Why is there something rather than nothing Why is there something rather than nothing? Baryogenesis and leptogenesis Krzysztof Turzyński Institute of Theoretical Physics Faculty of Physics, University of Warsaw

Early natural philosophy Leibniz, 1697 Nothingness is spontaneous, while an existing Universe must have required work to form. Swinburne Nothingness is uniquely natural, because simpler than anything else.

Outline Rudiments Electroweak baryogenesis Baryogenesis through leptogenesis Leptogenesis vs neutrino and other experiments M. Olechowski, S. Pokorski, K. Turzyński, J.D. Wells, “Reheating Temperature in Gauge Mediated Models of Supersymmetry Breaking”, JHEP 0912 (2009)

The paradigm observations consistent with hot Biga Bang • nucleosynthesis (T1MeV) ligt element abundances • decoupling of radiation (T1eV) power spectrum of the cosmic microwave background BBN: im mniej barionów, tym później fotony nie są w stanie efektywnie rozbijać jąder deuteru, tym później rozpoczyna się cykl reakcji jądrowych, ale do tego czasu rozpadnie się więcej neutronów -> mniej He CMB: Im więcej barionów, tym większy potencjał grawitacyjny nakłada się na zaburzenia DM I przeciwdziała rozrzedzaniu zaburzeń w płynie barionowo-fotonowym -> niski drugi pik w CMB details of both processes depend on relatice densities of baryons and photons

The number WMAP+BAO+SNe BBN after Davidson et al., 0802.2962 WMAP+BAO+SNe BBN • corresponds to 20 000 000 001 quarks vs 20 000 000 000 antiquarks – small ! Mozna tez wyznaczac z CMB przy zalozeniu LambdaCDM i spektrum HZ

The number WMAP+BAO+SNe after Davidson et al., 0802.2962 WMAP+BAO+SNe • corresponds to 20 000 000 001 quarks vs 20 000 000 000 antiquarks – small ! • too big for a fluctuation in the matter-antimatter symmetric Universe

A few equations metrics of the Universe Friedmann equation continuity equation input from particle physics equation of state

History of a particle species Photons of avg energy T cannot create efficiently create particles of mass >T Universe too rarefied for the massive particles to meet at all 1

interaction rate > expansion rate

Sakharov conditions Conditions necessary for dynamical generation of a nonzero baryon number in the initially matter-antimatter symmetric Universe. 1 B violation 2 C and CP violation 3 departure from thermal equilibrium

Sakharov conditions Remark 1. Any quantum number will do L, B – L, B + L ... Remark 2. If B violating interactions are even back to equilibrium, they completely wash out previously generated asymmetry.

CP in the Standard Model daL ubL W+ ig2Vab daL ubL W– C daR ubR W– ig2Vab* daR ubR W– ig2Vab CP 

Sphaleron field configurations locally maximizing energy Sphalerons Sphaleron field configurations locally maximizing energy V  DB=3 DL=3 B – L conserved B + L violated Tunelling between vacua in equilibrium for 1012GeV > T > Tew 

Electroweak phase transistion T>>Tc T<<Tc  V T<<Tc T>>Tc V   

Bubble wall allows more quarks than antiquarks inside A bubble of broken phase forms. It expands rapidly, coallescing with other bubbles. Eventually the entire Universe sits inside a bubble of broken phase. Bubble wall allows more quarks than antiquarks inside You are here phase of broken symmetry Remaining antiquarks are destroyed in sphaleron transitions phase of unbroken symmetry

Sphalerons B+L=0 L Sphaleron transitions • conserve B–L • wash B+L out B–L=const Sphaleron transitions • conserve B–L • wash B+L out L asymmetry is reprocessed into B asymmetry

Neutrino masses 1. Oscillations 2. Tritium decay 3. Cosmology (CMB vs LSS) WMAP WMAP+BAO+SNe WMAP+BAO+Sne+HST+MegaZ after Thomas et al, 0911.5291

Fermion interacting with a spinless particle changes helicity. Neutrino masses L R Fermion interacting with a spinless particle changes helicity. Interactions with a constant vacuum expectation value of a scalar field => mass: Higgs mechanism

Neutrino masses L R R= R L two possibilities Dirac particle R – new state – sterile neutrino (not interacting with W,Z0) only SM states – but lepton number broken (so what?) Dirac particle Majorana particle

Neutrino masses L R= R NR NL= NL seesaw mechanism – 2 possibilities in 1 L R= R NR NL= NL N: singlet of SU(2), fermion (Type I) triplet of SU(2), skalar (Type II) triplet of SU(2), fermion (Type III) m= (MEW)2 / MBig MN = MBig

Generating L asymmetry genation washout generatione washout

Generating L asymmetry CP violation

Generating L asymmetry Equilibrium (in N production) > Fast production processes => equilibrium distribution for RH neutrinos Strong washout:

Generating L asymmetry Out of equlibrium (N decay)

Generowanie asymetrii w L

Summary I The origin of the baryon asymmetry of the Universe remains a mystery. Different options are still possible, but some have already been ruled out. Leptogenesis appears a reasonably natural option

Leptogenesis vs low-energy CP violation CP asymmetry relevant for leptogenesis Neutrino Yukawa couplings ? CP asymmetry potentially observable in terrestrial experiments

CP violation: from low to high energies There are only low-energy (Dirac and Majorana) phases Branco, Gonzalez Felipe & Joaquim, 2006

CP violation: from low to high energies SUSY enters the game: in mSUGRA models additional constraints from LFV processes and electron EDM Joaquim, Masina & Riotto, 2006

CP violation: from high to low energies Davidson, Garayoa, Palorini & Rius, 2008 Markov chain Monte Carlo analysis phase 1 phase 2 Does successful leptogenesis prefer any values of the low-energy CP phases in the neutrino sector?

Summary II The origin of the baryon asymmetry of the Universe remains a mystery. Different options are still possible, but some have already been ruled out. Leptogenesis appears a reasonably natural option Alas, not testable! Generically requires T>109 GeV. In SUSY models this leads to overproduction of gravitinos, ruining nucleosynthesis