Dario Gueter (TUM/MPP) - uni-bielefeld.de...Dario Gueter (TUM/MPP) based on 1606.6690 and 1609.09069 with Marco Drewes, Bj¨orn Garbrecht and Juraj Klari ´c 12th Kosmologietag in

Introduction Testing the seesaw Testing leptogenesis Conclusions

Testing the low scale seesaw and leptogenesis

Dario Gueter (TUM/MPP)based on 1606.6690 and 1609.09069 with Marco Drewes, Bjorn Garbrecht and Juraj Klaric

12th Kosmologietag in Bielefeld

Bielefeld, 18. May 2017

Dario Gueter (TUM/MPP) 12th Kosmologietag in BielefeldTesting the low scale seesaw and leptogenesis 1/20


Remaining puzzles of the universeBAU baryon asymmetry of the universe

WMAP, Planck and Big bangnucleosynthesis:

nB/nγ = 6.05(7)× 10−10

Neutrino massesNobel prize 2015Kajita, McDonald

SM is not enough

⇒ Need to go beyond the SM





nB/nγ = 6.05(7)× 10−10


SM is not enough






nB/nγ = 6.05(7)× 10−10


SM is not enough




Extending the Standard Model by RH neutrinos

left

rightu

up

2.3 MeV

left

rightd

down

4.8 MeV

left

righte

electron

511 keV

left νe

e neutrino

< 2 eV

left

rightc

charm

1.28 GeV

left

rights

strange

95 MeV

left

right

µmuon

105.7 MeV

left νµ

µ neutrino

< 190 keVleft

rightttop

173.2 GeV

left

rightb

bottom

4.7 GeV

left

rightτ

tau

1.777 GeV

left ντ

τ neutrino

< 18.2 MeV

W±80.4 GeV

Z91.2 GeV

γphoton

ggluon

HHiggs

125.1 GeV

N1 right N2 right N3 right

quarksleptons

I II III



Extending the Standard Model by RH neutrinos

left

rightu

up

2.3 MeV

left

rightd

down

4.8 MeV

left

righte

electron

511 keV

left νe

e neutrino

< 2 eV

left

rightc

charm

1.28 GeV

left

rights

strange

95 MeV

left

right

µmuon

105.7 MeV

left νµ

µ neutrino

< 190 keVleft

rightttop

173.2 GeV

left

rightb

bottom

4.7 GeV

left

rightτ

tau

1.777 GeV

left ντ

τ neutrino

< 18.2 MeV

W±80.4 GeV

Z91.2 GeV

γphoton

ggluon

HHiggs

125.1 GeV

N1 right N2 right N3 right

quarksleptons

I II III



RH neutrinos could solve these puzzles

BAU baryon asymmetry of the universe


nB/nγ = 6.05(7)× 10−10

LEPTOGENESIS


SEE-SAW MECHANISM

mν = −v2Y †M−1M Y ∗



Neutrino masses via seesaw mechanism

Add RH neutrinos (SM singlets) νR to SM

L ⊃ `LY †νRΦ− 12ν

cRMMνR + h.c.

Two sets of Majorana mass states after EW symmetry breaking

ν ' Uν(νL + θνcR)light neutrinosmostly active doubletlight masses:mν ' v2Y †M−1

M Y ∗

N ' νR + θT νcLheavy neutrinosmostly sterile singletsheavy masses:MN 'MM � mν

⇒ N only interact via small mixing U2ai ≡ |θai|2 � 1



Constraints on RHN parameters

Direct constraints - past experimentsSeesaw constraints - neutrino oscillation dataCosmological constraints - BBN τN < 0.1 sIndirect constraints

neutrinoless double β decaylepton universalityCKM universalityelectroweak precision datarare lepton decays



Direct constraints

[Plot from arXiv:1502.00477]



Seesaw constraints

0.5 1 5 10 50

10-11

10-8

10-5

M [GeV]

U2

seesaw



Constraints on flavour patterns: Normal hierarchy

0.00 0.02 0.04 0.06 0.08 0.10 0.12

0.0

0.2

0.4

0.6

0.8

Ue2/U2

Uμ

2/U

2 sin2θ23 = 0.451

sin2θ23 = 0.574

δ = 272°



Constraints on flavour patterns: Inverted hierarchy

0.0 0.2 0.4 0.6 0.8

0.0

0.1

0.2

0.3

0.4

0.5

Ue2/U2

Uμ

2/U

2 sin2θ23 = 0.576

sin2θ23 = 0.45

δ = 256°



Cosmological constraints - BBN

0.5 1 5 10 50

10-11

10-8

10-5

M [GeV]

U2

seesaw

BBN



Global constraints - Inverted neutrino mass hierarchy

0.5 1 5 10 5010

-14

10-12

10-10

10-8

10-6

10-4

M [GeV]

Uμ

2

global constraints



Global constraints - Inverted neutrino mass hierarchy

0.5 1 5 10 5010

-14

10-12

10-10

10-8

10-6

10-4

M [GeV]

Uμ

2

global constraints

LEPTOGENESIS?



Evolution Equations

RHN density matrix

dndz = − i

2 [H,n]− 12 {Γ, n− n

eq} − Γq`

Active lepton equations

dq`dz = S`(n)

T−Wq` + W qN

Density matrix of theRHNn =

(n11 n12n21 n22

)Effective HamiltonianH of the RHN ∼M2

Production rateΓ ∼ Y 2

Source term S` of theactive neutrinosWashout term W



Oscillatory regime → small mixing angles

SM Thermal Bath

CP - even RHN CP - odd RHN

Lepton Number Asymmetry

Baryon Number Asymmetry

-4. × 10-5

-2. × 10-5

0.2. × 10-5

4. × 10-5

Re[

n12

odd]/

s-4. × 10-9

-2. × 10-9

0.2. × 10-9

4. × 10-9

Δa/s

10-11

10-10|Y

B|

10-2 10-1 100

z=TEW /T



Overdamped regime → large mixing angles

SM Thermal Bath

CP - even RHN CP - odd RHN

Lepton Number Asymmetry

Baryon Number Asymmetry

-2. × 10-6

-1. × 10-6

0.1. × 10-6

2. × 10-6

Re[

n12

odd]/

s-4. × 10-9

-2. × 10-9

0.2. × 10-9

4. × 10-9

Δa/s

10-11

10-10|Y

B|

10-1 100

z=TEW /T



Results: Inverted hierarchy

0.5 1 5 10 50

10-13

10-11

10-9

10-7

10-5

M [GeV]

U2

SHiPLBNE

FCC-ee(Z)

CEPC

ILC

BAU (upper bound)

BAU (lower bound)

disfavoured by global constraints

[Drewes/Garbrecht/Gueter/Klaric 1609.09069]Dario Gueter (TUM/MPP) 12th Kosmologietag in BielefeldTesting the low scale seesaw and leptogenesis 16/20


Results: Inverted hierarchy

0.5 1 5 10 50

10-13

10-11

10-9

10-7

10-5

M [GeV]

Uμ2

SHiP

FCC-ee(W)

FCC-ee(B)

NA62

Belle

II

LHC

T2K

BAU (upper bound)

BAU (lower bound)

disfavoured by global constraints

[Drewes/Garbrecht/Gueter/Klaric 1609.09069]Dario Gueter (TUM/MPP) 12th Kosmologietag in BielefeldTesting the low scale seesaw and leptogenesis 16/20


Flavour patterns from leptogenesis: Normal hierarchy

0.00 0.02 0.04 0.06 0.08 0.10 0.120.0

0.2

0.4

0.6

0.8

Ue2/U2

Uμ

2/U

2

M = 1 GeV

U2

2.×10-7

3.×10-7

4.×10-7

5.×10-7

6.×10-7

7.×10-7

8.×10-7

9.×10-7

[Drewes/Garbrecht/Gueter/Klaric 1609.09069]



Flavour patterns from leptogenesis: Inverted hierarchy

0.0 0.2 0.4 0.6 0.8 1.00.0

0.1

0.2

0.3

0.4

0.5

Ue2/U2

Uμ

2/U

2

M = 1 GeV

U2

2.50×10-7

5.00×10-7

7.50×10-7

1.00×10-6

1.25×10-6

1.50×10-6

1.75×10-6

2.00×10-6

2.25×10-6

5.0×10-8

7.5×10-8

[Drewes/Garbrecht/Gueter/Klaric 1609.09069]



Leptogenesis and neutrinoless double β decay

mmin → 0

[Bilenky 1203.5250]



Leptogenesis and neutrinoless double β decay

[Eijima/Drewes 1606.06221]



Conclusions

GeV scale RHN could simultaneously generate the lightneutrino masses via the seesaw mechanism and the BAU vialeptogenesis.The requirement to explain both imposes constraints of theRHN masses spectrum, flavour mixing pattern and CPproperties.GeV scale neutrinos may be found at the proposed SHiPexperiment or a future high-energy collider.A combination of different observables could reconstructenough fundamental parameters in order to decide if thesecould in fact be responsible for the BAU.


Documents

Dario Gueter (TUM/MPP) - uni-bielefeld.de...Dario Gueter (TUM/MPP) based on 1606.6690 and 1609.09069 with Marco Drewes, Bj¨orn Garbrecht and Juraj Klari ´c 12th Kosmologietag in