Reheating-era leptogenesis Yuta Hamada (KEK&University of - - PowerPoint PPT Presentation

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Reheating-era leptogenesis Yuta Hamada (KEK&University of - - PowerPoint PPT Presentation

Jun 13, 2023 23 likes •324 views

Reheating-era leptogenesis Yuta Hamada (KEK&University of Wisconsin Madison) 1510.05186 with Kiyoharu Kawana (Kyoto) 1608.05256 Koji Tsumura & Daiki Yasuhara (Kyoto) 29th Sep. 2016 Fermilab 1 /30 Higgs boson 2 /30 M H =125GeV.

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SLIDE 1

Reheating-era leptogenesis

Yuta Hamada (KEK&University of Wisconsin Madison)

1510.05186 with Kiyoharu Kawana (Kyoto) 1608.05256 Koji Tsumura & Daiki Yasuhara (Kyoto)

29th Sep. 2016 Fermilab

1 /30

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SLIDE 2

Higgs boson

  • MH=125GeV.
  • consistent with SM prediction.
  • SM is completed.

2 /30

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SLIDE 3

Baryogenesis

3 /30

  • There remains mystery in particle physics.
  • We do not understand
  • dark energy
  • dark matter
  • why energy density of atom is


so large(baryon asymmetry)


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SLIDE 4

Sakharov’s three conditions

  • 1. Violation of baryon number
  • 2. Violation of C and CP
  • Initial state : C and CP symmetric


Final state : C and CP asymmetric

  • 3. Out of thermal equilibrium
  • therwise inverse process exists.

4 /30

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SLIDE 5

Leptogenesis

  • One of simplest scenarios : Leptogenesis

★ Asymmetry by decay of RH neutrino

  • RHν is produced in thermal plasma for TR ≳ MR



 by inflaton decay for minf ≳ MR

5 /30

[’86 Fukugita, Yanagida] [’91 Lazarides, Shafi]

Our work Asymmetry by scattering between lepton and Higgs at reheating era

[‘15 YH Kawana]

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SLIDE 6

Plan

  • 1. Leptogenesis at reheating-era
  • 2. seesaw models


6 /30

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SLIDE 7

Plan

  • 1. Leptogenesis at reheating-era
  • 2. seesaw models


7 /30

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SLIDE 8

Setup : Action

  • Assume the existence of inflaton other than SM.
  • Introduce following dim5 and 6 operators.

  • Inflaton sector is characterized by 


reheating temperature TR, inflaton mass minf and branching ratio of inflaton to L, BrL.

8 /30

[‘97 Aoki and Kawai]

LH ν Majorana mass Λ1～1014-15GeV For λ1=1 and mν=0.1eV. UV Model dep. If type-I seesaw Λ2～1015-16GeV(later).

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SLIDE 9

Intuitive explanation

  • before the reheating process is completed.
  • Collision between lepton in thermal plasma 


and one by inflaton decay.

  • LL→ΦΦ by
  • B is mainly produced 


@time 
 reheating is just 
 completed.

9 /30

[Kolb, Turner]

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SLIDE 10
  • 1. Violation of baryon number
  • L-number violation + sphaleron process


→ B-violation

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Sakharov’s three conditions

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SLIDE 11

Sakharov’s three conditions

  • 2. Violation of C and CP
  • Coupling λ1 becomes real by unitary

transformation

  • λ2 can have complex phase

11/30

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SLIDE 12

Sakharov’s three conditions

  • 3. Out of thermal equilibrium
  • After reheating, all SM particles are in thermal

plasma.

  • At the era of inflaton domination, 


universe is out of equilibrium.

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Thermal plasma Decay of inflaton L asymmetry

E~minf E~TR

L L Φ Φ

inf→X + L

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SLIDE 13

Rough estimation

  • The rough estimation of asymmetry

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Inflaton abundance

minf : inflaton mass TR : reheating temperature

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SLIDE 14

Rough estimation

  • The rough estimation of asymmetry

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Branching ratio of inflaton to leptons

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SLIDE 15

Rough estimation

  • The rough estimation of asymmetry

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Probability that lepton violation interaction occurs before L loses energy E~minf

vs L violation Thermalized w/o L violation

[‘13 Harigaya, Mukaida]

L L L Φ Φ

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SLIDE 16

Rough estimation

  • The rough estimation of asymmetry

16/27

interference between tree and one-loop L L Φ Φ

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SLIDE 17

Numerical calculation

  • Boltzmann equation for first contribution

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nL: lepton asymmetry nl: high energy(~minf) lepton radiation energy lepton asymmetry Γwash: washout rate Friedmann eq high energy(~minf) lepton inflaton energy

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SLIDE 18

Numerical Result

  • dashed : Λ2=1015 GeV


solid : Λ2=1014 GeV

18/30

[‘15 YH, Kawana]

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SLIDE 19

Plan

  • 1. Leptogenesis at reheating-era
  • 2. various seesaw models


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SLIDE 20

Origin of higher dimensional operator

  • rigin of dimension 5 & 6 operators
  • seesaw models
  • type-I, (-II, -III), tree-level seesaw
  • Ma model, radiative seesaw

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SLIDE 21
  • Lagrangian

type-I seesaw

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SLIDE 22

type-I seesaw

  • dim-5&6 terms
  • Casas-Ibarra

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R is complex orthogonal matrix

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SLIDE 23

type-I seesaw

  • We can see 


Λ1 ~ 1014-15 GeV for mν=0.1eV,
 Λ2 ~ 1015-16 GeV for mν=0.1eV & R=1-10.

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SLIDE 24

Parameter region

  • type-I





investigate region where BAU can be generated

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parameters: TR, minf, MR, R, Br, CP phase Take to maximize the asymmetry

  • r
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SLIDE 25

Figure: type-I seesaw

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Almost same result is obtained for inverted mass ordering case.

[‘15 YH, Tsumura, Yasuhara]

Br=1, CP phase=1 are taken

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SLIDE 26

Ma model(radiative seesaw)

  • Lagrangian, ν mass is radiatively generated.

26/30

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SLIDE 27

Ma model(radiative seesaw)

  • yI→yM, MR→MReff
  • We can see 


Λ1 ~ 1014-15 GeV for mν=0.1eV,
 Λ2 ~ 1013-15 GeV depending on parameters.

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SLIDE 28

Parameter region

  • Ma model


region where BAU can be generated

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parameters: TR,minf,MR, R2/λ5, Br, CP phase

to maximize the asymmetry

Take

  • r
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SLIDE 29

Figure: Ma model

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[‘15 YH, Tsumura, Yasuhara]

Br=1, CP phase=1, R=1 are taken

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SLIDE 30

Summary

  • We propose the new way to produce BAU.
  • Even if RHν is not produce in the early universe,

the baryon asymmetry can be explained.

  • Embedding in seesaw models are discussed.

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