HEPData Search

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Differential cross-sections of pi- p ---> gamma n for 317, 452, and 491 mev/c incident pion momentum

Berardo, P.A. ; Haddock, R.P. ; Nefkens, B.M.K. ; et al.

Phys.Rev.D 9 (1974) 621-643, 1974.

Inspire Record 93116 DOI 10.17182/hepdata.21950

The differential cross sections of π−p→γn at center-of-mass energy Ẽ=1363, 1337, and 1245 MeV are presented. The angular distributions are compared with recent γn→π−p experiments. Though the cross sections for π−p→γn are somewhat lower than those for the inverse reaction, when all uncertainties are considered, we find that our data are in acceptable agreement at all three energies with the inverse reaction determined from π−π+ ratio measurements, in support of time-reversal invariance. The agreement with bubble-chamber measurements at Ẽ=1363 and 1337 MeV is less satisfactory. The isotensor dip test applied to our data is inconclusive. Our measurements are compared with many multipole analyses, disagreeing with most, in particular with pure fixed- t dispersion relation calculations. We find no evidence, in the sense suggested by Donnachie, for the classification of the P11(1470) resonance in an SU(3) antidecuplet. The data are consistent with a small radiative decay of the P11(1470) resonance, as predicted by quark models.

6 data tables

Table 1

Axis error includes +- 6/6 contribution.

Table 2

Axis error includes +- 4.5/4.5 contribution.

Table 3

Axis error includes +- 4.2/4.2 contribution.

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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

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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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

Table 1

No description provided.

Table 2

BACKWARD-FORWARD PRODUCTION ASYMMETRY.

Table 3

AVERAGE LAMBDA POLARIZATION.

Measurement of the differential cross-section for pi- p ---> n pi0 at 317, 452, and 491 mev/c

Berardo, P.A. ; Haddock, R.P. ; Nefkens, B.M.K. ; et al.

Phys.Rev.D 6 (1972) 756-766, 1972.

Inspire Record 73968 DOI 10.17182/hepdata.3558

Seventeen differential cross sections of the pion-nucleon charge-exchange reaction have been measured at total center-of-mass energies of 1245, 1337, and 1363 MeV. Most measurements are based on the neutron-photon coincidence method, using carefully calibrated neutron counters and an efficient, large-area photon detector. The results are used to test the predictions of charge independence, with which they agree. The results also confirm the Ayed-Bareyre-Sonderegger phase-degeneracy hypothesis at θ̃π0=180°.

7 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.