electric dipole moments as probes of new physics · 2019. 8. 13. · physics; (iii) possibly...

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?



Precision Frontier(indirect access to UV d.o.f)(direct access to light d.o.f.)

1/Coupling

M

vEW

5

New physics: how?



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


6


* 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


7


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


7


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


11

Quark EDM and chromo-EDM

MSSM2HDM

MSSM


• Generated by a variety of BSM scenarios

Direct matching at high scale Λ12

Weinberg operator 2HDM

MSSM



Direct matching at high scale Λ13



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


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


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


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


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


20


+ ++

- --

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


20


+ ++

- --

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


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

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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

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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:


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:


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


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


LHC: Higgs production & decay

tTop

quark





Low Energy: induce electron, neutron, mercury EDM


LHC: Higgs production & decay

tTop

quark






1E-06

1E-04

1E-02

1E+00

EDMs LHC

Λ (TeV)

2.5

25

250

de de


• 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


1E-06

1E-04

1E-02

1E+00

EDMs LHC

Λ (TeV)

2.5

25

250

de de


• 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


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





“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




Fμν Fμν ~ E·B~

New Heavy quark

∝

CPV vertex

Ferreira-Fuks-Sanz-Sengupta Eur. Phys. J. C (2017) 77:675





Fμν Fμν ~ E·B~

New Heavy quark

∝

CPV vertex

Ferreira-Fuks-Sanz-Sengupta Eur. Phys. J. C (2017) 77:675


H-H-V-V~ V-V-V~

Six CPV couplings at O(1/Λ2)


H-H-V-V~ V-V-V~

• Induce CPV angular distributions in pp → h +2 jets, pp → V +2 jets, …



hV

V



H-H-V-V~ V-V-V~

• Induce light fermions (chromo)-EDMs at the 1-loop level



• Induce CPV angular distributions in pp → h +2 jets, pp → V +2 jets, …


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




Maximal CPV phases.Squark mixings fixed at 0.3

Current nEDM limitCurrent nEDM limit



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 and weak scale baryogenesis

For a review see: Morrissey & Ramsey-Musolf 1206.2942

• B violation

• C & CP violation

• Departure from thermal equilibrium

Sakharov 1967


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


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


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

electric dipole moments as probes of new physics · 2019. 8. 13. · physics; (iii) possibly...

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