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p-p Interactions at 2 Bev. 2. Multiple-Pion Production

Pickup, E. ; Robinson, D.K. ; Salant, E.O. ;

Phys.Rev. 125 (1962) 2091-2101, 1962.

Inspire Record 47226 DOI 10.17182/hepdata.26793

Analyses have been made for 871 four-prong events and 463 two-prong events corresponding to multiple pion production, resulting from p−p interactions at 2 Bev in the BNL 20-in. hydrogen bubble chamber. Cross sections have been obtained for all the observable double and triple pion production processes; the branching ratios predicted by the extended isobar model are shown to be in fair agreement with the data, but there are significant differences. The c.m. momentum distributions are also in fair agreement with the predictions of the model, although there are ambiguities in the interpretation. The pion-nucleon Q values give clear evidence for the importance of the (32, 32) resonant state in multiple pion production, but consideration of this state alone does not provide an explanation of the features of double pion production. Some contribution from another state, possibly the I=12 nucleon isobar, is necessary. In double production, the c.m. angular distributions of the nucleons show backward-forward peaking suggestive of a one-pion exchange process. The angular distributions of the nucleons from triple production are almost isotropic.

1 data table

Table 1

No description provided.

p-p Interactions at 2 Bev. 1. Single-Pion Production

Fickinger, W.J. ; Pickup, E. ; Robinson, D.K. ; et al.

Phys.Rev. 125 (1962) 2082-2090, 1962.

Inspire Record 46669 DOI 10.17182/hepdata.26851

3600 two-pronged events, obtained in p−p interactions at 2 Bev in the BNL 20-in. hydrogen bubble chamber, have been analyzed. Cross sections have been measured for elastic scattering, for the two modes of single-pion production, p+p→p+n+π+, p+p→p+p+π0, and for strange-particle production. The branching ratio for the two one-pion production reactions is σ(pnπ+)σ(ppπ0)=4.17±0.25. Momentum distributions and Q values indicate that single-pion production proceeds almost entirely through the (32, 32) resonant state. The data have been considered in terms of the extended isobar model and also a one-pion exchange model for production. The branching ratio and momentum distributions can be explained by including a small effect from the I=12 resonant state in addition to the dominant I=32 resonance. The c.m. angular distribution of the nucleons in single-pion production shows very marked backward-forward peaking indicating a one-pion exchange mechanism. Absolute differential cross sections as a function of laboratory kinetic energy have been calculated from Selleri's equation for the pnπ+ reaction. There is good agreement with the data for low four-momentum transfers [q2<0.15(Bev/c)2], but for higher momentum transfers the theoretical cross sections are larger than the experimental cross sections.

1 data table

Table 1

No description provided.

$pi^- -- p$ interactions at 905, 960, and 1100 {MeV}

Pickup, E. ; Robinson, D.K. ; Salant, E.O. ; et al.

Phys.Rev. 132 (1963) 1819-1830, 1963.

Inspire Record 44761 DOI 10.17182/hepdata.75462

Single-pion production in π−−p interactions has been studied at 905, 960, and 1100 MeV. Comparison with the isobar and one-pion-exchange (OPE) mechanisms of pion production shows that, below 1 BeV, pion production occurs primarily through the formation of an intermediate excited state of the nucleon (isobar), while at higher energies the influence of the ρ resonance in the ππ system becomes increasingly important. There is some evidence for an I=2 state in the events at the lower energies.

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Single and Multiple Pion Production in pi+n and pi-p Interactions at 1.7 GeV/c

Bacon, T.C. ; Fickinger, W.J. ; Hill, D.G. ; et al.

Phys.Rev. 157 (1967) 1263-1278, 1967.

Inspire Record 52416 DOI 10.17182/hepdata.26582

Meson production in π−p and π+n interactions at 1.7 GeV/c has been studied in two bubble-chamber exposures. Combined results are presented with emphasis on single-pion production (4300 events) which is dominated by the formation of the ρ0 meson in peripheral interactions, and on double-pion production (1100 events) which shows strong formation of the ω meson. These data are compared with the predictions of particle-exchange models, including absorption, and the effects of competing channels are discussed. Evidence for a two-pion decay mode of the ω is examined quantitatively. Processes with higher meson multiplicities are described.

1 data table

Table 1

No description provided.

Pion spectra from the reaction p p ---> pi+- + anything at 28.5 gev

Sims, W.H. ; Hanlon, J. ; Salant, E.O. ; et al.

Nucl.Phys.B 41 (1972) 317-335, 1972.

Inspire Record 75159 DOI 10.17182/hepdata.8021

The single-particle inclusive pion spectrum from the reaction p + p → π ± + anything at 28.5 GeV is presented in both tabular and graphical form. The data are from exposures in the BNL 203 cm bubble chamber. The emphasis of this paper is on exhibiting the single-particle spectra in sufficient detail so that the data will be useful to those interested in testing models and developing new concepts.

4 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Measurement of Asymmetry in Photoproduction of pi0 Meson in the Resonance Region

Avakian, R.O. ; Avakian, E.O. ; Avetisian, A.E. ; et al.

Yad.Fiz. 26 (1977) 1014-1017, 1977.

Inspire Record 126317 DOI 10.17182/hepdata.19036

None

1 data table

Table 1

Axis error includes +- 10/10 contribution.

MEASUREMENT OF POLARIZATION OF PROTONS IN THE REACTION GAMMA P ---> P PI0 IN A PHOTON LINEARLY POLARIZED BEAM. (IN RUSSIAN)

Avakian, R.O. ; Avakian, E.O. ; Avetisian, A.E. ; et al.

Yad.Fiz. 36 (1982) 393-399, 1982.

Inspire Record 183654 DOI 10.17182/hepdata.17730

None

1 data table

Table 1

Axis error includes +- 0.0/0.0 contribution (?////ERROR IN POLARIZATION OF INITIAL GAMMAS IS NOT GIVEN).

Search for shock waves in central interactions of carbon nuclei with copper and lead nuclei at 4.5 GeV/c per nucleon

Anikina, M.Kh. ; Vardenga, G.L. ; Golokhvastov, A.I. ; et al.

Yad.Fiz. 35 (1982) 105-107, 1982.

Inspire Record 178205 DOI 10.17182/hepdata.39680

Experimental data on angular distributions of secondaries in central interactions of carbon nuclei (4.5 GeV/c per nucleon) with copper and lead nuclei are given. Experiment was carried out on incident beam of synchrophasotron. Secondary particles are detected with counters. Angle between the axis of these counters and beam directions varies from 15 to 90 degrees. Target was oriented relative to the beam so, that absorption of particles in it escaping at an angle of 60 degrees may be minimum. This position does not change during measurements. Target thicknesses are the following: copper - 0.92 mm, lead -1.0 mm. At the 3-5% accuracy of measurements within 15-90 deg angle range to the beam direction no anomaly in angular distribution has been discovered which could serve as an evidence of shock wave appearance

4 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

ADMIXTURE OF PROTONS WITH MOMENTUM > 550 MEV AND PIONS WITH MOMENTUM > 100 MEV IS ABOUT 15 PCT.

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