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Pion production and elastic scattering in anti-proton-proton collisions at 6.94 bev/c

Ferbel, T. ; Johnson, J.A. ; Kraybill, H.L. ; et al.

Phys.Rev. 173 (1968) 1307-1314, 1968.

Inspire Record 55957 DOI 10.17182/hepdata.26499

We have studied nonstrange p¯−p interactions observed in 7000 pictures of the 80-in. Brookhaven National Laboratory hydrogen bubble chamber exposed to an antiproton beam with a momentum of 6.94 BeVc. The total cross section was measured to be 58.7±2.8 mb, and the elastic interaction cross section 14.2±1.2 mb. The elastic differential cross section for four-momentum transfers (−t)≤0.3 (BeVc)2 is well described by the exponential form dσeldt=(dσdt)t=0ebt, where b=13.1±1.1 (BeVc)−2. The single-pion production cross section is 4.0±0.9 mb. This channel proceeds 70% through resonance formation. N*(1238) isobar and anti-isobar formation dominates pion production in four- and six-pronged events; the double-isobar formation cross section in the final state pπ+p¯π− is 1.35±0.2 mb. Isobar production was observed to be consistent with the predictions of a dominant one-particle-exchange process. The pion-annihilation process, which has a cross section of 25±5 mb, shows substantial pion resonance formation.

1 data table

Table 1

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Pion production in $\pi^-$ - $p$ interactions at energies 790, 830, and 870 {MeV}

Cason, N.M. ; Derado, I. ; Lamsa, J.W. ; et al.

Phys.Rev. 150 (1966) 1134-1140, 1966.

Inspire Record 50370 DOI 10.17182/hepdata.26587

Single-pion production has been studied in the reactions π−p→π−π+n and π−p→π−π0p at 790, 830, and 870 MeV. A total of 4193 events in these two channels, divided approximately equally between the three energies, have been identified. The most interesting feature of the data is the tendency for events to concentrate at high values of mππ and low values of four-momentum transfer. These effects are discussed in terms of conventional isobar models and a model involving two-pion exchange. Partial cross sections for the reactions studied are reported for each energy.

1 data table

Table 1

No description provided.

pi+ proton, pi- proton and pp elastic scattering at 8.5, 12.4 and 18.4 GeV/c

Harting, D. ; Blackall, P. ; Elsner, B. ; et al.

Nuovo Cim. 38 (1965) 60, 1965.

Inspire Record 49759 DOI 10.17182/hepdata.1110

Approximately 60 000 events have been collected in a spark chamber experiment at the CERN Proton Synchrotron which studied elastic diffraction scattering of π--p and p-p at incident momenta of 8.5, 12.4 and 18.4 GeV/c and of π+-p at 8.5 and 12.4 GeV/c. Magnetic analysis of the incoming and diffraction scattered particle, together with measurement of all angles, permitted each event to be determined as elastic subject to three constraints, so that the inelastic background was rejected with. high efficiency, even at the larger momentum, transfers. Much of the data have been processed by the CERN Automatic Flying-Spot DigitizerHPD. A detailed description of the experimental technique and of the methods of analysis is given. The results, together with data from lower energies, confirm the remarkable energy-independence of the shape of the pion-proton diffraction scattering peak up to |t| = 1.5 (GeV/c)2, wheret is the square of the four-momentum transfer, over a range of pion energies from 2 to 18 GeV. Proton-proton scattering does however appear to show a shrinking diffraction peak. In general, the data agree with other experiments using both counter and bubble chamber techniques, but some differences do appear. During the experiment, data were taken which set an upper limit of 2·102 μb/(GeV/c)2 on the differential elastic cross-section dσ/dt over a range of |t| from 20.9 to 23.4 (GeV/c)2 at 13.4 GeV/c incident pion momentum.

18 data tables

Table 1

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Table 2

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Table 3

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