A Study of Parity Violation in Møller Scattering Mike Woods, SLAC. UC Santa Cruz M. Woods (SLAC www-project.slac.stanford.

Transcription

1 SLAC E-158E A Study of Parity Violation in Møller Scattering Mike Woods, SLAC UC Santa Cruz M. Woods (SLAC www-project.slac.stanford.edu/e158/ E-158) 1

2 Outline Physics Motivation E158 Beam and Beam Monitors LH 2 Target and Spectrometer Detectors Analysis Results & Outlook UC Santa Cruz M. Woods (SLAC E-158) 2

3 Beyond the Standard Model Energy Frontier Tevatron LHC (Linear Collider) Symmetry Violations Rare or Forbidden Processes Precision Electroweak Measurements Indirect access to TeV-scale physics Can clarify gauge structure and nature of New Physics discoveries at colliders Can motivate parameters for new colliders (ex. ILC, LHC upgrades, VLHC) Current Low Energy experiments can probe New Physics at (1 10) TeV! UC Santa Cruz M. Woods (SLAC E-158) 3

4 UC Santa Cruz M. Woods (SLAC E-158) 4

5 Precision Electroweak Measurements 3 SM gauge parameters g, g, v 0 α, G F, m Z from experiment α QED, known to 3 ppb: electron (g-2) G F, known to 9 ppm: muon lifetime m Z, known to 23 ppm: Z boson mass To compare precision measurements with SM predictions, need accurate radiative corrections, with input from Δα QED (Q 2 ), α S, m top γ π γ t W W g π b High energy measurements: Z lineshape, W mass, Z-pole asymmetries Low energy measurements: muon (g-2), ν-n DIS, atomic PV, e-e PV, e-n PV This talk A PV (e-e) UC Santa Cruz M. Woods (SLAC E-158) 5

6 Parity Violation in Moller Scattering e - e - e - e - e - Z 0 γ e - e - Z 0 γ e - Polarized electron beam; unpolarized electron target A A A PV PV meas PV σ = σ = Q M R R P 2 2 Z e σ + σ A L L PV M (1 4sin 2 R Z M M θ W γ ) L Z (γ-z interference) For E158, E=48 GeV, Q 2 =0.03 GeV 2 At tree level, A PV = -3 x 10-7 Weak Radiative Corrections reduce this by more than 50% UC Santa Cruz M. Woods (SLAC E-158) 6

7 Electroweak Theory: Parity Violation, Weak Mixing Angle SU(2) L x U(1), with isotriplet field A μ i SU(2) L coupling constant is g and isosinglet field B μ U(1) coupling constant is g A 1μ, A 2μ are charged fields and correspond to W +, W - particles A 3μ, B μ are neutral and can mix, giving the Z 0 and γ particles Weak mixing angle: g =g tanθ W W γ e ν f f f LH coupling g / Q f 2 g sinθ / 2 f f 2 Z ( g + g' ) ( I3 Q sin θw ) f W RH coupling 0 Q f ( g g sinθ 2 + g' 2 W ) 1/ 2 ( Q f 2 sin θ ) W UC Santa Cruz M. Woods (SLAC E-158) 7

8 Parity Violation at Low Q 2 (γ-z interference) Studies pioneered by SLAC E-122 (semi-leptonic DIS): first observation of PV in weak neutral scattering cornerstone experiment that solidified the Standard Model developed by Glashow, Weinberg and Salam sin 2 = ± θ W (A PV ~ 10-4 ) UC Santa Cruz M. Woods (SLAC E-158) 8

9 + e e Z 0 Parity Violation at the Z-poleZ f f A PV = A LR = σ σ L L σ + σ R R = eff [ 4 sin θ W ] 2 eff [ 1 4 sin θ ] W Very precise measurements by SLD at SLAC best measurement of weak mixing angle best indirect constraint on the Higgs mass sin ( M 2 ) = ± θ eff W Z (APV ~ -0.15) UC Santa Cruz M. Woods (SLAC E-158) 9

10 At high energy: precise M W and sin 2 θ W from LEP1, LEP2, SLC and Tevatron Data consistency within context of SM is generally good Higgs mass constraints: W mass and leptonic asymmetries predict light Higgs Hadronic asymmetries predict heavy Higgs UC Santa Cruz M. Woods (SLAC E-158) 10

11 Electroweak Measurements away from the Z-pole Z also needed! Better sensitivity to contact interactions, Z, other New Physics is possible with precision Low Energy measurements Running of α em and α S with Q 2 are well established What about the Q 2 evolution of sin 2 θ W? And does it agree with SM prediction? UC Santa Cruz M. Woods (SLAC E-158) 11

12 Running Coupling Constants, Unification Running of α S : From PDG: data from μ, τ width; ϒ decays; DIS; e + e - event rate at 25 GeV; event shapes at TRISTAN; Z width and e + e - event shapes at LEP-I, LEP-II. Running of α EM : established with data from Brookhaven (g-2) μ ; VENUS and TOPAZ at Tristan; L3 and OPAL at LEP (from M. Peskin, hep-ph/ ) SM Gauge coupling unification? g 1, g 2, g 3 are U(1), SU(2), and SU(3) 2 coupling constants, and g i SUSY 5 α α1 = 3 cos α EM α 2 = 2 sin θw α = α 3 S EM 2 θw α = i 4π Q (GeV) Q (GeV) UC Santa Cruz M. Woods (SLAC E-158) 12

13 e - Boulder Cs Q W (Cs) = -N+Z(1-4sin 2 θ W ) δ sin 2 N γ,z0 Low Q 2 Measurements of θ W 2 ( ) = θ W M Z ν μ Z 0 ν μ N FNAL NuTeV R δ sin 2 σ = σ NC vn CC vn ν μ σ σ NC vn CC vn W μ N 2 ( ) = θ W M Z e - e - γ,z 0 N JLAB Qweak (~2007) A δ sin PV 2 1 4sin 2 ( ) = θ W M Z 2 θ W Goal Purely leptonic ν μ ν μ γ,z 0 e - CERN CHARMII δ sin 2 2 ( ) = θ W M Z e - e - A δ sin γ,z 0 e - SLAC E158 PV 2 1 4sin 2 ( ) = θ W M Z 2 θ W UC Santa Cruz M. Woods (SLAC E-158) 13

14 References on Low Energy Electroweak Measurements: J. Erler and M.J. Ramsey-Musolf, hep-ph/ Low Energy Tests of the Weak Interaction UC Santa Cruz M. Woods (SLAC E-158) 14

15 SLAC E-158E 45 GeV P=85% L ~ cm -2 s -1 5x10 11 e - /pulse LH2 2 GHz End Station A integrating flux counter 4-7 mrad UC Santa Cruz M. Woods (SLAC E-158) 15

16 E158 Collaboration UC Berkeley Caltech Jefferson Lab Princeton Saclay SLAC Smith College Syracuse UMass Virginia 8 Ph.D. Students 60 physicists Sep 97: EPAC approval 2001: Engineering run 2002: Physics Runs 1 (Spring), 2 (Fall) 2003: Physics Run 3 (Summer) UC Santa Cruz M. Woods (SLAC E-158) 16

17 Key Ingredients Beam High beam polarization (85-90%!) and beam current Strict control of helicity-dependent systematics Passive asymmetry reversals Target and Spectrometer High power LH 2 target Spectrometer optimized for Møller kinematics UC Santa Cruz M. Woods (SLAC E-158) 17

18 E158 Physics Runs Run 1: Spring 2002 Run 2: Fall 2002 Run 3: Summer 2003 *1 Peta-Electron = electrons UC Santa Cruz M. Woods (SLAC E-158) 18

19 E-158 Beam Parameters Parameter Proposal Achieved Intensity at 45 GeV 6 x / pulse 5.3 x Intensity at 48 GeV 3.5 x x Polarization 80% 85-90% Repetition Rate 120 Hz 120 Hz Intensity jitter / pulse 2% rms 0.5% rms Energy jitter / pulse 0.4% rms 0.03% rms Energy spread % rms Delivered Charge (Peta-E) 345K 410K UC Santa Cruz M. Woods (SLAC E-158) 19

20 Polarized Source Laser System IA Feedback Loop IA cell applies a helicity-correlated phase shift to the beam. The cleanup polarizer transforms this into intensity asymmetry. POS Feedback Loop Piezomirror can deflect laser beam on a pulse-to-pulse basis. Can induce helicity-correlated position differences. CID CID Gun Gun Vault Vault UC Santa Cruz M. Woods (SLAC E-158) 20

21 Photocathode for Polarized Gun High doping for 10-nm GaAs surface overcomes charge limit. Low doping for most of active layer yields high polarization. NEW Cathode for Run 3 Gradient-doped strained superlattice; 5% higher polarization than for Runs 1, A 25μm 25μm Active Region GaAs 0.64 P 0.36 Buffer GaAs (1-x) P x Graded Layer GaAs Substrate GaAsP Strained GaAs GaAsP Strained GaAs GaAsP Strained GaAs 30 A 40 A UC Santa Cruz M. Woods (SLAC E-158) 21

22 Beam Monitoring Devices Energy dithering region Can compare measurements of neighboring devices to determine the precision of the measurement. σ toroid ~30 ppm σ BPM ~2 microns BPM24 X (MeV) Agreement (MeV) σ energy ~1 MeV BPM12 X (MeV) UC Santa Cruz M. Woods (SLAC E-158) 22

23 End Station A UC Santa Cruz M. Woods (SLAC E-158) 23

24 Scattering Chamber and Spectrometer Magnets LH 2 Scattering Chamber Sewer Pipe in front of Detector Cart UC Santa Cruz M. Woods (SLAC E-158) 24

25 Experimental Layout in ESA Target chamber Quadrupoles Concrete Shielding Detector Cart Precision Beam Monitors Dipoles Main Collimators Drift pipe Luminosity Monitor 60 m UC Santa Cruz M. Woods (SLAC E-158) 25

26 Liquid Hydrogen Target Refrigeration Capacity 1000W Max. Heat Load: - Beam 500W - Heat Leaks 200W - Pumping 100W Length 1.5 m Radiation Lengths 0.18 Volume 47 liters Flow Rate 5 m/s Disk 1 Disk 2 Disk 3 Disk 4 Wire mesh disks in target cell region to introduce turbulence at 2mm scale and a transverse velocity component. Total of 8 disks in target region. UC Santa Cruz M. Woods (SLAC E-158) 26

27 E158 Spectrometer Target is an 18% radiator Moller ring is 20 cm from the beam Chicane for Line-of-sight shielding UC Santa Cruz M. Woods (SLAC E-158) 27

28 Collimators UC Santa Cruz M. Woods (SLAC E-158) 28

29 Collimators Acceptance Collimator Insertable QC1A collimator, used for polarimetry UC Santa Cruz M. Woods (SLAC E-158) 29

30 Kinematics UC Santa Cruz M. Woods (SLAC E-158) 30

31 Detectors MOLLER, ep are copper/quartz fiber calorimeters PION is a quartz bar Cherenkov LUMI is an ion chamber with Al pre-radiator All detectors have azymuthal segmentation, and have PMT readout to 16-bit ADC σ θ θ 1 Eθ 1 E θ MOLLER σ MOTT LUMI lab MOLLER lab = 1.5mrad = 6.0mrad UC Santa Cruz M. Woods (SLAC E-158) 31

32 Moller, ep Detector 20 million 17 GeV electrons per pulse at 120 Hz 100 MRad radiation dose: Cu/Fused Silica Sandwich -State of the art in ultra-high flux calorimetry -Challenging cylindrical geometry ep ring Single Cu plate Møller ring End plate Lead shield Light guide PMT holder Lead shield UC Santa Cruz M. Woods (SLAC E-158) 32

33 Profile Detector 4 Quartz Cherenkov detectors with PMT readout insertable pre-radiators insertable shutter in front of PMTs Radial and azymuthal scans collimator alignment, spectrometer tuning background determination Q 2 measurement Cerenkov detector Linear drive Bearing wheels UC Santa Cruz M. Woods (SLAC E-158) 33

34 Scattered Flux Profile Moller Detector ep Detector ee Moller signal ep ep Background to Moller sample: 6% from elastic scattering 1% from inelastic scattering (29±4) ppb correction UC Santa Cruz M. Woods (SLAC E-158) 34

35 Pion Detector Quartz Cherenkov Detector with PMT readout ~ 0.2 % pion flux ~ 1 ppm asymmetry ~ (0 ± 2) ppb correction UC Santa Cruz M. Woods (SLAC E-158) 35

36 LUMI Detector Segmented ion chamber detector with Aluminum preradiator. 500W incident power (50W from synchrotron radiation) beam Signal: Motts and high energy Mollers 350M electrons per pulse; <E>~40 GeV A PV ~ -10ppb Enhanced sensitivity to beam fluctuations Null asymmetry measurement Diagnostic for luminosity fluctations, including target density fluctuations. UC Santa Cruz M. Woods (SLAC E-158) 36

37 Experimental Features Beam helicity is chosen pseudo-randomly at 120 Hz use electo-optical Pockels cell in Polarized Light Source sequence of pulse quadruplets; one quadruplet every 33 ms: R R R R R R R L R 4 Physics Asymmetry Reversals: Insertable Halfwave Plate in Polarized Light Source (g-2) spin precession in A-line (45 GeV and 48 GeV data) Null Asymmetry Cross-check is provided by a Luminosity Monitor measure very forward angle e-p (Mott) and Moller scattering Also, False Asymmetry Reversals: (reverse false beam position and angle asymmetries; physics asymmetry unchanged) Insertable -I/+I Inverter in Polarized Light Source UC Santa Cruz M. Woods (SLAC E-158) 37

38 φ det A PV Measurement I where: φ det : detected flux (20 million Moller electrons/spill) Eθ 4 I : beam intensity (φ det ~ σ phys L acceptance) E: beam energy θ : scattering angle Assume dependence on beam parameters is linear over the jitter range: meas phys A PV = P e A PV + A Q + Σ α ξ Δξ ξ ξ {E, x, y, x, y } Contribution due to False beam asymmetries α ξ = A PV ξ α E 1 ppb/ppb α x 1 ppb/nm α y 1 ppb/nm α x 2 ppb/nm α y 2 ppb/nm UC Santa Cruz M. Woods (SLAC E-158) 38

39 A PV Measurement 1. Measure asymmetry for each pair of pulses, p, p σr - σl A exp = σ + σ R L 2. Correct for difference in R/L beam properties, A p raw p = A exp iδx i a charge, position, angle, energy R-L differences coefficients determined experimentally by regression or from dithering coefficients 3. Sum over all pulse pairs, = 4. Obtain physics asymmetry: A PV = 1 A P ε b raw 1 f ΔA bkg bkg p A raw A raw backgrounds background dilutions beam polarization, linearity UC Santa Cruz M. Woods (SLAC E-158) 39

40 Moller Detector Regression Corrections In addition, independent analysis based on beam dithering UC Santa Cruz M. Woods (SLAC E-158) 40

41 Raw Asymmetry Systematics First order systematic effects False asymmetry in electronics Measured to be smaller than 1 ppb Errors in correction slopes Measured by comparing two 60 Hz timeslots Beam-induced asymmetries of ~1 ppm corrected to below stat errors of 50 ppb in multiple data samples Higher-order corrections Beam size fluctuations Measured by wire array Correlation between beam asymmetry and pulse length (intra-spill asymmetries) New electronics in Run III UC Santa Cruz M. Woods (SLAC E-158) 41

42 SLICES: Temporal Beam Profile SLICES readout in 10 bit ADCs Q : bpm31q (4) E : bpm12x (3) X : bpm41x (4) Y : bpm41y (4) dx : bpm31x (4) dy : bpm31y (4) S1 S2 S3 S4 Integration time : S1 : ns S2 : ns S3 : ns S3 : ns BPM 12X Real Waveform UC Santa Cruz M. Woods (SLAC E-158) 42

43 Additional Corrections OUT detector at edge of Møller acceptance most sensitive to beam systematics Use it to set limits on the grand asymmetry OUT OUT asymmetry detector with asymmetry SLICE correction vs sample Better! trouble UC Santa Cruz M. Woods (SLAC E-158) 43

44 e e e e e e Transverse ee Asymmetry e e A T αm e s s 200MeV E158 acceptance Prediction for 46 GeV: ~ -3.5 ppm Theory References: 1. A. O. Barut and C. Fronsdal, (1960) 2. L. L. DeRaad, Jr. and Y. J. Ng (1975) 3. Lance Dixon and Marc Schreiber:hep/ph (Included bremsstrahlung corrections: few percent) Observe ~ 2.5 ppm asymmetry First measurement of single-spin transverse asymmetry in e-e scattering. i) interesting signal, ii) potential background for A PV measurement UC Santa Cruz M. Woods (SLAC E-158) 44

45 Transverse ep Asymmetry Has the opposite sign! (preliminary!) ~ 25% inelastic ep Few percent pions (asymmetry small) Proton structure at E158! Moller ring ep ring φ (Azimuthal angle) 43 & 46 GeV ep ep ~ 24 hrs of data UC Santa Cruz M. Woods (SLAC E-158) 45

46 Longitudinal ep Asymmetry A RAW (45 GeV) = ± 0.05 ppm (stat. only) A RAW (48 GeV) = ± 0.08 ppm (stat. only) Ratio of asymmetries: A PV (48 GeV) /A PV (45 GeV) = 1.25 ± 0.08 (stat) ± 0.03 (syst) Consistent with expectations for inelastic ep asymmetry, but hard to interpret in terms of fundamental parameters UC Santa Cruz M. Woods (SLAC E-158) 46

47 Backgrounds for Møller Analysis Electron-proton elastic scattering Well-understood at our kinematics Radiative electron-proton inelastic scattering PV asymmetry unknown at our kinematics Naïve quark model prediction O(1 ppm) Pion production Two-photon exchange events with transverse polarization A bit of a surprise Other contributions at O(0.1%) level UC Santa Cruz M. Woods (SLAC E-158) 47

48 PV Corrections, ΔA, and dilution factors, f A PV Source ΔA (ppb) f Beam 1 (1 st order) (-) ± Beam (higher order) 0 ± 3 - Transverse polarization -4 ± 2 - e e + p e + p( γ ) ( ) + p e + X γ A PV 1 A = P ε b raw 1 ΔA, f -7 ± ± ± ± Brem and Compton electrons 0 ± ± Pions 1 ± ± High energy photons 3 ± ± Synchrotron photons 0 ± ± TOTAL -29 ± ± = 0.89 ± 0.04, ( linearity) = 0.99 ± Beam asymmetry correction to A exp is (-9.7 ± 1.4) ppb 2 Beam polarization measured using polarized foil target; same spectrometer used with dedicated movable detector UC Santa Cruz M. Woods (SLAC E-158) 48 P b ε 2

49 Moller Asymmetry, A PV A PV (e - e - at Q 2 = GeV 2 ): -131± 14 (stat) ± 10 (syst) parts per billion (preliminary) Significance of parity nonconservation in Møller scattering: 8.3σ UC Santa Cruz M. Woods (SLAC E-158) 49

50 from A PV to sin 2 θ eff W A PV = 2 GFQ 2πα 1+ y y ( 1 y) 4 F QED ( 2 eff 1 4sin θ ) W where: 2 G F Q 1 y y + y πα ( 1 ) 4 is an analyzing power factor; depends on kinematics and experimental geometry. Uncertainty is 1.5%. (y = Q 2 /s) F QED = (1.01 ± 0.01) is a correction for ISR and FSR; (but thick target ISR and FSR effects are included in the analyzing power calculation from a detailed MonteCarlo study) θ W eff is derived from an effective coupling constant, g ee eff, for the Zee coupling, with loop and vertex electroweak corrections absorbed into g ee eff UC Santa Cruz M. Woods (SLAC E-158) 50

51 Weak Mixing Angle Results 6σ Q 2 -dependence of θ W E158 final result: Phys.Rev.Lett.95:081601,2005 UC Santa Cruz M. Woods (SLAC E-158) 51

52 Future Low Energy Experiments / Proposals Atomic Parity Violation (0.35% expt, 0.5% theory for Cs is current precision) Paris Cs (0.1-1)% U. Washington Ba +, KVI Ra + sub-1% Berkeley Yb isotopes sub-1% ν-e scattering (δsin 2 θ W = is current precision) Reactor experiment? δ ( sin 2 θ W ) (hep-ex/ ) Future ν Factory?? ( sin 2 δ ) (Blondel talk at PAVI2004) θ W e scattering (δsin 2 θ W = is current precision) JLAB Q weak A PV (elastic e-p) δ sin 2 θ W 0. JLAB 12-GeV upgrade: A PV (DIS ed, ep) δ ( sin 2 θ W ) A PV (e-e)? δ ( sin 2 θ W ) Fixed target at ILC?? A PV (e-e) δ sin 2 0. ( ) 0007 ( ) 0001 θ W (Snowmass 2001 study) UC Santa Cruz M. Woods (SLAC E-158) 52

53 Elucidating the new Standard Model MSSM? Low energy + High energy RPV SUSY? Leptoquarks? Extra Z Extra dimensions? Precision measurements important! one example Kurylov, Ramsey-Musolf, Su (2003) RPV 95% CL MSSM loop JLAB Q weak ±1σ SLAC E158 ±1σ JLAB ee(12 GeV) ±1σ UC Santa Cruz M. Woods (SLAC E-158) 53

54 Summary: Physics results from E-158E Electro-weak parity violation first observation of parity violation in Møller scattering (8.3σ) running of the weak mixing angle established (6.2σ ) Probing TeV-scale physics: ~10 TeV limit on Λ LL, ~1 TeV limit on SO(10) Z inelastic e-p asymmetry consistent with quark picture Transverse asymmetries First measurement of e-e transverse asymmetry (QED) e-p transverse asymmetry measured (QCD) Weak Mixing Angle Final Result using all data (Q 2 = GeV 2 ) A PV (Moller) = (-131 ± 14 ±10) ppb sin 2 θ W eff = ± (stat) ± (syst) Best measurement of the weak mixing angle away from the Z-pole! UC Santa Cruz M. Woods (SLAC E-158) 54

55 Backup Slides UC Santa Cruz M. Woods (SLAC E-158) 55

56 δ CP Flash:Ti Intensity 1 PD L 3 Helicity Control Bench Helicity λ/2 filter plate remotely insertable -2I +2I Asymmetry inverter Stokes parameters for laser polarization: Left Pulse IA PSCP s s s -π/2 α CP +Δ CP Piezomirror Cleanup polarizer Intensity 2 PD = cos = sin = sin ( δ ) ( δ ) sin( δ ) ( δ ) cos( δ ) Allow for imperfect Pockels cells and phase shifts in downstream optics: Right Pulse +π/2 +α CP +Δ CP δ PS α PS +Δ PS α PS +Δ PS s 1 ~ α CP +Δ CP ~ α CP -Δ CP CP CP CP X Y = X + Y U V PS = U + V R L PS = R + L Laser Polarization Control And Analysis Electric Field Vector after PS Cell in Jones Matrix notation: E 2 CP 2 δ sin CP 2 = i( π + δ PS ) e cos δ ( s + s ) + s = L + C = (ex. C=0.998, L=0.063) Δ CP, Δ PS introduce significant linear polarization asymmetries s 2 ~ α PS +Δ PS ~ α PS -Δ PS UC Santa Cruz M. Woods (SLAC E-158) 56

57 Charge Asymmetry due to anisotropic strain* Sensitive to linear polarization In laser light Example L= ppm Charge Asym A PV 0. 1ppm Recall, and want ~ppb systematic errors! V QW = 2800V *Reference: R.A. Mair et al., Phys. Lett. A212, 231 (1996) UC Santa Cruz M. Woods (SLAC E-158) 57

58 At the start: Techniques for minimizing beam 1) Passive setup: 3) Slow reversals: ~1000 ppm, ~2 µm systematics beam A LR s Helicity bits delayed by 1 pulse and RF modulated prior to broadcast. Collimation of laser beam and minimization of spot size at CP, PS cells. Image CP, PS cells onto the cathode. OTS brought to atmospheric pressure to avoid stress-induced birefringence in windows. Select Pockels cells and carefully align to minimize systematics. Null A Q with Δ CP, Δ PS. ~100 ppm, ~0.5 µm 2) Active suppression with feedbacks: IA loop & POS loop. Double-feedback loop. <100 ppb, <100 nm Flip certain classes of asymmetries while leaving everything else unchanged. λ/2 plates (2) energy (g-2 precession) asymmetry inverter These can provide cancellation of systematics, but they also serve as a cross-check that systematics are well-understood. Multiple reversals are essential! UC Santa Cruz M. Woods (SLAC E-158) 58

59 Beam Asymmetries Charge asymmetry at 1 GeV Charge asymmetry agreement at 45 GeV Energy difference agreement in A line Energy difference in A line Position differences < 20 nm Position agreement ~ 1 nm UC Santa Cruz M. Woods (SLAC E-158) 59

60 Beam Systematics in Run 1 Beam Parameter Beam Monitors Monitor Agreement MOLLER correction Agreement E BPMs 12X, 24X (0.09 ± 0.24) kev (0.5 ± 1.3) ppb X Y X BPMs 41X, 42X BPMs 41Y, 42Y BPMs 31X, 32X (0.9 ± 0.6) nm (-1.0 ± 1.0) nm (-2.3 ± 2.1) nm (0.8 ± 0.5) ppb (-0.2 ± 0.2) ppb (-2.0 ± 2.0) ppb Y BPMs 31Y, 32Y (0.9 ± 1.0) nm (0.7 ± 0.8) ppb Q Toroids 2a, 3a (-2.9 ± 5.3) ppb (-2.9 ± 5.3) ppb But, some detector monitors show poor χ 2 and non-zero mean values. X sensitivity X sensitivity UC Santa Cruz M. Woods (SLAC E-158) 60

61 Detectors Luminosity Monitor region Profile Detector wheel UC Santa Cruz M. Woods (SLAC E-158) 61

62 Transverse Asymmetries Beam-Normal Asymmetry in elastic electron scattering Electron beam polarized transverse to beam direction A T 2π d(σ σ ) σ + σ dφ S e (k e k' e) sinφ Interference between one- and two-photon exchange A T αm e s = αm e 2m target E beam UC Santa Cruz M. Woods (SLAC E-158) 62

63 Brookhaven (g-2) μ e s 2m = a QED rs = g r s μ a a μ ( 2) g s = 2 a Had ( SM ) ( ) + ( ) a ( Weak) μ μ μ + μ a μ ( BNL E821) aμ ( SM) a ( SM) μ = 2.2 ± 0.5 ± 0.7 ( expt) ( theory) ppm UC Santa Cruz M. Woods (SLAC E-158) 63

64 a μ ( BNL E821) aμ ( SM e+ e- ) a ( SM) μ = 2.2 ± 0.5 ± 0.7 ( expt) ( theory) ppm 2.7σ Sensitive to weak corrections: a μ a ( weak) ( SM ) μ = 1.3 ppm Deviation from New Physics? Hints of SUSY?? Future experiments? BNL E969 proposal to reach 0.2 ppm total expt error (scientific approval by Lab in Fall 04; needs funding) LOI submitted to J-PARC to reach 0.1 ppm Need reduced error in hadronic corrections: δaμ ( had, LO) = 0.5 ppm currently, δa μ a μ ( had, LBL) a μ = 0.3 ppm Additional e + e - data needed: BaBar, Belle, KLOE UC Santa Cruz M. Woods (SLAC E-158) 64

65 NuTeV Neutrino Experiment 690 ton ν target Target / Calorimeter Toroidal Spectrometer sin 2 R = σ ( on shell ) = ± ( stat. ) ± ( syst. ) NC NC σ vn vn ρ sin CC CC σ vn σ vn 2 θw Standard Model prediction is UC Santa Cruz M. Woods (SLAC E-158) 65 θ W (3σ deviation)

66 NuTeV Result: New Physics? notmssm or RPV SUSY Z possible Old Physics? Isospin symmetry violated? ( x) d ( x)? 5% effect needed to move result to SM Difficult to constrain Asymmetric strange sea? s( x) s( x)? Unlikely from NuTeV direct measurement NLO QCD? Theoretically small, being checked by NuTeV Electroweak radiative corrections? ISR, FSR and exp t acceptance New calculations and RC codes being checked in NuTeV simulation u Jury is still out p δr R 0.5% UC Santa Cruz M. Woods (SLAC E-158) 66 n

67 APV: Boulder Cs Experiment 133 measure APV component of 6s 7s transition in Cs ; interferes with E1 (Stark) transition 5 reversals to isolate APV signal and suppress systematics APV signal is ~ 6 ppm of total rate, measured to 0.7% (40 ppb!) Q W = N + Z ( 1 4sin 2 θ ) W Q W 133 ( Cs) = ± 0.29 (expt) ± = ± 0.13 ( SM) 0.36 (theory) UC Santa Cruz M. Woods (SLAC E-158) 67

68 Q W 133 ( Cs) = ± 0.46 (expt) = ± 0.13 ( SM) Currently <1σ deviation Deviation between experiment and SM has been as large as 2.5σ. Atomic theory corrections since 2000, have resulted in current consistency: Breit interaction, -0.6% Vacuum Polarization, +0.4% αz Vertex Corrections, - 0.7% Nuclear Skin Effect, - 0.2% (Ginges and Flambaum, Phys.Rept.397:63-154,2004) Future Atomic PV experiments Paris group: Cs 6S 7S, but with different systematics than Boulder expt; 2.7% current accuracy, 1% within reach and 0.1% (expt) may be possible (physics/ , 2004) single Ba + ion (U. Washington), Ra + ion (KVI) (talk by Fortson at subz Workshop 2004; sub-1% possible) Berkeley group: Yb isotopes (talk by Budker at LEPEM2002 Workshop; sub-1% possible) UC Santa Cruz M. Woods (SLAC E-158) 68

69 A PV (Møller ller) ) at JLAB 12 GeV-upgrade (slide from K. Kumar, JLAB review April 05) E : 3-6 GeV I beam = 90 µa θ lab = 0.53 o o 150 cm LH 2 target A PV = 40 ppb 4000 hours Toroidal spectrometer ring focus δ(a PV )=0.58 ppb Beam systematics: steady progress (E158 Run III: 3 ppb) Focus alleviates backgrounds: ep ep(γ), ep ex(γ) Radiation-hard integrating detector Normalization requirements similar to other planned experiments Cryogenics, density fluctuations and electronics will push the stateof-the-art UC Santa Cruz M. Woods (SLAC E-158) 69