Photoproduction of Positive Pions from Protons

Uretsky, Jack L. ; Kenney, Robert W. ; Knapp, Edward A. ; et al.
Phys.Rev.Lett. 1 (1958) 12-14, 1958.
Inspire Record 944927 DOI 10.17182/hepdata.21871

None

2 data tables

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Production of High Transverse Momentum Low Mass Electron - Positron Pairs in High-energy $p p$ Collisions

Chilingarov, A. ; Clark, A.G. ; Darriulat, P. ; et al.
Nucl.Phys.B 151 (1979) 29-45, 1979.
Inspire Record 133024 DOI 10.17182/hepdata.34778

The production of electron-positron pairs of masses below 1200 MeV/ c 2 and of transverse momentum above 1.8 GeV/ c has been studied in pp collisions at √ s = 53 and 63 GeV. The cross section for ϱ, ω, and φ production are presented. The continuum below 600 MeV/ c 2 is consistent with origination from Dalitz decays of η and ω mesons and from semileptonic decay of D and D mesons.

1 data table

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Large Transverse Momentum $\pi^0$ Production in Proton Proton, Deuteron Proton, and Deuteron-deuteron Collisions at the {CERN} {ISR}

Clark, A.G. ; Darriulat, P. ; Eggert, K. ; et al.
Nucl.Phys.B 142 (1978) 189-204, 1978.
Inspire Record 130468 DOI 10.17182/hepdata.35022

Measurements are presented of the inclusive π 0 production cross section, in the transverse momentum range 2.3 ⪅ p T ⪅4.5 GeV/c, for dd and dp interactions at total c.m. energies of √ s = 52.7 GeV and √ s = 63.2 GeV and for pp interactions at √ s = 52.7 GeV. The produced π 0 's are detected by identifying both protons from the decay π 0 → γγ . As in pp interactions, the data can be adequately described by a p T −n ƒ(x T ) dependence with n ≌ 8 . The data are approximately consistent with the expectations of free nucleon scattering. No significant differenceare observed in either the charged or the neutral particle distributions associated with π 0 , for dd, dp and pp interactions.

5 data tables

GLOBAL NORMALIZATION UNCERTAINTY = 12 PCT. RELATIVE NORMALIZATION UNCERTAINTY = 5 PCT.

GLOBAL NORMALIZATION UNCERTAINTY = 10 PCT. RELATIVE NORMALIZATION UNCERTAINTY = 6 PCT.

GLOBAL NORMALIZATION UNCERTAINTY = 15 PCT. RELATIVE NORMALIZATION UNCERTAINTY = 7 PCT.

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Inclusive $\pi^0$ Production From High-energy $P P$ Collisions at Very Large Transverse Momenta

Clark, A.G. ; Darriulat, P. ; Dittmann, P. ; et al.
Phys.Lett.B 74 (1978) 267-272, 1978.
Inspire Record 6427 DOI 10.17182/hepdata.27460

We report on measurements of inclusive π 0 production at c.m. energies of 53 and 63 GeV, θ ≅90°, from p-p collisions at the CERN ISR. In the range 0.2< x t <0.45 the data can be described by a form: Ed 3 σ d p 3 ∝p − (6.6±0.8) t (1−x t ) (9.6±1.0) .

2 data tables

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Elastic Scattering of Negative Pions by Protons at 230, 290, 370, and 427 Mev

Goodwin, Lester K. ; Kenney, Robert W. ; Perez-Mendez, Victor ;
Phys.Rev. 122 (1961) 655-664, 1961.
Inspire Record 944985 DOI 10.17182/hepdata.26809

The elastic differential cross section for the scattering of negative pions by hydrogen was measured at laboratory-system pion kinetic energies of 230, 290, 370, and 427 Mev. The elastically scattered pions were detected by a counter telescope which discriminated against recoil protons and inelastic pions on the basis of range. Differential cross sections were obtained at nine angles for each energy and were fitted by a least-squares program to a series of Legendre polynomials. At the three higher energies, D waves are required to give satisfactory fits to the data. The real parts of the forward-scattering amplitudes calculated from this experiment are in agreement with the predictions of dispersion theory. The results of this experiment, in conjunction with data from other pion-nucleon scattering experiments, support the hypothesis of charge independence at these higher energies.

4 data tables

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Total Cross Sections for Negative Pions on Protons at 230, 290, 370, 427, and 460 Mev

Caris, John C. ; Goodwin, Lester K. ; Kenney, Robert W. ; et al.
Phys.Rev. 122 (1961) 262-264, 1961.
Inspire Record 944986 DOI 10.17182/hepdata.26810

Total cross sections for negative pions on protons were measured at laboratory energies of 230, 290, 370, 427, and 460 Mev. The measurements were made in the same pion beams as and at energies identical with those of our π−−p differential scattering experiments. Comparisons of the total and differential scattering can be made with the dispersion theory at a given energy without introducing the systematic errors that would normally enter due to uncertainties in the parameters of more than one pion beam. The measured total cross sections are found to agree within statistics with other measured values, and with the sums of elastic, inelastic, and charge-exchange cross sections measured at this laboratory. The results are:

1 data table

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Angular Distributions of Photopions from Hydrogen

Knapp, Edward A. ; Kenney, Robert W. ; Perez-Mendez, Victor ;
Phys.Rev. 114 (1959) 605-611, 1959.
Inspire Record 944992 DOI 10.17182/hepdata.26850

An accurate measurement of the differential cross section for the photoproduction of positive pions from protons has been made at the Berkeley synchrotron for photon energies of 260 and 290 Mev. The mesons were produced in a thin-walled liquid-hydrogen target, and the meson-detection apparatus utilized the characteristic decay of the pion. The measurements were done in two steps, from 0° to 50° with equipment specifically designed to reduce a very high forward-angle positron background, and from 30° to 160° with equipment whose efficiency and solid angle could be accurately determined. The abrupt flattening of the observed cross section in the region forward of 40° is due to "photoelectric ejection" of pions from the cloud surrounding the nucleon. The results are compared to the theory of photo-production derived from the dispersion relations, and the agreement is satisfactory within the limitations of the theory.

2 data tables

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Charge-Exchange Scattering of Negative Pions by Hydrogen at 230, 260, 290, 317, and 371 Mev

Caris, John C. ; Kenney, Robert W. ; Perez-Mendez, Victor ; et al.
Phys.Rev. 121 (1961) 893-904, 1961.
Inspire Record 944987 DOI 10.17182/hepdata.805

The differential cross section for charge-exchange scattering of negative pions by hydrogen has been observed at 230, 260, 290, 317, and 371 Mev. The reaction was observed by detecting one gamma ray from the π0 decay with a scintillation-counter telescope. A least-squares analysis was performed to fit the observations to the function dσdω=Σl=15alPl−1(cosθ) in the c.m. frame. The best fit to our experimental measurements requires only s- and p-wave scattering. The results (in mb) are: The least-squares analysis indicates that d-wave scattering is not established in this energy range.

4 data tables

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Pion-Proton Charge-Exchange Scattering from 500 to 1300 MeV

Chiu, Charles B. ; Eandi, Richard D. ; Helmholz, A.Carl ; et al.
Phys.Rev. 156 (1967) 1415-1426, 1967.
Inspire Record 52278 DOI 10.17182/hepdata.750

Differential cross sections for the reaction π−p→π0n were measured at nine incident-pion kinetic energies in the interval from 500 to 1300 MeV. The negative pion beam from the bevatron was focused on a liquidhydrogen target completely surrounded by a cubic array of six steel-plate spark chambers. The spark chambers were triggered on events with neutral final states. Charge-exchange events were identified from the one-shower and two-shower events in the spark-chamber pictures. By the Monte Carlo technique, the π0 distributions were calculated from the bisector distributions of the two-shower π0 events together with the observed γ-ray distributions of the one-shower π0 events. These π0 distributions were fitted with both Legendre-polynomial expansions and power-series expansions by the method of least squares. The extrapolated forward differential cross sections are in good agreement with the dispersion calculations. The Legendre coefficients for the differential cross sections in isospin state T=12 were obtained by combining our results with available data on π±p elastic scattering. In the light of existing phase-shift solutions, the behavior of these coefficients is discussed. The D5F5 interference term that peaks near 900 MeV is verified to be in isospin state T=12 only. We report here also the total neutral cross sections and the cross sections for the production of neutral multipion final states 2π0n and 3π0n. The 4π solid angle and the calibrated energy response of the spark chambers contribute to the accuracy of the results.

19 data tables

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Elastic-Differential Cross Section of pi++p at 1.5, 2.0, and 2.5 BeV/c

Cook, Victor ; Cork, Bruce ; Holley, William R. ; et al.
Phys.Rev. 130 (1963) 762-765, 1963.
Inspire Record 944975 DOI 10.17182/hepdata.599

We measured elastic-scattering angular distributions for π++p scattering at 1.5, 2.0, and 2.5 BeV/c using spark chambers to detect scattered pions and protons. A bump that decreases in amplitude with increasing momentum is observed in the backward hemisphere in the 1.5- and 2.0-BeV/c distributions, but is not observed in the 2.5-BeV/c distributions. It appears reasonable to attribute this phenomenon to the 1.45-BeV/c resonance observed in the π++p total cross section. The data are compared with π−+p data and are found to support the theoretical prediction that the scattering cross sections for both charge states should become equal at high energies. We fit the angular distributions with a power series in cosθ*, and compare the extrapolated values for the scattering cross section in the backward direction with the calculation of the neutron-exchange pole contribution to the cross section. The "elementary" neutron-pole term contribution is calculated to be 90 mb/sr at 2.0 BeV/c, in violent disagreement with the extrapolated value, ≈0.5 mb/sr.

4 data tables

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