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Electron(positron)/pion separation is done by using both Cerenkov counter and shower-preshower detector. For details please refer to previous report posted on http://www.jlab.org/ xiaochao/testrun/memo2.ps.
Cross section can be calculated by:
where
is the total beam charge during the run,
is the momentum accpectance of the spectrometer given by
,
is the effective solid angle of the spectrometer, for 4cm target,
msr; for 15cm target,
msr
is the target length given by:
and number of events
is given by:
where for e
and e
,
is number of events detected by the spectrometer; for
,
is number of events corrected by decay ratio.
so
Results of
,
and
cross sections are shown in table 1.
Kinematics: Beam energy = 5.650 GeV,
Target: 4 cm LH2 for electron runs, 15 cm LH2 for positron runs
![$p_e$](img28.png) |
run# |
Scaler per |
total |
![$e^-$](img4.png) |
total |
![$\pi^-$](img5.png) |
![$\big(\frac{\mathrm{d}^2\sigma}{\mathrm{d}\Omega\mathrm{d}E'}\big)_{e^-}$](img29.png) |
![$\big(\frac{\mathrm{d}^2\sigma}{\mathrm{d}\Omega\mathrm{d}E'}\big)_{\pi^-}$](img30.png) |
(GeV/c) |
|
Charge(3x) |
accepted |
( ) |
(global |
(detected) |
((
) |
(nb/GeV |
|
|
(mC ) |
triggers |
|
cuts) |
|
(nb/GeV-sr) |
-sr) |
1.50 |
2773 |
3121.6 |
393070 |
29185 |
318337 |
289152 |
0.20141 |
4.7858 |
|
2774 |
3151.4 |
173370 |
12780 |
139499 |
126719 |
0.20187 |
4.8006 |
|
2786 |
62367.3 |
1803176 |
(77) |
1572702 |
- |
(0.00079) |
- |
|
2788 |
63072.8 |
352291 |
( 9) |
305428 |
- |
(0.00048) |
- |
|
2789 |
63371.2 |
944823 |
(46) |
818330 |
- |
(0.00092) |
- |
|
2790 |
62528.3 |
1804377 |
(67) |
1579627 |
- |
(0.00069) |
- |
0.90 |
2775 |
70717.9 |
765012 |
9789 |
692503 |
682714 |
1.3106 |
249.97 |
|
2776 |
71144.2 |
303126 |
3980 |
274530 |
270550 |
1.3529 |
251.51 |
|
2791 |
1171888.0 |
1805844 |
(611) |
1288158 |
- |
(0.1963) |
- |
|
2793 |
1173312.6 |
1805590 |
(640) |
1290782 |
- |
(0.2059) |
- |
|
2794 |
1173717.5 |
1808156 |
(668) |
1291353 |
- |
(0.2147) |
- |
0.55 |
2777 |
198758.1 |
1310365 |
14570 |
1159028 |
1144458 |
5.2375 |
1585.2 |
|
2778 |
198813.6 |
926232 |
10372 |
813698 |
803326 |
5.2762 |
1574.6 |
|
2814 |
3392409.5 |
1805373 |
(1612) |
1118462 |
- |
(2.4542) |
- |
|
2815 |
3394497.9 |
1809950 |
(1679) |
1122901 |
- |
(2.5513) |
- |
|
2816 |
3394932.6 |
1810738 |
(1655) |
1130667 |
- |
(2.5141) |
- |
|
2817 |
3397113.2 |
1808348 |
(1627) |
1143697 |
- |
(2.4764) |
- |
Next: Comparison between code and
Up: Test run , and
Previous: Test run , and
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Xiaochao Zheng
2001-05-01