Archil Kobakhidze

Based on work with Lei Wu and Jason Yue (to appear)

Electroweak Baryogenesis with Anomalous Higgs Couplings

 

KITPC/ITP SEMINAR 17th JUN 2015, BEIJING

CosPA 2015 International Symposium on Particle Physics & Cosmology

12-16 October 2015, Daejeon, Korea

Outline

!  Higgs after Run 1 !  Non-linear Realisation of the Electrowek Symmetry

!  Electroweak Baryogenesis with Higgs Anomalous Couplings

!  Conclusion

   

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The discovery of the Higgs boson uncovers the origin of mass of the observed elementary particles. More generally, it confirms the validity of foundational pillars of modern physics, quantum mechanics and relativity, at unprecedented small distances (~10-17cm!)

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Higgs after Run 1: Spin and Parity

Exclusion limits on Spin-2 parity-even Higgs Impostor with minimal

couplings: ATLAS - @99.9% CL from WW, ZZ, γγ decays

CMS - @99.9% CL from WW, ZZ  

 

 

 

 

 

 

 

 

 

 

Spin-2 Higgs Impostor with non-minimal couplings are also excluded from theoretical considerations [A.K., J. Yue, Phys.Lett. B727 (2013) 456]

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Higgs after Run 1: Couplings

mh = 125.36± 0.37(stat.)± 0.18(syst.) GeV mh = 125.03+0.26�0.27(stat.)

+0.13�0.15(syst.) GeV

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Many important properties of the Higgs boson still need to be verified. In particular, precision measurements of the Higgs couplings are important to determine the nature of the electroweak symmetry and of the electroweak phase transition in the early universe.

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Parameterizing new physics

!  High-dimensional operators consistent with gauge invariance

!  Non-linear realisation –

SU(3)⇥ SU(2)⇥ U(1)

O6 =c6⇤2

(H†H)3 ) �

3h3

Otth =ctt̄h⇤2

(H†H)QLHtR ,) ytt̄th

[SU(3)⇥ SU(2)⇥ U(1)] / [SU(3)⇥ U(1)EM]

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Non-linear realisation

!  Parameterize coset with

!  Higgs is residing in a singlet field

!  Connection with the SM Higgs doublet

X (x) = e

i2⇡i(x)Ti

✓01

◆

⇢(x) = h(x) + v

H(x) =⇢(x)p

2X (x)

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Non-linear realisation

!  Many new couplings – constraints from electroweak precision data, flavour data, violation of perturbative unitarity…

!  Simplified model – less constrained, relevant for the

electroweaak baryogenesis –

LH�T = �hm0

t + Yt⇢/p2iQ̄LX̃ tR + h.c. , Yt = yte

i⇠

V =µ2

2⇢2 +

3⇢3 +

�

4⇢4

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Non-linear realisation

!  Perturbative unitarity –

!  No 1-loop corrections to S, T, U parameters

!  Fermion EDM

E & 10 TeV

df/d̄f =4

9sin ⇠

✓m0

t

mt

◆✓ytvp2mt

◆ln

✓m2

t

m2h

◆

⇡ 0.29 sin ⇠

✓ytySMt

◆✓m0

t

mt

◆.

d̄f =|Qf |↵mf

16⇡3v2, d̄e ⇡ 2.5 · 10�27 e · cm

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Anomalous Higgs-Top interactions [A.K., L. Wu, J. Yue, JHEP 1410 (2014) 100 [arXiv:1406.1961]]

Cs = yt cos ⇠/ySMt

Cp = yt sin ⇠/ySMt

LHiggs�Top = �ySMtp2t̄�Cs + �5Cp

�th

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Anomalous Higgs-Top interactions [A.K., L. Wu, J. Yue, JHEP 1410 (2014) 100 [arXiv:1406.1961]]

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Anomalous Higgs-Top interactions [A.K., L. Wu, J. Yue, JHEP 1410 (2014) 100 [arXiv:1406.1961]]

pp ! thj ! bl+⌫bb̄j

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Anomalous Higgs-Top interactions [A.K., L. Wu, J. Yue, JHEP 1410 (2014) 100 [arXiv:1406.1961]]

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Cosmological baryogenesis at the electroweak scale

(nucleosynthesis, CMBR+LSS) Sakharov’s conditions are met within the SM: •  CP violation – Kobayashi-Maskawa mechanism •  B-violation – nonperturbative sphaleron effects •  Non-equilibrium – electroweak phase transition Phase transition

V (H) = m2H |H|2 + �|H|4

VT (H) = (m2H + ↵T 2)|H|2 + �T |H|3+�T |H|4

⌘B =nB � nB̄

n�⇡ 6 · 10�10

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Cosmological baryogenesis at electroweak scale !  SM fails to reproduce the desired asymmetry,

for 2 reasons: (i)  Not enough CP-violation;

(ii)  The phase transition is not enough strongly 1st order

!  Anomalous trilinear Higgs coupling may enhance the 1st order phase transition

!  Anomalous Higgs-top coupling may contain additional CP violation

⌘SMB ⇠ 10�20 <<< ⌘B

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Electroweak Baryogenesis: Phase transition !  Finite temperature potential:

Sphaleron rate –

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V (�c, T ) =�

4

�4c +

3

�3c + �2

c

✓�µ2

2

+

T 2

32

(3g22 + g21 + 4�+ 4y2t )

◆

+

T 2

12

(+ 3

p2ytm

0t cos ⇠)�c + ...

� /✓�c

T

◆7

exp (�Esph/T )

Electroweak Baryogenesis: Phase transition

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Electroweak Baryogenesis: CP-violation

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Mt(z) = mt(z)ei✓t(z)

mt(z) =

s✓m0

t +ytp2

h(z) cos ⇠

◆2

+

✓ytp2

h(z) sin ⇠

◆2

tan ✓t(z) =yth(z) sin ⇠p

2m0t + yth(z) cos ⇠

Electroweak Baryogenesis: Baryon number

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Dqn00B(z)� vwn

0B(z)� 3�ws(z)nL(z) = 0

nB(z > 0) ⇡ �3�ws

vw

Z 0

�1dz0 nL(z0)

Electroweak Baryogenesis: Baryon number

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Conclusions  

!  The discovery of the Higgs boson is a groundbreaking breakthrough in particles physics. However, the nature of the electroweak symmetry breaking is

!  Important goal – precise measurement of Higgs couplings, especially Higgs-top and trilinear Higgs couplings, which may reveal connection with the fundamental origin of matter-antimatter asymmetry in the universe

!  Successful electroweak baryogenesis is still a viable option within the effective SM with nonlinearly realised electroweak symmetry

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