References - Bogoliubov Laboratory of Theoretical Physics - JINR

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KH80
SM95
SP06
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ITEP(91)
ALBROW(72) @ 1.73
YUKOSAWA(74) @ 1.7
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Figure 3: Asymmetry in π − p elastic scattering at 1.78 GeV/c (a) and 2.07 GeV/c (b).
CMB80
KH80
SM95
SP06
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MARTIN(75) @ 0.803
ALBROW(70) @ 0.815
EANDI(64) @ 0.817
MARTIN(75) @ 0.820
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(a) (b) (c)
Figure 4: Asymmetry in π + p elastic scattering at 0.80 GeV/c (a), 1.94GeV/c(b) and 2.07 GeV/c
(c).
on the actual cross section values the background conditions are also very much different
(compare figures 2a and 2b) and the ratio of the background to the elastic signal lays in
the range Bg/S =0.15 − 1.2 in various kinematic areas of the experiment.
Figures 3,4 present the results of the measurements (closed circles) as a function of
the c.m. scattering angle. The errors are only statistical and account for the elastic
event numbers, the background error matrix and the intensity normalization uncertainty.
The overall scale error due to the target polarization measurement is below 3% (typically
1.5%). Continuous lines show the PWA predictions [1]- [4]. Previous experimental data
at smaller angles and in the overlapping regions are also shown with open symbols.
The points at 1.78 GeV/c in π − p (fig. 3a) were taken to check the setup. Partial wave
analysis do not show large variations from each other. The data show best agreement
with CMB80, while the deviation of KH80 from the data points is obviously statistically
significant. The point at 153.6 o coincides with earlier data and supports even deeper
minimum than any of the analysis show.
The data at 2.07 GeV/c with negative pions (fig. 3b) are not exactly followed by any of
the PWA solutions. Yet the closest two are SM95 and CMB80, while SP06 and KH80 do
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