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The Pion Formfactor Experiment

HEEP Check Done On Sept

(1) Introduction

In this webpage, we first try to illustrate you in detail how we do heepcheck for one run and one settings. Then we list all the results for all available settings and make some dicussions.

(2) Tables for fpi2 heep runs

Table.1 dW,Emissing, Pm_par,Pm_per for Run 47048-47051 (in these runs
Psos=1.5808GeV/c,sostheta=51.00,Phms=3.4419,hmstheta=20.90 and Ebeam=4210 MeV)
Run NumberdWEmissingPm_parPm_per
47048 -9.7 MeV/c2 -9.2 MeV -4.875 MeV/c2 -7.45 MeV/c2
47049 -9.3 MeV/c2 -9.04 MeV -5.01 MeV/c2 -7.08 MeV/c2
47050 -10.0 MeV/c2 -9.02 MeV -4.66 MeV/c2 -7.26 MeV/c2
47051 -10.9 MeV/c2 -9.08 MeV -4.96 MeV/c2 -7.59 MeV/c2
average of above-10.0 MeV/c2 -9.08 MeV-4.88 MeV/c2-7.35 MeV/c2

Table.2 dW,Emissing, Pm_par,Pm_per for Run 47354-47356(in these runs
Psos=1.74GeV/c,sostheta=50.01,Phms=4.3754,hmstheta=18.00 and Ebeam=5247 MeV)
Run NumberdWEmissingPm_parPm_per
47354 -9.9 MeV/c2 -10.0 MeV -6.20 MeV/c2 -9.14 MeV/c2
47355 -10.8 MeV/c2 -10.65 MeV -7.48 MeV/c2 -8.99 MeV/c2
47356 -11.2 MeV/c2 -8.83 MeV -4.24 MeV/c2 -9.30 MeV/c2
average of above-10.35 MeV/c2 -10.30 MeV-6.84 MeV/c2-9.06 MeV/c2

Table.3 dW,Emissing, Pm_par,Pm_per for Run 47576-47581(in these runs
Psos=1.4196GeV/c,sostheta=54.00,Phms=3.154,hmstheta=21.40 and Ebeam=3779 MeV)
Run NumberdWEmissingPm_parPm_per
47576 -12.9 MeV/c2 -8.65 MeV -2.76 MeV/c2 -6.55 MeV/c2
47577 -13.0 MeV/c2 -9.13 MeV -3.44 MeV/c2 -7.15 MeV/c2
47578 -13.0 MeV/c2 -8.65 MeV -3.62 MeV/c2 -6.55 MeV/c2
47579 -12.9 MeV/c2 -8.44 MeV -2.95 MeV/c2 -6.52 MeV/c2
47580 -14.1 MeV/c2 -8.53 MeV -3.36 MeV/c2 -7.35 MeV/c2
47581 -12.2 MeV/c2 -6.69 MeV -1.99 MeV/c2 -7.21 MeV/c2
average of above-13.18 MeV/c2 -8.68 MeV-3.20 MeV/c2-6.82 MeV/c2

Table.4 dW,Emissing, Pm_par,Pm_per for Run 47679-47685(in these runs
Psos=1.74GeV/c,sostheta=48.005,Phms=3.7559,hmstheta=20.50 and Ebeam=4709 MeV)
Run NumberdWEmissingPm_parPm_per
47679 -11.0 MeV/c2 10.55 MeV 14.24 MeV/c2 -7.64 MeV/c2
47680 -11.5 MeV/c2 10.46 MeV 14.51 MeV/c2 -7.035 MeV/c2
47681 -10.4 MeV/c2 10.53 MeV 14.33 MeV/c2 -6.64 MeV/c2
47682 -11.0 MeV/c2 10.79 MeV 14.17 MeV/c2 -6.63 MeV/c2
47683 -10.8 MeV/c2 10.77 MeV 14.49 MeV/c2 -6.89 MeV/c2
47684 -9.0 MeV/c2 10.14 MeV 13.08 MeV/c2 -7.60 MeV/c2
47685 -12.2 MeV/c2 10.22 MeV 13.70 MeV/c2 -7.26 MeV/c2
average of above-10.9 MeV/c2 10.49 MeV14.07 MeV/c2-7.10 MeV/c2

(3) Tables for heepcheck runs of previous experiments

Table.5 dW,Emissing, Pm_par,Pm_per for Run 45906-45907(in these runs
Psos=1.2GeV/c,sostheta=50.405,Phms=1.74,hmstheta=32.09 and Ebeam=3045 MeV)
Run NumberdWEmissingPm_parPm_per
45906 -6.3 MeV/c2 -5.5 MeV -1.6 MeV/c2 -5.7 MeV/c2
45607 -7.8 MeV/c2 -5.7 MeV -2.6 MeV/c2 -6.2 MeV/c2
average of above-7.3 MeV/c2 -5.6 MeV-2.0 MeV/c2-6.0 MeV/c2

Table.6 dW,Emissing, Pm_par,Pm_per for Run 45162 and 45165(in these runs
Psos=1.74GeV/c,sostheta=48.005,Phms=3.7559,hmstheta=20.50 and Ebeam=2238 MeV)
Run NumberdWEmissingPm_parPm_per
45162 -7.8 MeV/c2 -7.6 MeV -2.8 MeV/c2 -5.97 MeV/c2
45165 -7.9 MeV/c2 -7.7 MeV -2.9 MeV/c2 -5.93 MeV/c2
average of above-7.9 MeV/c2 -7.7 MeV-2.8 MeV/c2-5.9 MeV/c2

Table.7 dW,Emissing, Pm_par,Pm_per for Run 45014 (in this run
Psos=0.905GeV/c,sostheta=39.03,Phms=0.725,hmstheta=51.75 and Ebeam=1150 MeV)
Run NumberdWEmissingPm_parPm_per
45014 -4.0 MeV/c2 -2.4 MeV 2.5 MeV/c2 -2.0 MeV/c2

(4) Do heepcheck setting by setting

Each table above are of one setting.

For settings with more than one runs, we use average value (some times we remove a few runs if they deviate from average too much). Then we get dW Emissing, Pm_par, Pmper for each setings, and make heepcheck analysis seperatgely.

Let's do as follows.

In setting
Psos=1.5808GeV/c,sostheta=51.00, Phms=3.4419,hmstheta=20.90 and Ebeam=4210 MeV,

We have
dW Emissing Pm_par Pmpar:
-10.0 -9.08 -4.88 -7.35

How can we explain these "shift"?

By using heepcheck programme, if we suppose,

de0, dthe, dpe, dthp, dpp:
-0.3 -1 4 0 0,

it would lead to the following:

dW dE_m dp_m(par) dp_m(perp)
-11.8 -5.26 -4.65 -5.97

In setting
Psos=1.74GeV/c,sostheta=50.01, Phms=4.3754,hmstheta=18.00 and Ebeam=5247 MeV,

we have
dW Emissing Pm_par Pmpar:
-10.35 -10.30 -6.84 ,-9.06

How can we explain these "shift"?

By using heepcheck programme, if we suppose,
de0, dthe, dpe, dthp, dpp:
-0.7 -1 4 0 0,

it would lead to the following:

dW dE_m dp_m(par) dp_m(perp)
-14.74 -7.67 -7.73 -6.97

In setting
Psos=1.4196GeV/c,sostheta=54.00, Phms=3.154,hmstheta=21.40 and Ebeam=3779 MeV,

we have
dW, Emissing, Pm_par, Pmpar:
-13.18 ,-8.68 ,-3.20 ,-6.82

How can we explain these "shift"?

By using heepcheck programme, if we suppose,
de0, dthe, dpe, dthp, dpp: -0.4 -1 4.7 0 0,
it would lead to the following:

dW dE_m dp_m(par) dp_m(perp)
-13.72 -6.21 -4.47 -6.65

In setting
Psos=1.74GeV/c,sostheta=48.005, Phms=3.7559,hmstheta=20.50 and Ebeam=4709 MeV,

we have
dW, Emissing, Pm_par, Pmpar:
-10.9 ,10.49 ,14.07,-7.64

How can we explain these "shift"?

By using heepcheck programme, if we suppose,
de0, dthe, dpe, dthp, dpp: 0 -1 3.8 0 0,
it would lead to the following:

dW dE_m dp_m(par) dp_m(perp)
-11.31 -3.8 -4.11 -5.61

By using heepcheck programme, if we suppose,
de0, dthe, dpe, dthp, dpp: 0 -1 3.8 0 -4.5,
it would lead to the following:

dW dE_m dp_m(par) dp_m(perp)
-11.31 12.63 12.82 -5.61

In setting
Psos=1.2GeV/c,sostheta=50.405, Phms=1.74,hmstheta=32.09 and Ebeam=3045 MeV,

we have
dW, Emissing, Pm_par, Pmpar:
-7.3 ,-5.6,-2.0 ,-6.0

How can we explain these "shift"?

By using heepcheck programme, if we suppose,
de0, dthe, dpe, dthp, dpp:
0 -1 3.8 0 0,
it would lead to the following:

dW dE_m dp_m(par) dp_m(perp)
-7.97 -3.8 -3.62 -5.81

In setting
Psos=1.74GeV/c,sostheta=48.005, Phms=3.7559,hmstheta=20.50 and Ebeam=2238 MeV,

we have
dW, Emissing, Pm_par, Pmpar:
-7.3 ,-5.6 ,-2.0 ,-6.0

How can we explain these "shift"?

By using heepcheck programme, if we suppose,
de0, dthe, dpe, dthp, dpp:
0 -1 5.5 0 0,
it would lead to the following:

dW dE_m dp_m(par) dp_m(perp)
-10.11 -5.5 -2.05 -6.39

In setting
Psos=0.905GeV/c,sostheta=39.03, Phms=0.725,hmstheta=51.75 and Ebeam=1150 MeV,

we have
dW, Emissing, Pm_par, Pmpar:
-4.0 ,-2.3 ,1.9 ,-2.6

How can we explain these "shift"?

By using heepcheck programme, if we suppose,
de0, dthe, dpe, dthp, dpp:
0 -1 3.5 0 0,
it would lead to the following:

dW dE_m dp_m(par) dp_m(perp)
-3.33 -3.5 -0.86 -3.17

(5) Saturation effect of SOS?


Fig.1 Psos offset.vs.Psos "Satutation effect"

Is sounds like that Jochen's Saturation correction works rather well, except that we mustr have an aditional 0.4 % offset.

(6) Conclusion

Sorry here I did not include any error bar in my tables. (But they shoud not be more than 0.7 MeV). In second iteration, I will include error bar in our fitting.

One of our settings (run47679-47685) seems to have serious problems. If we suppose HMS momentum offset of 4.5 (* 0.1 percent), we could explain the data. So problably the magnet recycling of HMS was not done well for that setting.

First round, we did not find any saturation effect. But instead we find a good "universal" offset of Psos = -4.0 (*0.1 percent) and sostheta_central_offset to be 1 mrad..

The starting point of offset in this analysis:

hthetacentral_offset = -0.001 ; (rad)
sphicentral_offset = 0.0026 ; (rad)
hphicentral_offset = 0.00155 ; (rad)
all other offset are set to be 0.0.

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