1. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Parity Violation in Deep Inelastic Region at JLab 6 GeV — Experiment 05-007 – Motivation, PVDIS, Implication on EW standard model and hadronic physics; – Requirement on Instrumentation and Status – Summary and Outlook Xiaochao Zheng Massachusetts Institute of Technology May 19, 2006

2. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Observables — parity violating asymmetries ( A PV ) (polarized beam + unpolarized target) study nuclear matter (neutron skin) PREx study hadron structure elastic scattering: strange form factors A4, G0, HAPPEX, SAMPLE DIS: non-perturbative higher twist effects, etc... PVDIS test EW standard model E158, Atomic PV, Qweak Parity Violation in Electron Scattering

3. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology SM works well at present energy range, however: Data exist: cannot be explained by the SM ( m n ? NuTeV anomaly?..); Conceptual reasons: What happens in the “high-energy desert” (250GeV ~ 5 x 10 14 GeV ~ 2.4 x 10 18 GeV)? Search for Physics beyond the Standard Model Direct: LEP, LHC Indirect: E158, Atomic PV, NuTeV, Qweak, PVDIS Electro-Weak Standard Model

4. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology From A d can extract C 1,2q and sin 2 q W. PV DIS Asymmetries For a deuterium target In the SM, tree level Rc,Rs,Rv : nucleon PDF; Y : kinematic factor

5. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology DIS Parity Experiment – History and Future 1970's, result from SLAC E122 consistent with sin 2 q W =1/4, confirmed the Standard Model prediction; C.Y. Prescott, et al., Phys. Lett. B77, 347 (1978) Development in experimental technique allows to search for new physics If all hadronic effects are small or can be understood, then any deviation of sin 2 q W or C iq from their SM predictions would be a hint of new physics. P. Bosted, et al., SLAC E149 (1993), LOI2003-1;

6. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Current Knowledge on Weak Coupling Coeffecients J. Erler, M.J. Ramsey-Musolf, hep-ph/0404291 or Prog. Part. Nucl. Phys. 54, 351 (2005)

7. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology JLab Experiment 05-007 Use 85mA, 6 GeV, 80% polarized beam on a 25-cm LD2 target; Two Hall A High Resolution Spectrometers (HRS) detect scattered electrons; Measure A d at Q 2 =1.10 and 1.90 GeV 2 to about 2% (stat.); Co-spokesperson & contact: X. Zheng (MIT) Co-spokesperson: P.E. Reimer (ANL), R. Michaels (JLab) (Hall-A Collaboration Experiment, approved by PAC27, rated A-) ANL, Calstate, FIU, Jlab, Kentucky, U. of Ljubljana (Slovenia), MIT, UMD, UMass, UNH, Universidad Nacional Autonoma de Mexico, Rutgers, Smith C., Syracuse, UVa, W&M

8. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology From A d at Q 2 =1.90 (GeV/c) 2, can extract (2C 2u -C 2d ) to ±0.03 — order of magnitude improvement compared to world data (PDG); provide constraints on new physics up to 1 TeV mass limit (complementary to Qweak, E158); Z' Searches; Compositeness; Leptoquarks. help to extract C 3q = g A e g A q from CERN m  - DIS data E05-007 Physics Goals (for review of new physics from PVES:J. Ramsey-Musolf, et al., hep- ph/0001250; hep-ph/0307270; nucl-th/0501023; SM

9. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology To cleanly separate higher-twist (HT) from New Physics will require precision measurement at various kinematics, and we are making the first step now; Existing models show negligible HT effects; A d at Q 2 =1.10 (GeV/c) 2 will help to investigate if there are significant HT effects: Will help to investigate the HT contribution to the NuTeV anomaly: May provide “clean” extraction of HT, and help with DIS analysis: extract a S at low Q 2 from DIS data — test pQCD and understand confinement. Will provide important guidance for the future PVDIS program; E05-007 Physics Goals

10. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology If 80% of this deviation is from HT, it would imply a 6% HT contribution to our A d at Q 2 = 1.9 and 10% at Q 2 = 1.1 (GeV/c) 2, way larger than our expected error bar; The NuTeV Anomaly and Higher Twist sin 2 q W reported by NuTeV is 3  away from SM; Possible hadronic causes: CSV, strange sea asymmetry, HT, etc. M. Gluck and E. Reya, Phys. Rev. Lett. 47, 1104 (1981); also: G.A. Miller & A.W. thomas, hep-ex/0204007 G.P. Zeller et al, PRL88,091802(2002) T. Londergan, PAVI06 E158: P.L. Anthoney et al., PRL95, 081601 (2005) Cs-APV: S.C. Bennett, C.E. Wieman, PRL82,2484(1999)

11. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Extraction of a S at Low Q 2 and Higher Twist a S extracted from Bjorken sum rule at low Q includes HT; HT from DIS (F2, g1...) — difficult to separate from higher order effects; HT from PVDIS: Leading Twist unambiguously determined by the SM; More precise than polDIS; If can use PVDIS HT for low Q DIS analysis, then may correct HT and compare a S with pQCD predictions  Test standard model of strong interaction. A. Deur, V. Burkert, J.P. Chen, W. Korsch, hep-ph/0509113 Perhaps PVDIS can serve as a (powerful?) tool to study some long-lasting problem in hadronic physics — HT, d/u, anything else???

12. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology EXPERIMENTAL HALLS INJECTOR RECIRCULATION ARCs (Magnets) NORTH LINAC SOUTH LINAC C B A “parity-quality” beam since 1998 K. Paschke, PAVI06 The Accelerator at Jefferson Lab, Virginia, USA

13. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Experimental Hall A

14. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology PV-DIS (E05-007) Requirements and Status

15. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology PV-DIS (E05-007) Requirements and Status upgrade from IR to green laser to provide 1% precision upgrade to flash-ADC based DAQ to count 1MHz rate

16. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Compton Polarimetry Compton polarimeter: measure asymmetry of Compton scattering of electron beam and high power laser (Fabry-Pérot cavity); Non-invasive, high current capacity; Currently using: 200mW 1064nm laser; Difficult for < 2GeV beam; Providing 2-3% precision for 4 GeV beam, larger for <4 GeV; see also: J. Diefenbach, PAVI06

17. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Upgrade required by: PVDIS, PRex, 12 GeV Upgrade includes: from IR to Green (532nm) laser, completely new optics including the Fabry- Pérot cavity, factor of 4 increase in FOM — JLab; Green Compton Upgrade new electron detectors (narrower micro-strip) to improve resolution — Univ. of Clement-Ferrand; Photon integration method — improve systematics (JLab); Will provide 1% precision down to 1 GeV beam energy; (PRex) R. Michaels, PAVI06

18. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Green Compton Lab

19. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Green Compton Optics Setup Currently In Progress

20. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Green Compton Cavity Alignment

21. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Green Compton Optics Setup Green laser with safty cover FOI L1 QWP PA510 L2 Aiming in cavity locking July/August 2006.

22. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology DAQ Upgrade Current Hall A HRS DAQ: Max event rate 4KHz (VDC limited); Previous Hall A PV Experiments (HAPPEX) used Integrating DAQ Will not work for DIS (large pion background); Flash ADC (FADC) based DAQ is required: FADC: 250MHz main sampling rate with on-board processor (FPGA); Provide on-board fast PID on a counting basis up to 1MHz; Full event information sampled at lower rate for cross-check; Can be used for other high rate experiments.

23. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology FADC DAQ on HRS Inputs: Scintillators (S1, S2, 12 channels each); Gas cherenkov (GC,10CH); Lead glass counter (“Pre-shower” 48CH, “Shower” 80CH);

24. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology FADC DAQ on HRS On-board Processing: S1+S2 for track quality evaluation; sum GC, Lead glass for PID; segments GC and Lead glass blocks for pile-up rejection; pile-up separation (signal shape analysis); Shower sum pions electrons Outputs: helicity-gated electron and pion counts (per ~second); full event sampling at low rate for quality control, including pile-up events for further off-line evaluation; cross check with regular DAQ at low event rate (<4KHz); Pre-Shower sum Regular DAQ Spectrum

25. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Status: Preliminary test using a 100 MHz module (no processor built-in) completed — design algorithm, signal shape analysis (Oct.2005): Specification/algorithm provided to JLab DAQ group — Dec 2005; First prototype will be available in summer 2006, more tests will follow; Expect to completely test the full system in late 2007. Schedule of E05-007: Phase I (13 days) approved, will run in late 2008 – early 2009; Will re-propose phase II (33 days) soon, hopefully will complete both at the same time; FADC DAQ on HRS

26. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology The approval of E05-007 started the PV-DIS program @ JLab: SM test, precision C 2q and sin 2 q W (complimentary to other HEP and Nuclear experiments) Study of hadronic effects: Higher-twist study (low Q 2 a S, test pQCD); Using a proton target: measure PDF ratio d/u at high x; Measure Charge Symmetry Violation (CSV). Leading program @ 12 GeV upgrade (2012?~) Future of PV-DIS at JLab JLab Hall A pCDR P.E. Reimer, PAVI06

27. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Summary PV-DIS is a powerful tool to test the Standard Model and to study many interesting hadronic effects: C 2q 's, sin q W ; low Q 2 a S, d/u at high x, higher twist... Anything else? This program will start soon at JLab (E05-007): Two major instrumentation need to be upgraded, in progress; Will run in late 2008-2009; extract (2C 2u -C 2d ) to ±0.03, factor of 8 improvement w.r.t PDG; first HT extraction from PVDIS. Will be one of the leading experiments of JLab 12 GeV.

28. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Experimental Hall A

29. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology The Collaboration A. Afanasev, D.S. Armstrong, J. Arrington, T.D. Averett, E.J. Beise, W. Bertozzi, P.E. Bosted, J.R. Calarco, G.D. Cates, J.-P. Chen, E. Chudakov, P. Decowski, A. Deur, J. Erler, R. Feuerbach, J.M. Finn, O. Gayou, S. Gilad, R. Gilman, C. Glashausser, K.A. Griffioen, K. Hafidi, J.-O. Hansen, R. Holmes, R.J. Holt, T. Holmstrom, H.E. Jackson, X. Jiang, W. Korsch, K. Kumar, N. Liyanage, D.J. Mack, D.J. Margoziotis, P. Markowitz, R. Michaels (co-spokesperson), P. Monaghan, V. Nelyubin, K. Paschke, D.H. Potterveld, A.J. Puckett, Y. Qiang, R. Ransome, P.E. Reimer (co-spokesperson), B. Reitz, E.C. Schulte, J. Singh, S. Sirca, R. Snyder, P. Souder, V. Sulkosky, W.A. Tobias, B. Zeidman, X. Zhan, X. Zheng (spokesperon) The Hall A Collaboration ANL, Calstate, FIU, Jlab, Kentucky, U. of Ljubljana (Slovenia), MIT, UMD, Umass, UNH, Universidad Nacional Autonoma de Mexico, Rutgers, Smith C., Syracuse, Uva, W&M We have strong support from theorists and experts of parity experiments.

30. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Beam Time Allocation for Running In Two Phases Phase I: 13 days 4 days of commissioning and systematic checks including: Commissioning fast counting DAQ and Compton 9 days with the HRS-L at Q 2 =1.10 (GeV/c) 2 and the HRS-R at Q 2 =1.90 (GeV/c) 2 Phase II: 33 days complete both Q 2 measurements. Approved (Jan.2005), rated A-

31. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Data Analysis Electron asymmetries 3 He asymmetries From 3 He to Neutron

32. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Exploring Nucleon Structure Using EM Probe (cont.) elastic quasi-elastic resonances DIS The nucleon changes its appearance with the way we study it, and we have developed different models/languages for each facet; However, all of them shall form a coherent picture, and perhaps one day all these aspects can be unified within QCD.

33. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Scaling Violation in QCD Bjorken limit:, x Bj fixed, (strict) one photon exchange no scale (Q 2 )dependence, scaling High, soft gluon emission, logQ 2 dependence Low, hard gluon emission 1/(Q 2 ) (t-2) dependence “higher-twist effects”

34. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Structure Functions in the Quark-Parton Model After 35 years of DIS experiments, the unpolarized structure of the nucleon is reasonably well understood (for moderate x Bj region). in the infinite momentum frame (IMF) (P  ∞)

35. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Jlab 6 GeV

36. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Upgrade magnets and power supplies CHL-2 Jlab 6 GeV 12 Add new hall Enhance equipment in existing halls

37. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Design on-board algorithm; Event pile-up at 3% level at 1MHz (e-e pileup <1%), on- board identification possible; Preliminary test using 100MHz module and 1-2 CH/detector (Oct.2005): Gas cherenkov (10 ch sum) Pre-shower (2ch sum) Shower (1ch) First FADC Test and Design for Algorithm

38. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology Extraction of a S at Low Q 2 and Higher Twist A. Deur, V. Burkert, J.P. Chen, W. Korsch, hep-ph/0509113 a S extracted from Bjorken sum rule at low Q includes HT; HT from DIS (F2, g1...) — difficult to separate from higher order effects; HT from PVDIS: Leading Twist unambiguously determined by the SM; More precise than polDIS; If can use PVDIS HT for low Q DIS analysis, then may correct HT and compare a S with pQCD predictions  Test standard model of strong interaction. Perhaps PVDIS can serve as a (powerful?) tool to study some long-lasting problem in hadronic physics — HT, d/u, anything else??? Preliminary!

39. X. Zheng, PAVI06, Milos, Greece Massachusetts Institute of Technology The Accelerator at Jefferson Lab, Virginia, USA