EDM constraint on NP associated with BEH bosonFanrong Xu (徐繁荣 )
National Taiwan University
Nov. 8, 2013 @ AS
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Introduction0
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Introduction
“Discovery” of Higgs Boson rated year’s top scientific achievement of 2012.
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The life of Higgs
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Production
Decay
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The discovery @ LHC Signal Strength
ICHEP2012, summer 2012
HCP2012, winter 2012
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Higgs XSWG
Once upon a time, there was a hot word called
“h-gamma-gamma”…
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The discovery @ LHC
Moriond 2013
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EW
QCD
excess or fluctuation?
What could be hidden
in current data: NP or SM?
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The discovery @ LHC
EPS-HEP 2013
LS1
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Further Identification Spin and CP
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J. Bendavid, EPS-HEP 2013
excludes hypothesis at
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?
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NP
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Byproduct: Cutoff Scale Mass scale of exotic degrees of freedom: (0.4~8) TeV
(cutoff)
CMS@ICHEP2012
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ATLAS@HCP2012
Can we get a hint for the NP scale?
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Strategy
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SM+NP
EDM+(g-2)
EFT
Based on We-Fu Chang, Wei-Ping Pan and FX, PRD 88,033004 (2013).
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Gauge-Higgs Operators1
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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
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GIMR, JHEP10 (2010)085;BW, NPB268 (1986) 621.
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Effective Theory
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Effective Operators Motivated by diphoton excess and DOF(s) beyond SM, we assume New Physics can be captured by the effective gauge-Higgs operators
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.
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Manohar, Wise;X. Zhang, B.-L. Young;McKenn,Pospelov,Ritz
……
GJMT, 1301.2588; MEMP,1302.5661
Oblique correction: S
QCD theta term
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Effective interactions
CP even/odd tree level h-V-V’ interaction is brought in
Also anomalous gauge coupling is introduced
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SM-like Anomalous coupling
CP-even CP-odd
Effective coupling : the combination of WCs
Form factors
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Higgs Physics2
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Production and decay
Signal strength: co-determined by both production and decay
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Error source: PDF +
Higgs XSWG
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Modification @ loop level
diphoton decay:
production: gluon fusion dominates
unmeasured decay channel:
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CP-even CP-odd
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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
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All the final state fermions are summed up
All the fermions are massless
CP-even CP-oddGHO @ AS,2013/11/08
Numerical Analysis
Numerical expressions at cutoff 1TeV
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Rescaling:
The story of 6 parameters
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Pseudo global fit
Input experimental data (up to Moriond 2013)
68 % C.L. correlation among alpha’s:
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Current LHC data agrees with SM;Larger GF production smaller Higgs decay width
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Constraint on Wilson coefficients
95 % C.L. correlation among Wilson coefficients:
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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.
SM:
LHC:
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Constraint on Effective couplings
The constraints on Wilson coefficients can be translated to constraints on effective coupling
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The effective coupling can be obtained after a coordinate rotation from WCs.
This coupling strength is checkable by different groups.
SM
LHC
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The relation between ZZ and WW:
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The boundary of decay width ratio and signal is obvious
A linear relation of signal strength between WW and ZZ is found
SM
LHC
Prediction
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EDM, MDM3
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EDM
EDM and MDM have different CP property
nEDM in SM
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EDM Current nEDM
Current eEDM
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UK US
ACME collaboration, 1310.7534
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AMDM
AMDM: the SM deviation from experimental measurement provides a room for NP SM calculation:
Measurement: muon: muon (g-2) col.,
2006
electron: Hanneke et. al., PRA2011
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GHO @ Nankai U.,2013/09/22
Aoyama-Hayakawa-Kinoshita., 2007
Less known
2-loop
HVP LBL
3
1.3 but error could be reduced
EDM and AMDM in EFT
One loop EDM and g-2 can be generated due to the effective operators
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CP-odd (EDM); CP-even (g-2)
McKeen-Pospelov-Ritz, PRD86, 113004 (2012)
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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,
But the combination of EDM and Higgs can largely reduce allowed region
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EDM constrain parameter on a long and narrow band
Higgs best fit
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Constraint on CP-even sector
With a best fit of muon and electron g-2, a linear relation is obtained
g-2, giving another band with different slope from Higgs constraint, helps to further determine parameter space of CP-even sector.
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g-2 Higgs best fit
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A global constraint on WCs Take into account all the above experiments, we can get a
limited region in Wilson coefficient space.
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CP-odd sector are severely constrained, reduced to order of 1, which also gives an indication for NP models.
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Constraints on effective coupling
The constraints on Wilson coefficients can be translated to constraints on effective coupling
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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.
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The relation between ZZ and WW:
The interesting relation between WW/ZZ and AZ
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But hard to detect
Prediction
SM
LHC
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Discussion4
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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.
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The solution will bring a large deviation from SM, and would be easily checked (ruled out) by future experiments.
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2. Wise-Manohar Model
Wise-Manohar model: color-octet scalar
Custodial symmetry leads to and
The physical CPV phase appears in potential, could it be the source of CP-odd operators?
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WM, PRD’06; HVY,JHEP’11
……
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The mechanism to generate effective operators
From a naïve dimensional analysis, constraints on model parameters can be obtained from current LHC data
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CP-even CP-odd
CP-even operators can be generated at 1-loop level;
CP-odd operators cannot be generated purely from potential.
2. Wise-Manohar Model
a complement to WM modelGHO @ AS,2013/11/08
The mechanism to generate effective operators
Such a toy model
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CP-even CP-odd
CP-even operators can be generated at 1-loop level;
CP-odd operators can be produced by adding CP-violating Yukawa interaction.
2’. Another UV-complete model
Chang, Pan and Xu, work in progressGHO @ AS,2013/11/08
3. Prediction for CPV decays
CP violation fraction
A not very predictive prediction (hard to analyze CP for photon)
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The CPV fraction in WW/ZZ mode is small
There could be large CPV component in gamma-gamma/gamma-Z mode
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Summary5
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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.
Summary
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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
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