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
University of Victoria / Perimeter Institute
C.-Y. C, J. Kozaczuk and I. M. Lewis, 1704.0xxxx
ACFI Workshop: Making EWPT a
April 7, 2017
[Quigg lecture at the 2004 SLAC Summer Institute. ]
[Quigg lecture at the 2004 SLAC Summer Institute. ]
[Quigg lecture at the 2004 SLAC Summer Institute. ]
Strong indication
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: 1)
EW phase transition is a crossover, instead of 1st order
2)
CP violation is too small
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
v SM Higgs doublet H mixes with an additional singlet S.
v SM Higgs doublet H mixes with an additional singlet S.
v SM Higgs doublet H mixes with an additional singlet S.
v SM Higgs doublet H mixes with an additional singlet S.
v SM Higgs doublet H mixes with an additional singlet S.
If apply Z2 symmetry: S-> -S
v SM Higgs doublet H mixes with an additional singlet S.
v After spontaneous symmetry breaking:
, in unitary gauge
v Mass eigenstates and mixing angle:
cos θ
v
: Heavy Higgs; its couplings to fermions and gauge bosons are universally suppressed by a factor of .
h1 h2
v
: the Higgs we observed; its couplings to fermions and gauge bosons are universally suppressed by a factor of .
θ h S
h1
Mass eigenstates Gauge eigenstates
v Cubic terms: v Quartic terms are not very relevant for EWBG
∼ λ221
v breakdown
Veff(φh, φs, T) = V0(φh, φs) + V CW
1
(φh, φs) + VT (φh, φs, T) + V ring
T
(φh, φs, T)
+ : bosons − : fermions
φi : background fields m2
j(φh, φs) : field dependent
mass squared
[Espinosa et al. NPB 854(2012)]
nj: degrees of freedom
[Profumo, Ramsey-Musolf, Shaughnessy (2007)]
h1 h1 h1
h1 h1
λ111 Observed Higgs
v Important because it can be used to measure the
In SM:
h1 h1 h1
h2 h1 h1
h1 h1
λ211
λ111 Observed Higgs
v Production cross section of di-Higgs can be enhanced
v Important because it can be used to measure the
In SM: BSM:
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]. …
v Non-resonant production dominates v What if is small and ?
BSM: and
v Small angle regions are mostly dominated by v Plot for 100 TeV is similar σ(h2h2)
v Vacuum stability: no vacuum exit at T=0 that is deeper than EW
vaccum with v=246 GeV and vs = 0 GeV
v Perturbativity: all dimensionless couplings < 4 pi at the EW scale v Perturbative unitarity: v Number of free parameter (once fix and ) v
[Lee et al. PRD 16(1977)]
sin θ
m2
v Shaded region: satisfy all constraints v Blue regions show strongly first-order phase transition (SFOPT)
allowed region
v Signal: v f v Background: v Jets fakes leptons: dominant background, t tbar v 3 prompt leptons: v WZ (W ) v WWW v ttW v ttZ or tt v tt
v Transverse mass : v
: useful in rejecting backgrounds with non-prompt leptons.
mT (a, b) ≡ q (Ea
T + Eb T )2 − (~
pa
T + ~
pb
T )2
(Ea
T )2 = (pa T )2 + m2 a
: can be a particle or a group of particles
a, b
v
: reconstruct mass of the mother particle ( ) when final states involves missing energy.
v Two possibilities:
j j
h2
h2
h2
W +
W +
W −
W −
Emiss
T 1
Emiss
T 2
1)m1
T 2 =Min
⇥ mT (jj`1, Emiss
T 1 ), mT (`2`0, Emiss T 2 )
⇤ Emiss
T 1
+ Emiss
T 2
= Emiss
T
2)m2
T 2 =m1 T 2(`1 ↔ `2)
v Total invariant mass of visible particles:
v LHC 14 TeV at 3/ab:
v LHC 14 TeV at 3/ab:
v LHC 14 TeV at 3/ab: v LHC 100 TeV at 30/ab:
v mmin
T
CEPC and ILC
v Presence of an addition scalar, alters the Zh1 production
cross section due to contributions to the wave-function renormalization of h1
v Sensitivity of lepton colliders:
Higgs self-coupling measurement at pp collider
for HL-LHC for 100 TeV pp collider [Craig et al. PRL 111(2013), Curtin et al. JHEP1411 (2014), Huang et al. PRD.94 (2016) ] [Curtin et al. JHEP 1411(2014)] [Dawson, et al. 1310.8361)]
δZh1 > 1%
[Dawson, et al. 1310.8361)]
Excluded by HL-LHC ILC or CEPC (to the right) Higgs self- coupling measurement (to the right)
λ111
v Muon v Leptonic dipole moments:
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
ILC or CEPC (dashed, to the right) Higgs self- coupling measurement (solid, to the right)
v Direct probe of EWPT in non-resonantscalar pair
v At 14 TeV LHC, measurement of the h1 self-coupling as
v At a 100 TeV collider, non-resonant production with
v
v
v Light Higgs coupling measurements: v combine v Independent of branching ratios of new decay channels v Independent of m2 v Heavy Higgs searches: v Depend on branching ratios of new decay channels v E.g. take Bnew=0, for ≡ sin2 θ < 0.12
ATLAS-CONF-2014-010 arXiv: 1504.00936, CMS
sin2 θ < 0.2
40
200 < m2 < 600 GeV
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
v mT 2
v mvis