EDM constraint on NP
associated with BEH boson
Fanrong Xu (徐繁荣)
National Taiwan University
Nov. 8, 2013 @ AS
0
Introduction
GHO @ AS,2013/11/08
1
F. Xu
Introduction
 “Discovery” of Higgs Boson rated year’s top scientific
achievement of 2012.
GHO @ AS,2013/11/08
2
F. Xu
The life of Higgs
Decay
Production
GHO @ AS,2013/11/08
3
F. Xu
The discovery @ LHC
 Signal Strength
 ICHEP2012, summer 2012
Higgs XSWG
 HCP2012, winter 2012
Once upon a time,
there was a hot
word called “hgamma-gamma”…
GHO @ AS,2013/11/08
4
F. Xu
The discovery @ LHC
 Moriond 2013
EW
excess or fluctuation?
 What could be hidden in
current data: NP or SM?
QCD
GHO @ AS,2013/11/08
5
F. Xu
The discovery @ LHC
 EPS-HEP 2013
 LS1
GHO @ AS,2013/11/08
6
F. Xu
Further Identification
 Spin and CP
excludes 2+
𝑚 hypothesis at 2.84𝜎
J. Bendavid, EPS-HEP 2013
no significant discrimination yet
D. Schaefer, EPS-HEP 2013
 More data is required for
accurate analysis of spin
and CP!
 What information of spin
and CP can be digged out
from current data?
GHO @ AS,2013/11/08
7
F. Xu
NP
GHO @ AS,2013/11/08
8
F. Xu
Byproduct: Cutoff Scale
 Mass scale of exotic degrees of freedom: (0.4~8) TeV (cutoff)
CMS@ICHEP2012
ATLAS@HCP2012
 Can we get a hint for
the NP scale?
GHO @ AS,2013/11/08
9
F. Xu
Strategy
EDM+(g-2)
SM+NP
EFT
Based on We-Fu Chang, Wei-Ping Pan and FX, PRD 88,033004 (2013).
GHO @ AS,2013/11/08
10
F. Xu
1
Gauge-Higgs Operators
GHO @ AS,2013/11/08
11
F. Xu
Effective Theory
 Bottom-up approach:
SM is the low energy effective theory;
The full Lagrangian can be expanded by (1/cutoff)
 There are limited (59) gauge invariant independent dimension-6
operators
GIMR, JHEP10 (2010)085;
BW, NPB268 (1986) 621.
GHO @ AS,2013/11/08
12
F. Xu
Effective Theory
GHO @ AS,2013/11/08
13
F. Xu
Effective Operators
 Motivated by diphoton excess and DOF(s) beyond SM, we
assume New Physics can be captured by the effective
gauge-Higgs operators
Oblique correction: S
QCD theta term
Manohar, Wise;
X. Zhang, B.-L. Young;
McKenn,Pospelov,Ritz
……
 These operators form a subset, the other 3 gauge-Higgs
operators are strictly constrained by EW precision tests.
 The RG running effect will not be involved in this work.
GJMT, 1301.2588;
MEMP,1302.5661
GHO @ AS,2013/11/08
14
F. Xu
Effective interactions
 CP even/odd tree level h-V-V’ interaction is brought in
CP-even
CP-odd
Form factors
Effective coupling 𝒂𝒊 :
the combination of
WCs 𝒄𝒊
 Also anomalous gauge coupling is introduced
Anomalous coupling
SM-like
GHO @ AS,2013/11/08
15
F. Xu
2
Higgs Physics
GHO @ AS,2013/11/08
16
F. Xu
Production and decay
Error source: PDF + 𝜶𝒔 + ⋯
Higgs XSWG
 Signal strength: co-determined by both production and decay
GHO @ AS,2013/11/08
17
F. Xu
Modification @ loop level
 diphoton decay:
CP-even
 production: gluon fusion dominates
CP-odd
 unmeasured decay channel:
GHO @ AS,2013/11/08
18
F. Xu
Modification @ tree level
 The tree level decay
SM contribution is contained in CP-even part,
phase space integral of 3-body decay needs to be treated.
 Assumptions
 All the final state
fermions are summed up
 All the fermions are
massless
CP-even
CP-odd
GHO @ AS,2013/11/08
19
F. Xu
Numerical Analysis
 Numerical expressions at cutoff 1TeV
The story of 6 parameters
 Rescaling:
GHO @ AS,2013/11/08
20
F. Xu
Pseudo global fit
 Input experimental data (up to Moriond 2013)
 68 % C.L. correlation among alpha’s:
 Current LHC data agrees with SM;
 Larger GF production  smaller Higgs decay width
GHO @ AS,2013/11/08
21
F. Xu
Constraint on Wilson coefficients
 95 % C.L. correlation among Wilson coefficients:
SM: 𝝁 = 𝟏
LHC: 𝝁𝒆𝒙𝒑.




Both CP-even and CP-odd Wilson coefficients have a boundary
CP-even Wilson coefficients are well constrained, a few
Constraints on CP-odd sector are poor,
There is still allowance for NP, from SM theoretical errors.
GHO @ AS,2013/11/08
22
F. Xu
Constraint on Effective couplings
 The constraints on Wilson coefficients can be translated to
constraints on effective coupling
SM
LHC
 The effective coupling can be obtained
after a coordinate rotation from WCs.
 This coupling strength is checkable by
different groups.
GHO @ AS,2013/11/08
23
F. Xu
Prediction
 The relation between ZZ and WW:
SM
LHC
 The boundary of decay width ratio and signal is obvious
 A linear relation of signal strength between WW and ZZ is found
GHO @ AS,2013/11/08
24
F. Xu
3
EDM, MDM
GHO @ AS,2013/11/08
25
F. Xu
EDM
 EDM and MDM have different CP property
 nEDM in SM
GHO @ AS,2013/11/08
26
F. Xu
EDM
 Current nEDM
 Current eEDM
UK
US
ACME collaboration, 1310.7534
GHO @ AS,2013/11/08
27
F. Xu
AMDM
 AMDM: the SM deviation from experimental measurement
provides a room for NP
 SM calculation:
Aoyama-Hayakawa-Kinoshita., 2007
2-loop
Less known
HVP
 Measurement:
 muon:
LBL
muon (g-2) col., 2006
3𝜎
 electron:
Hanneke et. al., PRA2011
1.3 𝜎, but error could be reduced
GHO @ Nankai U.,2013/09/22
28
F. Xu
EDM and AMDM in EFT
 One loop EDM and g-2 can be generated due to the effective
operators
McKeen-Pospelov-Ritz, PRD86, 113004 (2012)
CP-odd (EDM); CP-even (g-2)
GHO @ AS,2013/11/08
29
F. Xu
Constraint on CP-odd sector
 Neutron and electron EDM upper bound provides a constraint on 3D
space.
 Project to 2D plane by setting the third parameter in a certain
region,
EDM constrain parameter on a long and narrow band
 But the combination of EDM and Higgs can largely reduce allowed
region
Higgs best fit
GHO @ AS,2013/11/08
30
F. Xu
Constraint on CP-even sector
 With a best fit of muon and electron g-2, a linear relation is
obtained
g-2
Higgs best fit
 g-2, giving another band with different slope from Higgs
constraint, helps to further determine parameter space of
CP-even sector.
GHO @ AS,2013/11/08
31
F. Xu
A global constraint on WCs
 Take into account all the above experiments, we can get a limited
region in Wilson coefficient space.
 CP-odd sector are severely constrained, reduced to order of 1,
which also gives an indication for NP models.
GHO @ AS,2013/11/08
32
F. Xu
Constraints on effective
coupling
 The constraints on Wilson coefficients can be translated to
constraints on effective coupling
SM
LHC
 The stringent constraint on the CP-odd
sector, O(100)O(1), is because of EDM.
 g-2 does not improve the constraint on
CP-even sector too much.
GHO @ AS,2013/11/08
33
F. Xu
Prediction
 The relation between ZZ and WW:
SM
LHC
 The interesting relation between WW/ZZ and AZ
 But hard to detect
GHO @ AS,2013/11/08
34
F. Xu
4
Discussion
GHO @ AS,2013/11/08
35
F. Xu
1. Discriminate c3
 In the presence of effective operators, we have
 One way to discriminate the degenerate solutions is by Higgs
pair production in future LHC experiments.
 The solution
will bring a large deviation from SM, and
would be easily checked (ruled out) by future experiments.
GHO @ AS,2013/11/08
36
F. Xu
2. Wise-Manohar Model
 Wise-Manohar model:
color-octet scalar
WM, PRD’06;
HVY,JHEP’11
……
 Custodial symmetry leads to
and
 The physical CPV phase appears in potential, could it be the
source of CP-odd operators?
GHO @ AS,2013/11/08
37
F. Xu
2. Wise-Manohar Model
 The mechanism to generate effective operators
 CP-even operators can
be generated at 1-loop
level;
 CP-odd operators
cannot be generated
purely from potential.
CP-even
CP-odd
 From a naïve dimensional analysis, constraints on model
parameters can be obtained from current LHC data
a complement to WM model
GHO @ AS,2013/11/08
38
F. Xu
2’. Another UV-complete model
 The mechanism to generate effective operators
 CP-even operators can
be generated at 1-loop
level;
 CP-odd operators can
be produced by adding
CP-violating Yukawa
interaction.
CP-even
CP-odd
 Such a toy model
GHO @ AS,2013/11/08
39
Chang, Pan and Xu, work in progress
F. Xu
3. Prediction for CPV decays
 CP violation fraction
 The CPV fraction in
WW/ZZ mode is small
 There could be large
CPV component in
gamma-gamma/gammaZ mode
 A not very predictive prediction (hard to analyze CP for photon)
GHO @ AS,2013/11/08
40
F. Xu
5
Summary
GHO @ AS,2013/11/08
41
F. Xu
Summary
 We have provided an EFT approach to 125 GeV Higgs boson, and find even
all Higgs decay channels agree with SM predictions, SM theoretical
uncertainty still provides a room for NP.
 From current LHC data we have got a global constraint of Wilson
coefficients, which indicates NP models, a toy model is constructed as a
typical example.
 From current LHC data, we find a linear relation between WW and ZZ,
and get the limits of signal strength for different di-boson decay modes.
 When EDM and AMDM are taken into account, CP-odd operators are
constrained severely. An interesting relation between ZZ(WW) and
gammaZ is predicted.
 The potentially interesting CPV fraction in diphoton and gammaZ mode is
pointed out.
 We also provide a way to discriminate a degenerated solution of c3.
GHO @ AS,2013/11/08
42
F. Xu
Backup: Another toy model
 Color 27-plet scalar + two vector-like fermion
 Scalar potential is same as color octet model
 The typical diagrams for generating CP-odd gauge-Higgs
operators
GHO @ AS,2013/11/08
44
F. Xu