The serendipity of EW baryogenesis Géraldine SERVANT DESY/U.Hamburg Higgs Cosmology workshop, Kavli Royal Society Centre, March 28 2017 DESY
Aim: Exploring the cosmological interplay between Flavour dynamics and EW baryogenesis A rich programme ● Effect of varying Yukawas on EW phase transition Baldes, Konstandin, Servant, 1604.04526 ● Implementation in Froggatt-Nielsen Baldes, Konstandin, Servant, 1608.03254 ● Natural realisation of Yukawa variation in Randall-Sundrum Von Harling, Servant, 1612.02447 ● Calculation of baryon asymmetry in models of variable Yukawas Bruggisser, Konstandin, Servant, to appear 2
Matter Anti-matter asymmetry of the universe η = n B − n ¯ B ≡ η 10 × 10 − 10 n γ R R : 5 . 7 ≤ η 10 ≤ 6 . 7 (95%CL) 3
remains unexplained within the Standard Model η double failure: - lack of out-of-equilibrium condition - so far, no baryogenesis mechanism that works with only SM CP violation (CKM phase) proven for standard Gavela, P. Hernandez, Orloff, Pene ’94 EW baryogenesis Konstandin, Prokopec, Schmidt ’04 attempts in cold EW Tranberg, A. Hernandez, Konstandin, Schmidt ’09 baryogenesis Brauner, Taanila,Tranberg,Vuorinen ’12 4
Baryogenesis at a first-order EW phase transition [image credit:1304.2433] 5
Baryon asymmetry and thf EW scale Kuzmin, Rubakov, Shaposhnikov’85 Cohen, Kaplan, Nelson’91 1) nucleation and expansion of bubbles of broken phase 2) CP violation at phase interface responsible for mechanism of charge separation broken phase < Φ > ≠ 0 3) In symmetric phase ,< Φ >=0, very active sphalerons convert chiral Baryon number asymmetry into baryon asymmetry is frozen Chirality Flux CP in front of the wall Q Q H U U Electroweak baryogenesis mechanism relies on a first-order phase transition satisfying h Φ ( T n ) i & 1 T n 6
The Electroweak Baryogenesis Miracle: Esph φ ( T ) Γ ws = 10 − 6 T e − T v - 6 - 4 - 2 2 4 6 Broken Symmetric 7
The Electroweak Baryogenesis Miracle: Esph φ ( T ) Γ ws = 10 − 6 T e − T v η B ∼ Γ ws µ L L w g ∗ T 00 M ∼ δ CP L w ∼ 1 µ L ∼ M L 2 T w T B ∼ 10 − 6 δ CP η B ∼ Γ ws δ CP ∼ 10 − 8 δ CP g ∗ L w T 2 g ∗ All parameters fixed by electroweak physics. If new CP violating source of order 1 then we get just the right baryon asymmetry. 8
Objective # I Strong 1st-order EW phase transition 9
first-order or cross over ⤵ V � Φ �� v 4 V � Φ �� v 4 → T 0.02 0.01 0.0075 0.01 0.005 Φ � GeV � 0.0025 50 100 150 200 250 300 Φ � GeV � � 0.01 50 100 150 200 250 300 � 0.0025 � 0.02 � 0.005 In the SM, a 1rst-order phase transition can occur due to thermally generated cubic Higgs interactions: V ( φ , T ) ≈ 1 h + cT 2 ) φ 2 + λ 2( − µ 2 4 φ 4 − ET φ 3 − ET φ 3 ⊂ − T � Sum over all bosons which couple to the Higgs m 3 i ( φ ) 12 π i � � ≃ In the SM: not enough i W,Z for M H > 72 GeV, no 1st order phase transition In the MSSM: new bosonic degrees of freedom with large coupling to the Higgs Main effect due to the stop 10
The most common way to obtain a strongly 1st order phase transition by inducing a barrier in the effective potential is due to thermal loops of BOSONIC modes. One adds new scalar coupled to the Higgs I. Thermally H BEC L Driven Effective Potential @ V eff D + H -m 2 + c T 2 L h 2 - T H h 2 L 3 ê 2 + h 4 Very constrained by LHC ! Katz, Perelstein ’14 Higgs Field @ h D Driven A strong 1st order PT leads to sizable deviations in hgg and eff D h ƔƔ couplings and therefore in Higgs production rate and 2 4 6 decays in ƔƔ e.g: Light stop scenario in Minimal @ h D Supersymmetric Standard Model 11
The (former) EW baryogenesis window in the Minimal Supersymmetric − → Standard Model: A Stop-split supersymmetry spectrum γ ~ f from EDM bounds ~ ~ 10 TeV t , f ~ f f χ 0 L 1,2 s from Higgs mass bound g g i h y b d d n e a d u s t l c n x e e m e s r e u h s c a r e a m e s p o t s 1 TeV γ see 1207.6330 χ λ 3 γ h, H, A ~ ~ 0 h , t , h , λ R u,d 1,2 0.1 TeV for sufficient CP for strong 1st order ∝ Im ( µM 2 ) violation phase transition The light stop scenario: testable at the LHC bounds get relaxed when adding singlets or in BSSM 12
〉 〈 Higgs mass measurement does not constrain the nature of the EW phase transition Easily seen in effective field theory approach: Add a non-renormalizable Φ 6 term to the SM Higgs potential and allow a negative quartic coupling h | Φ | 2 − λ | Φ | 4 + | Φ | 6 V ( Φ ) = µ 2 Λ 2 “strength” of the transition does not rely on the one-loop thermally generated negative self cubic Higgs coupling 2000 complete one-loop potential 〈 φ n 〉 Tn 1750 strong enough for EW baryogenesis 1500 if Λ 1.3 TeV � Λ (GeV) 1250 1 2 3 1000 4 region where EW phase 750 transition is 1st order 500 250 Grojean-Servant-Wells ’04 Delaunay-Grojean-Wells ’08 125 150 175 225 250 275 100 200 13 m h (GeV)
but Typically large deviations to the Higgs self-couplings + 6 v 3 where µ = 3 m 2 L = m 2 2 H 2 + µ 3! H 3 + η 4! H 4 + ... 0 H H Λ 2 v 0 + 36 v 2 η = 3 m 2 0 H Λ 2 v 2 0 The dotted lines delimit the region for a strong 1rst order phase transition deviations between a factor 0.7 and 2 at a Hadron Collider at an e 14
The easiest way: Two-stage EW phase transition e.g 1409.0005 example: the SM+ a real scalar singlet V 0 = � µ 2 | H | 2 + λ | H | 4 + 1 S S 2 + λ HS | H | 2 S 2 + 1 2 µ 2 4 λ S S 4 . p S has no VEV today: no Higgs-S mixing-> no EW precision tests , tiny EW preserving g modifications of higgs couplings at colliders min. Poorly constrained V ( H, S ) EW broken min. -> Espinosa et al, 1107.5441 from F. Riva see also Cline et al 15
Another easy way to get a strong 1st-order PT: dilaton-like potential naturally leads to supercooling Konstandin Servant ‘11 not a polynomial V = V ( σ ) + λ v 2 4( φ 2 − c σ 2 ) 2 c = h σ i 2 Higgs vev controlled by dilaton vev (e.g. Randall-Sundrum scenario) V ( σ ) = σ 4 ⇥ f ( σ ✏ ) ( a scale invariant function modulated by a slow evolution through the term σ ✏ for | ε |<<1 similar to Coleman-Weinberg mechanism where a slow Renormalization Group evolution of potential parameters can generate widely separated scales Nucleation temperature can be parametrically much smaller than the weak scale 16
Deconfining phase transition Quarks/gluons that are confined in the broken phase induce a difference in free tunnel? energy between the two phases Creminelli, Nicolis, Rattazzi’01 Nardini,Quiros,Wulzer’07 Randall, Servant’06 Konstandin,Nardini,Quiros’10 Hassanain, March-Russell, Schwellinger’07 Konstandin,Servant’1 17
sorry, notation switched from to μ V ( µ ) = µ 4 P (( µ/µ 0 ) � ) . Konstandin Servant ‘11 σ The position of the maximum μ + and of the minimum μ - can be very far apart in contrast with standard polynomial potentials where they are of the same order 0.16 y λ ( µ 2 − µ 2 0 ) 2 + 1 Λ 2 ( µ 2 − µ 2 0 ) 3 polynomial Goldberger-Wise for ε =0.2 0.14 0.12 4 V( µ) / TeV 0.1 0.08 0.06 0.04 0.02 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 µ / TeV position of the maximum √ µ + µ − � µ − . The tunneling value can be as low as μ r 18
Baryogenesis from strong CP Application: violation and the QCD axion EW field strength a ( t ) F ˜ A coupling of the type ~ F 2 f a will induce from the motion of the axion field a chemical potential for baryon number given by ∂ t a ( t ) f a This is non-zero only once the axion starts to oscillate after it gets a potential around the QCD phase transition. Time variation of axion field can be CP violating source for baryogenesis if EW phase transition is supercooled Servant, 1407.0030 Cold Baryogenesis requires a coupling between the Higgs and an additional light scalar: testable @ LHC & compatible with usual QCD axion Dark matter predictions 19
Cold Baryogenesis main idea: During quenched EWPT, SU(2) textures can be produced. They can lead to B-violation when they decay. Turok, Zadrozny ’90 Lue, Rajagopal, Trodden, ‘96 ∆ B = 3 ∆ N CS . Garcia-Bellido, Grigoriev, Kusenko, Shaposhnikov, ’99 Tranberg et al, ’06 N CS vacua sphaleron gauge dressing by thermal fluctuations by classical dynamics N H Higgs winding by classical dynamics 20
Requirements for cold baryogenesis 1) large Higgs quenching to produce Higgs winding number in the first place 2) unsuppressed CP violation at the time of quenching so that a net baryon number can be produced 3) a reheat temperature below the sphaleron freese-out temperature T ~ 130 GeV to avoid washout of B by sphalerons can occur during supercooled EW phase transition, 1407.0030 21
LHC constraints on the scale of conformal symmetry breaking (dilaton) LHC TEV LEP 2000 VEV of dilaton 1000 f [ GeV ] model A LHC 500 200 LHC model B 100 0 200 400 600 800 1000 m � [ GeV ] [1410.1873] 22
Summary of this part SM+ 1 singlet scalar: the most minimal and easiest way to get ● a strong 1st order EW phase transition Dilaton-like potentials: a class of well-motivated and naturally ● strong 1st order phase transitions, with large supercooling 23
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