Walking Technicolor in light of LHC-Run II Shinya Matsuzaki - - PowerPoint PPT Presentation
Walking Technicolor in light of LHC-Run II Shinya Matsuzaki Department of Physics & Institute for Advanced Research, Nagoya U. Collaborators: M.Kurachi, K.Yamawaki (KMI, Nagoya U) K.Terashi (Tokyo U)
Shinya Matsuzaki
Department of Physics & Institute for Advanced Research, Nagoya U. @ Toyama Univ. 12/05/2014
Walking Technicolor in light of LHC-Run II
Collaborators: M.Kurachi, K.Yamawaki (KMI, Nagoya U) K.Terashi (Tokyo U) (involving works in progress) References: S.M. and K. Yamawaki, PRD85, 86, 86 (‘12), PRD87(‘12), PLB719(‘13), 1304.4882 (proc. of SCGT12), PRD90(‘14), PRD90(‘14), PRL113(‘14), and works in progress
CMS-PAS-HIG-14-009
Current status on 125 GeV Higgs discovered at LHC * measured coupling properties consistent w/ the SM Higgs so far * BUT, is it really the SM Higgs?
ATLAS-CONF-2014-009
It could be a composite scalar, “Technidilaton (TD)”
* TD = a composite scalar:
giving dynamical origin of mass by technifermion condensate
(approximate) scale symmetry technifermion condensate
and hence can be, say, ~ 125 GeV. S.M. and K.Yamawaki, PRD86 (‘12)
Yamawaki et al (‘86); Bando et al (‘86)
* 125 GeV TD signatures at LHC are consistent with current data
S.M. and K. Yamawaki, PRD85,86 (‘12), PLB719 (‘13); S.M. 1304.4882; talk at SCGT14mini and PPP (‘14) LatKMI Collaboration, PRD89(‘14)
QCD-like
“walking”
~1000TeV ~ O(4 π Fπ) = O(1TeV)
The idea of technicolor (TC)
* SU(3)c x SU(2)L x U(1)Y invariant gauge kin. fermion kin. Yukawa Higgs
The idea of technicolor (TC)
* SU(3)c x SU(2)L x U(1)Y invariant gauge kin. fermion kin. Yukawa Higgs New color dynamics, Technicolor (TC) Extended TC Unnatural Higgs dynamics replaced by natural gauge dynamics
Dynamical EWSB by technicolor
* A typical TC model: one-family (Farhi-Susskind) model
* Q: techniquarks * L: technileptons replaced by (+ ETC-induced term) SU(NTC) gauge theory
w/ 8 techni-flavors
Susskind (‘79);Farhi-Susskind(‘85)
QCD-like * SU(NTC)(vector-like) gauge theory breaks the chiral symmetry as in QCD
α gets strong at the IR scale
=O(EW)
SSB
QCD-like * SU(NTC)(vector-like) gauge theory breaks the chiral symmetry as in QCD
α gets strong at the IR scale
=O(EW)
SSB 63 composite NGBs emerge
and
QCD-like * SU(NTC)(vector-like) gauge theory breaks the chiral symmetry like QCD
α gets strong at the IR scale
=O(EW)
SSB
Dynamical W,Z mass-generation
W,Z W,Z Dynamical explanation of origin of EWSB and W,Z masses
subgroup includes EW SU(2) x U(1) in the SM
# of EW doublets
:technipion decay const.
QCD-like * SU(NTC)(vector-like) gauge theory breaks the chiral symmetry like QCD
α gets strong at the IR scale
=O(EW)
SSB 60 get massive (technipions), 3 eaten by W & Z
SM gauge turned on: SU(3) x SU(2) x U(1) breaks the global sym. SU(3) Main source “ETC”
QCD-like * SU(NTC)(vector-like) gauge theory breaks the chiral symmetry like QCD
α gets strong at the IR scale
=O(EW)
SSB 63 composite vector mesons (technirhos) emerge
In addition,
SM fermion mass generation by “Extended TC”
ETC1 ETC2 ETC3
ETCi F F Dynamical explanation of Yukawa interaction!
Thus, TC provides:
* dynamical origin of Higgs potential (mechanism of EWSB)
* solution of naturalness problem/hierarchy problem * rich spectra (techni-hadrons; technipions & technirhos) at O(TeV)
Theoretically, TC is much better than SM!!
However, TC should not be QCD-like at all
* QCD-like TC was phenomenologically killed 3 times !!
2nd 2nd No symmetry to protect the lightness
QCD-like
However, TC should not be QCD-like at all
2nd 2nd No symmetry to protect the lightness
QCD-like
Yamawaki,Bando, Matumoto (‘86) Haba, Matsuzaki, Yamawaki (‘08,’10,) Matsuzaki, Yamawaki (‘12,’13)
* Walking TC can be viable, solve problems by which QCD-like TC was killed:
“Technidilaton”
Contents of this talk:
and technivector mesons
technidilaton (TD)
A schematic view of walking TC
QCD-like * all things related to the dynamics characterized by a single scale
(violent running coupling)
A schematic view of walking TC
QCD-like QCD-like QCD-like * all things related to the dynamics characterized by a single scale
(violent running coupling) deform
A schematic view of walking TC
QCD-like * all things related to the dynamics characterized by a single scale
(violent running coupling) QCD-like QCD-like “walking” * Theory divided into two scale regions: between them, the coupling is slowly running (walking): approximately scale-invariant
QCD-like QCD-like “walking”
at
the IR scale (chiral breaking scale)
I) explicitly broken due to QCD-like (perturbative) running characterized by II) spontaneously broken due to the dynamical mas generation Until the scale mF, the theory is approximately scale-invariant (hard-breaking washed out) region (I) region (II)
QCD-like QCD-like “walking”
at
the IR scale (chiral breaking scale)
I) explicitly broken due to QCD-like (perturbative) running characterized by Until the scale mF, the theory is approximately scale-invariant (hard-breaking washed out) II) spontaneously broken due to the dynamical mas generation Simultaneously, explicitly broken “Miransky scaling”
(Miransky (1985)) α starts “running” (walking) up to mF
region (I) region (II)
SSB of (approximate) scale sym.
α starts “running”
(walking) up to mF
induced by mF itself
TD gets massive
ii) spontaneously broken due to the dynamical mas generation Simultaneously, explicitly broken
QCD-like QCD-like “walking”
* A composite Higgs(~FFbar) = Technidilaton (TD) emerges as (p)NGB for approx. scale symmetry
Yamawaki et al (1986); Bando et al (1986)
Be “Walking” Holdom (1981);
Yamawaki et al (1986); Bando et al (1986); Akiba et al (1986); Appelquist et al (1986); (1987)
The explicit proposal based on ladder SD eq analysis
to solve FCNC problem
Historically,
QCD-like QCD-like “walking” “walking” β
:Pseudo FP Note presence of pseudo FP
* What would be like a realistic walking gauge theory?
A candidate for the walking gauge theory
* QCD with many flavors (large Nf QCD)
Large fermionic Nf balances with gluonic Nc to realize walking!
* Search for walking TC by lattice simulations
Slide from Yamazaki’s talk at PPP2014
* Search for walking TC by lattice simulations
Slide from Yamazaki’s talk at PPP2014
Light techni-dilaton(i)
* A straightforward nonpert. calc. of large Nf QCD in the ladder approximation
Kurachi et al,(‘06)
implies the tendency of lightness for the TD (even in the ladder approximation)
Light techni-dilaton(ii)
125 GeV
* One suggestion from holographic formula for TD mass
S.M and K.Yamawaki , PRD86 (2012)
125 GeV TD is realized by a large gluonic effect : G 〜 10 for one-family model w/ Fπ = 123 GeV (c.f. QCD case, G ~ 0.25 )
“conformal limit”
Conclusive answer will be given by lattice simulations
Slide from Yamazaki’s talk at PPP2014
Light techni-dilaton(iii)
113 (2014) 113 (2014)
TD Lagrangian below mF S.M. and K. Yamawaki, PRD86 (2012)
walking regime ~O(TeV)
* effective theory below mF after TF decoupled/integrated out & confinement : governed by TD and other light TC hadrons * Nonlinear realization of scale and chiral symmetries
Nonlinear base χ for scale sym. w/ TD field Φ Nonlinear base U for chiral sym. w/ TC pion field π associated decay constant FΦ
i) The scale anomaly-free part:
ii) The anomalous part (made invariant by including spurion field “S”): reflecting ETC-induced TF 4-fermi w/ (3-γm)
iii) The scale anomaly part:
which correctly reproduces the underlying scale anomaly (PCDC relation): βF: TF-loop contribution t0 beta function
* TD couplings to W/Z boson (from L_inv) * TD couplings to γγ and gg (from L_S)
βF: TF-loop contribution t0 beta function
TD couplings to the SM particles
* TD couplings to W/Z boson (from L_inv) * TD couplings to γγ and gg (from L_S)
βF: TF-loop contribution t0 beta function
TD couplings to the SM particles The same form as SM Higgs couplings except FΦ and betas
* TD couplings to SM fermions *
in WTC to get realitic masses w/o FCNC concerning 1st and 2nd generations
*
2
in Strong ETC to accommodate masses of the 3rd generations (t, b, tau)
Miransky et al (1989); Matsumoto (1989); Appelquist et al (1989)
1
Thus , the TD couplings to SM particles essentially take the same form as those of the SM Higgs! : Just a simple scaling from the SM Higgs: But, note φ-gg, φ-γγ depending on particle contents of WTC models.
βF: TF-loop contribution t0 beta function
Take one-family model (1FM) evaluate betas at one-loop level:
* relevant production processes at LHC
Φ bb : ~ 19 % Φ WW : ~ 3.5% Φ ττ : ~ 1.1 % Φ ZZ : ~ 0.4% Φ γγ : ~ 0.1% BR enhanced by extra colored techni-quark contribution similar to SM Higgs: ggF , VBF, VH, ttH
* relevant decay channels (for NTC=4)
S.M. and K. Yamawaki, PLB719 (‘13); S.M. 1304.4882
The signal strength fit to the LHC-Run I full data
*
NTC=4 NTC=3 NTC=5
One-parameter fit (Fφ) Compared w/ SM Higgs χ^2/d.o.f = 17/18 = 1.0
Current LHC has favored TD at almost the same level as SM Higgs!
Updated from S.M. and Yamawaki PLB719(2013)
Characteristic coupling property of 125 GeV TD in 1FM (w/ NTC=4) at the LHC
W,Z W*,Z* b,τ b,τ g γ g γ φ φ φ φ
F, t F, t gφ gφ= (vEW/FΦ) gH=0.24 gH gφ gφ
di-weak bosons quark, lepton pairs digluon diphoton
suppressed suppressed moderately enhanced moderately suppressed v.s. SM Higgs
QCD-colored TF contributions EM-charged TF contributions
The TD signal strengths (μ = σ x BR/SM Higgs)
(i) ggF+ttH category
* one-family model w/ NTC=4, vEW/Fφ = 0.24 ATLAS CMS TD signal strength * Data as of ICHEP, July 2014
Consistent
The TD signal strengths (μ = σ x BR/SM Higgs) vs the current data (ii)
(ii) VBF +VH category
* Consistent within about 1 sigma error * VBF: ~ 30% contamination from ggF, compensating direct VBF coupling suppression: gg Φ + gg highly enhanced, due to TQ loop, compared to SM Higgs case! * Smaller VBF+VH signal (particularly, bb-channel), compared to the SM Higgs ATLAS CMS TD signal strength * Data as of ICHEP, July 2014
What do we expect next to discovery of the “Higgs”? New particles signaling the WTC as BSM = > Walking techni-pions & techni-vector mesons (technirho mesons) ! = smoking-gun of WTC SM Higgs, or TD?
and technivector mesons
Walking technipions and technirho mesons
* one-family (Farhi-Susskind) model w/ SU(8)L x SU(8)R SU(8)V * 63 NGBs emerge: 3 = eaten by W,Z, 60 = pseudos, Technipions * pNGB masses are of O(a few TeV), due to the walking feature
M.Kurachi, S.M. and K. Yamawaki, PRD90(‘14)
* For Ntc = 4 and S parameter (S^TC) = 1.0 0.1
* Current LHC limits on 60 technipions
* Most stringent constraints from pp ggF isosinglet technipions tt (and scalar leptoquark search for color-triplet Tc ) * Coupling properties fixed by SU(8)L x SU(8)R /SU(8)V , scale-inv. chiral Lagrangian
TPs predominantly decay to tt and gg, so can be mainly produced via ggF at LHC
* Current LHC limits on 60 technipions
* Most stringent constraints from pp ggF isosinglet technipions tt (and scalar leptoquark search for color-triplet Tc ) exclude TPs w/ masses color-octet (θa) < 1.5—1.6 TeV color-triplet (Tc) < 1.0 – 1.1 TeV color-singlet (P) < 800 GeV * Coupling properties fixed by SU(8)L x SU(8)R /SU(8)V , scale-inv. chiral Lagrangian
TPs predominantly decay to tt and gg, so can be mainly produced via ggF at LHC
M.Kurachi, S.M. and K. Yamawaki, PRD90(‘14)
* Expect to discover TPs w/ higher masses at LHC-Run II
* Search for walking techni-rho mesons @ LHC
* 63 vector mesons in a way similar to TPs
Techni-rho meson | color | isopin
* all masses are expected to be around a few TeV scale:
S.M. and K. Yamawaki, PRD86 (‘12);
* Relevant couplings: ρ – f-f, ρ – π –W/Z, ρ – W –W/Z and interesting interactions involving TD (Higgs):
Color-octet Color-singlet
Φ: TD (Higgs) Φ: TD (Higgs) g γ
Bando, et al, PTP79 (‘88); Bando, et al, PR164 (‘88)
* Coupling properties fixed by [SU(8)L x SU(8)R x [SU(8)V]_HLS ]/SU(8)V scale-inv. Hidden Local Symmetry (HLS) Lagrangian
* Relevant couplings: ρ – f-f, ρ – π –W/Z, ρ – W –W/Z and interesting interactions involving TD (Higgs):
Color-octet Color-singlet
Φ: TD (Higgs) Φ: TD (Higgs) g γ
Bando, et al, PTP79 (‘88); Bando, et al, PR164 (‘88)
* Coupling properties fixed by [SU(8)L x SU(8)R x [SU(8)V]_HLS ]/SU(8)V scale-inv. Hidden Local Symmetry (HLS) Lagrangian * 4 model parameters can be fixed:
VEW, best-fit of Signal strength, VMD for TP vary
Slide from M.Kurachi’s talk at SCGT14Mini, March 2014
Slide from M.Kurachi’s talk at SCGT14Mini, March 2014
Color-singlet iso-triplet (EM neutral)
Color-singlet iso-triplet (EM charged)
* Dominant production process @ LHC = Drell-Yan (DY) LHC cross section (LO): pp qqbar rho
* Current LHC limits on 63 technirho mesons
CMS8TeV CMS8TeV CMS8TeV CMS8TeV ATLAS8TeV ATLAS8TeV ATLAS8TeV dijet dilepton dilepton WZ(3lnu)
constrains masses to be
Slide from M.Kurachi’s talk at SCGT14Mini, March 2014
* Discovering technirho mesons associated w/ TD(Higgs)
Slide from M.Kurachi’s talk at SCGT14Mini, March 2014
Slide from K.Terashi’s talk at SCGT14Mini, March 2014 M.Kurachi, S.M., K.Terashi & K.Yamawaki, in progress
smoking-gun: technipion & techni-vectors, masses of order of just reach for upcoming Run II in particular, processes involving TD intrinsic to WTC! Stay tune with WTC!! Thank you very much!
Backup Slides
Direct consequences of Ward-Takahashi identities
S.M. and K. Yamawaki, PRD86 (2012) TC
* Coupling to techni-fermions
Dilaton pole dominance w/ TD decay constant Fphi
Yukawa vertex func.
* Couplings to SM fermions
transform No direct coupling ETC induced 4-fermi Techni-fermion loop induces
Yukawa coupling to SM-fermion
f-fermion mass: TC
* Couplings to SM gauge bosons
TC WT identity scale anomaly term + anomaly-free term p TC TF The loop integrals are actually saturated by IR contributions (γm = 2) TF TD pole βF: TF-loop contribution t0 beta function
βF: TF-loop contribution t0 beta function * For SU(2)W gauge bosons: W –”broken” currents
Coupling to W
* For unbroken currents coupled to photon, gluon:
Coupling to γγ & gluons
ND = TF -EW-doublets
TF
Yukawa vertex Ladder approx. The loop is dominated at IR (γm = 2) IR IR constant (well approximated by constant mass ) * Calculation of beta functions The resultant betas coincide just one-loop perturbative expressions:
TD mass stability below mF
S.M. and K. Yamawaki, PRD86 (2012) walking regime = scale symm well protected (natural enough) ~1TeV ~10^3TeV
Can TD mass be as small as 125GeV below mF? YES!!! Work on the eff. TD Lagrangian:
Dominant corrections come from top-loop (quadratic div.) cutoff by mF ~ 4 π Fπ ~ 1TeV (~ FΦ) :
naturally light thanks to large FΦ (i.e. weak coupling)
w/
Technicolor should not be QCD-like at all
Extended TC: SM fermion mass generation ETC FCNC constraint ETC2
e.g. Naive scale-up of QCD:
Needs enhancement by
Holdom (1981) associated w/ strange quark mass
ETC1
S parameter
Other pheno. issues in TC scenarios
: # EW doublets
Cf: S(exp) < 0.1 around T =0 One resolution: ETC-induced “delocalization” operator too large!
ETC
vector channel in low-energy w/ modifies SM f-couplings to W, Z contributes to S “negatively”
Chivukula et al (2005)
Top quark mass generation ETC
too small! One resolution: Strong ETC Miransky et al (1989)
ETC scale associated w/ top mass
enough to trigger chiral symm. breaking (almost by NJL dynamics) boost-up
T parameter (Strong) ETC generates large isospin breaking
highly model-dependent issue