Comparison of 20 exclusive reactions at large t

White, C. ; Appel, R. ; Barton, D.S. ; et al.
Phys.Rev.D 49 (1994) 58-78, 1994.
Inspire Record 377535 DOI 10.17182/hepdata.50306

We report a study of 20 exclusive reactions measured at the AGS at 5.9 GeV/c incident momentum, 90° center of mass. This experiment confirms the strong quark flow dependence of two-body hadron-hadron scattering at large angle. At 9.9 GeV/c an upper limit had been set for the ratio of cross sections for (p¯p→p¯p)(pp→pp) at 90° c.m., with the ratio less than 4%. The present experiment was performed at lower energy to gain sensitivity, but was still within the fixed angle scaling region. A ratio R(p¯ppp)≈140 was measured at 5.9 GeV/c, 90° c.m. in comparison to a ratio near 1.7 for small angle scattering. In addition, many other reactions were measured, often for the first time at 90° c.m. in the scaling region, using beams of π±, K±, p, and p¯ on a hydrogen target. There are similar large differences in cross sections for other reactions: R(K−p→π+Σ−K−p→π−Σ+)≈112, for example. The relative magnitudes of the different cross sections are consistent with the dominance of quark interchange in these 90° reactions, and indicate that pure gluon exchange and quark-antiquark annihilation diagrams are much less important. The angular dependence of several elastic cross sections and the energy dependence at a fixed angle of many of the reactions are also presented.

21 data tables

Cross sections at 90 degrees in the centre-of-mass.

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Search for structure in pi- p ---> lambda k0 at sigma k threshold

Nelson, B. ; Knasel, T.M. ; Lindquist, J. ; et al.
Phys.Rev.Lett. 31 (1973) 901-904, 1973.
Inspire Record 83771 DOI 10.17182/hepdata.21338

We have measured the cross section, the angular distribution, and the Λ polarization for the reaction π−p→ΛK0. A spark-chamber spectrometer was used to collect 8400 ΛK0 events at fourteen beam momenta near ΣK threshold. Our data do not show the prominent cross-section enhancement suggested by some previous experiments. However, detailed structure in the cross section and the angular distribution agrees well with a simple model which includes a cusp effect at ΣK threshold.

3 data tables

No description provided.

BACKWARD-FORWARD PRODUCTION ASYMMETRY.

AVERAGE LAMBDA POLARIZATION.


Experimental study of the reaction $\pi^- p \to \Lambda K^0$ at beam momenta between 930 and 1130 MeV/c

Knasel, T.M. ; Lindquist, J. ; Nelson, B. ; et al.
Phys.Rev.D 11 (1975) 1-13, 1975.
Inspire Record 107188 DOI 10.17182/hepdata.24916

We have used an optical spark-chamber spectrometer to perform a systematic study of the reaction π−p→ΛK0 at beam momenta between 930 and 1130 MeV/c. The cross section, angular distribution, and Λ polarization have been measured. We present our complete data from a sample of 11 400 events along with Legendre polynomial coefficients for the angular distributions. No striking cross-section enhancement at ΣK threshold is observed, but there is evidence for a small cusp effect. A simple model which takes account of the ΣK channel provides a good fit to our data.

4 data tables

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Cross-Sections of Strange Particle Production in pi- p Interactions at 5-GeV/c

Budagov, Yu.A. ; Vinogradov, V.B. ; Volodko, A.G. ; et al.
Yad.Fiz. 25 (1977) 1195-1200, 1977.
Inspire Record 124565 DOI 10.17182/hepdata.19039

None

1 data table

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Measurement of Differential Cross-Section and Polarization in the Backward Peak of the Reactions pi- p --> Lambda K0 and pi- p --> Lambda K* (890) at 8-GeV/c

Brundiers, H. ; Hartung, R. ; Runge, K. ; et al.
Nucl.Phys.B 119 (1977) 349-361, 1977.
Inspire Record 123952 DOI 10.17182/hepdata.35527

Differential cross sections and polarizations have been measured for the backward peaks in the reactions π − p →Λ K 0 and π − p →Λ K ∗ (890) at 8 GeV/c. The experiment was performed with a liquid hydrogen target at the ω spectrometer. The cross sections for u′>−2 ( GeV /c) 2 are 0.27 ± 0.03 μ b for π − p →Λ+ K 0 and 0.55±0.07 μ b for π − p →Λ K ∗0 . Large positive Λ polarization was observed in both reactions for u ′>−0.5 (GeV/ c ) 2 . The dominant production mechanism was found to be unnatural baryon exchange.

3 data tables

Axis error includes +- 0.0/0.0 contribution (?////).

Axis error includes +- 0.0/0.0 contribution (?////).

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Measurement of the Differential Cross-Section and the Spin-Correlation Parameters P,A, and R in the Backward Peak of pi- p --> K0 Lambda at 5-GeV/c

Astbury, P. ; Gallivan, J. ; Jafar, J. ; et al.
Nucl.Phys.B 99 (1975) 30-52, 1975.
Inspire Record 98667 DOI 10.17182/hepdata.31861

We present measurements for the baryon-exchange reaction π − p→ Λ K 0 at 5 GeV/ c over the range − u <2(GeV/ c ) 2 . The differential cross section is obtained from events produced on a liquid hydrogen target. These data are combined with events produced on a butanol polarized target and the parameters P , A , and R are then determined from an analysis of the decay angular distribution of the forward-going Λ. From our data it is possible to determine the magnitudes and the relative phase of the two invariant amplitudes A ′ and B . The consequences for the ratio B / A ′ are discussed in detail.

4 data tables

No description provided.

THE ERRORS QUOTED IN D(SIG)/DU DO NOT INCLUDE THE ERROR ASSIGNED TO THE OVERALL U-INDEPENDENT CORRECTIONS FACTOR (4.62 +- 0.36), OR OTHER POSSIBLE NORMALIZATION ERRORS.

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