precision electroweak physics and qcd at an eic m.j. ramsey-musolf wisconsin-madison npac...

Precision Electroweak Physics and QCD at an EIC

M.J. Ramsey-MusolfWisconsin-MadisonQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.

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http://www.physics.wisc.edu/groups/particle-theory/

NPACTheoretical Nuclear, Particle, Astrophysics & Cosmology

LBL, December 2008

Questions

• What are the opportunities for probing the “new Standard Model” and novel aspects of nucleon structure with electroweak processes at an EIC?

• What EIC measurements are likely to be relevant after a decade of LHC operations and after completion of the Jefferson Lab electroweak program?

• How might a prospective EIC electroweak program complement or shed light on other key studies of neutrino properties and fundamental symmetries in nuclear physics?

Outline

• Lepton flavor violation: e-+A K - + A

• Neutral Current Processes: PV DIS & PV Moller

• Charged Current Processes: e-+A K ET + j

Disclaimer: some ideas worked out in detail; others need more research

Lepton Number & Flavor Violation

• LNV & Neutrino Mass

• Mechanism Problem

• CLFV as a Probe

• K e Conversion at EIC ?

Uncovering the flavor structure of the new SM and its relationship with the origin of neutrino mass is an important task. The observation of charged lepton flavor violation would be a major discovery in its own right.

-Decay: LNV? Mass Term?

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e−

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e−

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M

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W −

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W −

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A Z,N( )

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A Z − 2,N + 2( )0.1

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10

100

1000

Effective

( )Mass meV

12 3 4 5 6 7

12 3 4 5 6 7

12 3 4 5 6 7

1 ( )Minimum Neutrino Mass meV

U1e=.866δm2

sol=7meV

2

U2e=.5δm2

atm=2meV

2

U 3e =

Inverted

Normal

Degenerate

Dirac Majorana

-decayLong baseline

?

?

Theory Challenge: matrix elements+ mechanism

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mν

EFF= Uek

2mk e2iδ

k

∑

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e−

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e−

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χ 0

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˜ e −

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u

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u

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d

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˜ e −€

e−

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M

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W −

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W −

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u

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d

mEFF & neutrino spectrum

Normal Inverted

-Decay: Mechanism

Dirac Majorana

Theory Challenge: matrix elements+ mechanism

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mν

EFF= Uek

2mk e2iδ

k

∑

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e−

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e−

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χ 0

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˜ e −

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u

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d

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W −

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u

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d

Mechanism: does light M exchange dominate ?

How to calc effects reliably ? How to disentangle H & L ?

O(1) for ~ TeV

-Decay: Interpretation

0.1

1

10

100

1000

Effective

( )Mass meV

12 3 4 5 6 7

12 3 4 5 6 7

12 3 4 5 6 7

1 ( )Minimum Neutrino Mass meV

U1e=.866δm2

sol=7meV

2

U2e=.5δm2

atm=2meV

2

U 3e =

Inverted

Normal

Degeneratesignal equivalent to degenerate hierarchy

Loop contribution to m of inverted hierarchy scale

Sorting out the mechanism

• Models w/ Majorana masses (LNV) typically also contain CLFV interactions

RPV SUSY, LRSM, GUTs (w/ LQ’s)

• If the LNV process of arises from TeV scale particle exchange, one expects signatures in CLFV processes

• K e Conversion at EIC could be one probe

CLFV, LNV & the Scale of New Physics

Present universe Early universe

Weak scale Planck scale

log10(μ / μ0)

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αS−1

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αL−1

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αY−1

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μ

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e

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γ

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μ

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A Z,N( )

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A Z,N( )

MEG: μγ ~ 5 x 10-14

μ2e: Bμ->e ~ 5 x 10-17

??

R = Bμ->e

Bμ->eγ

Also PRIME

μ!eγ: M1





μ!e: M1 ! R ~ α

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Lepton Flavor & Number Violation

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μ

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μ

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A Z,N( )

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MEG: Bμ->eγ ~ 5 x 10-14

μ2e: Bμ->e ~ 5 x 10-17

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μ

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e

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γ*

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e+

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Δ−−

Logarithmic enhancements of R

Raidal, Santamaria; Cirigliano, Kurylov, R-M, Vogel

0decay

RPV SUSY

LRSM





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γ*

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are needed to see this picture.Tree Level

Low scale LFV: R ~ O(1) GUT scale LFV: R ~ Oα

Lepton Flavor & Number Violation

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Exp: B->eγ ~ 1.1 x 10-7

EIC: ~ 103 | A1e|2 fb

Raidal, Santamaria; Cirigliano, Kurylov, R-M, Vogel

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γ*

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˜ ν

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γ*

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Δ−−

Logarithmic enhancements of R

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|A2e|2 < 10-8

EIC: ~ 10-5 fb

If |A2e|2 ~ |A1

e|2

Log or tree-level enhancement:

|A1e|2 / |A2

e|2 ~ | ln me / 1 TeV |2 ~ 100

BKeγ48 3α|A2e|2

Need ~ 1000 fb

M1 operator

Penguin op

CLFV & Other Probes

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γ

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A Z,N( )

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X

Exp: B->eγ ~ 1.1 x 10-7

EIC: ~ 103 | A1e|2 fb

hμe hee

+ hμμ hμe

+ hμ he

if RH; PV Moller if LH

Ke(γ

Doubly Charged Scalars

μKe(γ hee he

+ heμ hμ

+ he h

All hab $ m if part of see-saw

LHC: ΔΔBRs (in pair prod)

LFV with leptons: HERA

Veelken (H1, Zeus) (2007)

Leptoquark Exchange: Like RPV SUSY /w /





eqq eff op

lq|2 < 10-4 (MLQ / 100 GeV)2

HW Assignment:

• Induce Keγat one loop?

• Consistent with BKeγ? HERA limits look stronger

• Connection w/ m & in GUTS ?

• Applicable to other models that generate tree-level ops?

LFV with leptons: recent theory



Kanemura et al (2005)



μqq eff opSUSY Higgs Exchange

lq|2 < 2 x 10-2 (MLQ / 100 GeV)2

lq|2 < 10-4 (MLQ / 100 GeV)2 HERA

Neutral Current Probes: PV

• Basics of PV electron scattering

• Standard Model: What we know

• New physics ? SUSY as illustration

• Probing QCD

PV Electron Scattering

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Z 0

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γ

Parity-Violating electron scattering

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APV =N↑↑ − N↑↓

N↑↑ + N↑↓

=GFQ2

4 2παQW + F(Q2,θ)[ ]

“Weak Charge” ~ 0.1 in SM

Enhanced transparency to new physics

Small QCD uncertainties (Marciano & Sirlin; Erler & R-M)

QCD effects (s-quarks): measured (MIT-Bates, Mainz, JLab)

Effective PV e-q interaction & QW

Low energy effective PV eq interaction

Weak Charge:

Nu C1u + Nd C1d

Proton:

QWP = 2 C1u + C1d = 1-4 sin2W ~ 0.1

Electron:

QWe = C1e = -1+4 sin2W ~ - 0.1

QW and Radiative Corrections

Tree Level

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QWf = gV

f gAe

Radiative Corrections

QWf =ρPV (2I3

f −4QfκPV )+λ fsin2 θW

Flavor-independent

Normalization Scale-dependent effective weak mixing

Flavor-dependent

Constrained by Z-pole precision observables

Large logs in

Sum to all orders with running sin2W & RGE

Weak Mixing in the Standard Model

Scale-dependence of Weak Mixing

JLab Future

SLAC Moller

Parity-violating electron scattering

Z0 pole tension

PVES & New Physics

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˜ q Lj

1j1

1j1


RPV

SUSY Z/ Bosons Leptoquarks


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LQ

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Semi-leptonic only

Moller only

PVES & APV Probes of SUSY

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δQ

WP

, S

US

Y /

QW

P,

SM

RPV: No SUSY DM Majorana s

SUSY Loops

δQWe, SUSY / QW

e, SM

gμ-2

12 GeV

6 GeV

E158

Q-Weak (ep)

Moller (ee)

Kurylov, RM, Su

Hyrodgen APV or isotope ratios

Global fit: MW, APV, CKM, l2,…

Effective PV e-q interaction & PVDIS


PV DIS eD asymmetry: leading twistWeak Charge:

Nu C1u + Nd C1d

Proton:

QWP = 2 C1u + C1d = 1-4 sin2W ~ 0.1

Electron:

QWe = C1e = -1+4 sin2W ~ - 0.1

Model Independent Constraints

P. Reimer, X. Zheng

Comparing AdDIS and Qw

p,e

e

p

RPV

Loops

PVES, New Physics, & the LHC

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RPV

SUSY Z/ Bosons Leptoquarks


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′Z

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LQ

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< 1.5 TeV Masses

~ few 100 GeV & large tan

Moller: ~ 2.5% on APV

PVDIS: ~ 0.5% on APV

Need L ~ 1033 - 1034

Deep Inelastic PV: Beyond the Parton Model & SM

e-

N X

e-

Z* γ*

d(x)/u(x): large x Electroweak test: e-q couplings & sin2W

Higher Twist: qq and qqg correlations

Charge sym in pdfs

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up (x) = dn (x)?

d p (x) = un (x)?

PVDIS & QCD


PV DIS eD asymmetry: leading twist

Higher Twist (J Lab)

CSV (J Lab, EIC)

d/u (J Lab, EIC) +

PVDIS & CSV

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up (x) = dn (x)?

d p (x) = un (x)?

•Direct observation of parton-level CSV would be very exciting!•Important implications for high energy collider pdfs•Could explain significant portion of the NuTeV anomaly

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δu(x) = up (x) − dn (x)

δd(x) = d p (x) − un (x)

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RCSV =δAPV (x)

APV (x)= 0.28

δu(x) −δd(x)

u(x) + d(x)

Londergan & Murdock

Few percent δA/A

Adapted from K. Kumar

PVDIS & d(x)/u(x): xK1

Adapted from K. Kumar

SU(6): d/u~1/2Valence Quark: d/u~0

Perturbative QCD: d/u~1/5

PV-DIS off the proton(hydrogen target)

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APV =GFQ2

2παa(x) + f (y)b(x)[ ]

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a(x) =u(x) + 0.91d(x)

u(x) + 0.25d(x)

Very sensitive to d(x)/u(x)

δA/A ~ 0.01

C-Odd SD Structure Functions



C-odd

C-odd

Anselmino, Gambino, Kalinowski ‘94

Target Spin Asymmetries



Polarized Long & trans target spin asymmetries (parity even)

Unpolarized Long & trans target spin asymmetry (parity odd)



Bilenky et al ‘75; Anselmino et al ‘94

PVES at an EIC


JLab Future

SLAC Moller

Parity-violating electron scattering

EIC PVDIS ?

Z0 pole tension

EIC Moller ?

Charged Current Processes

• The NuTeV Puzzle

• HERA Studies

• W Production at an EIC ? CC/NC ratios ?

Weak Mixing in the Standard Model


JLab Future

SLAC Moller

nucleus deep inelasticscattering

Z0 pole tension

The NuTeV Puzzle

Rν =σνNNC σνN

CC =gL2 +rgR

2

Rν =σν NNC σ ν N

CC =gL2 +r−1gR

2

gL,R2 =

ρνNNC

ρνNCC

⎛

⎝ ⎜ ⎞

⎠ ⎟

2

(εL ,Rq

q∑ )2

r =σνNCC σν N

CC

Rνexp−Rν

SM =−0.0033±0.0007

Rν exp−Rν

SM =−0.0019±0.0016

R− =

Rν −rRν

1−r=(1−2sin2θW) /2+L

Paschos-Wolfenstein

SUSY Loops

RPV SUSY

Wrong sign

Other New CC Physics?

Low-Energy Probes

Nuclear & neutron decay

Pion leptonic decay

Polarized μ-decay

δO / OSM ~ 10-3

δO / OSM ~ 10-4

δO / OSM ~ 10-2

HERA W production



δO / OSM ~ 10-1

A. Schoning (H1, Zeus)

CC Structure Functions: more promising?







Summary

• Precision studies and symmetry tests are poised to discovery key ingredients of the new Standard Model during the next decade

• There may be a role for an EIC in the post-LHC era

• Promising: PV Moller & PV DIS for neutral currents

• Homework: Charged Current probes -- can they complement LHC & low-energy studies?

• Intriguing: LFV with eK conversion:

€

L dt ~ 103 fb∫

Back Matter

• Precision studies and symmetry tests with neutrons are poised to discovery key ingredients of the new Standard Model during the next decade

• Physics “reach” complements and can even exceed that of colliders: dn~10-28 e-cm ; δO/OSM ~ 10-4

• Substantial experimental and theoretical progress has set the foundation for this era of discovery

• The precision frontier is richly interdisciplinary: nuclear, particle, hadronic, atomic, cosmology

PVES Probes of RPV SUSY

111/ ~ 0.06 for mSUSY ~ 1 TeV

sensitivity

k31 ~ 0.15 for mSUSY ~ 1 TeV

μ->eγ LFV Probes of RPV:


μ->e LFV Probes of RPV:

12k ~ 0.3 for mSUSY ~ 1 TeV & δQWe / QW

e ~ 5%




m LNV Probes of RPV:



Probing Leptoquarks with PVES

General classification: SU(3)C x SU(2)L x U(1)Y



Q-Weak sensitivities:



SU(5) GUT: m

, prot

LQ 2 15H

Dorsner & Fileviez Perez, NPB 723 (2005) 53

Fileviez Perez, Han, Li, R-M 0810.4238


SU(5) GUT:

mvia type II

see saw LQ 2 15H





PV Sensitivities






4% QWp

(MLQ=100 GeV)

Z Pole Tension

⇒ mH = 89 +38-28

GeV⇒ S = -0.13 ± 0.10

ALR AFB (Z→ bb)

sin2θw = 0.2310(3)

↓mH = 35 +26

-17 GeVS= -0.11 ± 17

sin2θw = 0.2322(3)

↓mH = 480 +350

-230

GeVS= +0.55 ± 17

Rules out the SM! Rules out SUSY!Favors Technicolor!

Rules out Technicolor!Favors SUSY!

(also APV in Cs) (also Moller @ E158)

W. MarcianoThe Average: sin2θw = 0.23122(17)

3σ apart

•Precision sin2W measurements at colliders very challenging•Neutrino scattering cannot compete statistically•No resolution of this issue in next decade

K. Kumar

precision electroweak physics and qcd at an eic m.j. ramsey-musolf wisconsin-madison npac...

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