Non-resonant Collider Signatures of a Singlet-Driven Electroweak - PowerPoint PPT Presentation

Non-resonant Collider Signatures of a Singlet-Driven Electroweak Phase Transition Chien-Yi Chen University of Victoria / Perimeter Institute C.-Y. C, J. Kozaczuk and I. M. Lewis, 1704.0xxxx ACFI Workshop: Making EWPT a April 7, 2017

Holy grails [Quigg lecture at the 2004 SLAC Summer Institute. ]

Holy grails [Quigg lecture at the 2004 SLAC Summer Institute. ]

Holy grails Strong indication of new physics [Quigg lecture at the 2004 SLAC Summer Institute. ]

Baryogenesis v Evidence from cosmology: v Sakharov’s 3 conditions (1967), for baryogenesis v Baryon number violation v Out of equilibrium v C and CP violation v EW baryogenesis is one of the potential solutions v Need new physics because in SM: EW phase transition is a crossover, instead of 1 st order 1) CP violation is too small 2)

Testability v LHC is running! v What’s the sensitivity of HL-LHC, 100 TeV pp colliders, and future e+ e- colliders to the region of parameter space where SFOPT is allowed? v Gravitational waves: Bubble collisions

Model: SM+singlet

SM + Singlet v SM Higgs doublet H mixes with an additional singlet S. The singlet doesn’t couple to SM fermions and gauge bosons.

SM + Singlet v SM Higgs doublet H mixes with an additional singlet S. The singlet doesn’t couple to SM fermions and gauge bosons.

SM + Singlet v SM Higgs doublet H mixes with an additional singlet S. The singlet doesn’t couple to SM fermions and gauge bosons.

SM + Singlet v SM Higgs doublet H mixes with an additional singlet S. The singlet doesn’t couple to SM fermions and gauge bosons.

SM + Singlet v SM Higgs doublet H mixes with an additional singlet S. The singlet doesn’t couple to SM fermions and gauge bosons. If apply Z 2 symmetry: S-> -S

SM + Singlet v SM Higgs doublet H mixes with an additional singlet S. The singlet doesn’t couple to SM fermions and gauge bosons. v After spontaneous symmetry breaking: ✓ ◆ 1 0 H → , in unitary gauge √ h + v 2 S → S + x

SM + Singlet v Mass eigenstates and mixing angle: S h 2 h 1 θ h h 1 = h cos θ + S sin θ h 2 = − h sin θ + S cos θ Mass eigenstates Gauge eigenstates : the Higgs we observed; its couplings to fermions and gauge v h 1 bosons are universally suppressed by a factor of . cos θ : Heavy Higgs; its couplings to fermions and gauge bosons are v h 2 universally suppressed by a factor of . sin θ f f

SM + Singlet v Cubic terms: ∼ λ 221 v Quartic terms are not very relevant for EWBG

Effective potential V e ff ( φ h , φ s , T ) = V 0 ( φ h , φ s ) + V CW ( φ h , φ s ) 1 + V T ( φ h , φ s , T ) + V ring ( φ h , φ s , T ) T v breakdown + : bosons − : fermions φ i : background fields n j : degrees of freedom m 2 j ( φ h , φ s ) : field dependent [Profumo, Ramsey-Musolf, Shaughnessy (2007)] mass squared [Espinosa et al. NPB 854(2012)]

Double Higgs Production

Double Higgs Production through Gluon Fusion v Important because it can be used to measure the Higgs self-couplings Observed Higgs In SM: h 1 h 1 h 1 h 1 h 1 λ 111

Double Higgs Production through Gluon Fusion v Important because it can be used to measure the Higgs self-couplings Observed Higgs In SM: h 1 h 1 h 1 h 1 h 1 λ 111 BSM: h 2 h 1 h 1 λ 211 v Production cross section of di-Higgs can be enhanced due to the decay of heavy resonances if m 2 > 2 m 1

Double Higgs Production through Gluon Fusion v Resonant production in the singlet model and its implication for EWBG [1] J. M. No and M. Ramsey-Musolf, Phys. Rev. D 89, no. 9, 095031 (2014) [2] K. Assamagan et al., arXiv:1604.05324 [hep-ph]. [3] A. V. Kotwal, M. J. Ramsey-Musolf, J. M. No and P. Winslow, arXiv:1605.06123 [hep-ph]. [4] T. Huang, J. M. No, L. Pernié, M. Ramsey-Musolf, A. Safonov, M. Spannowsky and P. Winslow, arXiv:1701.04442 [hep-ph]. [5] R. Contino et al., arXiv:1606.09408 [hep-ph]. …

Double Higgs Production through Gluon Fusion v What if is small and ? sin θ m 2 < 2 m 1 v Non-resonant production dominates BSM: σ ( h 2 h 2 ) and σ ( h 1 h 2 )

Parameter space v Small angle regions are mostly dominated by σ ( h 2 h 2 ) v Plot for 100 TeV is similar

Constraints on scalar potential v Vacuum stability: no vacuum exit at T=0 that is deeper than EW vaccum with v=246 GeV and v s = 0 GeV v Perturbativity: all dimensionless couplings < 4 pi at the EW scale v Perturbative unitarity: [Lee et al. PRD 16(1977)] v Number of free parameter (once fix and ) sin θ m 2 a 2 , b 3 and b 4 v

Parameter space v Shaded region: satisfy all constraints v Blue regions show strongly first-order phase transition (SFOPT) allowed region

Collider signatures: trilepton channel v Signal: v f v Background: v Jets fakes leptons: dominant background, t tbar v 3 prompt leptons: v WZ (W ) γ ∗ v WWW v ttW v ttZ or tt γ ∗ v tt

Collider signatures: variables v Transverse mass : m T a q ( E a T + E b p a p b m T ( a, b ) ≡ T ) 2 − ( ~ T + ~ T ) 2 b T ) 2 = ( p a T ) 2 + m 2 ( E a a : can be a particle or a group of particles a , b : useful in rejecting backgrounds with non-prompt v leptons. V. Khachatryan et al. [CMS Collaboration], Eur. Phys. J. C 76, no. 8, 439 (2016)

Collider signatures: variables j j ν W − h 2 p W + ν W + p ¯ h 2 ν W − : reconstruct mass of the mother particle ( ) when final v h 2 m T 2 states involves missing energy. v Two possibilities: 1) m 1 � ⇥ m T ( jj ` 1 , E miss T 1 ) , m T ( ` 2 ` 0 , E miss ⇤ T 2 =Min Max T 2 ) E miss + E miss = E miss E miss E miss T 1 T 2 T T 1 T 2 2) m 2 T 2 = m 1 T 2 ( ` 1 ↔ ` 2 ) 0

Collider signatures: variables v Total invariant mass of visible particles:

Collider signatures: benchmark points v LHC 14 TeV at 3/ab:

Collider signatures: benchmark points v LHC 14 TeV at 3/ab:

Collider signatures: benchmark points v LHC 14 TeV at 3/ab: v LHC 100 TeV at 30/ab:

Collider signatures v m min T

Additional probes CEPC and ILC v Presence of an addition scalar, alters the Zh 1 production cross section due to contributions to the wave-function renormalization of h 1 [Craig et al. PRL 111(2013), Curtin et al. JHEP1411 (2014), Huang et al. PRD.94 (2016) ] v Sensitivity of lepton colliders: δ Zh 1 > 1% [Dawson, et al. 1310.8361)] Higgs self-coupling measurement at pp collider for HL-LHC for 100 TeV pp collider [Dawson, et al. 1310.8361)] [Curtin et al. JHEP 1411(2014)]

HL-LHC λ 111 Higgs self- coupling measurement (to the right) Excluded by HL-LHC ILC or CEPC (to the right)

100 TeV collider v Muon Higgs self- v Leptonic dipole moments: coupling measurement (solid, to the right) ILC or CEPC (dashed, to the right) v Green region: 5 sigma discovery using trilepton channel at 100 TeV with 30/ab v Yellow region: excluded by 2 sigma using trilepton channel at 100 TeV wth 30/ab

Take Home Message v Direct probe of EWPT in non-resonantscalar pair production channels at both 14 TeV LHC and 100 TeV collider v At 14 TeV LHC, measurement of the h 1 self-coupling as well as that from lepton colliders will provide better coverage v At a 100 TeV collider, non-resonant production with m 2 ~170 GeV is sensitive to most of the parameter space with SFOPT.

Take Home Message Prospect: channel σ ( h 1 h 2 ) v : displaced decay of h 2 m 2 < m 1 v

THANK YOU!

BACKUP

Constraints on Mixing Angle v Light Higgs coupling measurements: ≡ sin 2 θ < 0 . 12 v combine v Independent of branching ratios of new decay channels v Independent of m 2 ATLAS-CONF-2014-010 v Heavy Higgs searches: v Depend on branching ratios of new decay channels v E.g. take B new =0, for sin 2 θ < 0 . 2 200 < m 2 < 600 GeV arXiv: 1504.00936, CMS 40

Parameter space v Purple: satisfy all requirement at both tree and 1-loop level v circled: satisfy all requirement when 1-loop correction is added

14 TeV 100 TeV

Collider signatures v m T 2

Collider signatures v m vis