2021年度国立天文台将来シンポジウム【SG: 横軸5】宇宙論（宇宙初期、ダークマター、ニュートリノ質量と階層）

素粒子物理学的アプローチ
Cosmology: Particle Physics Approach
Kazunori Kohri

郡和範

Theory Center, IPNS, KEK
Sokendai
Kavli IPMU, U of TokyokeV axion (X-ray)keV axion (X-ray)missing baryon (X-ray)missing baryon (X-ray)
TeV WIMP (e+, 𝑝)
PeV DM (CR)TeV DM, PBH (γ-ray)
PeV DM, ν mass/CP, νR
proton decay, ν mass/CP,
νR , ALPs, DMν mass/CP, νR , axion, DM
WIMP, ALPs (DD)
WIMP, ALPs (DD)
WIMP gas detector (CF4)dark matter (DD)DM, PBH ( 𝑛, 𝑝)
MeVγ DM, PBH (γ-ray)

I am working as a theoretical member of• KAGRA:A member of Scientific Congress (KSC) / Theory ofgravitational waves a(GWs) /Primordial Black Holes (PBHs)• LiteBIRD: A member of the Publication Board / Theory of Inflation/CMB• CTA:
A leader of dark matter/fundamental physics in CTA-Japan /theory of gamma-ray astrophys and dark matter• CALET: A member of theoretical analyses / theory of dark matter,
antiparticles in cosmic rays
• SKA:
A member of Cosmology group in SKA-Japan / theory ofneutrino mass , GWs, density perturbation• DECIGO: Theory of GWs/PBHs produced in the early Universe

Interdisciplinary Subjects infundamental Physics

COSMOLOGY: An academic field to discuss evolutions of the past, thepresent and the future of the whole Universe
Particle physics

Cosmology

Astronomy
Astrophysics

Nuclear physics

laeRitv
itgr,
yitv
ay

Hadron physics

Concept of values in particle physics• The ultimate dream: Unification of three forces(electromagnetic, weak and strong interactions,i.e., GUT) and gravity under a symmetry such as
SU(3)xSU(2)xU(1), SU(5), SO(10), SUSY, E(8)xE(8)etc.
• Looking for new physics beyond the standardmodel (the electroweak theory)• Finding a new physical law by which the current
physical law of particle physics must be rewritten
定義により、常に新しい物理学理論を追い求めることを意味する
プロジェクト主義ではなく、目的主義

New Physics beyond the Standard Model• Inflation• Dark matter

Today’s talk• Neutrino masses/hierarchy and CP violation• Dark energy• Matter-antimatter asymmetry• …

GUT (Grand Unified Theory)

Unification of three coupling constants at 1016 GeV
Ugo Amaldi, Wim de Boer, Hermann Furstenau, 1991

Inverse offine structure constant(s)Can we confirm it observationally/experimentally?
U(1)Electromagnetic

Weak interaction

WithSupersymmetry(SUSY)↓SUSY+SO(10)?

SU(2)
SU(3)

Strong interaction

1016 GeV(z ~ 1029)

Energy Scale (GeV)

Further unification?
Landscape(supergravity?/superstring?
/quantum gravity?)(SUSY)GUT
Neutrino mass?

Inflaton?

Electro-weakStrong(StandardModel)(QCD) Axion?
WIMP?

baryogenesis?

gravity

Dark energy?

Swamp Land?

History of the Universe
Birth of the Universe
Cosmic time

10-43

EnergyInflation?
Neutrino mass?
GUT phase transition
Baryogenesis?
Electroweak phase transition WIMP? DM?
QCD phase transition axion DM? PBH DM?
Big-bang
Neutrino decoupling
Nucleosynthesis
Electron-positron annihilation(BBN)
Planck scale

Matter-radiation equality
Last scatting of CMB

dark energy?

PresentInflation

Inflation• We need an exponentially-growing phase a(t)∝eHt in theearly Universe, t 〜10-38 sec?, T 〜 V1/4 〜 1016 GeV? (=GUT scale?) to solve the horizon problem, the flatness
problem, to produce primordial density perturbation, …
• [Q] What is the scalar field which induces inflation? Whatis the model in which the scalar field is embedded?
• [Obs] B-mode polarization in CMB (POLARBEAR-2, Simons
Array, Simons Observatory, LiteBIRD, CMB-S4), Primordial
stochastic gravitational wave (KAGRA, ET, DECIGO, BBO), …

Inflation produces curvature
perturbation and gravitational wave
Potential
V(φ)
Obeying symmetry such as

SU(5), SO(10), SUSY, E(8)xE(8) etc.

０Inflaton φCurvature perturbation Pζ
じくうをゆらがせる郡和範他、理化学研究所「元素の起源」より

ぼうちょう
させるQuantumfluctuation
いるGWs

The e-folding number during
inflation to be N > 60
• Cosmic expansiona(t) ∝ Exp[N]• Lower bound on N

• Reheating temperature after inflation

TReheat = ? ＜ 1016 GeVUpper bounds on reheating temperature not to
produce so many dangerous gravitinos insupersymmetry/supergravity from BBN
Kawasaki, Kohri, and Moroi (2004)/4He

95% C.L.

Predictions from inflation• Temperature (scalar curvature) fluctuation• Spectral index of scalar curvature fluctuation• Tensor (gravitational wave) to scalar ratio (will beobserved by CMB B-mode polarization in future)

Energy scale
Potential of infaton fieldYes,. we can prove the GUT scale by CMB B-mode polarization

Hubble expansion rate during inflation⎛⎞r
14
H = 10  ⎜⎟⎝ 0.1 ⎠

1/2BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves
using Planck, WMAP, and BICEP/Keck Observations through the 2018
Observing Season

BICEP/Keck Collaboration: P.A.R. Ade et al, arXiv:2110.00483 [astro-ph.CO]

Future sensitivities on the Tensor mode (B-mode polarization)
by LiteBIRD and the Simons Observatory

Tensor to Scalar ratio r

M. Hazumi, et al, the LiteBIRD collaboration, arXiv:2101.12449

Fiducial valuer = 4x10-3

We can prove the GUT
scale by CMB B-mode
polarization

Spectral index nsΩGW h2

Future sensitivities on GWs produced
by inflation

BBNCMB
Inflation

Kazunori Kohri, “Neutrino and Gravitational wave”
郡 和範 著 「ニュートリノと重⼒波」ベレ出版 (2021)

Curvature perturbation Pζ (k)Amplitude of curvature perturbation

Small-scales are the new frontier in future cosmology!

Kohri, Lin, Lyth, 2008
Alabidi, Kohri, Sendouda, Sasaki, 2013
Kohri and T.Terada, 2018
Planck(KAGRA, DECIGO)
PIXIE

at 68% C.L.

UCMHs (CTA,CMB-S4, SKA)

wave number k = p x a

Multi-field inflation with non-gaussian
fluctuation?
Daisuke Yamauchi and Keitaro Takahashi 2015
Daisuke Yamauchi et al, the SKA-Japan collaboration, arXiv:1603.01959↑ Suyama-Yamaguchi inequality
Suyama and Yamauchi, 2008

DarkMatterDark Matter• We need cold dark matter (CDM) to form the largescale structure (LSS)• [Q] Revealing the identity of the CDM and the newtheory in which the CDM is embedded• [obs] Collider experiments (HL-LHC, ILC), Direct
detections(XMASS, XENON-NT, DARWIN,
NEWAGE/CYGNUS), Indirect detections (Calet, CTA,Magic, IceCube, GAPS, GRAMS, SMILE, TibetAS, Mega
ALPACA), Consistencies with the cosmic history(HSC,TMT,LiteBIRD,CMB-S4), etc. …

We are in a minority groupContents in the Universe
Atoms arecalled baryon

Dark Energy
68%
Cosmological constant?
Quintessence?

Matter32%

Dark Matter27%
Atoms
5%Radiation
0.01%
Planck Satellite experiments 2015

Candidate of Dark Matter• WIMP

HL-LHC, ILC, XMASS, XENON-NT, DARWIN,NEWAGE/CYGNUS, CALET, CTA, Magic,IceCube, GAPS, GRAMS, SMILE, TibetAS,Mega ALPACA• Axion• Primordial Black Hole• ...

XRISM, ATHENA,Fermi, HESS,CTA, Magic,HSC, TMT,CIBER, AKARIKAGRA, …
XRISM, ATHENA,GRAMS, SMILE
Fermi, HESS,CTA, Magic,CALET, GAPS,HSC, TMT,KAGRA, ET
LiteBIRD,CMB-S4

Time-evolution of the fluctuation
to produce a galaxyFirst, dark matter halo was produced in theearly universe

Then a galaxy (made by baryons) is produced
inside the CDM halo due to the gravity of dark matterρDMρbaryon~5

WIMP χ(neutralinoin SUSY, …)

1) Production of WIMP in the early
Universe• Left from the cosmic expansion (freeze-out)
⎛⎞
ρχ
σv
⎜
⎟Ωχ ≡∼ 0.25 ⎜2⎟
ρ total0.1⎜⎟⎝
TeV ⎠(σv2021/11/30

canonicalKazunori Kohri (KEK/Sokendai)= 3 × 103cm−26sec~)

0.34(TeV)2−1

LHC bounds on WIMP (neutralino)

Jia Liu, Navin McGinnis, Carlos E.M. Wagner, Xiao-Ping Wang, arXiv:2006.07389 [hep-ph]

LHC exp. : p + p à χ + …

mass of DM
neutralino χ10

mass of chargino

GAMBIT analyses of LHC data constraining the relicDM density and the SI elastic scattering cross section
The GAMBIT Collaboration: Peter Athron, arXiv:1809.02097 [hep-ph]

LHC exp. : p + p à χ + …

Upper bound on (Spin-independent)
elastic cross section by Xenon and XMASS
Direct detection : nuclei + χ à nuclei + χ

E. Aprile et al, XENON1T
collaborations, arXiv:1907.12771[hep-ex]Snowmass Community Summer Study 2013 CF1:
WIMP Dark Matter Detection

Indirect detection of DM

Indirect detection : χ + χ à γ-rays or Cosmic-rays + …
Annihilation or Decay?

Daughter particles

Propagations of charged particles

Upper bound on annihilation cross section
N.Hiroshima, M.Hayashida, and KK, arXiv:1905.12940 [astro-ph.HE]
NFW
BurkertCore (flat)

winoBBN

IceCube

CTA dwarfs

AMS-02CALET
CMB

Fermi+ Magic← canonicalcross section

Future sensitivity of upper bouns onannihilation cross section by CTA toward
the galactic center

A. Acharyya et al, The Cherenkov Telescope Array Consortium, arXiv:2007.16129[astro-ph.HE]

AxionorAxion-LikeParticle (ALP)
2021/11/30

Kaz Kohri (KEK)What is the (QCD) axion?
l Breakdown of the U(1) Peccei-Quinn symmetryl The Nambu-Goldstone boson (angular component)
is called “axion”

QCD

oscillating
like matter ρ∝1/a3-Fa
2021/11/30

Fa0Fa

Oscillation probability• Probability2⎤⎡⎛⎞gBr
Ε1⎥
2 ⎢ aγ*Pa↔γ =sin ⎢1+ ⎜ ⎟ ⎥22Εγ ⎠⎝⎛Ε ⎞⎢⎥*⎣⎦
1+ ⎜ ⎟⎝ Εγ ⎠• For efficient oscillation,
2a2021/11/30

mEγ > E* =2g aγ B

andKaz Kohri (KEK)r ≥ rHa ≡2g aγ BADMX bounds on QCD axions
C. Bartram, et al, the ADMX collaboration, arXiv: 2110.06096
https://arxiv.org/abs/2110.06096

BabyIAXO for axion-like-particles
Javier Galan, arXiv:2110.15668 [hep-ph]Kanji Mori, Tomoya Takiwaki,
Kei Kotake, arXiv:2107.12661
Pre-SNKAGRA/LIGONagano et al, arXiv:2106.06800

ExcludedpositiveTeVγ

Cosmic Infrared Background (CIB) by CIBER
2016, IRTS 2013, Akari 2013

γ (AGN) →axion (IGM)→γ (Milky-Way)

γTeV + γIR à e+ + e-

2021/12/9

Kaz Kohri (KEK)We need axion or ALPs
z=0.186
r=680Mpc

z=0.165
r=610Mpc

Kohri and Kodama, arXiv:2017.05189

Photon-axion mixing through gammaray emission from 6 galactic pulsars
Jhilik Majumdar, Francesca Calore, Dieter Horns, arXiv:1801.08813 [hep-ph]

CTA/Magicshould
give usstrongerbounds
CIBER : Femi+HESS+CIBER, Kohri and Kodama (2017)
2021/11/30

Kaz Kohri (KEK)PrimordialBlack Holes(PBHs)

Primordial Black Hole (PBH)• Large perturbation at small scales
was produced by Inflation at around> 10-36 second

2021/11/30

Kazunori Kohri (KEK/Sokendai)

GW150914 and its merger rate
Rate of GW140914

M. Sasaki, T. Suyama, T. Tanaka and S. Yokoyama (2016).

3-body is important for theBBH formations
See also, Ali-Haimound, Kovetz and Kamionkowski (2017)

f=10-3

f=10-2

fraction to CDM (ffraction)

DECIGO discriminates BPBHs from thenormal BBHs

Takashi Nakamura et al, arXiv:1607.00897 [astro-ph.HE]

1/z ~a (t )a (t 0 )(~ t / 10Gyr)

2/3

Upper bounds on the fraction to CDM

LIGOGamm

a-ray

Gravitational
Lensing

Dionre t
Ac c C M B
a nd

2nd GW

1017 gDM

10−5 M ⊙OGLE

MPBH

30M ⊙GWs

Acoustc rehearing
CMB µ- distortion

isk

fPBH=ΩPBH/ΩCDM

Carr, Kohri, Sendouda, J.Yokoyama (2009)(2020)

104.5 M ⊙Seed ofSMBH

Mass in gram

Type-III Hilltop inflationGerman,models
Ross, Sarkar (01)l Potential in supergravity, e.g.,

Kohri, Lin and Lyth (07)+⇢W =Cp 3,Mpl⇠ Cm3/2 /Mpl

in SUGRA

Allahverdi, Kusenko, Mazumdar (06)

N=60
N=0
Ending by a water-fall mechanismφCurvature perturbation Pζ (k)Amplitude of curvature perturbation

Small-scales are the new frontier in future cosmology!

Kohri, Lin, Lyth, 2008
Alabidi, Kohri, Sendouda, Sasaki, 2013
Kohri and T.Terada, 2018
Planck(KAGRA, DECIGO)
PIXIE

at 68% C.L.

UCMHs (CTA,CMB-S4, SKA)

wave number k = p x aZaven Arzoumanian, et al, The NANOGrav Collaboration, arXiv:2009.04496

NANOGrav 12.5 yr(North American Nanohertz Observatory for Gravitational Waves)found stochastic GWs through pulsar timing ?

https://www.nasa.gov/sites/default/files/thumbnails/image/arecibo_ao002.jpg

The 305-meter dish of the William E.
Gordon Telescope, The Arecibo Obs.

https://science.nasa.gov/science-red/s3fs-public/atoms/files/JLazio_PlanetaryScienceAdvisoryCommittee-February-v2=TAGGED.pdf

The 100-meter Green Bank Telescope

NANOGrav12.5yr and solar mass PBHs

K. Kohri and T. Terada, arXiv:arXiv:2009.11853

LIGO (H+L) + VIRGO (V) + Indigo (I) + KAGRA (K)Yoichi Aso, et al, arXiv:1306.6747 [gr-qc]

2021/11/30

Kaz Kohri (KEK)2nd order GWs enhanced at asudden transition from MD to RD
Inomata, Kohri, Nakama, Terada, Phys. Rev. D 100, 043532 (2019),
arXiv:1904.12879~ ∫∫f2(u,v,x,xR)

This is big!

• Gravitational potential• Enhancement at TR
Amplitude should be less than unity
The transition occurs in a finite timeeMDRDNeutrino
masses/hierarchyand CP violation

Neutrino masses mν
• The mass differences among neutrinos have beenmeasured by Super-Kamiokande, KamLAND, etc. …
• [Q] How large are the nonzero absolute values of mν ?
How is the hierarchy among the three masses?
• By measuring them, we can obtain a hint of the newtheory which gives mν (e.g., GUT, Seesaw mechanism,Leptogenesis etc. … )• [obs] Cosmological 21cm line (SKA), CMB lensing(POLARBERAR-2, Simons Array/ Observatory, CMB-S4),
Ocillation exp. (Hyper-K), the Inverse beta-decay exp.
(PTOLEMY), …

Neutrino mass and # of species Nν
From oscillation experiments∑=ν> ∑=ν>  

From the current cosmological observations such as CMB + ...,∑

=ν<  σ  ν=  ±  σ Neutrinos with mν=O(0.01) eV become
non-relativistic at 3T=mν=O(0.01) eV• Much after the recombination (3T << 0.3eV)• Much before galaxy formation (3T >> 0.001eV)

21cm line + CMB lensed B-mode
polarization should be the best tool toconstrain mass hierarchy with mν~0.05
eVFuture constraints on neutrino hierarchy
by 21cm, CMB, BAO, H0Oyama, Kohri, Hazumi (2015)• Hierarchy parameterrν ≡m 3 − m1
Σmi⎧⎪ > 0 normal hierarchy=⎨⎪⎩ < 0 inverted hierarchy

DarkEnergy

Dark Energy• We need the source for the accelerating expansion ofthe Universe at present (〜 the cosmological constant)• Building a theoretical model to explain it• [Q] We have to reveal it: Why is it so small andconstant with ρ1/4〜meV?
• [Obs] Weak lensing? 21cm? Measurements of massesof axion or neutrino? Modified gravity?

Neutrino mass scale ~ O(1) meV
Afshordi, Zaldarriaga, Kohri, arXiv:astro-ph/0506663• A scalar coupled with neutrinos with V(φ)1/4〜O(1) meV• However, there is an instability which makes
DE fragment into dark matter halos
with cs2 < 0for 1/mφ < 1/k < 1/H0

Forecast in future experiments with
future 21cm+CMB+BA0+SNeIa+H0

Kazunori Kohri, Yoshihiko Oyama, Toyokazu Sekiguchi, Tomo Takahashi,
arXiv:1608.01601 [astro-ph.CO]Matterantimatterasymmetry

Matter-antimatter asymmetry• We need nB/nγ=baryon # / photon # ~ 10-10 suggested
by Big Bang Nucleosynthesis (BBN) and CMB• [Q} How nB/nγ was produced from nothing? Building
models to produce nonzero nB/nγ• [obs] Measuring another CP phases in quarks,
neutrinos (left or right handed) by T2K, Hyper-K orobtaining a hint of nonthermal phenomena such as 1storder phase transition or decaying topological defects(e.g., cosmic string) in the early Universe through GWs
by SKA, NANOGrav, KAGRA, ET, DECIGO, ET, CE

Baryogenesis/Leptogenesis
andSakharov’s three conditions

110−101 − 10−10①B# violation②CP violation③deviation fromthermal equilibrium

A net of baryon

Anti-Baryon(anti-nucleon)

Baryon (nucleon)annihilation

10−10Leptogenesis Fukugita and Yanagida, 1986

• Decay of massive right-handed neutrino νR• We need the CP violation in the neutrino sector• Lepton number nL/s is converted into baryon number nB/s
through the Sphaleron process at T 〜O(100) GeV

CP phases in active and sterile neutrinos by
future T2HK (T2-Hyper-K), Dune, NoνaSanjib Kumar Agarwalla, Sabya Sachi, Chatterjee, and Antonio Palazzod, arXiv:1801.04855v1

Seesaw and Leptogenesis searched byfuture GW

Jeff A. Dror, Takashi Hiramatsu, Kazunori Kohri, Hitoshi Murayama, Graham White,
arXiv:1908.03227 [hep-ph]← including νR
Decay of cosmic strings
à a flat GW spectrum

Cosmic strings were formed

SKA, NANOGrav, LISA, BB0, DECIGO, ET, CE

素粒子的宇宙論の発展において何が大きな課題か？
What is the most important goal(s) in progress on particle cosmology?

• Building the true model of inflation which should be hopefully
verified by future CMB and/or GW observations• We have to reveal the identity of the CDM• Measuring neutrino masses with their hierarchy, and CP violation• Building the true model of dark energy which will be verified by
future observations• Discriminating the true model of baryogenesis/leptogenesis from theothers cosmologically• From astronomy, can we again make a breakthrough in observations
which causes a paradigm shift even in fundamental physics (such asDM, or DE )?どんなアプローチが考えられるのか？
What kind of approaches?
Checking consistencies between observations andpredictions in new physics (SUSY, GUT, superstring,modified gravity, etc. ) by applying them to cosmology• By new ideas, launching a new project to astronomically probe newphysics such as Inflation (r, etc.), WIMP, axion, PBHs, neutrino mass/CP,
dark energy, baryon-asymmetry, which must stimulate the Japanese
astronomy communities• We have to build several leaders who understand concepts of values
in both astronomy and fundamental physics from a wide-ranging
perspective in the communities• Not for the project, but for the purpose to look for new physics