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Leptogenesis with scalar triplets and right handed neutrinos Anjan - - PowerPoint PPT Presentation

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Leptogenesis with scalar triplets and right handed neutrinos Anjan Giri IIT Hyderabad TAUP 2019 9 th September, 2019 Toyama, Japan Introduction Baryon asymmetry of the Universe (BAU) Why leptogenesis? See-saw and Leptogenesis

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Leptogenesis with scalar triplets and right handed neutrinos

Anjan Giri IIT Hyderabad

TAUP 2019 9th September, 2019 Toyama, Japan

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Introduction

  • Baryon asymmetry of the Universe (BAU)
  • Why leptogenesis?
  • See-saw and Leptogenesis
  • Many studies with symmetries A4, S4
  • We will focus here on S3
  • Summary
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  • When the BAU was generated?
  • Should not be before Inflation
  • But presumably before BBN
  • ---Inflation

100 GeV---- EW phase transition 1 MeV ---- BBN 3 K ---- Now

Why BSM is required

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BAU

  • SM: quarks, leptons, gauge bosons, and Higgs
  • Sakharov’s conditions (1967)

a) B number violation b) C and CP violation c) Out of equilibrium  Beyond the SM is required

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Leptogenesis

  • Generate lepton asymmetry by right handed ν (RHN) decays (CPV)
  • B violation required (L violation)
  • Thermal leptogenesis: Fukugita & Yanagida

Sphalerons

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R(D)- R(D*) puzzle

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EPS-HEP-2019

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S3 basics

  • S3- smallest discrete symmetry group
  • S3 contains one doublet irreducible repn. and two singlets

(The feature is useful to separate first two generation from the third)

  • S3 group has two generators (S and T)
  • S2 = T3= (ST)2 =1
  • possible realization: ω’= exp(i2/3)
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RHN

Type – I, II and III seesaw

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Particle Contents

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Type I+ II scenario

To explain neutrino phenomenology and leptogenesis

  • yi and yli are Yukawa couplings of neutral and charged leptons
  • MiR are the Majorana masses of the RHN
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Neutrino sector

  • To discuss the neutrino masses and mixings we consider type-I:
  • The light neutrino mass formula is given by the seesaw formula:
  • One can obtain the flavor structure for Dirac mass matrices for neutral

and charged leptons

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  • Extended Higgs sector contains 3 SU(2) scalar doublets and 2 triplets
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Higgs sector

  • To suppress the FCNC, non-SM Higgs to be very heavy (fine tuning)
  • Further, we consider the mixing
  • The stability conditions are:
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  • Diagonalization:
  • Similarly, for the type-I, we get
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The mass matrix in type-I+II is given by

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Leptogenesis: Scalar triplets

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* High Scale leptogenesis:

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`

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Low scale Leptogenesis: O(2 TeV)

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LFV and g-2

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Summary

  • Neutrino data & leptogenesis with S3
  • hint from B sector discrepancies
  • Is there any connection???
  • High scale and low scale leptogenesis scenarios
  • Future results to provide clarity
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Thank you

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Why Leptogenesis

  • At high temp >> 100 GeV
  • B and L violating processes (sphalerons)
  • If Baryon symmetry is produced by B-L conserving process then at the

end B=0 at equilibrium (by sphalerons)

  • So we need B-L violating process
  • It will work also by L violating process, like Majorana ν’s and 0νββ