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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,

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PV: Past, Present, & Future 1970sSLAC DISStandard Model Atomic PVsin 2 W ~ 10% 1980sMainz 8 BePV eq couplings MIT 12 C ~ 10% Prehistory

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PV: Past, Present, & Future 2000sSLAC MollerStandard Model & beyond JLabQWeaksin 2 W < 1% APVAnapole moment JLabG A N MainzHWI ( S=0): d A VVCS: A n 1990sMITG s E,M ~ few % JLabG A & rad corrections Mainz n (r) APV sin 2 W ~ 1% Anapole moment Modern Era

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2010sJLabDIS-ParityStandard Model & beyond Moller (2)sin 2 W < 1% 2020sNLCMoller (3) sin 2 W < 0.1% Future PV: Past, Present, & Future

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Quarks, Gluons, & the Light Elements How does QCD make hadronic matter? 1.0 1.5 2.0 2.5 qq Mesons L = 0123 4 Hybrids exotic nonets PV & strange quarks Gluonic effects GPDs: Wigner Distributions (X. Ji) Pentaquark, m q -dependence of nuclear properties Lattice QCD What is the internal landscape of the nucleon? What does QCD predict for the properties of nuclear matter? Where is the glue that binds quarks into strongly-interacting particles and what are its properties? Tribble Report

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Strange Quarks in the Nucleon: What have we learned? Effects in are much less pronounced than in, Jaffe 89 Hammer, Meissner, Drechsel 95 Dispersion Relations Narrow Resonances High Q 2 ansatz OZI violation

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Strange Quarks in the Nucleon: What have we learned? Effects in are much less pronounced than in, 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 / m s ~ 1 No HQET m K / ~ 1/2 PT ? Symmetry is impotent J s = J B - 2 J EM, I=0 Unknown constants Theory: how do we understand dynamics of small ss effects in vector current channel ? Challenge to understand QCD at deep, detailed level

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What PT can (cannot) say Strange magnetism Ito & R-M; Hemmert, Meissner, Kubis; Hammer, Zhu, Puglia, R-M The SU(3) chiral expansion for B : O (p 2 ) m q -independent

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What PT can (cannot) say Strange magnetism Ito & R-M; Hemmert, Meissner, Kubis; Hammer, Zhu, Puglia, R-M The SU(3) chiral expansion for B : O (p 3 ) non-analytic in m q unique to loops leading SU(3)

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What PT can (cannot) say Strange magnetism Ito & R-M; Hemmert, Meissner, Kubis; Hammer, Zhu, Puglia, R-M The SU(3) chiral expansion for B : O (p 4 ) non-analytic in m q (logs)

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What PT can (cannot) say Strange magnetism Ito & R-M; Hemmert, Meissner, Kubis; Hammer, Zhu, Puglia, R-M The SU(3) chiral expansion for B : SU(3) Sym breaking O (p 4 ) Two-deriv operators + 1/m N terms M = diag (0,0,1)

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What PT can (cannot) say Strange magnetism Ito & R-M; Hemmert, Meissner, Kubis; Hammer, Zhu, Puglia, R-M The SU(3) chiral expansion for B : O (p 2 ) O (p 3 ) O (p 4 ) converges as (m K / ) n good description of SU(3) SB

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What PT can (cannot) say Strange magnetism Ito & R-M; Hemmert, Meissner, Kubis; Hammer, Zhu, Puglia, R-M Implications for s : O (p 2 ) singlet O (p 3,p 4 ) loop only O (p 2,p 4 ) octet Near cancellation of O (p 2,p 4 ) octet & loop terms Expt: b 0 + 0.6 b 8 terms slightly > 0 Models: different assumptions for b 0 + 0.6 b 8 terms O (p 4 ) octet only O (p 4 ) singlet

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Q 2 -dependence of G s M G 0 projected Dispersion theory Chiral perturbation theory reasonable range for slope SAMPLE 2003 Happex projected Lattice QCD theory

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What PT can (cannot) say Strange magnetism O (p 4 ), unknown LEC O (p 3 ), parameter free O (p 4 ), cancellation O (p 4 ), octet

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What PT can (cannot) say Strange magnetism O (p 3,p 4 ), loops O (p 4 ), octet O (p 4 ), unknown LEC

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What PT can (cannot) say Strange electricity Ito & R-M; Hemmert, Meissner, Kubis; Hammer, Zhu, Puglia, R-M The SU(3) chiral expansion for s : O (p 3 ): non-analytic in m q (loops) + m q - independent cts

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What PT can (cannot) say Strange electricity Ito & R-M; Hemmert, Meissner, Kubis; Hammer, Zhu, Puglia, R-M The SU(3) chiral expansion for s : O (p 3 ), octet O (p 3 ), unknown LEC O (p 3 ), loops

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Loops vs poles No dichotomy: kaon cloud is resonant

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Kaon cloud Not sufficient to explain G s E,M

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Kaon cloud models Not reliable guide to sign or magnitude of G s E,M

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Chiral models Implicit assumptions about b 0, c 0, b 0 r, …

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Disconnected Insertions ~+… Still a challenge

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Dispersion theory Jaffe Hammer, Drechsel, R-M Strong interaction scattering amplitudes e+ e - K + K -, etc. Contributing States

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Dispersion theory Jaffe Hammer, Drechsel, R-M Strong interaction scattering amplitudes e+ e - K + K -, etc.

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Dispersion theory Jaffe Hammer, Drechsel, R-M Strong interaction scattering amplitudes e+ e - K + K -, etc.

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Hammer & R-M Dispersion theory All orders Naïve pert thy O (g 2 ) Kaon cloud models Unitarity violating Unitarity

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Hammer & R-M Dispersion theory All orders Unitarity res S-quarks are not inert Non-perturbative effects dominate (LECs) Kaon cloud is resonant

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Hammer & R-M Dispersion theory Kaon cloud not dominant Not sufficient data to include other states Kaon cloud

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Lattice Computations 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 See also Leinweber et al

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Lattice Computations Leinweber et al Disconn s/dCharge Sym B expt

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Lattice Computations Leinweber et al d loop : Lattice s : kaon loops Charge Symmetry s/d loop ratio Charge symmetry Measured octet m.m.s Lattice d loop Kaon loops

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Disconnected Insertions ~+… Still a challenge

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Combining PT, dispersion theory, & lattice QCD R A Reasonable range: lattice & disp rel SAMPLE

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Chiral models Implicit assumptions about b 0, c 0, b 0 r, …

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Jido & Weise Implicit assumptions about b 0, c 0, b 0 r, … No b 0,8 =0

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Implicit assumptions about b 0, c 0, b 0 r, … s > 0 Jido & Weise

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Implicit assumptions about b 0, c 0, b 0 r, … Zou & Riska (QM) Give wrong sign ??? ~ s in g.s. s in excited state (p wave)

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Implicit assumptions about b 0, c 0, b 0 r, … Give right sign ??? ~ s in g.s., (s wave) s in excited state Zou & Riska (QM) s > 0

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Implicit assumptions about b 0, c 0, b 0 r, … Zou & Riska (QM) s < 0 t-channel resonances?

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Implicit assumptions about b 0, c 0, b 0 r, … Chiral Quark Soliton s > 0 Implicit kaon cloud + b 3-7 … resonances ?

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Strange Quarks in the Nucleon: What have we learned? Dispersion Theory Models Lattice QCD J s = J B - 2 J EM, I=0 Unknown constants Its all in the low energy constants Implicit assumptions about b 0, c 0, b 0 r, … Chiral Quark Soliton s < 0 Implicit kaon cloud + b 3-7 … resonances ?

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Strange Quarks in the Nucleon: What have we learned? J s = J B - 2 J EM, I=0 Unknown constants New puzzles: higher Q 2 -dependence

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Radiative Corrections & the Hadronic Weak Interaction G A e N ! PV photo- and electro-production (threshold) Vector analyzing power ( )

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at Q 2 =0.1 (GeV/c) 2 R. Hasty et al., Science 290, 2117 (2000). s-quarks contribute less than 5% (1 ) to the protons magnetic form factor. protons axial structure is complicated! Models for s Radiative corrections

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Axial Radiative Corrections Anapole effects : Hadronic Weak Interaction + Nucleon Greens Fn : Analogous effects in neutron -decay, PC electron scattering…

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Anapole Effects Zhu, Puglia, Holstein, R-M ( PT) Maekawa & van Kolck ( PT) Riska (Model) Zhu et al. Hadronic PV Cant account for a large reduction in G e A

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Nuclear PV Effects PV NN interaction Carlson, Paris, Schiavilla Liu, Prezeau, Ramsey-Musolf Suppressed by ~ 1000

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at Q 2 =0.1 (GeV/c) 2 125 MeV: no background similar sensitivity to G A e (T=1) SAMPLE Results R. Hasty et al., Science 290, 2117 (2000). 200 MeV update 2003: Improved EM radiative corr. Improved acceptance model Correction for background s-quarks contribute less than 5% (1 ) to the protons magnetic moment. 200 MeV data Mar 2003 D2D2 H2H2 Zhu, et al. E. Beise, U Maryland Radiative corrections

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Transition Axial Form Factor Off Diagonal Goldberger-Treiman Relation Zhu, R-M O (p 2 ) chiral corrections ~ few % N ! N ~ 5% Rad corrections, anapole ~ 25% Study G A N (Q 2 )/ G A N (0)

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Measuring G A N (Q 2 ) G A N & d Axial response, G A N only A LR ~ Q 2 (1-2sin 2 W ) Zhu, Maekawa, Sacco, Holstein, R-M Nonzero A LR (Q 2 = 0)

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Weak interactions of s-quarks are puzzling Hyperon weak decays S-Wave: Parity-violating P-Wave: Parity- conserving symmetry not sufficient

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Weak interactions of s-quarks are puzzling M1 (PC) E1 (PV) Thy Expt

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Weak interactions of s-quarks are puzzling Resonance saturation Holstein & Borasoy S 11 Roper S-Wave P-Wave Fit matrix elements

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Weak interactions of s-quarks are puzzling Resonance saturation Holstein & Borasoy S 11 Roper S-Wave P-Wave Fit matrix elements S/P wave fit Close gap with BB

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Weak interactions of s-quarks are puzzling Natural Fit Is deviation from QCD-based expectations due to presence of s-quarks or more fundamental dynamics?

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We have a S=0 probe Use PV to filter out EM transition Zhu, Maekawa, Holstein, MR-M PV, E1 Amplitude PV Asymmetry Large N C, spin-flavor SU(4) Finite N C Low energy constant

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We have a S=0 probe Naïve dimensional analysis (NDA) Resonance saturation d ~ g d ~ 25g

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Measuring d d = 100 g enhanced H W S=0 d = 0, G A N only A LR ~ Q 2 (1-2sin 2 W ) Zhu, Maekawa, Sacco, Holstein, R-M

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N! Transition Measure Q 2 -dependence of A LR to learn d G A N Q 2 )/ G A N 0) R A

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Radiative Corrections & the Hadronic Weak Interaction G A e N ! PV photo- and electro-production (threshold) Vector analyzing power ( ) Theory for R A good to ~ 25% Further test of R A d & H W qq EFT for low energy good to ~ 25%; more tests! New window on electroweak VVCS: -decay, sin 2 W,…

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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: G E p /G M p, -decay… SAMPLE, Mainz, JLab experiments What specifically could we learn? V ud

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Vector Analyzing Power + V= : VVCS Re M ( M box M cross )Rosenbluth Im M M box VAP V=W,Z: Electroweak VVCS Re M V ( M V box M V cross ) -decay, R A,… Im M V M V box -decay T-violation Direct probe

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Vector Analyzing Power Mott: M N !1 SAMPLE EFT to O (p 2 ) Diaconescu, R-M I=1, r 2 O (p 0 ) O (p 4 ) 146 0

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Vector Analyzing Power Constrained by SAMPLE 30 0 Dynamical s?

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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: Q w e,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 new QCD testing ground: G A N, d Electroweak box graphs: new insights from ?

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