Probing physics behind the electroweak symmetry breaking at future - - PowerPoint PPT Presentation

Probing physics behind the electroweak symmetry breaking at future gravitational wave and collider experiments

Mitsuru Kakizaki (University of Toyama)

May 12, 2016 Mitsuru KAKIZAKI 1 l Collaborators:

Katsuya Hashino, Shinya Kanemura (University of Toyama) and Toshinori Matsui (University of Toyama à KIAS)

l References:

• MK, Kanemura, Matsui, PRD 92, no. 11, 115007 (2015) [arXiv:1509.08394]
• Hashino, MK, Kanemura, Matsui, arXiv:1604.02069

The 17th Regular Meeting of the New Higgs Working Group May 12, 2016 @ University of Toyama

Contents

• 1. Introduction
• 2. Models with additional singlet scalars (without CSI)
• 3. CSI models with additional singlet scalars
• 4. Synergy between measurements of gravitational waves

and triple Higgs boson coupling

• 5. Summary

May 12, 2016 Mitsuru KAKIZAKI 2

Motivation

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l The Higgs sector is still vague:

l

Guiding principle?

l

Shape of the Higgs potential (multiplets, symmetries, ...)?

l Dynamics behind the electroweak symmetry breaking (EWSB)?

l Higgs sector = Window to New Physics

Informa8on on new physics can be obtained by inves8ga8ng the proper8es of the Higgs sector

l Discovery of the 125 GeV Higgs boson at the CERN LHC: l The Standard Model (SM) has been established

as a low-energy effective theory below GeV This is not the end of the story

h

l Phenomena beyond the SM (BSM) reported:

l

Baryon asymmetry of the Universe (BAU)

l Existence of dark matter l Cosmic inflation l Neutrino oscillations

O(100)

l The structure of the Higgs sector is related to BSM models

l Electroweak phase transition (EWPT) is NOT of 1st

• rder for

Electroweak baryogenesis

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1st OPT

l Sakharov’s conditions for BAU

• 1. Baryon number violation
• 2. Violation of C and CP
• 3. Departure from thermal equilibrium

Sphaleron process Extended Higgs sctor Strongly first order phase transition (1st OPT):

Potential barrier

ϕ

ϕc

l SM Higgs sector w/ one doublet:

mh = 125 GeV

l Electroweak baryogenesis (EWBG) is an important physics

case relating the Higgs sector to BSM phenomena

True vacuum Tunneling

l Condition for strongly 1st OPT:

Strongly 1st OPT and triple Higgs boson coupling

May 12, 2016 Mitsuru KAKIZAKI 5

l e.g. Two Higgs doublet model (2HDM):

[Kanemura, Okada, Senaha (2005)]

Large deviation in the triple Higgs boson coupling

(∆λhhh/λSM

hhh & 10%)

EWBG can be tested at future colliders

l ILC 1 TeV can measure

at 10% accuracy

[Fujii et al. (2015)]

ϕc/Tc & 1

λhhh

l Models with extended Higgs sector: l 1st OPT is easily realized l Signatures are testable at colliders

Gravitational waves (GWs) as a probe of EWPT

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l Future space-based interferometers (eLISA, DECIGO, BBO) l Ground-based interferometers (aLIGO, KAGRA, aVirgo) l To investigate testability of models of EWSB

using the synergy between the measurements

• f the GWs and the coupling

l Sensitive to GWs from the early Universe

(Strongly 1st OPT, cosmic inflation, ...)

[LIGO and Virgo (2016)]

l Goal of our work:

New era of GW astronomy

l Targets: GWs from binary systems, supernovae, ...

New era for fundamental physics

l To exemplify this using models with additional isospin singlet

scalars with and without classical scale invariance (CSI)

GWs Higgs sector BAU BSM

l aLIGO made the first direct observation of GWs

Synopsis

hhh hhh

Contents

• 1. Introduction
• 2. Models with additional singlet scalars (without CSI)
• 3. CSI models with additional singlet scalars
• 4. Synergy between measurements of gravitational waves

and triple Higgs boson coupling

• 5. Summary

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Models with additional singlet scalars (without CSI)

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l Tree-level scalar potential: l Idea:

[MK, Kanemura, Matsui (2015)]

l To generally handle strongly 1st OPT via thermal loop,

isosinglet scalars are introduced

l For simplicity, symmetry is imposed

O(N)

N

Si (i = 1, · · · , N)

Φ : SM Higgs doublet

l Singlet scalar boson mass: l Undetermined parameters:

µS, mS for each model

O(N)

Models with additional singlet scalars (without CSI) (contd.)

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l Finite temperature effective potential

(high temperature expansion):

l Effective potential:

[MK, Kanemura, Matsui (2015)] Non decoupling loop effect from additional scalars

ϕc/Tc

Typically deviation in for strongly 1st OPT

λhhh

O(10)%

ϕc Tc ∝

Non decoupling loop effect from additional scalars

Contents

• 1. Introduction
• 2. Models with additional singlet scalars (without CSI)
• 3. CSI models with additional singlet scalars
• 4. Synergy between measurements of gravitational waves

and triple Higgs boson coupling

• 5. Summary

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CSI models with additional singlet scalars

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l Tree-level potential: l Idea:

[Hashino, Kanemura, Orikasa (2015)]

l Mass parameters are absent in the original Lagrangian

due to CSI

l EWPT is directly caused by thermal loop effects

Φ: SM Higgs doublet

l Singlet scalar boson mass: l Triple Higgs boson coupling:

[Hashino, MK, Kanemura, Matsui (2015)] See Hashino’s talk

ϕc/Tc

[Hashino, Kanemura, Orikasa (2015)] independent of N [Bardeen (1995)]

Contents

• 1. Introduction
• 2. Models with additional singlet scalars (without CSI)
• 3. CSI models with additional singlet scalars
• 4. Synergy between measurements of gravitational waves

and triple Higgs boson coupling

• 5. Summary

May 12, 2016 Mitsuru KAKIZAKI 12

Important quantities for GW spectrum

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l Parameter l Transition temperature :

Tt

α

Released false vacuum energy (Latent heat)

'

l Parameter

' Inverse of the duration of phase transition

β(˜

β)

l Bubble nucleation rate per unit volume per unit time:

φ = 0 φ = 0 φ ≠ 0

l

GW spectrum is derived from finite temperature effective potential

Bubble nucleation Bubbles collision

• 1. Collision of walls
• 2. Compression wave of plasma
• 3. Plasma turbulence

l

Sources of GWs: Veff

See Jinno and Takimoto’s talk

l In CSI models,

scale invariance is violated at finite temperatures Constraints on and for each model

Predicted values of and

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[Hashino, MK, Kanemura, Matsui (2016)] CSI models

O(N)

O(N)

models without CSI

Γ H4

• T =Tt

= 1

ϕc Tc = 1

l and to be determined

by GW observation are useful measures in probing extended scalar sectors

l Condition for strongly 1st OPT

α

α

˜ β

˜ β

O(N)

and depend on though is common

α

˜ β

N

λhhh

α ˜ β

l and : efficiency factors

Characteristic relic abundance and frequency of GWs

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l Sound waves (Compression waves of thermal plasma): l Collision of walls (Envelope approximation):

[Caprini et al. (2015)]

l Magnetohydrodynamic (MHD) turbulence:

vb

l : wall velocity

✏ = 0.05 κ = κ(α, vb)

GW spectrum in CSI models

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[Hashino, MK, Kanemura, Matsui (2016)]

O(N)

vb = 0.95

eLISA DECIGO

l Sound wave: l MHD Turbulence: l Collision:

N = 1, 4, 12, 60

l Benchmark points:

from the bottom

l Contribution from sound waves is dominant and detectable

at future space-based interferometers, eLISA and DECIGO

l Contribution to GWs: l Experimental prospects:

l eLISA: l DECIGO:

[Caprini et al. (2015)] [Kawamura et al. (2011)]

l models

without CSI

Comparison of GW spectra

May 12, 2016 Mitsuru KAKIZAKI 17

[Hashino, MK, Kanemura, Matsui (2016)]

O(N)

l CSI

models

O(N)

vb = 0.95

vb = 0.2

q µ2

S = 0

l N.B. subsonic wall

velocity is preferred for EWBG but not necessarily [No (2011)]

Synergy of measurements of the triple Higgs boson coupling and GWs

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l Models with and without CSI

can be distinguished at future GW interferometers even if they share common coupling

[Hashino, MK, Kanemura, Matsui (2016)]

l What if the coupling

is found to be at future colliders?

hhh

∆λhhh/λSM

hhh = 2/3(' 70%)

hhh

O(N)

l models without CSI predicting l CSI models

O(N)

∆λhhh/λSM

hhh = 2/3(' 70%) l Models:

Transition temperature and wall velocity dependence of detectability of GWs

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Tt = 50 GeV Tt = 100 GeV vb = 0.2

vb = 0.95

[Hashino, MK, Kanemura, Matsui (2016)]

• 5. Summary

May 12, 2016 Mitsuru KAKIZAKI 20

l We have discussed the

complementarity of measurements

• f the triple Higgs boson coupling

and GW spectrum in models with extra scalars with and without CSI

l Synergy between observation of GWs and measurement

• f the triple Higgs boson coupling at future experiments is

powerful in revealing dynamics behind the EWSB

l Models with strongly 1st order

EWPT predict large deviation in the triple Higgs boson coupling and generate GWs

Backup slides

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Efficiency factor

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κ

[Caprini et al (2015)]