫1 ⌫2 ⌫3

Normal

⌫1⌫2

⌫3Inverted



29

Parametrization mattersVagnozzi et. al. 1701.08172

Xm⌫ < 0.12 eVPlanck+BAO Degenerate

Planck+BAO Normal Hierarchy (vary mlight)X

m⌫ < 0.15 eV

bounds from Choudhury & Hannestad 1907.12598

Planck+BAO Inverted Hierarchy (vary mlight)X

m⌫ < 0.17 eV

Mahony et. al. 1907.04331Choudhury & Hannestad 1907.12598

Gariazzo et. al. 1801.04946 Loureiro et. al. 1811.02578

Constraints are prior dependent (see next talk by Constance)

⌫1⌫2

⌫3

Degenerate

⌫1 ⌫2 ⌫3

Normal

⌫1⌫2

⌫3Inverted

Neutrino Cosmology in 2020: Where do we Stand? · 2020. 1. 28. · Choudhury & Hannestad 19'...

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