Low-scale baryogenesis

@Vietnam (2014/08/01)

Takehiko Asaka (Niigata Univ.)

Xth Rencontres du VietnamFlavor Physics Conference

ICISE, QUY NHON, VN(27 July-2 August 2014)

Baryon asymmetry of the universe (BAU)

2014/08/01

[Strumia 06]

Planck 2013 resultsarXiv:1303.5076

Baryon number densityEntropy density

Baryon Number = (# of baryons) (# of antibaryons)

:Bn:s

Takehiko Asaka (Niigata Univ.)

2

Introduction Neutrino mass scales

Atmospheric: ≃ 2.4 10 eV Solar： ≃ 7.5 10 eV⇒ Need for physics beyond the SM !

Important questions: “What is the origin of neutrino masses?” “What is the implications of it?” “How do we test it experimentally?”

2014/08/01Takehiko Asaka (Niigata Univ.)

3

Extension by RH neutrinos

Seesaw mechanism ( Φ ≪ )

Light active neutrinos , ,→ explain neutrino oscillations

Heavy neutral leptons , , Mass Mixing Θ /

+ h.c.2

cMR R R R R

ML i F Lμμδ ν γ ν ν ν ν= ∂ − Φ −

0 01 1( , ) . ( , ) . .02 2

c cDc L

L R TD R

c

M M

M ML h c h c

M NMN

Mννν ν

ννν

− = + = +

1T

D DM

M M MMν = −

1 2 3( , , )TU M U diag m m mν =

mixing in CC current

Minkowski ’77Yanagida ’79Gell-Mann, Ramond, Slansky ‘79Glashow ‘79

2014/08/01Takehiko Asaka (Niigata Univ.)

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Scale of Majorana mass The simplest case: one pair of and

221 /TD D M

M

M M M F M MMν ν= − = Φ

2atmM mν = Δ

Majorana Mass

Neut

rino

Yuka

wa

Coup

ling

-12

-10

-8

-6

-4

-2

0

2

-10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16

log 1

0(F)

log10(MM/GeV)

tF F=

eF F=

2014/08/01Takehiko Asaka (Niigata Univ.)

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Scale of Majorana mass The simplest case: one pair of and

221 /TD D M

M

M M M F M MMν ν= − = Φ

Majorana Mass

Neut

rino

Yuka

wa

Coup

ling

-12

-10

-8

-6

-4

-2

0

2

-10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16

log 1

0(F)

log10(MM/GeV)

tF F=

eF F=

Baryogenesis via leptogenesisFukugita, Yanagida ‘86

2014/08/01Takehiko Asaka (Niigata Univ.)

6

Talk by Stephane Lavignac

Scale of Majorana mass The simplest case: one pair of and

221 /TD D M

M

M M M F M MMν ν= − = Φ

Majorana Mass

Neut

rino

Yuka

wa

Coup

ling

-12

-10

-8

-6

-4

-2

0

2

-10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16

log 1

0(F)

log10(MM/GeV)

tF F=

eF F=

Baryogenesis via leptogenesisFukugita, Yanagida ‘86

2014/08/01Takehiko Asaka (Niigata Univ.)

7

Scale of Majorana mass The simplest case: one pair of and

221 /TD D M

M

M M M F M MMν ν= − = Φ

Majorana Mass

Neut

rino

Yuka

wa

Coup

ling

-12

-10

-8

-6

-4

-2

0

2

-10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16

log 1

0(F)

log10(MM/GeV)

tF F=

eF F=

Baryogenesis via leptogenesisFukugita, Yanagida ‘86

Baryogenesis via neutrino osc.

Akhmedov, Rubakov, Smirnov ‘98

TA, Shaposhnikov ‘05

2014/08/01Takehiko Asaka (Niigata Univ.)

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The νMSM :no new mass scale between and

Lightest one among 3 heavy neutral leptons with keVmass can be dark matter !!

Oscillation of heavy neutral leptons and can generate baryon asymmetry of the universe !

Dark matter can be tested by cosmic X-ray obs.

Physics of heavy neutral leptons and can be tested by experiments !!!

Dodelson, Widrow ‘94,…

Akhmedov, Rubakov, Smirnov ’98, TA, Shaposhnikov ‘05

≃ 4 10 100GeV 0.05eVTA, Blanchet, Shappshnikov ‘05,TA, Shaposhnikov ‘05

2014/08/01Takehiko Asaka (Niigata Univ.)

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Talk by Oleg Ruchayskiy

Baryogenesis via Neutrino Oscillation

§

2014/08/01Takehiko Asaka (Niigata Univ.)

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Baryogenesis in the νMSM

B and L violations B violation due to EW sphaleron L violation due to Majorana masses

negligible for baryogenesis temperature since ≲ C and CP violations

1 CP phase in quark sector 6 CP phases in lepton sector

3 CP phases associated with , are relevant for baryogenesis Out of equilibrium

No 1st order EW phase transition as in the SM , can be out of equilibrium for ≳ ,if Yukawa couplings are small enough

Conditions for Baryogenesis (Sakharov ‘67)

2014/08/01Takehiko Asaka (Niigata Univ.)

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Baryogenesis via neutrino osc. Oscillation of HNLs can be a source of BAU

Oscillation starts at ~ /

Asymmetries are generated since evolution rates of and are different due to CPV

Akhmedov, Rubakov, Smirnov (’98) / TA, Shaposhnikov (‘05)Shaposhnikov (’08), Canetti, Shaposhnikov (‘10)TA, Ishida (‘10), Canetti, Drewes, Shaposhnikov (’12), TA, Eijima, Ishida (‘12)Canetti, Drewes, Shaposhnikov (‘12), Canetti, Drewes, Frossard, Shaposhnikov (‘12)

N NL

Medium effects

8

12

Key points

Baryogenesis via leptogenesis

Baryogenesis via neutrino osc.

BB

LL

sphaleron

sphaleron

B L B L

2014/08/01Takehiko Asaka (Niigata Univ.)

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Evolution of asymmetries

2014/08/01

[Kuzmin, Rubakov, Shaposhnikov]

Shaleron converts Δ partially into baryon asymmetry

8.55~9.00 10[Planck 2013]

Yield of BAU depends on (even PMNS matrix !!) and masses, especially, CP violating parameters and mass difference~ /

2.5 10 Δ

Takehiko Asaka (Niigata Univ.)

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BAU and Phases and

21/11/2012

0

0.5

1

0 0.5 1 1.5 2

η/π

δ/π

-2E-902E-9

4E-96E-9

8E-9

-0.5

0

0.5

0 0.5 1 1.5 2

Reω

/π

δ/π

-8E-9

-6E-9-4E-9

-2E-90

8E-9

6E-94E-9

2E-9

IH case

Yield of BAU depends on (even PMNS matrix !!) and masses, especially, CP violating parameters and mass difference~ /Takehiko Asaka (Niigata Univ.)

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Baryogenesis via neutrino osc.Region accounting for

TA, Eijima ‘13

10-410-310-210-1100101102103104105106107

10-4 10-3 10-2 10-1 100

ΔΜ

[eV

]

MN[GeV]

NHIH

8.55-9.00) 10IH

NH

Canetti, Shaposhnikov ‘10

2.1 MeV (NH) 0.7 MeV (IH)

2014/08/01Takehiko Asaka (Niigata Univ.)

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Direct search experiment PS191

Beam dump experimentperformed at CERN in 1984

Production Detection

Upper bounds mixing elements Θ⇒ Lower bound on lifetime of ,

[Bernardi et al ‘86, ’88]

, → ⟶ ℓ ℓ , ℓ

2014/08/01Takehiko Asaka (Niigata Univ.)

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Constraints on light RH neutrinos

10-3

10-2

10-1

100

200 300 400τ N

[sec

]MN[MeV]

10-3

10-2

10-1

100

200 300 400

τ N [s

ec]

MN [MeV]

Cosmology

Direct search

Normal hierarchy Inverted hierarchy

MeV MeVMeV

TA, Eijima ‘13

PS191

2014/08/01Takehiko Asaka (Niigata Univ.)

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Search for heavy neutral leptons (HNLs)

§

2014/08/01Takehiko Asaka (Niigata Univ.)

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SHIP A new fixed-target experiment at the CERN SPS accelerator is

proposed that will use decays of charm mesons to search for Heavy Neutral Leptons

arXiv:1310.1762

2014/08/01Takehiko Asaka (Niigata Univ.)

20Talk by Nicola Serra

Search for HNLs at T2KProduction of Detection of →ℓ → ℓ ℓ

TA, Eijima, Watanabe[JHEP1303 (2013) 125]

PS191

T2K 61.25m 9m10 POT

0.86 10 POT

2014/08/01Takehiko Asaka (Niigata Univ.)

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Sensitivity: PS191 vs T2K

T2K at 10 POT has a better sensitivity than PS191 (0.86 10 POT) !

PS191

T2K

Takehiko Asaka (Niigata Univ.) 02, May/2014

TA, Eijima, Watanabe ‘13

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Summary We have considered the νMSM with three right-handed neutrinos

which are lighter than weak scale.

We have found the possible region for neutrino oscillations and BAU, allowed from search and cosmological constraints.

Search for these heavy neutral leptons are crucial to solve the origin of neutrino masses as well asthe mysteries of our universe, DM and BAU !!!

Neutrino masses by seesaw mechanism Dark matter (lightest HNL with ~keV mass) Baryogenesis via neutrino oscillations of , Direct search of , is possible

163 MeV (NH)188 269 MeV and 285MeV (IH)

2014/08/01Takehiko Asaka (Niigata Univ.)

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Backup

2014/08/01Takehiko Asaka (Niigata Univ.)

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BBN constraint on lifetime Long-lived , may spoil the success of BBN

Speed up the expansion of the universe

, ⇒ p-n conv. decouples earlier ⟹ overproduction of He

Distortion of spectrum of active neutrinos , → ̅ , , … Additional neutrinos may not be thermalized⇒ Upper bound on lifetime of ,

Dolgov, Hansen, Rafflet, Semikoz (’00) One family case:

⟷ , …

0.1 secfor2014/08/01Takehiko Asaka (Niigata Univ.)

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Constraints on HNLs and Canetti, Drewes, Frossard, Shaposhnikov ‘13

NH IH

Gorbunov and Shaposhnikov ’07 [arXiv:0705.1729]Atre, Han, Pascoli, Zhang ‘09 [arXiv:0901.3589]See

2014/08/01Takehiko Asaka (Niigata Univ.)

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Neutrino Yukawa couplings for ,1/2 1/2

PMNS /NF U D Dν= Ω Φ

2 31/2 diag( , )ND M M=

1 2 31/2 diag( , , )0D m m mν = =

0 0

cos sin

sin cos

ω ωω ωξ ξ

Ω = −

12 13 12 13 13

PMNS 23 12 23 12 13 23 12 23 12 13 23 13

23 12 23 12 13 23 12 23 12 13 23 13

1

1

i

i i i

i i

c c s c s e

U c s s c s e c c s s s e s c e

s s c c s e s c c s s e c c

δ

δ δ η

δ δ

−

= − − −

− − −

[Casas, Ibarra ’01]

Parameters of active neutrinos

Parameters of sterile neutrinos

: active ν masses

: sterile ν masses

1ξ = ±

Dirac phase δ

Imω

(in NH)

Majorana phase η

:complex number

2014/08/01Takehiko Asaka (Niigata Univ.)

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