YN scattering data: EN66
The experiment:
In the Saclay 81 cm Hydrogen Bubble Chamber which was exposed to a beam
of K- mesons from the Proton-Synchroton at CERN.
Reactions of the produced Σ- particles were studied.
200000 pictures were scanned.
489 events were recorded.
The data:
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Σ- p → Σ0 n
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total cross section (SGT)
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momentum range number of SGT [mb]
[MeV/c] events
105 - 115 ) 395 +/- 95
115 - 125 ) 160 +/- 40
125 - 135 ) 171 160 +/- 30
135 - 145 ) 125 +/- 25
145 - 155 ) 110 +/- 20
155 - 165 ) 115 +/- 15
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Σ- p → Λ n
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total cross section (SGT)
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|
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momentum range number of SGT [mb]
[MeV/c] events
105 - 115 ) 170 +/- 50
115 - 125 ) 170 +/- 45
125 - 135 ) 240 140 +/- 30
135 - 145 ) 160 +/- 30
145 - 155 ) 140 +/- 20
155 - 165 ) 115 +/- 15
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differential cross section (DSG)
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based on 289 events in the range 100 - 170 MeV/c
cos(theta) DSG [mb]
-1.0 - -0.8 75 +/- 15
-0.8 - -0.6 80 +/- 15
-0.6 - -0.4 65 +/- 15
-0.4 - -0.2 60 +/- 12
-0.2 - 0.0 90 +/- 17
0.0 - 0.2 70 +/- 14
0.2 - 0.4 60 +/- 12
0.4 - 0.6 96 +/- 17
0.6 - 0.8 85 +/- 15
0.8 - 1.0 85 +/- 15
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differential cross section (DSG)
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|
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based on 144 events in the range 150 - 170 MeV/c
cos(theta) DSG [mb]
-1.0 - -0.8 45 +/- 13
-0.8 - -0.6 55 +/- 16
-0.6 - -0.4 38 +/- 13
-0.4 - -0.2 60 +/- 18
-0.2 - 0.0 79 +/- 20
0.0 - 0.2 60 +/- 17
0.2 - 0.4 40 +/- 15
0.4 - 0.6 80 +/- 20
0.6 - 0.8 105 +/- 25
0.8 - 1.0 95 +/- 20
These events are included in the events of the
previous table!
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Notes:
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The numbers were taken from PDG (read from a graph). M.M. Nagels
gives different numbers in his thesis (tables 2.6 and 2.8)
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The cross sections were calculated using a Σ- lifetime
of 1.58d-10 sec.
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The value of PDG94 is 1.479e-10 sec. This would decrease the
values of the cross sections. I don't know how much
(about 10% probably is suggested).
The uncertainties are statistical only.
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Theta is the angle that the Λ particle makes with the
Σ-
beam in the CM system.
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Also some kind of Λ polarization is determined.
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The capture ratio in flight was determined to be
rf = 0.47 ± 0.03
