Baryogenesis and ParticleAntiparticle Oscillations Seyda Ipek UC - PowerPoint PPT Presentation

Baryogenesis and Particle—Antiparticle Oscillations Seyda Ipek UC Irvine SI, John March-Russell, arXiv:1604.00009

Sneak peek • There is more matter than antimatter - baryogenesis • SM cannot explain this • There is baryon number violation • Not enough CP violation • No out-of-equilibrium processes • CP violation is enhanced in particle—antiparticle oscillations • Can these oscillations play a role in baryogenesis? Seyda Ipek (UCI) 2

There is more matter than antimatter Ω Λ ∼ 0 . 69 Ω DM ∼ 0 . 27 Ω B ∼ 0 . 04 number of baryons: η = n B � n ¯ B n γ CMB ' 6 ⇥ 10 − 10 PDG Seyda Ipek (UCI) 3

How Fermilab produces its baryons 4 Seyda Ipek (UCI)

How the Universe would do Need to produce 1 extra quark for every 10 billion antiquarks! Sakharov Conditions Sakharov, JETP Lett. 5, 24 (1967) Three conditions must be satisfied: ✔ 1) Baryon number (B) must be violated can’t have a baryon asymmetry w/o violating baryon number! 2) C and CP must be violated ✘ a way to differentiate matter from antimatter 3) B and CP violating processes must happen out of equilibrium equilibrium destroys the produced baryon number ✘ Seyda Ipek (UCI) 5

We need New Physics Couple to the SM Extra CP violation Some out-of-equilibrium process Seyda Ipek (UCI) 6

Old New Physics First-order phase transition Extra scalar fields CP violation in the scalar sector 2HDM, MSSM, NMSSM, … Out-of-equilibrium decays Leptogenesis CP violation from interference of tree-level and loop processes Heavy right-handed neutrinos,… Asymmetry Asymmetry in the in the dark sector visible sector asymmetric dark matter + Affleck-Dine 7 Seyda Ipek (UCI)

We need New Physics Couple to the SM Let’s re-visit SM CP violation Extra CP violation Some out-of-equilibrium process Seyda Ipek (UCI) 8

CP Violation in Neutral Meson Mixing We see SM CP violation through neutral meson mixing B d − B d B s − B s K − K D − D • A few Nobel prizes Are particle—antiparticle • CKM matrix oscillations special for CP • Top quark violation? 9 Seyda Ipek (UCI)

Particle—Antiparticle Oscillations Take a Dirac fermion with an approximately broken U(1) charge − L mass = M ψ ψ + m 2 ( ψ c ψ + ψ ψ c ) Dirac mass Majorana mass with interactions − L int = g 1 ψ X Y + g 2 ψ c X Y + h . c . We will want the final state XY ψ : pseudo-Dirac fermion to carry either baryon or lepton number 10 Seyda Ipek (UCI)

Particle—Antiparticle Oscillations ✓ M ◆ m M = H = M − i m M Hamiltonian: 2 Γ ✓ 2 r e i φ Γ ◆ 1 Γ ' Γ 2 r e − i φ Γ 1 r = | g 2 | | ψ H,L i = p | ψ i ± q | ψ c i eigenvalues: | g 1 | ⌧ 1 mass states ≠ interaction states OSCILLATIONS! 11 Seyda Ipek (UCI)

Particle—Antiparticle Oscillations 1.0 important parameter: 0.8 1 / Γ 0.6 Probability x ≡ ∆ m Γ 0.4 1 / ∆ m 0.2 ∆ m = M H � M L ' 2 m 0.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 time Goldilocks principle for oscillations x � 1 x ⌧ 1 x ∼ 1 Too fast Just right Too slow Seyda Ipek (UCI) 12

CP Violation in Oscillations Z ∞ dt Γ ( / c → f ) − Γ ( / c → ¯ f ) ✏ = Γ ( / c → f ) + Γ ( / c → ¯ f ) 0 r = | g 2 | For | g 1 | ⌧ 1 10 - 1 r = 0 . 1 sin φ Γ = 0 . 5 10 - 2 ✏ ' 2 x r sin � Γ 1 + x 2 10 - 3 ϵ 10 - 4 exact CP violation is approximation 10 - 5 maximized for x ~ 1 10 - 4 10 - 2 10 4 1 100 x = 2m / Γ 13 Seyda Ipek (UCI)

CP Violation ✔ ✏ ' 2 x r sin � Γ 1 + x 2 Baryon Number Violation ✔ e.g. RPV SUSY Say the final state f has baryon number +1 g u d d ˜ Baryon asymmetry is produced due to oscillations and decays: n B − n ¯ B = ✏ n ψ 14 Seyda Ipek (UCI)

How to decay out of thermal equilibrium? Oscillations in the early Universe? 15 Seyda Ipek (UCI)

Oscillations in the early Universe are complicated 1 M ∼ 300 GeV 10 - 2 Rates H u ( eV ) b b 10 - 4 l e r a t e 10 - 6 Big Bang? 1 10 100 z = M / T Time 16 Seyda Ipek (UCI)

Oscillations in the early Universe are complicated 1 M ∼ 300 GeV 10 - 2 Rates H u ( eV ) b b 10 - 4 l e r a t e Decay rate Big Bang? 10 - 6 1 10 100 z = M / T Time Out-of-equilibrium decay: Γ . H ( T ∼ M ) 17 Seyda Ipek (UCI)

Oscillations in the early Universe are complicated 1 M ∼ 300 GeV Oscillations start when 10 - 2 ω osc > H Rates H u ( eV ) b b 10 - 4 l e r a t e ω osc = 2 m Decay rate Big Bang? 10 - 6 1 10 100 z = M / T Time Out-of-equilibrium decay: Γ . H ( T ∼ M ) 18 Seyda Ipek (UCI)

Oscillations in the early Universe are complicated Particles/antiparticles are − L scat = 1 in a hot/dense plasma Λ 2 ¯ ψ Γ a ψ ¯ f Γ a f with interactions Seyda Ipek (UCI) 19

Oscillations in the early Universe are complicated What if interactions can tell the difference between a particle and antiparticle? Quantum Zeno effect Oscillations delayed till ω osc > Γ ann , Γ scat Seyda Ipek (UCI) 20

Oscillations in the early Universe are complicated 1 M ∼ 300 GeV A Elastic scattering rate n n i h i 10 - 2 l a t i o n r a Rates t e H u ( eV ) b b 10 - 4 l e r a t e ω osc = 2 m Decay rate 10 - 6 Big Bang? 1 10 100 z = M / T oscillations are Time further delayed 21 Seyda Ipek (UCI)

Oscillations in the early Universe are complicated Described by the time evolution of the density matrix Vanishes if scatterings Oscillations are flavor blind zH d Y � Γ ± HY � YH † � � dz = � i 2 [ O ± , [ O ± , Y ]] ✓ 1 ◆ 2 { Y , O ± ¯ Y O ± } � Y 2 � s h σ v i ± eq H : Hamiltonian Annihilations Y : Density matrix z = M/T not redshift! O ± = diag(1 , ± 1) 22 Seyda Ipek (UCI)

Oscillations + Decays M = 300 GeV , Γ = 10 − 6 eV : particle asymmetry ∆ ( z ) ≡ Y ψ − Y ψ c m = 5 x 10 - 6 eV, 0.000014 Symmetric initial x = 10 m = 2 x 10 - 6 eV, conditions: ∆ (0) = 0 0.000012 x = 4 m = 0.25 x 10 - 6 eV, x = 0.5 0.00001 Oscillations are delayed 8. × 10 - 6 r = 0 . 1 Δ ( z ) for smaller m sin φ Γ = 0 . 5 6. × 10 - 6 4. × 10 - 6 2. × 10 - 6 Smaller asymmetry 0 0 10 20 30 40 50 z = M/T z ✓ ◆ ✓ ◆ Γ m sin 2 ∆ ( z ) = ✏ Y eq (1) exp − 2 H ( z ) 2 H ( z ) 23 Seyda Ipek (UCI)

Oscillations + Decays + Annihilations/Scatterings Two types of interactions flavor-blind flavor-sensitive ψ → ψ c : L → − L L → L e.g. scalar e.g. vector − L = 1 − L = 1 ψ γ µ ψ ¯ Λ 2 ¯ ψψ ¯ Λ 2 ¯ ff f γ µ f f Λ : interaction scale : (massless) fermion 24 Seyda Ipek (UCI)

Elastic scatterings/Annihilations delay oscillations Ignoring decays, particle asymmetry is given by d 2 ∆ ( y ) d ∆ ( y ) + ω 2 + 2 ξ ω 0 0 ∆ ( y ) = 0 y = z 2 dy 2 dy z = M/T ξ ≡ Γ S ann / Γ V ω 0 ≡ m scat yH , ∆ ( z ) ≡ Y ψ − Y ψ c 2 m overdamped, no oscillations ξ � 1 underdamped, system oscillates ξ < 1 25 Seyda Ipek (UCI)

Elastic scatterings/Annihilations delay oscillations flavor-sensitive interactions flavor-blind interactions ω osc = Γ scat ( z osc ) ω osc = Γ ann ( z osc ) when 100 oscillations 50 start z osc z osc 10 σ 0 = 1 fb σ 0 = 1 ab 1 10 - 6 10 - 4 10 - 2 1 z = M/T mass difference (eV) m ( eV ) 26 Seyda Ipek (UCI)

Oscillations + Decays + Annihilations/Scatterings : total number of particles Σ ( z ) ≡ Y ψ + Y ψ c M = 300 GeV 10 - 3 m − 2 × 10 − 6 eV Γ = 10 − 6 eV No annihilation 10 - 6 < σ v > = 10 - 2 ab sin φ Γ = 0 . 5 Σ ( z ) < σ v > = 1 ab r = 0 . 1 − 0 . 3 10 - 9 η 10 - 12 1 10 100 flavor-sensitive z = M/T z 27 Seyda Ipek (UCI)

Oscillations + Decays + Annihilations/Scatterings ✓ ◆ ✓ ◆ Γ m sin 2 ∆ ( z ) ' ✏ Y eq ( z osc ) exp � 2 H ( z ) 2 H ( z ) M = 300 GeV No annihilation 10 - 3 m − 2 × 10 − 6 eV < σ v > = 10 - 2 ab Γ = 10 − 6 eV < σ v > = 1 ab 10 - 6 sin φ Γ = 0 . 5 Δ ( z ) r = 0 . 1 − 0 . 3 10 - 9 Oscillations are delayed 10 - 12 Smaller asymmetry 1 10 100 z = M/T z 28 Seyda Ipek (UCI)

How about baryon asymmetry? 1 A Annihilations freeze-out n n i h i l z f ' 20 10 - 2 a t i o n r a H u t b e b 10 - 4 l e r Rates a t e ω osc ( eV ) 10 - 6 Decay rate 10 - 8 1 5 10 50 100 z = M / T 29 Seyda Ipek (UCI)

How about baryon asymmetry? 1 A Elastic scattering rate Annihilations freeze-out n n i h i l z f ' 20 10 - 2 a t i o n r a H u t b e Oscillations start b 10 - 4 l e r Rates a t e ω osc ( eV ) z osc ' 60 10 - 6 Decay rate 10 - 8 1 5 10 50 100 z = M / T 30 Seyda Ipek (UCI)

How about baryon asymmetry? 1 A Elastic scattering rate Annihilations freeze-out n n i h i l z f ' 20 10 - 2 a t i o n r a H u t b e Oscillations start b 10 - 4 l e r Rates a t e ω osc ( eV ) z osc ' 60 10 - 6 Decay rate Annihilations are Boltzmann suppressed 10 - 8 Γ ann ⌧ Γ 1 5 10 50 100 z = M / T Oscillate a few times Produce the baryon asymmetry ⌘ ' ✏ Σ ( z osc ) ⇠ 10 − 10 31 Seyda Ipek (UCI)