Electric Dipole Moments as probes of New Physics
Vincenzo CiriglianoLos Alamos National Laboratory
1
FRIB TA Topical Program Hadronic electric dipole moments in the FRIB era: from the proton to protactinium
MSU, East Lansing, August 13 2019
• The quest for new physics and the special role of EDMs
• Connecting EDMs to new sources of CP violation
• (Selected topics in) EDM phenomenology in the LHC era:
• Non-standard Higgs couplings
• High-scale supersymmetry
• Connection to Baryogenesis
Outline
2
New physics: why?
X
While remarkably successful in explaining phenomena over a wide range of energies, the SM is probably not the whole story
No Matter, no Dark Matter, no Dark Energy
3
1/Coupling
M
vEW
4
Unexplored
New physics: where?
• New degrees of freedom: Heavy? Light & weakly coupled?
1/Coupling
M
vEW
5
New physics: how?
• Two complementary approaches
Energy Frontier(direct access to UV d.o.f)
1/Coupling
M
vEW
5
New physics: how?
• Two complementary approaches
Energy Frontier(direct access to UV d.o.f)
Precision Frontier(indirect access to UV d.o.f)(direct access to light d.o.f.)
1/Coupling
M
vEW
5
New physics: how?
• Two complementary approaches
Energy Frontier(direct access to UV d.o.f)
Precision Frontier(indirect access to UV d.o.f)(direct access to light d.o.f.)
• Two complementary approaches, both needed to reconstruct BSM dynamics: structure, symmetries, and parameters of LBSM
Special role of EDMs
6
• Probe P and T symmetry violation (CP) in flavor diagonal transitions: (i) highly suppressed in SM; (ii) sensitive to broad spectrum of new physics; (iii) possibly related to baryon asymmetry in the universe
Special role of EDMs
6
• Probe P and T symmetry violation (CP) in flavor diagonal transitions: (i) highly suppressed in SM; (ii) sensitive to broad spectrum of new physics; (iii) possibly related to baryon asymmetry in the universe
* Observation would signal new physics or a tiny QCD θ-term (< 10-10). Multiple measurements can disentangle the two effects
Th0
ACME-IIAndreev et al.,
Nature Vol. 562, p.355, Oct 2018
Special role of EDMs
7
• Probe P and T symmetry violation (CP) in flavor diagonal transitions: (i) highly suppressed in SM; (ii) sensitive to broad spectrum of new physics; (iii) possibly related to baryon asymmetry in the universe
1/Coupling
M
vEW
UV physics, up to PeV scale
Dark sectors, ALP’s, axion DM, …
d ~ (v/Λ)2 10-22 e cm → Λ ~ 102-3 TeV
Special role of EDMs
7
• Probe P and T symmetry violation (CP) in flavor diagonal transitions: (i) highly suppressed in SM; (ii) sensitive to broad spectrum of new physics; (iii) possibly related to baryon asymmetry in the universe
1/Coupling
M
vEW
UV physics, up to PeV scale
Dark sectors, ALP’s, axion DM, …
Dzuba, Flambaum, Samsonov, Stadnik, 1805.01234 Abel et al., 1708.06367
LeDall, Pospelov, Ritz 1505.01865 Mantry, Pitschmann, Ramsey-Musolf 1401.7339
…
Focus of this talk
d ~ (v/Λ)2 10-22 e cm → Λ ~ 102-3 TeV
Special role of EDMs
7
• Probe P and T symmetry violation (CP) in flavor diagonal transitions: (i) highly suppressed in SM; (ii) sensitive to broad spectrum of new physics; (iii) possibly related to baryon asymmetry in the universe
1/Coupling
M
vEW
UV physics, up to PeV scale
Dark sectors, ALP’s, axion DM, …
Dzuba, Flambaum, Samsonov, Stadnik, 1805.01234 Abel et al., 1708.06367
LeDall, Pospelov, Ritz 1505.01865 Mantry, Pitschmann, Ramsey-Musolf 1401.7339
…
Focus of this talk
d ~ (v/Λ)2 10-22 e cm → Λ ~ 102-3 TeV
Connecting EDMs to new physics
8
Connecting scalesTo connect UV physics to nuclei & atoms, use multiple EFTs
9
Connecting scalesTo connect UV physics to nuclei & atoms, use multiple EFTs
Perturbative
Non-perturbative
Non-perturbative
9
CPV at the quark-gluon level• At E ~GeV, leading BSM effects encoded in handful of dim-6 operators
Perturbative
10
Electric and chromo-electric dipoles of fermions
Gluon chromo-EDM (Weinberg operator)
Semileptonic and 4-quark
J⋅E J⋅Ec
CPV at the quark-gluon level• At E ~GeV, leading BSM effects encoded in handful of dim-6 operators
11
Quark EDM and chromo-EDM
MSSM2HDM
MSSM
CPV at the quark-gluon level• At E ~GeV, leading BSM effects encoded in handful of dim-6 operators
• Generated by a variety of BSM scenarios
Direct matching at high scale Λ12
Weinberg operator 2HDM
MSSM
CPV at the quark-gluon level• At E ~GeV, leading BSM effects encoded in handful of dim-6 operators
• Generated by a variety of BSM scenarios
Direct matching at high scale Λ13
CPV at the quark-gluon level• At E ~GeV, leading BSM effects encoded in handful of dim-6 operators
• Generated by a variety of BSM scenarios
Operator mixing (quantum effects) between Λ and weak scale14
CPV at the hadronic level• Leading pion-nucleon CPV interactions characterized by few LECs
Non-perturbative
CPV at the hadronic level• Leading pion-nucleon CPV interactions characterized by few LECs
Non-perturbative
• At E ~ Λχ ~ mN ~ GeV, map CPV Lagrangian onto π, N operators with same chiral properties
• Organize expansion according to power counting in Q/Λχ (Q ~ kF ~ mπ)
de Vries, Mereghetti, Timmermans, van Kolck, 1212.0990
T-odd P-odd pion-nucleon couplings
Electron and Nucleon EDMs
Short-range 4N and 2N2e coupling
N N
γ
N N
π
N N
e e
CPV at the hadronic level• Leading pion-nucleon CPV interactions characterized by few LECs
16
T-odd P-odd pion-nucleon couplings
Electron and Nucleon EDMs
Short-range 4N and 2N2e coupling
N N
γ
N N
π
N N
e e
dN[dq] and 2N2e couplings known at 10% level (lattice QCD)
Other O(100%) uncertainty
CPV at the hadronic level• Leading pion-nucleon CPV interactions characterized by few LECs
16
CPV at the hadronic level
QCD Sum Rules (50% error estimate)
QCD Sum Rules + NDA (~100%)2nd line: Pospelov-Ritz hep-ph/0504231 and refs therein
μ=2GeV
1st line (Lattice QCD): Bhattacharya et al. 1506.04196 & 1808.07597
17
• Example: nucleon EDM master formula
• Leading pion-nucleon CPV interactions characterized by few LECs
CPV at the hadronic level
QCD Sum Rules (50% error estimate)
QCD Sum Rules + NDA (~100%)2nd line: Pospelov-Ritz hep-ph/0504231 and refs therein
μ=2GeV
1st line (Lattice QCD): Bhattacharya et al. 1506.04196 & 1808.07597
17
Ongoing Lattice QCD calculations @ BNL, LANL, MSU
• Example: nucleon EDM master formula
• Leading pion-nucleon CPV interactions characterized by few LECs
CPV at the hadronic level• Leading pion-nucleon CPV interactions characterized by few LECs
18
Pospelov-Ritz hep-ph/0504231 and refs therein
Towards lattice QCD calculation: Walker-Loud and Mereghetti
• Example: pion-nucleon couplings
See also US-QCD white paper on Lattice QCD and Fundamental Symmetries, VC, Davoudi et al, 1904.09704
CP Violation at atomic level
Non-perturbative
19
• Need to work against Schiff ’s theorem: dA[de, dnucl]=0 for point-like non-relativistic constituents (charged constituents rearrange to screen applied Eext)
+ ++
- --
Eext
Eint
CP Violation at atomic level
20
• Need to work against Schiff ’s theorem: dA[de, dnucl]=0 for point-like non-relativistic constituents (charged constituents rearrange to screen applied Eext)
+ ++
- --
Eext
Eint
• Evading Schiff screening: finite size effects in diamagnetic atoms make dA[dnucl] ≠0. Suppression dA ~ Z2 (RN/RA)2 dnucl
Eextde
α2Z3 EextSandars 1965
Schiff 1963Eext
dnucl
Nuclear charge
distribution
• Evading Schiff screening: relativistic effects in paramagnetic atoms (and molecules) make dA[de] ≠0. Enhancement dA ~ α2Z3 de
CP Violation at atomic level
20
• Need to work against Schiff ’s theorem: dA[de, dnucl]=0 for point-like non-relativistic constituents (charged constituents rearrange to screen applied Eext)
+ ++
- --
Eext
Eint
• Evading Schiff screening: finite size effects in diamagnetic atoms make dA[dnucl] ≠0. Suppression dA ~ Z2 (RN/RA)2 dnucl
Eextde
α2Z3 EextSandars 1965
Schiff 1963Eext
dnucl
Nuclear charge
distribution
• Evading Schiff screening: relativistic effects in paramagnetic atoms (and molecules) make dA[de] ≠0. Enhancement dA ~ α2Z3 de
CP Violation at atomic level
O(few 100%) uncertainties
O(10%) uncertainties
20
Summary: the “EDM matrix”
αij
Nuclear and atomic matrix elements
βjk
Hadronic matrix elements (LQCD)
i ∈ {n, p, …, ThO, …, 199Hg}
BSM sources of CP violation
Hadronic scale effective couplings
21
Summary: the “EDM matrix”
• To constrain / disentangle new CPV sources need multiple probes
• Most coefficients αij and βjk are currently poorly known:
• need both α’s and β’s to connect EDMs to new physics [ck’s]
• good prospects of improvement for dn,p from Lattice QCD
αij
Nuclear and atomic matrix elements
βjk
Hadronic matrix elements (LQCD)
i ∈ {n, p, …, ThO, …, 199Hg}
BSM sources of CP violation
Hadronic scale effective couplings
21
Example: paramagnetic systems• Constraints on cj (de and CS) → connection to ck’s is relatively simple~
Chupp, Fierlinger, Ramsey-Musolf, Singh, 1710.02504
22
Phenomenology of EDMs in the LHC era
23
• LHC output so far:
• Higgs boson @ 125 GeV
• Everything else is quite heavier (or very light)
EDMs in the LHC era
Unexplored
• EDMs more relevant than ever:
• Strongest constraints of non-standard CP V Higgs couplings
• One of few observables probing PeV scale supersymmetry
• Strong constraints on weak scale baryogenesis models
24
• Still room for deviations: is this the SM Higgs? Key question at LHC Run 2, 3
• EDMs can help constraining non-standard CPV Higgs couplings
• So far, Higgs properties are compatible with SM expectations
EDMs and CPV Higgs couplings
25
• Leading (1/Λ2) CP-violating BSM interactions involving the Higgs:
EDMs and CPV Higgs couplings
H-qL-qR-V: dipole H-qL-qR: pseudo-scalarYukawa coupling
H-H-V-V~
V = g, Wa, BFμν Fμν ~ E·B~
• Leading (1/Λ2) CP-violating BSM interactions involving the Higgs:
EDMs and CPV Higgs couplings
H-qL-qR-V: dipole H-qL-qR: pseudo-scalarYukawa coupling
H-H-V-V~
V = g, Wa, B
Brod-Stamou, 1812.12303…
Chien-VC-Dekens-de Vries-Mereghetti, 1510.00725
Brod Haisch Zupan 1310.1385
Fuyuto & Ramsey-Musolf 1706.08548
…
VC-Dekens-de Vries-Mereghetti, 1603.03049
McKeen-Pospelov-Ritz1208.4597
…VC, Crivellin,, Dekens, de Vries,
Hoferichter, Mereghetti, 1903.03625, Phys. Rev. Lett. 123, 051801 (2019)
…
Fμν Fμν ~ E·B~
Yukawa couplings to quarks
Brod Haisch Zupan 1310.1385
Y.-T. Chien, VC, W. Dekens, J. de Vries, E. Mereghetti, JHEP 1602 (2016) 011 [1510.00725]
Pseudo-scalar coupling σ·(pf -pi)
is zero in the Standard Model
Yukawa couplings to quarks
LHC: Higgs production & decay
tTop
quark
Brod Haisch Zupan 1310.1385
Y.-T. Chien, VC, W. Dekens, J. de Vries, E. Mereghetti, JHEP 1602 (2016) 011 [1510.00725]
Pseudo-scalar coupling σ·(pf -pi)
is zero in the Standard Model
Low Energy: induce electron, neutron, mercury EDM
Yukawa couplings to quarks
LHC: Higgs production & decay
tTop
quark
Brod Haisch Zupan 1310.1385
Y.-T. Chien, VC, W. Dekens, J. de Vries, E. Mereghetti, JHEP 1602 (2016) 011 [1510.00725]
Pseudo-scalar coupling σ·(pf -pi)
is zero in the Standard Model
Yukawa couplings to quarks
1E-06
1E-04
1E-02
1E+00
EDMs LHC
Λ (TeV)
2.5
25
250
de de
Y.-T. Chien, VC, W. Dekens, J. de Vries, E. Mereghetti, JHEP 1602 (2016) 011 [1510.00725]
• EDMs are teaching us something about the Higgs!
• Future: factor of 2 at LHC; EDM constraints scale linearly
• Uncertainty in matrix elements strongly dilutes EDM constraints
Yukawa couplings to quarks
1E-06
1E-04
1E-02
1E+00
EDMs LHC
Λ (TeV)
2.5
25
250
de de
Y.-T. Chien, VC, W. Dekens, J. de Vries, E. Mereghetti, JHEP 1602 (2016) 011 [1510.00725]
• Much stronger impact of nEDM with reduced uncertainties
• Experiment at 5 x 10-27 e cm and improved matrix elements will make nEDM the strongest probe for all couplings
25% 50%
Target for Lattice QCD in the 5-year time scale
Yukawa couplings to quarks
1E-06
1E-04
1E-02
1E+00
EDMs LHC
Λ (TeV)
2.5
25
250
de
• Dominant sources of CPV (together with VVV) in so-called universal theories
Higgs-gauge CPV couplings
Peskin-Takeuchi, PRL 65, 964 (1990) Barbieri-Pomarol-Rattazzi-Strumia hep-ph/0405040
Wells-Zhang, 1510.08462
• Dominant sources of CPV (together with VVV) in so-called universal theories
Higgs-gauge CPV couplings
Peskin-Takeuchi, PRL 65, 964 (1990) Barbieri-Pomarol-Rattazzi-Strumia hep-ph/0405040
Wells-Zhang, 1510.08462
“Universal theories”
• New physics couples to SM bosons, and / or to SM fermions through SM currents
• Consistent framework to analyze EW precision tests (oblique corrections, etc)
• Evade flavor constraints (Minimal Flavor Violation is automatic), scale can be low New Heavy quark
Example
Higgs-gauge CPV couplings
Peskin-Takeuchi, PRL 65, 964 (1990) Barbieri-Pomarol-Rattazzi-Strumia hep-ph/0405040
Wells-Zhang, 1510.08462
Fμν Fμν ~ E·B~
New Heavy quark
∝
CPV vertex
Ferreira-Fuks-Sanz-Sengupta Eur. Phys. J. C (2017) 77:675
• Dominant sources of CPV (together with VVV) in so-called universal theories
Higgs-gauge CPV couplings
Peskin-Takeuchi, PRL 65, 964 (1990) Barbieri-Pomarol-Rattazzi-Strumia hep-ph/0405040
Wells-Zhang, 1510.08462
Fμν Fμν ~ E·B~
New Heavy quark
∝
CPV vertex
Ferreira-Fuks-Sanz-Sengupta Eur. Phys. J. C (2017) 77:675
• Dominant sources of CPV (together with VVV) in so-called universal theories
H-H-V-V~ V-V-V~
Six CPV couplings at O(1/Λ2)
Higgs-gauge CPV couplings
H-H-V-V~ V-V-V~
• Induce CPV angular distributions in pp → h +2 jets, pp → V +2 jets, …
Peskin-Takeuchi, PRL 65, 964 (1990) Barbieri-Pomarol-Rattazzi-Strumia hep-ph/0405040
Wells-Zhang, 1510.08462
hV
V
• Dominant sources of CPV (together with VVV) in so-called universal theories
Higgs-gauge CPV couplings
H-H-V-V~ V-V-V~
• Induce light fermions (chromo)-EDMs at the 1-loop level
Peskin-Takeuchi, PRL 65, 964 (1990) Barbieri-Pomarol-Rattazzi-Strumia hep-ph/0405040
Wells-Zhang, 1510.08462
• Induce CPV angular distributions in pp → h +2 jets, pp → V +2 jets, …
• Dominant sources of CPV (together with VVV) in so-called universal theories
Higgs-gauge CPV couplings• Current constraints, “turning on” one coupling at a time: EDMs vs LHC
VC, A. Crivellin, W. Dekens, J. de Vries, M. Hoferichter, E. Mereghetti, 1903.03625, Phys. Rev. Lett. 123, 051801 (2019)
1E-06
1E-04
1E-02
1E+00
EDMs (no th error)EDMs (with th error)LHC
Λ (TeV)
2.5
25
250
LHC limits from : ATLAS, 1703.04362 & Bernlochner et al., 1808.06577
dHg
dn
dHg
dn
de de de
de
Higgs-gauge CPV couplings• Prospective constraints, turing on all couplings: low-energy vs LHC
95% CL
LHC projections
from Bernlochner
et al., 1808.06577
|dn,p,d,Ra| < 10-27 e cm + improved theory errors
Phys. Rev. Lett. 123, 051801 (2019)
Higgs-gauge CPV couplings• Prospective constraints, turing on all couplings: low-energy vs LHC
95% CL
LHC projections
from Bernlochner
et al., 1808.06577
Low-energy measurements have far stronger constraining power → highly correlated allowed regions. Distinctive pattern that could be probed at the high-luminosity LHC
|dn,p,d,Ra| < 10-27 e cm + improved theory errors
Phys. Rev. Lett. 123, 051801 (2019)
EDMs in high-scale SUSY
• “Split-SUSY”: tuned spectrum but retains DM candidate and unification
Arkani-Hamed, Dimopoulos 2004, Giudice, Romanino 2004, Arkani-Hamed et al 2012, Altmannshofer-Harnik-Zupan 1308.3653, …
_
_1 TeV
103 TeV
Gauginos (M1,2,3)Higgsino (μ)
Squarks, sleptons (mf) ~
EDMs among a handful of observables
capable of probing such high scales
36
Altmannshofer-Harnik-Zupan 1308.3653
EDMs in high-scale SUSY
Altmannshofer-Harnik-Zupan 1308.3653
EDMs in high-scale SUSY
Maximal CPV phases.Squark mixings fixed at 0.3
Current nEDM limitCurrent nEDM limit
Altmannshofer-Harnik-Zupan 1308.3653
EDMs in high-scale SUSY
For |μ| < 10 TeV, mq ~ 1000 TeV, same CPV phase controls de, dn [dq] → correlation?~
Maximal CPV phases.Squark mixings fixed at 0.3
Current nEDM limitCurrent nEDM limit
• Studying the ratio dn /de with precise matrix elements (LQCD) → stringent upper bound dn < 4.1 ×10-29 e cm
• Split-SUSY can be falsified by current EDM searches
Example of model diagnosing enabled by multiple measurements (e,n) and controlled theoretical uncertainty
sin(ϕ2)=1 tan(β)=1
Bhattacharya, VC, Gupta, Lin, Yoon 1506.04196 , 1808.07597
Limit from ThO (ACME-II)
EXCLU
DED
38
EDMs in high-scale SUSY
EDMs and weak scale baryogenesis
For a review see: Morrissey & Ramsey-Musolf 1206.2942
• B violation
• C & CP violation
• Departure from thermal equilibrium
Sakharov 1967
EDMs and weak scale baryogenesis
For a review see: Morrissey & Ramsey-Musolf 1206.2942
• Requirements on BSM scenarios:
• 1st order phase transition (testable at LHC & future colliders)
• New CPV (EDMs often provide strongest constraint)
• Rich literature: (N)MSSM, Higgs portal (scalar extensions), flavored baryogenesis,…
• B violation
• C & CP violation
• Departure from thermal equilibrium
Sakharov 1967
• In Supersymmetry, 1st order phase transition disfavored by LHC in minimal model (MSSM), need singlet extension (NMSSM)
• CPV phases appearing in the gaugino-higgsino mixing contribute to both BAU and EDM
• In scenario with universal phases φ1=φ2, successful baryogenesis implies a “guaranteed signal” for next generation EDMs searches
Compatible with baryon asymmetry
Next generation neutron EDM Li, Profumo, Ramsey-Musolf
0811.1987 VC, Li, Profumo, Ramsey-Musolf,
0910.458940
EDMs and weak scale baryogenesis
Sin
(φ1)
• In Supersymmetry, 1st order phase transition disfavored by LHC in minimal model (MSSM), need singlet extension (NMSSM)
• CPV phases appearing in the gaugino-higgsino mixing contribute to both BAU and EDM
• In scenario with universal phases φ1=φ2, successful baryogenesis implies a “guaranteed signal” for next generation EDMs searches
Compatible with baryon asymmetry
Next generation neutron EDM Li, Profumo, Ramsey-Musolf
0811.1987 VC, Li, Profumo, Ramsey-Musolf,
0910.458940
EDMs and weak scale baryogenesis
Sin
(φ1)
CAVEAT: current uncertainties in 1) hadronic matrix elements; 2) early universe calculations;
may shift these lines and alter the conclusions
VC, C. Lee, S. Tulin, 1106/0747
Summary
41
• EDMs are a powerful probe of new sources of CP violation
• Most stringent constraints on CPV couplings of the Higgs
• Probe extremely high-scale BSM scenarios
• Interpretation of null (for now) or positive EDM searches requires bridging scales: from BSM to hadronic, nuclear, and atomic
• Improving theory uncertainties is essential
• LQCD can have big impact on hadronic matrix elements
Outlook
42
• May lead to the discovery of new physics (before colliders)
• Will have major impact on elucidating CP properties of new physics that might be discovered at LHC or future colliders
• If new physics exists only at very high scale, EDMs may be among few observables to probe it
EDMs will continue to play unique role in the next decade(s)
These prospects strongly motivate the many experimental efforts and theory calculations to refine hadronic and nuclear matrix elements
Thank you!
A drawing by Bruno Touschek 43