P. Bosted PAC291 P. Bosted, J. Arrington, V. Dharmawardane, H. Mkrtchyan, X. Zheng  Physics Overview: Resonance structure, Duality, Nuclear effects in PV scattering  Experiment  Projected Results  Summary: “Easy” experiment Never done before Relevant to wider community PR Parity Violating Electron Scattering in the Resonance Region (Res-Parity)

P. Bosted PAC292  The cross section in terms of electromagnetic, weak and interference contribution  Asymmetry due to interference between Z 0 and  Electron can scatter off of proton by exchanging either a virtual photon or a Z 0 e’ e P e’ e P Z0Z0  + Parity Violating Asymmetry

P. Bosted PAC293 Physics Overview Extraction of resonance structure in PVES First test of local and global duality in PVES Isospin and nuclear dependence Physics input to future and PV-DIS studies ELASTIC Strangeness (G M s,G E s ) Axial FF RESONANCE Res. Isospin decomposition Axial hadronic current DIS PDFs (d/u, s/u), standard model xF 3 PVES -scattering

P. Bosted PAC294  First measurements of the parity violating asymmetry over the full resonance region *  Sensitive to isospin decomposition of resonance region  Explore both global and local quark-hadron duality with the previously un-studied combination of structure functions Physics Goals - Proton * E will measure  region, but at large angle and only on a proton target

For inelastic scattering, A RL can be written in terms of response functions Isospin symmetry relates weak and EM vector current Sensitive to axial hadronic current also Details have so far been worked out only for N → ∆(1232) weakly sensitive to axial vector transition form factor Resonance Region asymmetry

For an isolated resonance, A RL can be written in terms of response functions Isospin symmetry relates weak and EM vector current Sensitive to axial hadronic current also Details have so far been worked out only for N → ∆(1232) weakly sensitive to axial vector transition form factor Resonance Region Asymmetry

P. Bosted PAC297 In QCD, can be understood from an OPE of moments of structure functions Duality is described in OPE as higher twist (HT) effects being small or cancelling For spin-averaged structure function, duality works remarkably well to low values of Q 2 Quark-Hadron Duality

P. Bosted PAC298 Explanation by Close and Isgur ( Phys. Lett. B509, 81) DIS limit The magnitude of structure function is proportional to the sum of the squares of the constituent charges For a “resonant” state (made of two equal quarks) If duality holds: Odd and even angular momentum states sum to equal strengths DIS case

Leading order criteria DATA NEEDED! Duality is satisfied if on average  n /  p = 2/3 PROTON Simple Model  No reliable model for n/p ratio in res. region: use simple toy model  Will data look anything like this?  Duality good to ~5% in F 2, our goal is to measure A LR to ~5% locally and <3% globally DIS model Resonance model DUALITY for  -Z interference tensor?

Leading order criteria Duality is satisfied if on average  n /  p = 2/3 PROTON Simple Model  No reliable model for n/p ratio in res. region: use simple toy model  Will data look anything like this?  Duality good to ~5% in F 2, our goal is to measure A LR to ~5% locally and <3% globally DIS model Resonance model DUALITY for  -Z interference tensor?

P. Bosted PAC2911  Parity violating asymmetries over the full resonance region for proton, deuteron, and carbon  Global and local quark-hadron duality in nuclei. Better precision for global/local duality then proton data (higher luminosity targets), but W resolution limited by Fermi motion.  First look at EMC effect with Z-boson probe  Important input to other PVES and - scattering measurements on nuclear targets Physics Goals – Nuclear targets

P. Bosted PAC2912 If photon and Z-exchange terms have identical dependence on PDFs and EMC effect is flavor- independent, then we expect NO EMC effect in A RL  If we see nuclear dependence  Unexpected (?) physics  Flavor dependence of EMC effect  Different effect for Z-exchange  If we observe no nuclear dependence  important constraint for PVES, -scattering on heavy targets  We cover x-region where nuclear dependence predicted to be largest in most models (0.2<x<0.7). Nuclear dependence (EMC effect)

P. Bosted PAC2913  The results are of practical importance : Modeling -A cross sections needed for oscillation experiments Understanding backgrounds in future PV experiments (e.g. 11 GeV Moller) SLAC E158: inelastic background  A/A=4% 11 GeV: goal is 2-3% total uncertainty Constraining radiative corrections and Higher Twist effects in current (E05-007) and future (11 GeV) DIS-PV experiments Impact on Future Experiments

P. Bosted PAC2914 Neutrino Oscillation Major world-wide program to study neutrino mass, mixing Interpretation requires neutrino cross sections in few GeV region on various nuclei: direct measurements difficult - rely in part on models Res-Parity will constrain these models, especially the isospin dependence and nuclear dependence

P. Bosted PAC2915 Neutrino Oscillation Resonance region probed by Res-Parity dominates total cross section for 1 < E  < 5 GeV, important to MINER A and MINOS neutrinoantineutrino

P. Bosted PAC2916 Significant fraction of measured events (F res ) come from Res. region for DIS at 6 and 11 GeV Effect of varying Res. asymmetry by 20% is significant: need data to provide constraints Q 2 (GeV 2 )E (GeV)F res  A/A %5% %2.5% %1% Corrections to DIS-PV For the DIS-PV (deuterium at x=0.25), we can provide factor of two improvement on HT limits. Measure from x=0.2 to x=0.7 for H, D, and C

P. Bosted PAC2917 Electrons detected in two HRS independently Fast counting DAQ can take 1MHz rate with 10 3 pion rejection C, LD2, LH2 targets (highest cooling power) 4.8 GeV 85% polarized e - beam, 80  A,  P b /P b = 1.2% Beam intensity asymmetry controlled by parity DAQ Target density fluctuation, other false asymmetries measured by the Luminosity Monitor Experimental Setup

P. Bosted PAC2918  Rates similar to PV-DIS (E05-007)  Pion/electron ratio smaller  Low E’ settings in HRS-R, high E’ in HRS-L x Y Q 2 E’ W  /e MHz  A/A % % % % for LD2 target KINEMATICS AND RATES

P. Bosted PAC2919 Source  A/A Beam Polarization Kinematic determination of Q 2 DAQ deadtime and pile-up effects Electromagnetic radiative corrections Beam asymmetry Pion contamination Pair symmetric background Target purity and density fluctuations Pole-tip background Total0.018 Smaller systematic error on target ratios (about 1%) Statistics 4-6% per W bin, ~2.5% when integrated over full W range – always statistics limited SYSTEMATIC ERRORS

P. Bosted PAC2920  Relative error of 5-7% per bin for 12 W bins shown (8- 10% for H)  Local duality (3 res.regions) tested to <4% (~5% for H): comparable to F 2 and g 1  Global duality tested to <3%  Ratio of H/D [“d/u”] and C/D [“EMC effect”] tested to 3-4% globally, ~5% locally: Nuclear effects in F 2 are >10% PROTON DEUTERON, CARBON PROJECTED ERRORS

P. Bosted PAC2921 E Target P HRS (L,R) time 4.8 GeV LH2 4.0, 3.2 GeV 5 days 4.8 GeV LH2 3.6, 2.8 GeV 4 days 4.8 GeV LD2 4.0, 3.2 GeV 4 days 4.8 GeV LD2 3.6, 2.8 GeV 4 days 4.8 GeV C 4.0, 3.2 GeV 6 days 4.8 GeV C 3.6, 2.8 GeV 6 days Pass Change from E hours Polarization measurements 8 hours e + asymmetry 8 hours BEAM REQUEST Total request: 30 days of 80  A, 85% Polarization, parity quality beam (mostly longitudinal, some transverse to measure 2-photon background) Non-standard equipment: fast DAQ, upgraded Compton. Both required for E (PV-DIS)

P. Bosted PAC2922  Experience in PV (E158, HAPPEX, G0)  3 young, enthusiastic co-spokespersons P. E. Bosted (spokesperson), E. Chudakov, V. Dharmawardane (co-spokesperson), A. Duer, R. Ent, D. Gaskell, J. Gomez, X. Jiang, M. Jones, R. Michaels, B. Reitz, J. Roche, B. Wojtsekhowski Jefferson Lab, Newport News, VA J. Arrington (co-spokesperson), K. Hafidi, R. Holt, H. Jackson, D. Potterveld, P. E. Reimer, X. Zheng (co-spokesperson) Argonne National Lab,Argonne, IL W. Boeglin, P Markowitz Florida International University, Miami, FL C Keppel Hampton University, Hampton VA E. Hungerford University of Houston, Houston, TX G. Niculescu, I Niculescu James Madison University, Harrisonburg, VA T. Forest, N. Simicevic, S. Wells Louisiana Tech University, Ruston, LA E. J. Beise, F. Benmokhtar University of Maryland, College Park, MD K. Kumar, K. Paschke University of Massachusetts, Amherst, MA F. R. Wesselmann Norfolk State University, Norfolk, VA Y. Liang, A. Opper Ohio University, Athens, OH P. Decowski Smith College, Northampton, MA R. Holmes, P. Souder University of Syracuse, Syracuse, NY S. Connell, M. Dalton University of Witwatersrand, Johannesburg, South Africa R. Asaturyan, H. Mkrtchyan (co-spokesperson), T. Navasardyan, V. Tadevosyan Yerevan Physics Institute, Yerven, Armenia and the Hall A Collaboration Collaboration

P. Bosted PAC2923  Measure A p, A d, and A C for M = 0.8 GeV 2  First weak current measurements in full resonance region. Surprises possible.  New regime for study of duality, higher twist effects, and EMC effect Summary

P. Bosted PAC2924  These data are imperative to constrain models needed for neutrino oscillation studies, backgrounds to other PV experiments (e.g. Moller scattering), radiative corrections and higher twist contributions to DIS PV measurements  Relatively easy (for PV) experiment using same equipment as approved E Ready to run soon.  Can only be done at JLab Summary (continued)

P. Bosted PAC2925  One of most cited results from Jlab: Gep using polarization transfer. Originally considered as relatively uninteresting engineering experiment, but relatively easy to do, so why not.  One of the the most cited results from SLAC is the EMC effect: originally thought to be quite uninteresting. But, still not fully understood!  A diverse and balanced program at Jlab really should include PVES in resonance region! Perspective

P. Bosted PAC2926 BACKUP SLIDES

P. Bosted PAC2927 In the Standard Model and assuming quark degrees of freedom, at LO In the valence region, for a proton target: ≈ 1-x Deep Inelastic asymmetry

P. Bosted PAC2928  sin 2  W = 0.25  axial current suppressed  Isospin symmetry  Negligible strange and charm form factors PROTON DEUTERON Different dependencies in the resonant and DIS cases  Resonant case the current is expressed through the square of the sum over parton charges  DIS case the sum of the square gives the current Assume r(W) depends on (I=0)/(I=1) A Simple Model

P. Bosted PAC2929 Why study duality? Have a great impact on our ability to access kinematic regions that are difficult to access otherwise Duality in PV electron scattering will provide new constraints for models trying to understand duality and its QCD origins Would provide significant limits on the contributions of higher twists to 12 GeV DIS region

P. Bosted PAC2930 Background in Moller Scattering SLAC E158 found (20§4)% background correction to Moller scattering from low Q 2 ep inelastic scattering (mostly resonance region) Res-PV will constrain models of the background for future extension aiming at 2% to 3% precision using 11 GeV at JLab (with 1.5 m long target as in E158)

P. Bosted PAC2931 Relation to E (DIS-Parity) Complementary: lower W and Q 2 Lower Q 2 and better statistics  factor of two greater sensitivity to HT Study HT for 0.2<x<0.8 (E has x=0.25) Extract HT for H, D, and C targets (E only measures deuterium) Res-Parity provides data to calculate radiative corrections and constrain HT for for high precision DIS-Parity measurement at 11 GeV

P. Bosted PAC2932 Relation to E Limited to Delta region (W<1.25 GeV) Lower Q 2 : GeV 2 (parasitic measurement - depends on G0 energies) Only on proton target Backward angle to emphasize sensitivity to axial form factor

P. Bosted PAC2933 Compton polarimeter: will use green laser (in progress); expect to achieve  P b /P b = 1.1% for electron analysis method. 2.5 gm/cm 2 C target (as used in Hall C); possibly an additional target cell. FADC-based and scaler-based fast counting DAQs, both being developed by the PV-DIS collaboration. New Instruments/Upgrades

P. Bosted PAC2934 DAQ: Comparison of two methods FADC-based: Is what we eventually need (12 GeV program) Full event sampling at low rate for detailed off-line analysis; Being developed by Jlab electronics group. Scaler-based: Similar to previous SLAC, and current Hall C scalers; Straightforward to set up; Only scaler info is recorded (on-line PID critical).

P. Bosted PAC2935 FADC-based Fast Counting DAQ

P. Bosted PAC2936 Scaler Electronics-based Fast Counting DAQ

P. Bosted PAC2937 Pion Background   /e ratio ranges to 0.8 : average about 0.2   signal ~20x smaller than electron signal in lead glass, usually no Chrenkov signal: net contamination average is tiny  Pion asymmetry will be measured with very high precision with both the scalar and FADC electronics

P. Bosted PAC2938 Kinematic Determination of Q 2   A/A proportional to  Q 2 /Q 2  From standard HRS uncertainties of  and in E’, central Q 2 determined to better than 0.5%  Uncertainties in Q 2 acceptance (plus beam, target, collimator, quadrupole positions) increase uncertainty in measured Q 2 to <0.9%  Will be checked using normal counting mode (with tracking) at low beam current. Elastic peak positions

P. Bosted PAC2939 RADIATIVE CORRECTIONS Un-radiated to radiated spin averaged cross section  The ratio of radiated to un-radiated ed parity violating asymmetry (R p ) is close to unity. Shape and magnitude of R p determined by the probability for an electron to radiate a hard photon. PV corrections under study ( Zhu and Ramsey Musolf)  Radiative corrections for A p will be determined by an iterative fit to the data of this proposal systematic error in A p < 1% Determined by the x, Q 2 dependence of F 2

P. Bosted PAC2940 HALL A vrs C Pro: better W resolution possible due to HRS optics (more momentum dispersion) Pro: PV-DIS electronics allows clean electron PID, pion rejection Pro: lower overhead due to common effort with approved PV-DIS Con: need about 30% more running time due to lower acceptance and HRS maximum momenta limitations