CPNR Workshop 2025

Neutrino with wave dark matter

From type oscillation to second leptogenesis

Yechan Kim

KAIST

PRD 108, 095028 (2023); JHEP 03 (2024) 003;

PRD 111, 055026 (2025); JHEP 07 (2025) 269

Neutrino with wave dark matter (Yechan Kim)

2

CPNR Workshop 2025

Neutrino with wave dark matter

- Neutrino absolute mass

…

- Sterile neutrino

- Neutrino oscillation parameters

- Neutrino is Dirac type or Majorana type?

Many unknowns in Neutrino physics

- CP violation in PMNS

- Cosmic neutrino background (CnuB)

- Leptogenesis for BAU

Neutrino with wave dark matter (Yechan Kim)

3

CPNR Workshop 2025

- Neutrino absolute mass

…

- Sterile neutrino

- Neutrino oscillation parameters

- Neutrino is Dirac type or Majorana type?

Many unknowns in Neutrino physics

- CP violation in PMNS

Wave dark matter

with ultra-light mass scale

Neutrino with wave dark matter

- Cosmic neutrino background (CnuB)

- Leptogenesis for BAU

Neutrino with wave dark matter (Yechan Kim)

4

CPNR Workshop 2025

Neutrino mass variation

A Berlin (2016);

G Krnjaic, PAN Machado, L Necib (2017) …

Dirac-Majorana neutrino

type oscillation

YL ChoeJo, Y Kim, HS Lee (2023)

Potential oscillation

Y Kim, HS Lee (2025)

Second leptogenesis

YL ChoeJo, K Enomoto, Y Kim, HS Lee (2023);

YL ChoeJo, K Enomoto, Y Kim, HS Lee (2024)

Neutrino with wave dark matter

Neutrino with wave dark matter (Yechan Kim)

5

CPNR Workshop 2025

Quasi-Dirac type

Seesaw is broken

Dirac-Majorana neutrino type oscillation

Seesaw

mechanism

Neutrinoless double

beta decay

Majorana type

LNV is suppressed

vs

Dirac

Majorana

Neutrino with wave dark matter (Yechan Kim)

6

CPNR Workshop 2025

Dirac-Majorana neutrino type oscillation

instantly

Pure-Dirac

“Dirac-Majorana

neutrino type oscillation”

Neutrino with wave dark matter (Yechan Kim)

7

CPNR Workshop 2025

Majorana

type

Quasi-Dirac

type

LNV

LNV

Dirac-Majorana neutrino type oscillation

Turn-on/off behavior of 0νββ decay

Neutrino with wave dark matter (Yechan Kim)

8

CPNR Workshop 2025

Potential oscillation

Neutrino with wave dark matter (Yechan Kim)

9

CPNR Workshop 2025

Potential oscillation

Symmetry-restored

Symmetry-broken

Neutrino with wave dark matter (Yechan Kim)

10

CPNR Workshop 2025

Potential oscillation

Neutrino with wave dark matter (Yechan Kim)

11

CPNR Workshop 2025

Potential oscillation

Implications for neutrino sector

Symmetry-restored

Symmetry-broken

Edoardo Vitagliano et al (2019)

Andrew J. Long et al (2014)

Neutrino with wave dark matter (Yechan Kim)

12

CPNR Workshop 2025

Second leptogenesis

Temperature-dependent mass of N

1st

Production

1st

Decay

2nd

Production

2nd

Decay

Neutrino with wave dark matter (Yechan Kim)

13

CPNR Workshop 2025

Second leptogenesis

Lepton Asymmetry

Sphaleron

Baryon Asymmetry

CP-violating out-of-equilibrium decay of

Heavy Majorana neutrino

Leptogenesis

Sphaleron decoupling

EWSB

Second leptogenesis

Neutrino with wave dark matter (Yechan Kim)

14

CPNR Workshop 2025

Second leptogenesis

Neutrino with wave dark matter (Yechan Kim)

15

CPNR Workshop 2025

Second leptogenesis

Sphaleron decoupling

LAU

BAU

1st LG

2nd LG

Neutrino with wave dark matter (Yechan Kim)

16

CPNR Workshop 2025

Summary

Thank You!

• The interaction between neutrino and wave DM induce time-varying mass of the neutrino and also for the evolution over cosmic history.
• The neutrino type may oscillate if the ratio of the Dirac and Majorana mass term varies.
• The wave DM can generate the periodic symmetry breaking and restoration of the potential, and this leads to the modulation behavior of CnuB.
• The temperature-dependent mass of the heavy neutrino provides the second leptogenesis, which can explain the large discrepancy between baryon and lepton asymmetries.

Neutrino with wave dark matter (Yechan Kim)

17

CPNR Workshop 2025

Back up

Quasi-Dirac & Majorana limits

Neutrino with wave dark matter (Yechan Kim)

18

CPNR Workshop 2025

Back up

Constraints on type oscillation

Neutrino with wave dark matter (Yechan Kim)

19

CPNR Workshop 2025

Back up

r: inter-nucleon distance (fm)

Neutrinoless double beta (0νββ) decay

Neutrino with wave dark matter (Yechan Kim)

20

CPNR Workshop 2025

Back up

Conditions and constraints on potential oscillation

Neutrino with wave dark matter (Yechan Kim)

21

CPNR Workshop 2025

Back up

Singlet scalar dynamics in potential oscillation

Neutrino with wave dark matter (Yechan Kim)

22

CPNR Workshop 2025

Back up

Remarks on potential oscillation

Neutrino with wave dark matter (Yechan Kim)

23

CPNR Workshop 2025

Back up

Remarks on potential oscillation

Neutrino with wave dark matter (Yechan Kim)

24

CPNR Workshop 2025

Back up

Parameter space for second LG

To avoid thermalization of wave DM by scattering

To avoid dominant quartic coupling

Neutrino with wave dark matter (Yechan Kim)

25

CPNR Workshop 2025

Back up

Decay, scattering, and CP asymmetry in second LG