Electroweak baryogenesis and beyond the SM (1) Chang Sub Shin (IBS-CTPU) at Summer Institute 2019 (Sandpine) Aug 18 – Aug 23, 2019 Outline Implication of the baryon number for the Standard Model Ideas of baryogenesis during EW phase transition (including basic of thermal field theory) EWBG models, constraints and possible new directions Basics of elementary particle for baryogenesis Baryon (βαρύς: heavy) and Lepton (λε̟τός: thin, small) Baryon : made by (an odd number of) quarks e.g. proton , neutron Nucleon is heavy because of quark confinement by strong interaction (+uncertainty principle) 939.6 MeV 938.3 MeV 20000.5 MeV 1000 MeV qu ark (Baryon) Proton , Neutron gluon (Baryon) PHYSICAL REVIEW LETTERS 121, 212001 (2018) Lepton : e lementary fermion which does not feel Electron strong interaction e.g. electron, neutrino (Lepton) Helium atom Antiparticle Predicted by theory (unexpectedly) P.A.M. Dirac provides the relativistic Schrödinger equation for electron: “Dirac equation” % ! " # $ & 2 ', )* 2+) Solution to the Dirac equation yields / , - .% % The negative energy solution was interpreted as “Dirac sea”. Excitation of electron from the sea gives the “hole”, the effective particle with the exactly same mass but the opposite charge prediction of positron After the relativistic Quantum Field Theory (QFT) was developed, the correct interpretation of the hole was made as the anti-particle: equally elementary particle with the same mass but opposite quantum numbers (charges) It turns out that all charged particle has its own antiparticle (e.g. antiquark, antineutrino) Stability of atom ? Classical electrodynamics for the atom Quantum mechanics for the hydrogen atom 13.6 ?% eV Life time: ,:;<=;<> $ % 0@ A 0.016ns 5 As the same way, is the positronium stable? No! 0 0.12ns $ 139ns % % , 23 $ 6.8 eV45 MeV 6 , 2 3 ,7 2389 Then why is the atom stable? Stability of atom ? An atom is made by baryons and leptons . BC 1, DC 0 B7 D7 0 B 0, D 1 If baryon number and lepton number are conserved , annihilation between the proton and electron is forbidden. Each particle is also stable: proton is the lightest baryon, electron is the lighted charged lepton. Atom is stable! Baryon/Lepton number conservation is essential for life. List of baryon/lepton number Notation: for a particle, , its antiparticle is denoted as (q: quark, l: lepton) & &E FFFG H HII J K- LM N B 143$143 0 0 0 0 0 0 D 0 0 1 $1 0 0 0 0 OPQ 243, $243, 0 0 0 1, $1 0 0 $143 143 R, SR G,,S SGG T, UT E,UG VM V- WM WGM B 1$10 0 0 0 1$1 D 0 0 1 $1 0 0 0 0 OPQ 1,0 $1,0 $1,0 1,0 0 1,$1 0 0 There is NO observed event that violates baryon and lepton number conservation Discrete spacetime (pseudo) symmetry Is there other symmetry of the theory ? fermions have the spin angular momentum ( ) XY -Z42 X[ X[ ^_ ^E_ X[" .[ .[ deeiciti ^E` ^` j.j X[ X[ C : Charge conjugation ( Q ) : Q 6 $O 6 $O, .[6 .[, X[6 X[ P : Parity ( ) : Q \[6 $\[ 6 O, .[6 $.[, X[6 X[ T : Time reversal ( ) : Q ] 6 $] 6 O, .[6 $.[, X[6 $X[ k b ^_ a ^E_ a a bc c c b ^` a ^E` e.g. Einstein, Maxwell, Dirac equation (so theory) is invariant under the C, P, and T. However the Standard Model is not invariant under the C, P, and T transformation. Evidence of matter-antimatter asymmetry At the present Universe matter + antimatter fast annihilation into energetic photons .I, 5E, I l ., 5, l Earth is made by matters (not antiatom, antimolecule) Sun is made by matters. No observation of antimatter comet in the solar system No evidence of gamma ray burst between two galaxy induced by intergalactic plasma Solar wind: energetic electrons, protons The early Universe The Universe was extremely hot ( %) in the beginning. All particles and antiparticles mk n o3 form thermal plasma. As the temperature decreases (cool down) and becomes %, mk p o3 most of particles and antiparticles with the mass ( ) are annihilated away o HOT Cold e.g. for HOT k n q rq 1066282st6 5 rqE 1066282st63 r7 1t22t600201 . .I 6 I 6 for k p C wx v rq 2 u r7 y wx v rqE 0 u r7 y r7 3555025512s Cold rq u 1 6 u 10 vz{ r7 Big Bang Nucleosynthesis (BBN) Light nuclei ( ) in the Universe were made between and . 1 sec 10 |sec Input rq4r7 ,:;<= 2.2 MeV € }C ~ • •4•q Annual Review of Nuclear and Particle Science, 60:539-568, 2010 Big Bang Nucleosynthesis (BBN) Light nuclei in the Universe were made between and : primordial abundance 1 sec 10 |sec The final abundances of them are sensitive to the initial baryon abundance . Observation of primordial light nuclei can predict the value of baryon asymmetry around ! 1 sec The larger the nucleon density, the higher the temperature at which nucleosynthesis began, and so the less time there was for neutron decay before nucleosynthesis, leading to a higher final 4He abundance. The higher the baryon density, the more complete will be the incorporation of neutrons into 4 , and hence the smaller the resulting He abundance of deuterium. [Weinberg , Cosmology] Cosmic Microwave Background (CMB) As the temperature becomes lower than the atomic energy ( ), nucleons and k ueV electrons are bound and form atoms. Photons are decoupled and freely propagate : CMB •7 6 b •I7 % % % 3 m m & 0 gravitational potential from Dark Matter PLANCK Satellite 1 3 / 3 1 3• q4t• 7 k 2.s K Δk u10 v k Cosmic Microwave Background (CMB) Baryon abundance is mostly determined by the heights of odd ( ), 3m]• 25 1• and even ( ) peaks 3m]• 25• 1 & ]• & % $ 2 cos3m]• $ % 3 3 100 (a) Curvature (b) Dark Energy 80 K) 60 m ( T D 40 Δk 20 Wtot WL PLANCK 2013 k 0.2 0.4 0.6 0.8 1.0 0.2 0.4 0.6 0.8 100 (c) Baryons (d) Matter •q 80 ‘ ~ • ’ K) 60 m ( T D 40 20 Wbh2 Wmh2 0.02 0.04 0.06 0.1 0.2 0.3 0.4 0.5 10 100 1000 10 100 1000 l l Hu, Dodelson , Ann.Rev.Astron.Astrophys.40:171 - Cosmic Microwave Background (CMB) Consistent with the value from the BBN! 100 (a) Curvature (b) Dark Energy 80 K) 60 m ( T D 40 20 Wtot WL 0.2 0.4 0.6 0.8 1.0 0.2 0.4 0.6 0.8 100 (c) Baryons (d) Matter % •q % ‘80 8 ~ 8 • ’ K) 60 m ( T D 40 20 Wbh2 Wmh2 0.02 0.04 0.06 0.1 0.2 0.3 0.4 0.5 10 100 1000 10 100 1000 l l Hu, Dodelson , Ann.Rev.Astron.Astrophys.40:171 - Baryo-genesis If the baryon asymmetry exists at the early Universe, , as vz{ , k MeV 1sec 5q 6 ” 10 57 the abundance of light nuclei and the shape of the CMB angular power spectrum, and non- observation of anti star, anti galaxy are all explained consistently. • $ •G ” M vM N What is the origin of this asymmetry? Is this just an initial condition of the Universe? Is there any dynamical mechanism for ? r•q 0 6 r•q – 0 Baryon number is the good quantum number for as we observed. BUT it should be 0— – 1sec strongly broken at the early Universe 0— 1sec Big Bang/ rq rqE rq 0 rq rqE rq 0 Inflation rq 0 vz{ 1sec 10 iear 10 sec 10 iear Possibility of baryogenesis in the SM Just an initial condition? It is commonly accepted that there is super accelerating period of the Universe. All previous abundance of any particles, asymmetries are diluted away. A new way to generate the asymmetry after inflation is necessary. The Sakharov’s conditions JETP Lett. 5, 24 (1967) In order to generate the asymmetry ( / ) of the Universe from to rq ~ ¡ B¡r¡ rq 0 B— – 0 1) Baryon number violation: For some initial, final states with different baryon numbers, , . B¢ B£ ¤ 6 ¥ 0 If , any process gives , so that . No generation ¦ 6 ¥ 0 ΔB 0 rq 0 2) C and CP violation: for ¤ 6 ^_ § ¤¨I 6 ^E_ ©ª ^E` §G r¢ r«I If the baryon number violating process preserves Charge conjugation, , Therefore . r¬• r¬E• r¬® r¬E® rq B¬• B¬® B¬E• B¬E® B¬• B¬® $ B¬• $ B¬® 0 Even if C is violated, if CP is conserved, , Therefore . r¬• r¬E® r¬® r¬E• rq B¬• B¬® B¬E• B¬E® B¬• B¬® $ B¬® $ B¬• 0 3) B-violating interactions out-of-thermal equilibrium: ¤ 6 ¥ y ¤¥ 6 y If the baryon number violating process is in thermal equilibrium, z v³¯4y z vz v³¯4y b r¯q Tr r¯q Tr bck bck r¯q ^_ a ^E_ °± °± a z v³¯4y vz = z v³¯4y a Tr bck r¯q bck $ Tr r¯q 0 bc °± °± c c We used . Any generated asymmetry is washed out. bck , •¯ 0 In other words, if CPT is broken as , b •¯ 6 •¯{ ´qr¯q r¯q µ ´q ^` a ^E` In the Standard Model ? How can we check Sakharov’s conditions in the SM? In the framework of QFT , the evolution of the Universe can be described by the Lagrangian density ¶\ 1 % ¶ ·¸ ¶¹º Δ¶q¹º 2 gluons, weak bosons, photons ¶¹º Higgs quark, lepton kinetic terms quark, lepton, Higgs Yukawa ints There is the possibility to satisfy Sakharov’s three conditions B violation in the SM 1) Baryon number seems conserved in the SM (stability of the atom), but not exactly.