Privacy and Security Notice

Privacy and Security Notice


Study of elastic asymmetry

Go to : Corrected counts asymmetry  (updated May 5, 2005)
Go to : Dilution factor    (updated May 5, 2005)
Go to : Physics asymmetry   (updated June 24, 2005)

Go to : Elastic Cross section   (updated Dec 20, 2005)


Go to : Nitrogen asymmetry contribution    (updated June 23, 2005)

Go to : Comparison of C+He to N+He background    (updated Apr. 5, 2005)


Go to : Asymmetries in four electron scattering angle regions    (updated May 6, 2005)

Go to :Asymmetries in two electron scattering angle regions   (updated May 23, 2005)

Go to :Systematic Studies   (updated July 8, 2005)

  • Corrected counts asymmetry:

  • Use the kumac to determine the corrected counts asymmetry as a function of W for a weighted average of all runs. Used cut of abs(hsdelta)<8 and 0.8<(hsshtrk/hsp)<1.4 .  The count asymmetries are corrected for the target and beam polarization for the run. In addition, the top target runs are corrected by a factor of 1/1.019 and the bottom by 1/1.018 . For parallel bottom target multiplied the asymmetry by 1.18 . The sign of the asymmetry is reversed in the kumac. Plots of the count asymmetry for parallel and perpendicular target runs.  ( Had problems with run 43801 so it was not used)
  • Use the kumac to determine the corrected counts asymmetry as a function of W for a weighted average of all runs. Used cut of abs(hsdelta)<12 and 0.8<(hsshtrk/hsp)<1.4 .  The count asymmetries are corrected for the target and beam polarization for the run. In addition, the top target runs are corrected by a factor of 1/1.019 and the bottom by 1/1.018 . For parallel bottom target multiplied the asymmetry by 1.18 . The sign of the asymmetry is reversed in the kumac. Plots of the count asymmetry for parallel and perpendicular target runs.  ( Had problems with run 43801 so it was not used)
  • Dilution factor:

  • Use the kumac to fit the background shape (which is a gaussian + a second order polynomial) to the C+He run. Used cut of abs(hsdelta)<8 and 0.8<(hsshtrk/hsp)<1.4 .  For parallel target field use run 43775. Plot of the fit to the data. For perpendicular target field use run 43407. Plot of the fit to the data.  Using this shape for the background, the dilution factor is determined using the kumac which sums all the runs and normalizes the background shape in the region 0.7 < W < 0.85 GeV. Plots of the dilution factor for parallel and perpendicular target field.
  • Use the kumac to extract the data  from combined  C+He runs. For parallel target field use runs 43775,43776 and 43799.Used cut of abs(hsdelta)<8 and 0.8<(hsshtrk/hsp)<1.4 .  Plot of  the data. For perpendicular target field use runs 43227,43230,43285,43324, 43395 and 43396. Plot of the data.  Using this shape for the background, the dilution factor is determined using the kumac which sums all the runs and normalizes the background shape in the region 0.7 < W < 0.85 GeV. Plots of the dilution factor for parallel and perpendicular target field.
  • Use the kumac to extract the data  from combined  C+He runs. For parallel target field use runs 43775,43776 and 43799.Used cut of abs(hsdelta)<8 and 0.8<(hsshtrk/hsp)<1.4 .  Plot of  the data. For perpendicular target field use runs 43227,43230,43285,43324, 43395 and 43396. Plot of the data.  Using this shape for the background, the dilution factor is determined using the kumac which sums all the runs and normalizes the background shape in the region 0.7 < W < 0.80 GeV. Plots of the dilution factor for parallel and perpendicular target field.
  • Use the kumac to extract the data  from combined  C+He runs. Used cut of abs(hsdelta)<12 and 0.8<(hsshtrk/hsp)<1.4 . For parallel target field use runs 43775,43776 and 43799. Plot of  the data. For perpendicular target field use runs 43227,43230,43285,43324, 43395 and 43396. Plot of the data.  Using this shape for the background, the dilution factor is determined using the kumac which sums all the runs and normalizes the background shape in the region 0.7 < W < 0.85 GeV. Plots of the dilution factor for parallel and perpendicular target field.
  • Did same as above but used -9<hsdelta<10 cut. Made 15 MeV W bins. Plots of the dilution factor for parallel and perpendicular target field. Data files for top parallel , bottom parallel and top perp   , bottom perp   .

  • Physics asymmetry: 

  • Use the kumac to combine the dilution factor and the corrected counts asymmetry into the physics asymmetry.
  • Plots of the TE calibration for parallel and perp proton so that the top parallel had three good TE measurements while the bottom only had one good TE. A report  by Oscar looked in detail at the TE for the parallel field proton target. The ratio of top to bottom TE's is 1.18 ( see mail).   Use this factor to multiply the parallel bottom counts asymmetry.
  •  ( Previously, found that for  parallel field the ratio of top/bottom asymmetry = 1.09 +- .028 . Averaging physics asymmetry for W > 1.34, one gets  top/bottom asymmetry = 1.12 +- .036 )
  1. For parallel target field expect the asymmetry = 0.2149 for theta_e = 12.97  (Q2 = 1.460) with phi_e = 182.46 degrees.  The ratio of expected asym to measured top (bottom target)  asymmetry is 1.045 +- 0.017 ( 0.965 +- 0.019). 
    Dilution factor method
    Physics
    Asymmetry plots

    Asymmetry Top target
    Asymmetry bottom target
    Fit c+he data  (one run) with
    g+p2 scale to NH3 data
     in region 0.7 < W< 0.85
    Cuts abs(hsdelta)<8
    and 0.8<(hsshtrk/hsp)<1.4

    0.2074 +- 0.0033 0.2260 +- 0.0048
    Extract C+he data ( multiple runs)
    scale to NH3 data
    in region 0.7 < W< 0.85
    Cuts abs(hsdelta)<8
    and 0.8<(hsshtrk/hsp)<1.4

    0.2125 +- 0.0033
    0.2315 +- 0.0049
    Extract C+he data ( multiple runs)
    scale to NH3  data
    in region 0.7 < W< 0.80
    Cuts abs(hsdelta)<8
    and 0.8<(hsshtrk/hsp)<1.4
    parallel 0.2100 +- 0.0033
    0.2282 +- 0.0049
    Extract C+he data
    ( multiple runs) scale to NH3
    data in region 0.7 < W< 0.85
    Cuts abs(hsdelta)<12
    and 0.8<(hsshtrk/hsp)<1.4
    parallel
    No 15N corr 0.208 +- 0.0032
    with 15N corr A(N) = -0.072
    A(N)= -A(p)/3
    0.208 +- 0.0032
    with 15N corr A(N) = -0.308+-0.223
    A(N) from data
    0.206 +-  0.0032

    No 15N corr 0.2262 +- 0.0046
    with 15N corr 0.2257 +- 0.0045
    with 15N corr
    0.2238 +-  0.0045

    Extract C+he data
    ( multiple runs) scale to NH3
    data in region 0.6 < W< 0.85
    Cuts abs(hsdelta)<12
    and 0.8<(hsshtrk/hsp)<1.4
    abs(hsxptar)<.12
    abs(hsyptar)<.04


    No 15N corr 0.2082 +- 0.0032
    with 15N corr A(N) = -0.072
    A(N)= -A(p)/3
    0.2071 +- 0.0032
    with 15N corr A(N) = -0.308+-0.223
    A(N) from data
    0.2052+-  0.0033

    No 15N corr 0.2260 +- 0.0045
    with 15N corr 0.2246+- 0.0045
    with 15N corr
    0.2227+-  0.0045

  2. For perpendicular target field, expect  the asymmetry = -0.103 for muGe/Gm = 0.837 at Q2 = 1.464 with phi_e = 169 degrees.
    Dilution factor method Physics
    Asym
     plots
    Asymmetry Top target Asymmetry bottom target
    Fit c+he data  (one run) with
    g+p2 scale to NH3 data
    in region 0.7 < W< 0.85
    Cuts abs(hsdelta)<8
    and 0.8<(hsshtrk/hsp)<1.4
    perp -0.1016 +- 0.0042 -0.1028 +- 0.0045
    Extract C+he data ( multiple runs)
    scale to NH3 data
    in region 0.7 < W< 0.85
    Cuts abs(hsdelta)<8
    and 0.8<(hsshtrk/hsp)<1.4
    perp -0.1002 +- 0.0043
    -0.0992 +- 0.0042
    Extract C+he data ( multiple runs)
    scale to NH3 data
    in region 0.7 < W< 0.80
    Cuts abs(hsdelta)<8
    and 0.8<(hsshtrk/hsp)<1.4
    perp -0.0981 +- 0.0041 -0.0991 +- 0.0043
    Extract C+he data
    ( multiple runs) scale to NH3
    data in region 0.7 < W< 0.85
    Cuts abs(hsdelta)<12
    and 0.8<(hsshtrk/hsp)<1.4
    perp
    No 15N corr
    -0.0992 +- 0.0041
     with 15N corr A(N)=  0.034
    A(N)= -A(p)/3
    -0.0988+-0.0041
    with 15N corr A(N)= -0.574+-0.245
    A(N) from data
    -0.1045 +-  0.0041


    No 15N corr -0.1003 +- 0.0043
    with 15N corr -0.1000 +- 0.0043
    with 15N corr -0.1053 +-  0.0043
    Extract C+he data
    ( multiple runs) scale to NH3
    data in region 0.6 < W< 0.85
    Cuts abs(hsdelta)<12
    and 0.8<(hsshtrk/hsp)<1.4
    abs(hsxptar)<.12
    abs(hsyptar)<.04


    No 15N corr
    -0.0992 +- 0.0041
     with 15N corr A(N)=  0.034
    A(N)= -A(p)/3
    -0.0989 +-0.0041
    with 15N corr A(N)= -0.574+-0.245
    A(N) from data
    -0.1043 +-  0.0042


    No 15N corr -0.1004 +- 0.0043
    with 15N corr -0.1000 +- 0.0043
    with 15N corr -0.1052 +-  0.0044


  • Comparison of pass2a and pass3: (update March 2005)

  • Plots of the dilution factor, corrected count asymmetry and physics asymmetry comparing pass2a to pass3 for parallel target field and top target cell.

  • Elastic cross section: (update Dec. 20, 2005)

  • Plots comparing the data to MC ( after fixing bug in MC which only effected elastic data).  In Column 1, the combination of target field and target cup is listed with the packing fraction used. In column 2, the ratio of data for C+He to data NH3 fitted in the region of 0.6 < W < 0.85 . The plot shows Nh3 data with the C+He data ( in blue) normalized to the NH3 data.  The elastic peak after subtracting the C+He data is shown in the bottom histogram in the figure. In column 3 is  the ratio C+He to N+He yields in the MC. The agreement with the data ratio indicates that possible contamination from frozen 14N or ND3 is limited. In column 4 is the ratio of data to MC in the region 1.1 < W < 1.4 GeV. They  are all about 1.1  which if attributed to the acceptance or luminosity being off would mean that the elastic data should  be divided by 1.1 . The ratio of elastic data to MC is about near 1 except of parallel bottom. If one divides by the 1.1 of the elastic ratio then the elastic data is off by about 0.90 except for the parallel bottom which is 0.80.
    Field/Cup
    ( packing fraction)

    Data (C+He)/(NH3)
    0.6 < W< 0.85

    MC (C+He)/(N+He)
    0.6 < W< 0.85
    Inelastic data/MC
    1.1 < W < 1.4

    Elastic Data/MC
    0.9 < W < 1.0

    Perp/Top (57.3)
    1.260 +- 0.013   (plot)
    1.22 +- 0.004(plot) 1.11  (plot) 1.02  (plot)
    Perp/Bottom (59.5)
    1.209 +- 0.012 (plot) 1.21 +- 0.004 (plot) 1.12 (plot) 0.98 (plot)
    Para/Top (53.2)
    1.223 +- 0.009 (plot) 1.27 +- 0.004 (plot) 1.13 (plot) 0.97 (plot)
    Para/Bottom (54.7)
    1.256 +- 0.011 (plot) 1.25 +- 0.004 (plot) 1.09 (plot) 0.91 (plot)

  • Nitrogen asymmetry contribution:

  • Use a kumac to determine the nitrogen dilution factor from the Monte Carlo assuming a packing fraction of 55%.  Plots of the 15N dilution factor for parallel and perpendicular target field.  In the region 0.7 < W < 0.85 the dilution factor, Ndf, is about 70%. This dilution factor is for the nucleus cross section,but it needs to be the dilution factor for the nucleon cross section in that nucleus. So Ndf needs to be multiplied by the ratio of nucleon cross section in 15N to the nucleus cross section, Rxn . A plot of Rxn shows that below W = 0.85, on average Rxn =  0.092 .
  • The predicted corrected count asymmetry for the nitrogen is -1/3*Ap*(Pn/Ph) *Ndf *Rxn in which Pn is the nitrogen polarization, Ph is the hydrogen polarization and Ap is the asymmetry for a free proton.  For the ratio of nitrogen polarization to hydrogen polarization, used  Pn/abs(Ph) = -1*(0.312/abs(Ph) + 5.831e-02 + 8.935e-2*abs(Ph) + 8.685e-2*abs(Ph)^2)  for each run and took average weighted by the charge per run. When the W range is extended to 0.90 ,the measured count asymmetry for perpendicular has a large change. This is due to a tail of the elastic, so one can only include up to W = 0.85 GeV.
    Field direction
    Target
    Pn/Ph
    Predicted Corrected
    Count
    Asymmetry

    Measured Corrected
    Count Asymmetry
      0.7 < W< .85
    abs(hsdelta)< 8.
    Measured Corrected
    Count Asymmetry
    0.7 < W< .90
    abs(hsdelta) < 12.
    Measured Corrected
    Count Asymmetry
    0.7 < W< .85
    abs(hsdelta) < 12.
    Parallel
    Top
    -.165
     0.0008
    0.0036 +- 0.0046 0.0031 +- 0.0024
    0.0026 +- 0.0031
    Parallel
    Bottom
    -.164
     0.0008
    -0.0059 +- 0.0059 0.0050 +- .0030
    0.0036 +- 0.0039

    Both


    0.000 +- 0.0036
    0.0038 +- 0.0018
    0.0029 +- 0.0024







    Perpendicular
    Top
    -.160
    -0.0004
    0.0098 +- 0.0057 0.0033 +- 0.0030
    0.011 +- 0.0039
    Perpendicular
    Bottom
    -.171
    -0.0004
    0.0091 +- 0.0054 0.0042 +- 0.0032
    0.0098 +- 0.0042

    Both


    0.0094 +- 0.0039  0.0037 +- 0.0022
    0.0105 +- 0.0029
  • Use a  kumac to determine the contribution from the nitrogen asymmetry to the total asymmetry.  The final proton asymmetry , Ap = Atot - (Ndf/Hdf)*(Pn/Ph)*An in which Ndf is the nitrogen dilution factor, Hdf is the hydrogen dilution factor and An = -1/3*Ap  or An is taken from data. Atot is the physics asymmetry and Ap is the final proton physics asymmetry .   Using An from the data, plots of the nitrogen asymmetry contribution for parallel and perpendicular target fields for cut of abs(hsdelta)<12. 
  • Field direction
    Target Measured Corrected
    Count Asymmetry
    0.6 < W< .70
    abs(hsdelta) < 12.
    Measured Corrected
    Count Asymmetry
    0.7 < W< .80
    abs(hsdelta) < 12.
    Measured Corrected
    Count Asymmetry
    0.8 < W< .85
    abs(hsdelta) < 12.
    Measured Corrected
    Count Asymmetry
    0.6 < W< .85
    abs(hsdelta) < 12.
    Parallel
    Combined
    0.0020 +- 0.0060
    0.0066 +- 0.0034
    0.0000 +- 0.0034
    0.0031 +- 0.0022






    Perp
    Combined
    -0.0180 +- 0.0068
    0.0115 +- 0.004
    0.0094 +- 0.0041
    0.006 +- 0.0026
    Field direction
    Target Measured Corrected
    Count Asymmetry
    0.6 < W< .70
    abs(hsdelta) < 12.
    abs(hsyptar)< .04
    para use abs(hsxptar)< .12
    perp use abs(hsxptar+.05)< .12
    Measured Corrected
    Count Asymmetry
    0.7 < W< .80
    abs(hsdelta) < 12.
    Measured Corrected
    Count Asymmetry
    0.8 < W< .85
    abs(hsdelta) < 12.
    Measured Corrected
    Count Asymmetry
    0.6 < W< .85
    abs(hsdelta) < 12.
    Parallel
    Combined
    0.0017 +- 0.0064
    0.0072 +- 0.0036
    -0.0002 +- 0.0037
    0.0033 +- 0.0024






    Perp
    Combined
    -0.0176 +- 0.0069
    0.0114 +- 0.004
    0.0092 +- 0.0041
    0.0062 +- 0.0026
  • Decide to use the measured count asymmetry from region 0.6 < W < 0.85 .
    Field Direction
    Measured Nitrogen Physics Asymmetry
    Predicted Nitrogen Physics Asymmetry
    Parallel
    0.0033/-.1645/.7/0.092 = -0.308 +- 0.223 -A(p)/3 = -0.072
    Perp
    0.0062/-.165/.7/0.092   = -0.574 +- 0.245
    -A(p)/3 =  0.034

         
  • Comparison of C+He to N+He background : 

  • Ran Monte Carlo with C+He target and NH3 target (55% packing fraction) for parallel and perpendicular field settings  at p_central = 4.703 and with kumac  determined the ratio of C+He yield  to N+He+other background. The ratio is plotted here and compares the perpendicular and parallel field settings. The ratios are fitted and there is a small W dependence to the ratio. The fit formula are given in the table with the error on the coefficient given in parenthesis. 
    Target field
    Fit to MC ratio ( Yield C+He)/( Yield NH3 background)
    Parallel
    1.281 (0.015) - 0.044*W (0.011)
    Perpendicular
    1.254 (0.014) - 0.027*W (0.012)

  • To compare to data , the kumac  chains together the NH3 runs and C+He runs and scales the yield by the total charge and average tracking efficiency. The ratio of normalized C+He yield to the NH3 normalized yield is given in the table. Data and MC agree.
    Target field Plots
    Ratio in region 0.7 < W< 0.85
    MC ratio at W =0.77
    Parallel
    top versus bottom
     1.22 +- 0.009 ( Top target) , 1.26 +- 0.010 ( Bottom target)
    1.25
    Perpendicular
    top versus bottom  1.25 +- 0.011 ( Top target) , 1.22 +- 0.011 ( Bottom target) 1.23

  • Asymmetries in four electron scattering angle regions :

  • Pick four regions of the electron scattering angle which give equal counts.
    Target field
    Angular cuts
    (Average scattering angle)
    Plots of
    Count asymmetry


    Plots of
    Dilution factor

    Plots of Physics Asymmetry
     versus scattering angle
    Parallel
    11.5 , 12.225, 12.775, 13.425, 15.
    (11.92,12.50,13.08,13.98)
    parallel parallel parallel
    Perpendicular
    11.5, 12.4875, 13.0875, 13.8125, 16.
    ( 12.16,12.79,13.43,14.37)
    perpendicular perpendicular perpendicular
  • Determine the counts asymmetry using the kumac. Used cut of abs(hsdelta)<12 and 0.8<(hsshtrk/hsp) .  The count asymmetries are corrected for the target and beam polarization for the run. In addition, the top target runs are corrected by a factor of 1/1.019 and the bottom by 1/1.018 . The sign of the asymmetry is reversed in the kumac.  ( Had problems with run 43801 so it was not used). Multiplied the bottom parallel counts asymmetry by 1.18 .
  • Used the kumac to extract the background shape for each angular region. The dilution factors were determined with the kumac by normalizing the background in the region of 0.7 < W < 0.85 .
  • Used the kumac to determined the physics asymmetry by combining the dilution factor and count asymmetries.  Averaging over the region of 0.9 < W < 1.0 , plots of the physics asymmetry versus scattering angle are in the above table. For the perpendicular target field , since the top and bottom target asymmetries agreed with each other, they were averaged together. For the parallel target field, the top and bottom targets are shown separately. 
  • Asymmetries in two electron scattering angle regions :

  • Pick two regions of the electron scattering angle which give equal counts.
    Target field
    Angular cuts
    (average scattering angle)
    Plots of
    Count
    asymmetry


    Plots of
    Dilution
    factor

    Plots of Physics
    Asymmetry
     versus W
    Plots of Physics Asymmetry
     versus scattering angle
    Parallel
    11.5 , 12.7625, 15.
    (12.39,13.77)
    (182.29,182.68)
    parallel parallel parallel


    15N corr ( from data)
    parallel
    Perpendicular
    11.5, 13.0875, 16.
    (12.31,13.70)
    (171.6,168.24)
    perp perp perp
    15N corr (from data)
    perp
    15N corr
    (from data)
    muGe/Gm plot
  • Determine the counts asymmetry using the kumac. Used cut of abs(hsdelta)<12 ,0.8<(hsshtrk/hsp), abs(hsyptar) < .04 and abs(hsxptar)< .12 ( parallel) or abs(hsxptar+0.05)<.12 (perp).  The count asymmetries are corrected for the target and beam polarization for the run. In addition, the top target runs are corrected by a factor of 1/1.019 and the bottom by 1/1.018 . The sign of the asymmetry is reversed in the kumac.  ( Had problems with run 43801 so it was not used). Multiplied the bottom parallel counts asymmetry by 1.18 .
  • Used the kumac to extract the background shape for each angular region. The dilution factors were determined with the kumac by normalizing the background in the region of 0.6 < W < 0.85 .
  • Used the kumac to determined the physics asymmetry by combining the dilution factor and count asymmetries.  Averaging over the region of 0.9 < W < 1.0 , plots of the physics asymmetry versus scattering angle are in the above table. For the perpendicular target field , since the top and bottom target asymmetries agreed with each other, they were averaged together. For the parallel target field, the top and bottom targets are shown separately.
  • Used the kumac to determine the nitrogen contribution to the total asymmetry. The final proton asymmetry , Ap = Atot - (Ndf/Hdf)*(Pn/Ph)*An in which Ndf is the nitrogen dilution factor, Hdf is the hydrogen dilution factor and An = -1/3*Ap . Atot is the physics asymmetry and Ap is the final proton physics asymmetry .   Plots of the nitrogen asymmetry contribution for parallel and perpendicular target fields.
  • Systematic Study
  • Systematic Error of Parallel Asymmetry
  • The largest systematic error is due to determination of the dilution factor. In the region 0.6 < W < 0.85 the normalization factor between the C+he data and the NH3 data is determined at the 0.3% level.  The main concern is how well does the shape of the C+He data mimic the shape of the N+He background under the elastic peak in the NH3.  In the region of 0.6 < W < 0.85, the ratio of C+He data ( normalized by a constant factor ) to the N+He data is constant, so at least in this W region the shape is understood. From the MC, one expects the ratio of C+He to N+He to change by 1% +- 0.3% from W = 0.77 to W =0.95. When determining the dilution factor, no change in the shape is assumed.  Conservatively this leads to Del(asym)/asym = 1% .
  • The sensitivity of the elastic asymmetry to the ratio of Ge/Gm is very small Del(asym)/asym = 0.016*Del(Ge/Gm)/(Ge/gm). So even assuming a 10% error in Ge/Gm then gives a 0.2% error on the asymmetry.
  • The sensitivity of the elastic asymmetry to the kinematics is given in this file. The following is a table for parallel target field.  The combined Del(asym)/asym = 0.3% all coming from the scattering angle uncertainty.
    Variable
    Del(Asym)/Del(Var)
    Del(Var)
    Del(Asym) or Del(Asym)/Asym
    Scattering angle
    0.0235 /deg or 0.0013 /mr
    0.5 mr
    0.0007 or 0.3%
    Polar target angle
    0.0013 /deg
    0.1 deg (?)
    0.0001 or 0.06%
    Azimuthal target angle
    0.0001/deg
    1 deg (?)
    0.0001 or 0.06%
    Beam Energy
    0.004 /GeV
    0.003 GeV
    0.00001 or 0.006%
    Scattered Electron energy
    0.005 /GeV
    0.005 GeV
    0.00003 or 0.018%
  • Systematic error of R = Ge/Gm from perpendicular target field.
  • Average the top and bottom targets asymmetries using the 15N asymmetry predicted assuming ( An = -Ap/3) then A = 0.0999 +- 0.0030 which gives R = 0.8876 +- 0.0267 .  For this kinematics Del(R)/R = 0.9 Del(A)/A , so the systematic errors on the asymmetry from beam polarization,target polarization and dilution factor transfer directly to R. The sysstematic error on R is 4.6% .  Formulas for the Del(R)/Del(var) are given in this file.
    Variable
    Del(R)/Del(Var)
    Del(Var)
    Del(R) or Del(R)/R
    Scattering angle
    0.0036 /mr
    0.5 mr
    0.0018 or 0.2%
    Polar target angle
    0.010 /deg
    0.1 deg (?)
    0.001 or 0.1%
    Azimuthal target angle
    0.004 /deg
    1 deg (?)
    0.004 or 0.45%
    Beam Energy
    0.017 /GeV
    0.003 GeV
    0.00005 or 0.005%
    Scattered Electron energy
    0.020 /GeV
    0.005 GeV
    0.0001 or 0.01%
    Dilution factor
       
    1%
       1%
    Beam Polarization

    2.5% (abs)
    3.6%
    Target Polarization

    2.9% (relative)
    2.5%
  • Dependence of Asymmetries on Run Number and Target Polarization.
  • Elastic asymmetry as a function of run number for para and perp. The elastic asymmetry versus target polarization for para and perp.  Determined the corrected asymmetry ( corrected for beam and target polarzation) in the  combined regions of 0.8< W< 1.1 and  1.3 < W< 2.0 as a function of run number for para at 4.723, perp at 4.723, para at 4.095 and perp at 4.095 and as a function of target polarization for para at 4.723, perp at 4.723, para at 4.095 and perp at 4.095.   Below is a table of the chi-squared/(number of points) when comparing the data to the average value of polarization. The perp settings look fine. The para settings have a high chi-sq/point = 1.7  for the bottom target for the "elastic" and "combined" setting at 4.723.  For para at 4.095 the chi-sq/point drops to 0.92 .
  • Target
    Field
    W region
    Central
    Momentum
    Chi-sq/point comparing average
    to value for each run
    Chi-sq/point comparing average
    to value for each target polarization bin
    Para
    Elastic
    4.723
    1.1 (Bot) and 0.53 ( Top)
    1.79 (Bot) and 1.25 ( Top)
    Para
    Combine
    4.723
    1.25 (Bot) and 1.02 ( Top) 1.61 (Bot) and 0.16 ( Top)
    Para
    1.3 < W < 2.0
    4.095
    0.37 (Bot) and 0.73 ( Top) 0.92 (Bot) and 0.92 ( Top)
    Perp
    Elastic
    4.723
    0.84 (Bot) and 1.03 ( Top) 1.09 (Bot) and 0.71 ( Top)
    Perp
    Combined
    4.723
    0.46 (Bot) and 0.62 ( Top) 0.41 (Bot) and 0.50 ( Top)
    Perp
    1.3 < W < 2.0 4.095
    0.41 (Bot) and 0.61 ( Top) 0.30  (Bot) and 0.18 ( Top)