Electroweak baryogenesis and scalar dark matter m>0 m>0 m>0 m=0 m>0 m>0 m>0 Jim Cline (McGill U.) in � ν isibles 13 Workshop, Durham IPPP, 19 July 2013 J.Cline, McGill U. – p. 1
Alternative to Vanilla Cosmology? Unfortunately vanilla cosmology does not tell us the origin of the the baryon asymmetry of the universe: n b = n p + n n − n ¯ p − n ¯ n ≡ η 10 × 10 − 10 n γ n γ 5 . 1 < η 10 < 6 . 5 (95% CL) • For many years, big bang nucleosynthesis (BBN) provided main constraint on the baryon asymmetry • Cosmic microwave background (CMB) now provides best measurement, consistent with BBN J.Cline, McGill U. – p. 2
BBN / WMAP determination of η 10 From PDG review http://pdg.lbl.gov/2012/reviews/ rpp2012-rev-bbang- nucleosynthesis.pdf J.Cline, McGill U. – p. 3
BBN / Planck determination of η 10 Planck Incorporating ω b from arXiv:1303.5076 (Planck 2013 Cosmological Parameters) J.Cline, McGill U. – p. 4
History of baryogenesis papers Affleck-Dine 6% Electroweak 36% BG + SUSY 6% "baryogenesis" papers 60 EWBG BG + dark matter 7% LHC 40 LEP ends 20 leptogenesis 767 baryogenesis = 806 0 1990 2000 2010 1985 1995 2005 year Electroweak baryogenesis (EWBG) is interesting because of its testability J.Cline, McGill U. – p. 5
EWBG in a nutshell • At critical temperature T c ∼ 100 GeV, bubbles of true vacuum ( � H � � = 0 ) form and start expanding. • Particles interact with wall in a CP violating way. • Baryon asymmetry forms inside the bubble. <H> = 0 〈 〉 <H> = v 〈 〉 L R baryon # L baryon conserved R violation by sphalerons J.Cline, McGill U. – p. 6
Needs new physics • Strongly 1st order EWPT, not present in SM; needs new fields coupling to Higgs • New source of CP violation near bubble wall, from complex, spatially varying fermion mass Only baryon violation by sphalerons is already present in SM J.Cline, McGill U. – p. 7
EWBG in MSSM has been tested Need m h < 127 GeV, m ˜ t R ≤ 120 GeV, m ˜ t L > 10 TeV, JC, Moore hep-ph/9806354; Carena, Quiros, Wagner 0809.3760 CP in µm 2 , light ∼ degenerate χ ± , χ 0 ✟ nearly maximal ✟ η 10 Contours of L E 5 P e x allowed c l u d e d JC, M. Joyce, K. Kainulainen, hep−ph/0110031 J.Cline, McGill U. – p. 8
EWBG in MSSM has been tested Carena, Quiros, Wagner hep-ph/0208043 are more optimistic: Disagreement with us about correct form of ✟ CP source in ✟ transport equations J.Cline, McGill U. – p. 9
LHC boosts interest in EWBG But no signs of SUSY yet. Two Higgs doublet models have been scrutinized – have several new CP-violating couplings: 2 v 2 � 2 + m 2 H † i H i − 1 1 ( S † i S i ) � V = λ ( m 2 2 H † i S i + h . c . ) + λ 1 ( H † i H i ) ( S † j S j ) + λ 2 ( H † i H j ) ( S † j S i ) + λ 3 H † i H † j S i S j + h . c . � � + λ 4 H † i S † j S i S j + λ 5 S † i H † j H i H j + h . c . + λ 6 ( S † i S i ) 2 � � + y t ¯ H 0 ∗ δ ti + ( η U δ ti + η ′ U V ∗ tb V bi ) S 0 ∗ � � q i + t L R (assuming minimal flavor violation (MFV) for new Yukawa couplings, JC, K. Kainulainen, M. Trott, arXiv:1107.3559) J.Cline, McGill U. – p. 10
EWBG in MFV 2HDMs Distribution of η B /η B, obs from Monte Carlo: mass full constraints: _ constraints Γ (Z → bb) R b = only Γ (Z → hadrons) EWPO, b → s γ, neutron EDM, Landau pole -4 -3 -2 -1 0 1 log η B / η obs JC, K. Kainulainen, M. Trott, arXiv:1107.3559 Only a few out of 10 4 models have large enough value! J.Cline, McGill U. – p. 11
Baryogenesis and dark matter There is significant recent interest in linking baryogenesis to dark matter. Much activity on simultaneous production of DM and baryon asymmetry (cogenesis), but I won’t cover this I will discuss how scalar dark matter can make EWBG more robust Work in collaboration with K. Kainulainen (also D. Borah, P. Scott and C. Weniger) J.Cline, McGill U. – p. 12
Inert Higgs Doublet Model A special case of 2HDMs, where the extra doublet S has Z 2 symmetry—does not couple to quarks or leptons. Lightest component of S is dark matter candidate Chowdhury, et al. , arXiv:1110.5334, noted that it can lead to strong electroweak phase transition, a necessary condition for EWBG D. Borah, JC, arXiv:1204.4722 revisited EWPT in IDM using full effective potential and particle physics constraints J.Cline, McGill U. – p. 13
IDM + EWPT is fine tuned Need m DM ∼ m h / 2 and λ DM ≡ λ 1 + λ 2 + 2 λ 3 ≪ λ i DM (S) λ DM h DM (S) λ DM is DM coupling to Higgs Much of parameter space with m DM < m h / 2 is ruled out by XENON100 and by Higgs invisible width constraint: BR ( h → SS ) < 19% Bélanger et al. , arXiv:1306.2941 J.Cline, McGill U. – p. 14
Fine tuning of λ DM in IDM Distributions of favorable parameter values: λ 1 λ 3 λ S λ 2 1.5 2 2.5 3 -2 -1.5 -1 -0.8 -0.6 -0.4 0 0.5 1 1.5 2 2.5 m DM m A m ± |λ DM | 0 0.02 0.04 0.06 60 62 64 66 200 250 300 200 250 300 Λ T c v c /T c log 10 σ SI 5e+03 1e+04 115 120 125 130 0.5 1 -47 -46 -45 -44 D. Borah, JC, arXiv:1204.4722 λ i like to be large to help give strong EWPT. Combination λ DM ≡ λ 1 + λ 2 + 2 λ 3 is tuned at the 2% level or worse J.Cline, McGill U. – p. 15
Solution to tuning: subdominant DM JC, K. Kainulainen, arXiv:1302.2614 Larger values of λ DM give smaller relic density n ∼ 1 /σ ann ∼ λ − 2 DM But direct detection signal scales as nλ 2 DM ∼ λ 0 DM − → can still have sizeable signal even if IDM dark matter is small fraction of total DM! λ DM DM DM h N N J.Cline, McGill U. – p. 16
Naturally large λ DM in IDM Distributions of favorable parameter values: JC, K. Kainulainen, arXiv:1302.2614 Combination λ DM ≡ λ 1 + λ 2 + 2 λ 3 is no longer tuned to be small J.Cline, McGill U. – p. 17
Subdominant DM is more likely Fraction f rel of full relic density versus m DM : JC, K. Kainulainen, arXiv:1302.2614 f rel may be as small as ∼ 10 − 3 , rarely O (1) J.Cline, McGill U. – p. 18
Subdominant DM is still discoverable Effective cross section on nuclei σ eff = σ SI × f rel � � σ SI = λ 2 DM f 2 µ 2 m 2 versus m DM : n 4 πm 4 h m 2 DM local DM density ) 2 1 0 2 ( uncertainty 0 0 1 N O N E X JC, K. Kainulainen, arXiv:1302.2614 Full parameter space will be ruled out by LUX or XENON1T J.Cline, McGill U. – p. 19
Maybe also discoverable at LHC New Higgs bosons A 0 and H ± must be relatively light: m < 340 GeV m A < 400 GeV ± ~ ~ H ± loop decreases γ BR ( h → 2 γ ) by ∼ 10 % v λ 1 h H ± γ (probably need ILC to detect it) JC, K. Kainulainen, arXiv:1302.2614 J.Cline, McGill U. – p. 20
Shortcomings of IDM + EWBG • Still relatively hard to get strong EWPT • We only explain EWPT, not mechanism of EWBG Singlet ( S ) dark matter can do better: • λ hs | H | 2 S 2 interaction gives potential barrier at tree-level − → strong phase transition Espinosa, Konstandin, Riva, arXiv:1107.5441 ( S can initially have VEV, unlike in IDM) • ( S/ Λ) 2 ¯ t L Ht R coupling can be new source of CP violation in top quark mass, allowing for EWBG J.Cline, McGill U. – p. 21
Potential barrier with singlet DM If λ hs coupling is large enough, there is barrier between H = 0 and S = 0 V vacua at T = 0 . v C Large λ hs leads again to EWPT S C H subdominant DM. S Small finite- T effects need only lift degeneracy of vacua. Strength of phase transition determined by tree-level potential. Analytic treatment of finite- T V eff is possible. J.Cline, McGill U. – p. 22
Subdominant singlet DM Scatter plot of models with strong EWPT: Models with v c / T c > 1 Allowed ) ( hs (λ < 1) hs (halo uncertainty) XENON100 JC, K. Kainulainen, arXiv:1210.4196 Relic density fraction is no more than 3%, yet direct detection already constrains parameter space J.Cline, McGill U. – p. 23
Direct detection with singlet DM Part of EWBG-favored parameter space is already excluded by XENON100: XENON100 local DM density uncertainty (λ < 1) hs hs Models with v c / T c > 1 JC, K. Kainulainen, arXiv:1210.4196 But much of the rest will be probed in the next 2 years! J.Cline, McGill U. – p. 24
Future detection of singlet DM Singlet DM will be probed to m S � 10 TeV by LUX, XENON1T in the near future JC, K. Kainulainen, P. Scott, C. Weniger, d e d u l c arXiv:1306.4710 x E J.Cline, McGill U. – p. 25
EWPT vs. direct detection XENON1T will exclude entire region shown here . . . JC, K. Kainulainen, P. Scott, C. Weniger, arXiv:1306.4710 J.Cline, McGill U. – p. 26
Resonant annihilation region . . . except for small sliver near m S = m h / 2 : allowed XENON100 (2012) × 5 Strong EWPT XENON100 × 20 XENON100 excluded by Allowed Relic density excluded Relic density excluded JC, K. Kainulainen, P. Scott, C. Weniger, arXiv:1306.4710 J.Cline, McGill U. – p. 27
Baryon asymmetry with singlet DM Dimension-6 operator ( S/ Λ) 2 ¯ t L Ht R with complex coefficient gives new source of CP violation for baryogenesis: η B / η B,obs Λ = 1 TeV @ or We get large enough Λ / 1 TeV ) 2 @ η B = η B,obs ( baryon asymmetry frequency much more frequently than in 2HDM. region of interest JC, K. Kainulainen, arXiv:1210.4196 J.Cline, McGill U. – p. 28
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