Date

π−-Proton Scattering at 950 MeV

Erwin, A.R. ; Kopp, J.K. ;
Phys.Rev. 109 (1958) 1364-1366, 1958.
Inspire Record 1498681 DOI 10.17182/hepdata.75449

Approximately 1200 π−-proton interactions in a liquid hydrogen bubble chamber were studied to obtain the elastic differential cross section and inelastic partial cross sections at 950±20 Mev mean laboratory energy. Relative cross sections were converted to absolute values using the total cross section obtained by Cool and co-workers with counters. The differential cross section is inconsistent with a resonance of definite total angular momentum and parity and can be fitted by a superposition of partial waves of angular momenta up to 3ℏ without spin-flip scattering. In the center-of-mass system, 30% of the pions scatter beyond a broad minimum of the cross section at 75°.

1 data table match query

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π- p interactions at 650 MeV

Feminò, S. ; Jannelli, S. ; Mezzanares, F. ;
Nuovo Cim.A 52 (1967) 892-902, 1967.
Inspire Record 1498682 DOI 10.17182/hepdata.75453

We have investigated the interactions of (650±15) MeV π— in a hydrogen bubble chamber. About 104 pictures were examined and 4561 events (1946 elastic, 1204 neutrals, 1315 single-pion production, 96 multi-pion production) were found along a 33.75·105 cm total track length. The values of the deduced cross-sections are σ(π--p, elastic) = = (17.82 ± 0.70) mb, σ(neutrals) = (11.35 ± 0.54) mb, σ(π-π0p) = (4.79 ± 0.26)mb, σ(π-π+n) = (7.05 ± 0.34)mb, σ(π-π+π0n) = (0.71 ± 0.08)mb, σ(π-π0π0p) = (0.05 ± 0.02)mb, σ(total) = (41.82 ± 0.15) mb For the elastic events, the differential cross-section was fitted by a fifth-order polynomial of cos ϑ and also expanded in a sum of Legendre polynomials: we deduce that the higher azimuthal states, up toF5/2, are present. For the single-pion production the effective mass distributions were compared with the Olsson-Yodh isobar model predictions. The agreement with the model is not very satisfactory for the enhancements in the mass effective spectra of the π+π-, π-π0, di-pion channels nor for the c.m.s. angular distributions.

1 data table match query

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pi-p Two-Prong Interactions at 4.16 GeV/c

Eisner, R.L. ; Johnson, P.B. ; Klein, P.R. ; et al.
Phys.Rev. 164 (1967) 1699-1710, 1967.
Inspire Record 52292 DOI 10.17182/hepdata.26569

An analysis of π−p two-prong interactions at 4.16 GeV/c is presented. The total two-prong cross section is 19.11±0.40 mb, based on 33 672 events. The elastic-scattering differential cross section shows an exponential behavior, Kexp(−AΔ2). With A=7.36±0.14 GeV−2, the "absorption parameters" are derived as C+=0.846±0.017 and γ+=0.040±0.001. The final-state π−π0p exhibits a strong ρ−, and the π−π+n a strong ρ0 and f0. The partial cross sections for the dominant resonant channels pρ−, π−Δ+(1236) (→pπ0), ρ0n, and f0n are 0.59±0.03, 0.17±0.01, 1.15±0.05, and 0.53±0.06 mb, respectively. The ρ− production and decay angular distributions do not agree with the predictions of the absorption-modified one-pion-exchange model. However, an inclusion of the contribution from ω exchange adequately accounts for the discrepancy. The ρ0 asymmetry is interpreted as a result of an interference of the resonant P wave and isospin-zero S wave, and the corresponding spin-density matrix elements are obtained. In the final state π−p+neutrals, a clear peak for the η meson and some evidence for the ω meson are seen.

1 data table match query

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


pi-p Interactions at 460 MeV

Poirier, C.P. ; Tilger, C.A. ; Alyea, E.D. ; et al.
Phys.Rev. 148 (1966) 1311-1314, 1966.
Inspire Record 50913 DOI 10.17182/hepdata.26590

A total of 1589 two-prong events were observed in an exposure of the Brookhaven National Laboratory 14-in. bubble chamber at the Cosmotron. The fit to the elastic angular distribution requires terms through cos4θc.m.. The ratio of the inelastic cross sections σ(π−p→π−π+n)σ(π−p→π−π0p) is 3.75±0.46. The π−p→π−π+n reaction is dominated by formation of the π−n isobar and an enhancement in the di-pion mass spectrum previously reported by Kirz. The π−p→π−π0p reaction shows no structure in the effective-mass spectra.

1 data table match query

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pi-p Elastic Scattering in the Energy Range 300-700 MeV

Ogden, Philip M. ; Hagge, Donald E. ; Helland, Jerome A. ; et al.
Phys.Rev. 137 (1965) B1115-B1125, 1965.
Inspire Record 944964 DOI 10.17182/hepdata.537

Differential cross sections for elastic π−p scattering were measured at eight energies for positive pions and seven energies for negative pions. Energies ranged from 310 to 650 MeV. These measurements were made at the 3-GeV proton synchrotron at Saclay, France. A beam of pions from an internal BeO target was directed into a liquid-hydrogen target. Fifty-one scintillation counters and a matrix-coincidence system were used to measure simultaneously elastic events at 21 angles and charged inelastic events at 78 π−p angle pairs. Events were detected by coincidence of pulses indicating the presence of an incident pion, scattered pion, and recoil proton, and the results were stored in the memory of a pulse-height analyzer. Various corrections were applied to the data and a least-squares fit was made to the results at each energy. The form of the fitting function was a power series in the cosine of the center-of-mass angle of the scattered pion. Integration under the fitted curves gave values for the total elastic cross sections (without charge exchange). The importance of certain angular-momentum states is discussed. The π−−p data are consistent with a D13 resonant state at 600 MeV, but do not necessarily require such a resonant state.

17 data tables match query

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pi-p ELASTIC SCATTERING AND SINGLE PION PRODUCTION AT 0.939-BeV/c

Baggetti, Lee, Jr. ;
UCRL-8302, 1958.
Inspire Record 44228 DOI 10.17182/hepdata.416

None

2 data tables match query

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pi--p Interactions at 683 MeV/c

Burnstein, R.A. ; Charlton, G.R. ; Day, T.B. ; et al.
Phys.Rev. 137 (1965) B1044-B1052, 1965.
Inspire Record 944965 DOI 10.17182/hepdata.983

Interactions of 683-MeV/c negative pions with protons were investigated using the BNL 14-in. hydrogen bubble chamber in a 17-kG field. Two thousand elastic scatterings were analyzed, yielding a cross section of 18.9±1.0 mb. No evidence for powers of cosθ higher than the second was observed in the elastic angular distribution. The angular distribution obtained was dσdω=(0.384±0.026)+(1.70±0.06)cosθ+(3.36±0.11)cos2θ mb/sr. The single-pion production reactions π−+p→π−+π0+p and π−+p→π−+π++n were studied in detail. A total of 441 π0 productions and 833 π+ productions were analyzed giving cross sections of 3.99±0.50 and 7.50±0.80 mb, respectively. The differential distributions for these inelastic processes are presented and compared with the predictions of the model of Olsson and Yodh. The distribution of events on the Dalitz plots for π0 production is accounted for by the model. However, for the π+ reaction, the model (so far developed) does not describe adequately the distribution of events on the Dalitz plot. In particular, the model fails to account for the enhancement at high (π+π−) effective masses in ππ mass distribution. The center-of-mass angular distributions for π0 and π+ production reactions are presented and compared with the model.

2 data tables match query

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pi--p Interactions at 604 MeV

Vittitoe, C.N. ; Riley, B.R. ; Fickinger, W.J. ; et al.
Phys.Rev. 135 (1964) B232-B240, 1964.
Inspire Record 46855 DOI 10.17182/hepdata.594

The interactions of 604 MeV π− mesons in a hydrogen bubble chamber have been systematically analyzed. In 33 000 pictures a total of 8052 usable events were found, corresponding to cross sections of 18.9±1.3 mb for σ(elastic), 4.98±0.54 mb for σ(π−pπ0), 7.87±0.91 mb for σ(π−nπ+), 14.0±1.0 mb for σ(neutrals), with σ(two−pionproduction)<0.2 mb, for a total cross section of 45.9±1.9 mb at this energy. The angular distribution for elastic scattering was fitted with a fifth-order polynomial in cosθ which gave a value of dσdΩ(0°) consistent with dispersion theory. The pion-pion effective-mass distributions for both single-pion-production channels showed pronounced peaking at high mass values, strongly inconsistent with simple isobar-production kinematics. Simple one-pion exchange does not appear to play a significant role.

1 data table match query

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pi--p Elastic Scattering at 310 MeV: Differential Cross Section and Recoil-Proton Polarization

Rugge, Hugo R. ; Vik, Olav T. ;
Phys.Rev. 129 (1963) 2300-2310, 1963.
Inspire Record 944977 DOI 10.17182/hepdata.623

The differential cross section and recoil-proton polarization in π−−p elastic scattering at 310-MeV incident-pion energy has been measured. The differential cross section was measured at 28 angles in the angular region 25<~θlab<~160 deg. The fractional rms errors were typically 3%. The reaction was observed by counting the scattered pions emerging from a liquid-hydrogen target with a counter telescope consisting of scintillation and Čerenkov counters. Simultaneously, the recoil-proton polarization was measured at four angles in the angular region 114<θc.m.<146 deg. The recoil protons from the liquid-hydrogen target were scattered from a carbon target and the left-right asymmetry was measured. Scintillation counters were used throughout to detect the particles.

2 data tables match query

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pi--p Elastic Scattering at 1.44 Bev

Chretien, M. ; Leitner, J. ; Samios, N.P. ; et al.
Phys.Rev. 108 (1957) 383-389, 1957.
Inspire Record 45962 DOI 10.17182/hepdata.26863

An investigation of π−+p elastic scattering, made in a liquid propane bubble chamber, is reported. Identification of events is made on the basis of kinematics. The problem of contamination by pion scattering from protons bound in carbon is considered in some detail; it is shown that the latter requires a correction of only 4±2.5% of the total number of events. The angular distribution is presented. It shows a large diffraction peak at small angles and an approximately isotropic plateau over the backward hemisphere. The forward peak is fitted to a black-sphere diffraction pattern with a radius of (1.08±0.06)×10−13 cm. The total elastic cross section is found to be σe=10.1±0.80 mb.

1 data table match query

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