Testing the Electroweak Baryogenesis at the LHC and CEPC

Transcription

1 Testing the Electroweak Baryogenesis at the LHC and CEPC Fa Peng Huang based on the works of arxiv : 1511.xxxxx with Xinmin Zhang, Xiaojun Bi, PeiHong Gu and PengFei Yin and Phy.Rev.D92, (2015)(arXiv : ) with Chong Sheng Li The mini-workshop at IHEP Oct 19, 2015

2 Testing the Electroweak Baryogenesis at the LHC and CEPC Fa Peng Huang based on the works of arxiv : 1511.xxxxx with Xinmin Zhang, Xiaojun Bi, PeiHong Gu and PengFei Yin and Phy.Rev.D92, (2015)(arXiv : ) with Chong Sheng Li The mini-workshop at IHEP Oct 19, 2015

3 Outline Motivation Electroweak baryogenesis in a nutshell scenario I scenario II Conclusion

4 Motivation Baryogenesis How to explain the baryon asymmetry of the universebaryogenesis η = n B n γ = n b b b n γ = 6.05(7) (CMB)(Planck) η can be determined from the CMB or BBN.

5 Baryogenesis Sakharvov Conditions Sakharov Conditions for baryogenesis (1967) violation of baryon number create baryonic charge; CP-violation and C violation distinguish matter from antimatter; departure from equilibrium dynamics or CPT violation provide a time arrow.

6 Baryogenesis Sakharvov Conditions in SM anomaly in B + L-current; C-violation (chiral gauge) CP-violation in KM matrix or extension of SM; First-order EWPT with expanding bubble walls.

7 B-violation in SM Sphaleron Process Phys.Lett.B266(1991) Sphalerons in the two doublet Higgs model Pecci, Zhang and Kastening Phys.RevD45, 8(1992) QCD sphalerons at high temperature and baryogenesis at the electroweak scale Rabindra N. Mohapatra and Xinmin Zhang

8 CP-violation The anomalous top coupling may provide the CP-violation source for baryogenesis. The current data still leave room for this source. Top quark decay via flavor changing neutral currents at hadron colliders, Tao Han, R.D. Peccei, X. Zhang. Nucl.Phys. B454 (1995) Nonstandard couplings of the top quark and precision measurements of the electroweak theory R.D. Peccei, S. Peris, X. Zhang. Nucl.Phys. B349 (1991) Dynamical Symmetry Breaking and Universality Breakdown R.D. Peccei, X. Zhang. Nucl.Phys. B337 (1990) CP-violation FCNC process Yan Wan, Fa Peng Huang,et,al. Phys. Rev. D86, (2012)

9 Departure from equilibrium dynamics Strong First Order Phase Transition Unravel the essence of the electroweak phase transition or the true potential of the Higgs field is the leading goal of the CEPC as shown in Nima s outlook talk for CEPC.

10 Electroweak baryogenesis scenario This electroweak baryogenesis can be tested at CEPC?

11 Implications on Electroweak baryogenesis for 125 GeV Higgs boson The discovery of the Higgs boson opens the door for studying the scalar sector of the SM(the Higgs potential), which can help us to understand the true mechanism of the electroweak phase transition and the origin of baryon asymmetry of the universe. The eletroweak baryogenesis becomes a particularly timely, interesting and testable scenario to explain the baryon asymmetry of our universe. However, the 125 GeV is too heavy for eletroweak baryogenesis. Any Extension of the Higgs sector is needed to be discussed.

12 Scenario I we follow the effective Lagrangian approaches to investigate the EWB in JCAP 1201 (2012) 012, L = L SM µs µ S µ2 S λs4 1 2 κs2 (Φ Φ) (1) + y t η Λ S Q L ΦtR + H.c. where η = a + ib is a complex parameter, S is a very light singlet scalar particle beyond the SM, λ and λ SM are assumed to be positive here. based on the works of the Phy. Rev D 92, (2015)( arxiv: ) Fa Peng Huang, Chong Sheng Li

13 Scenario I The full finite-temperature effective potential up to one-loop levlel V eff (H, σ, T ) = V tree (H, σ) + V T =0 1 (H, σ) + V T 0 1 (H, σ, T ), V1 T =0 (H, σ) is the Coleman-Weinberg potential; and V T 0 1 (H, σ, T ) is the leading thermal correction. Using the high-temperature expansion up to O(T 2 ), V eff = D H (T 2 T 2 0H )H2 +D σ (T 2 T 2 0σ)σ (λ SMH 4 +κh 2 σ 2 +λσ 4 ), D H = 1 32 (8λ SM + g 2 + 3g 2 + 4y 2 t + 2κ), D σ = 1 24 (2κ + 5λ + 6g 2 2 ),

14 Scenario I The condition of the SFOPT is v(t c ) T c 1 (2) By observing the vacuum structure of the Higgs sector at zero temperature, we find that µ 2 = µ 2 SM G 2λ SM (1 + δ µ 2), λ = ( G 2λ SM ) 2 λ SM (1 + δ λ ) will produce SFOPT.

15 Scenario I Here, the phase transition critical temperature is T c m H δλ 2δ µ 2 2, (3) D h D σ and the washout parameter is given by v(t c ) 2 DH D σ v T c m H δλ 2δ µ 2 (4)

16 Scenario I As long as δ λ 2δ µ 2 << 1, v(t c )/T c > 1 and the SFOPT can be realized.

17 κ Scenario I Higgs invisible decay L H SS = κ Φ S2 H, (5) 4 Γ inv (H SS) = κ2 Φ 2 1 4m2 S 32πm H m 2 κ2 Φ 2. (6) H 32πm H Γ inv /MeV We expect precise width of Higgs invisible decay at CEPC to obtain more straight constraints of κ.

18 Scenario I η B = 405Γ sph 4π 2 v σ g T dz µ BL f sph e 45 Γ sph z /(4v σ ), (7) σ/λ v c /T c

19 Scenario I g t S The numerical calculation gives d n e = (22 ± 10) abv 2 Λ cm. (8) d n e < cm, (9) Combining the numerical prediction and the experimental bound, we obtain the constraints on the NP scale Λ: Λ > [229, 374] ab GeV. (10)

20 Scenario I Constaints from LHC σ(pp MET + jet) < 6.1 fb, (11) Table: Sample results of the 95% C.L. lower limits on the NP scale Λ from the CMS analysis [?]. m S (GeV) Λ (GeV) for a = b = 1 at 8 TeV LHC [?]

21 conclusion of scenario I The dimsion-5 effective Lagrangian is introduced to explain the eletroweak baryogesis. Both the SFOPT and the CP-violation source can be provided. The constraints from the LHC and neutron EDM are discussed.

22 Scenario II Follow xinmin zhang s early work in 90, δl = (a + ib) ϕ ϕ Λ 2 q L ϕt R + H.c. κ Λ 2 (ϕ ϕ) 3, (12) arxiv:1511.xxxxx with Xinmin Zhang, Xiaojun Bi, PeiHong Gu and PengFei Yin(work in progress)

23 Scenario II V tree (h) = 1 2 µ2 h 2 + λ 4 h4 + κ 8Λ 2 h6. (13) V eff (h, T ) 1 ( µ 2 + c T 2) h 2 + λ 2 4 h4 + κ 8Λ 2 h6. (14) The finite temperature effects are in c = 1 16 (4y t 2 + 3g 2 + g m2 h 2 v 2 12κv ), (15) Λ2 To keep the observed m h and vev v, λ and µ 2 should be changed as λ ( = m2 h 2v 2 µ 2 = m2 h 2 1 Λ2 max, (16) ( ) Λ 2 max 1, (17) 2Λ 2 Λ 2 )

24 Scenario II µ T c = 2 λ 2 Λ 2 c 1, (18) 4µ 2 v(t c ) T c = c λ 2 1 4µ2 λ 2 Λ 2. (19)

25 Scenario II In order to guarantee the SFOPT, it needs µ 2 + ct 2 > 0, λ < 0 and the h 6 term to stabilize the EW-broken vacuum, namely Λ < Λ max = 3κv 2 /m h 840GeV when κ = 1. From the requirements of perturbativity, κ < 4π. If we choose a larger κ, we can get a larger upper bound Λ max. For example, if κ = 12.5, then Λ max = 3 TeV. T c > 0 gives the lower bound of Λ min = Λ max / 3

26 Scenario II 10 9 v/t c 8 δ h 7 6 ratio Λ(GeV) v(t c ) 1. (20) T c ( ) L hhh = 3 m2 h Λ2 min h 3 v Λ 2 (21) 3! The large deviation of the trilinear Higgs coupling may be test at HL-LHC and CEPC(SPPC).

27 CP-violation source the Lagrangian for top-higgs coupling is parameterized as L = m t v h t(1 + δ + t + iδ t γ 5 )t, (22) The iγ 5 term is CP-odd, and would provide the CPV source for the baryogenisis. δ + t = av 3 2Λ 2 m t (23) δ t = bv 3 2Λ 2 m t (24)

28 CP-violation source m t (z) = m t v (1 + δ+ t + iδt γ 5 )h(z) m t (z) e iθ(z), (25) η B = 405Γ sph 4π 2 dz µ BL f sph e 45 Γ sph z /(4v σ), (26) v σ g T From the preliminary numerical estimation, we can further take δ t = O(0.1 1), (27) to provide the CP violation source for a successful baryogenesis.

29 Higgs pair production The deviation from the SM case can be written as L = 1 ( 3m 2 ) h λ 3h h 3 + m t 3! v v h t(1 + δ t + + iδt γ 5 )t, (28) which λ 3h = (1 + δ h ) and δ h = 5 Λ2 min Λ 2. In the SM, λ 3h = 1, δ + t = 0 and δ t = 0.

30 Higgs pair production Using Feycalc, the partonic differential cross section for the g(p a )g(p b ) h(p c )h(p d ) process can be obtained = d ˆσ(gg hh) dˆt GF 2 { (1 α2 s + δh 512(2π) 3 )(1 + δ t + )P(ŝ)F A + (1 + δ t + ) 2 F AA + (δt ) 2 F BB + (1 + δ t + ) 2 G AA + (δt ) 2 G BB 2 + (1 + δ h )δt P(ŝ)F B + (1 + δ+ t )δt F AB 2 (29) 2 + (1 + δ t + )δt G AB 2}, Chien YiChen, Qi ShuYan, XiaoranZhao, Yi MingZhong, arxiv : QiangLi, ZhaoLi, Qi ShuYan, XiaoranZhaoPhys.Rev.D92(2015)1,

31 Higgs pair production The invariant mass distribution of the Higgs boson pair for PP hh at 14 TeV LHC, choosing the benchmark point δ h = 3, δ + t = 0.01, δ t = 0.2. ) -1 dσ/dm hh 1/σ (TeV SM EWB M hh (GeV)

32 Top-Higgs coupling The anomalous top-higgs coupling would modify the Higgs couplings to gg and γγ. Thus, the loop induced Higgs couplings c hgg and c hγ γ can be parameterized as g 2 hgg (1 + δ + t ) δ + t (1 + δ + t ) + 2.6δ t, g 2 hγγ ( δ + t ) 2 + (0.43δ t ) 2.

33 ZH production at CEPC e t Z e + δ t h

34 ZH production at CEPC Define the deviation of σ hz as δ σ = σ hz,δ h 0 σ hz,sm 1. (30) We can see that δ σ is approximately proportional to δ h as δ σ 1.6δ h %. For the future CEPC with the integrate luminosity of 10 ab 1, the precession of σ zh can be 0.4%. Therefore, it is possible to test δ h 25% at the CEPC.

35 ZH product at CEPC 1.0 e + e hz, m h = 125 GeV δ σ = σ / σ SM 1 (%) s = 240 GeV, 10 ab δ σ = 1.63 δ h % δ h Figure: The modification of the Higgs associated production cross section as a function of the anomalous trilinear coupling δ h (solid line) at the e + e collider with s = 240 GeV. The dashed lines denote the sensitivity to δ σhz of the e + e collider with the luminosity of 10 ab 1.

36 1.0 e + e hz, m h = 125 GeV δ σ = σ / σ SM 1 (%) s = 240 GeV, 10 ab -1 δ σ = 0.54 δ t + % δ t Figure: The modification of the Higgs associated production cross section as a function of the anomalous CP-even top-higgs coupling δ t + (solid line) at the e + e collider with s = 240 GeV. The dashed lines denote the sensitivity to δ σhz of the e + e collider with the luminosity of 10 ab 1.

37 Renormalizable model The dimension-6 operators can be induced from certain renormalizable extensions of the SM. Such as a class of realistic models with vector-like quarks and triplet Higgs. φ φ Σ Σ φ φ φ φ φ Σ Σ φ φ u R D L1 D L1 q L

38 Future collider signature Precise measurement of the following couplings are needed to test this scenario in HL-LHC and CEPC(SPPC): Higgs tri-linear coupling t th, Ht, H t production with CP-violation top Yukawa coupling:crosssecion, polarization... precise ZH measurement at CEPC.

39 Conclusion Since the 125 GeV Higgs boson has bee seen at the LHC, we might be able to test the Higgs potential and the EWB scenario just at the corner; But, there are so many possible concrete realization in this scenario, related to all the possibilities for the Higgs sector and the related BSM physics; concentrating on the key physics required to make EWG work Still challenge in experiments, e.g. the precise test of Higgs tri-linear coupling and the top quark coupling.

40 Thanks!