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

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 • Many studies with symmetries A 4 , S 4 • We will focus here on S 3 • Summary

Why BSM is required • 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

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

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

R(D)- R(D*) puzzle

EPS-HEP-2019

S 3 basics • S 3 - smallest discrete symmetry group • S 3 contains one doublet irreducible repn. and two singlets ( The feature is useful to separate first two generation from the third ) • S 3 group has two generators (S and T) S 2 = T 3 = (ST) 2 =1 • • possible realization: ω’= exp(i2  /3)

RHN Type – I, II and III seesaw

Particle Contents

Type I+ II scenario To explain neutrino phenomenology and leptogenesis • y  i and y li are Yukawa couplings of neutral and charged leptons • M iR are the Majorana masses of the RHN

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

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

Higgs sector • To suppress the FCNC, non-SM Higgs to be very heavy (fine tuning) • Further, we consider the mixing • The stability conditions are:

• Diagonalization: • Similarly, for the type-I, we get

The mass matrix in type-I+II is given by

Leptogenesis: Scalar triplets

* High Scale leptogenesis:

`

Low scale Leptogenesis: O(2 TeV)

LFV and g-2

Summary • Neutrino data & leptogenesis with S 3 • hint from B sector discrepancies • Is there any connection??? • High scale and low scale leptogenesis scenarios • Future results to provide clarity

Thank you

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 0 νββ