ParityViolation and Strange Quarks: Theoretical Perspectives

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Parity-Violation and Strange Quarks Theoretical
Perspectives
M.J. Ramsey-Musolf
Hall A Collaboration Meeting December 05
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Outline

• Historical Context
• Strange quarks what have we learned?
• Other aspects of parity-violation and QCD
  radiative corr, N to D , gg

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PV Past, Present, Future
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PV Past, Present, Future
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PV Past, Present, Future
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Quarks, Gluons, the Light Elements
Lattice QCD
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Strange Quarks in the NucleonWhat have we
learned?
Jaffe 89 Hammer, Meissner, Drechsel 95

• Dispersion Relations
• Narrow Resonances
• High Q2 ansatz

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Strange Quarks in the NucleonWhat have we
learned?
HAPPEX SAMPLE MAINZ G0
K. Aniol et al, nucl-ex/0506011
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Strange Quarks in the Nucleon What have we
learned?

• Strange quarks dont appear in the conventional
  Quark Model picture of the nucleon

• Perturbation theory is limited

?QCD / ms 1 No HQET
mK / ?c 1/2 ?PT ?

• Symmetry is impotent

J?s J?B - 2 J?EM, I0
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What ?PT can (cannot) say
Ito R-M Hemmert, Meissner, Kubis Hammer, Zhu,
Puglia, R-M
The SU(3) chiral expansion for mB
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What ?PT can (cannot) say
Ito R-M Hemmert, Meissner, Kubis Hammer, Zhu,
Puglia, R-M
The SU(3) chiral expansion for mB
O (p3) non-analytic in mq unique to
loops leading SU(3)
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What ?PT can (cannot) say
Ito R-M Hemmert, Meissner, Kubis Hammer, Zhu,
Puglia, R-M
The SU(3) chiral expansion for mB
O (p4) non-analytic in mq (logs)
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What ?PT can (cannot) say
Ito R-M Hemmert, Meissner, Kubis Hammer, Zhu,
Puglia, R-M
The SU(3) chiral expansion for mB
O (p4)
SU(3) Sym breaking
Two-deriv operators
1/mN terms
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What ?PT can (cannot) say
Ito R-M Hemmert, Meissner, Kubis Hammer, Zhu,
Puglia, R-M
The SU(3) chiral expansion for mB

• converges as (mK / Lc )n
• good description of SU(3) SB

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What ?PT can (cannot) say
Ito R-M Hemmert, Meissner, Kubis Hammer, Zhu,
Puglia, R-M
O (p4) octet only
Implications for ms
O (p2) singlet
O (p3,p4) loop only
O (p2,p4) octet
O (p4) singlet

• Near cancellation of O (p2,p4) octet loop
  terms
• Expt b0 0.6 b8 terms slightly gt 0
• Models different assumptions for b0 0.6 b8
  terms

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Q2 -dependenceof GsM
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What ?PT can (cannot) say
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What ?PT can (cannot) say
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What ?PT can (cannot) say
Ito R-M Hemmert, Meissner, Kubis Hammer, Zhu,
Puglia, R-M
O (p3) non-analytic in mq (loops) mq
-independent cts
The SU(3) chiral expansion for rs
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What ?PT can (cannot) say
Ito R-M Hemmert, Meissner, Kubis Hammer, Zhu,
Puglia, R-M
The SU(3) chiral expansion for rs
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Kaon cloud
Not sufficient to explain GsE,M
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Kaon cloud models
Not reliable guide to sign or magnitude of GsE,M
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Chiral models
Implicit assumptions about b0 , c0 , b0r ,
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Disconnected Insertions


Still a challenge
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Dispersion theory
Jaffe Hammer,
Drechsel, R-M
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Dispersion theory
Jaffe Hammer,
Drechsel, R-M
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Dispersion theory
Jaffe Hammer,
Drechsel, R-M
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Dispersion theory
Hammer R-M
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Dispersion theory
Hammer R-M
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Dispersion theory
Hammer R-M

• Kaon cloud not dominant
• Not sufficient data to include other states

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Lattice Computations
See also Leinweber et al
Dong, Liu, Williams (1998)
Lewis, Wilcox, Woloshyn (2003)

• Quenched QCD
• Wilson fermions
• 2000 gauge configurations
• 60-noise estimate/config

• Quenched QCD
• Wilson fermions
• 100 gauge configurations
• 300-noise estimate/config

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Lattice Computations
Leinweber et al
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Lattice Computations
Leinweber et al
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Disconnected Insertions


Still a challenge
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Combining ?PT, dispersion theory, lattice QCD
SAMPLE
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Chiral models
Implicit assumptions about b0 , c0 , b0r ,
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Jido Weise
No
Implicit assumptions about b0 , c0 , b0r ,
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Jido Weise
Implicit assumptions about b0 , c0 , b0r ,
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Zou Riska (QM)
Give wrong sign ???
Implicit assumptions about b0 , c0 , b0r ,
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Zou Riska (QM)
Give right sign ???
Implicit assumptions about b0 , c0 , b0r ,
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Zou Riska (QM)
t-channel resonances?
Implicit assumptions about b0 , c0 , b0r ,
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Chiral Quark Soliton
Implicit kaon cloud b3-7
resonances ?
Implicit assumptions about b0 , c0 , b0r ,
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Strange Quarks in the Nucleon What have we
learned?
Its all in the low energy constants
Chiral Quark Soliton
Implicit kaon cloud b3-7
resonances ?
Implicit assumptions about b0 , c0 , b0r ,
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Strange Quarks in the Nucleon What have we
learned?
New puzzles higher Q2-dependence
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Radiative Corrections the Hadronic Weak
Interaction

• GAe
• N !D
• PV p photo- and electro-production (threshold)
• Vector analyzing power (gg)

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at Q20.1 (GeV/c)2

• s-quarks contribute less than 5 (1s) to the
  protons magnetic form factor.
• protons axial structure is complicated!

R. Hasty et al., Science 290, 2117 (2000).
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Axial Radiative Corrections
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Anapole Effects
Hadronic PV
Cant account for a large reduction in GeA
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Nuclear PV Effects
PV NN interaction
Carlson, Paris, Schiavilla Liu,
Prezeau, Ramsey-Musolf
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SAMPLE Results
R. Hasty et al., Science 290, 2117 (2000).
at Q20.1 (GeV/c)2

• s-quarks contribute less than 5 (1s) to the
  protons magnetic moment.

200 MeV update 2003 Improved EM radiative
corr. Improved acceptance model Correction for p
background
125 MeV no p background similar sensitivity to
GAe(T1)
E. Beise, U Maryland
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Transition Axial Form Factor
Off Diagonal Goldberger-Treiman Relation
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Measuring GAND(Q2)
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Weak interactions of s-quarks are puzzling
Hyperon weak decays
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Weak interactions of s-quarks are puzzling
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Weak interactions of s-quarks are puzzling
Resonance saturation
Holstein Borasoy
S11 Roper
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Weak interactions of s-quarks are puzzling
Resonance saturation
Holstein Borasoy
S11 Roper
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Weak interactions of s-quarks are puzzling
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We have a DS0 probe
Use PV to filter out EM transition
Zhu, Maekawa, Holstein, MR-M
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We have a DS0 probe
Naïve dimensional analysis (NDA)
Resonance saturation
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Measuring dD
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N!D Transition
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Radiative Corrections the Hadronic Weak
Interaction

• GAe
• N !D
• PV p photo- and electro-production (threshold)
• Vector analyzing power (gg)

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Vector Analyzing Power

• T-odd, P-even correlation
• Doubly virtual compton scattering (VVCS) new
  probe of nucleon structure
• Implications for radiative corrections in
  other processes GEp/GMp, b-decay
• SAMPLE, Mainz, JLab experiments

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Vector Analyzing Power
Vg VVCS Re Mg(MggboxMggcross) Rosenbluth Im
MgMggbox VAP
VW,Z Electroweak VVCS Re MV(MVgboxMVgcross) b-
decay, RA, Im MVMVgbox b-decay
T-violation
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Vector Analyzing Power
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Vector Analyzing Power
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Conclusions

• Measurements of neutral weak form factors have
  challenged QCD theory
• PV program has stimulated a variety of other
  developments at the interface of QCD and weak
  interactions
• Powerful new probes of SM beyond Qwe,p , DIS

• Kaon cloud is resonant, but not dominant
• Loop calculations are unreliable guide
• Symmetry limited by presence of unknown
  constants
• Models remain interesting, but ad hoc (implicit
  LECs)
• Lattice challenged to obtain disconn insertions

• Axial radiative corrections consistent with
  experiment
• Axial N to D new QCD testing ground GAND , dD
• Electroweak box graphs new insights from gg ?