The Absorption of Pions by Deuterons

Durbin, R. ; Loar, H. ; Steinberger, J. ;
Phys.Rev. 84 (1951) 581-581, 1951.
Inspire Record 47326 DOI 10.17182/hepdata.26473

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4 data tables

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Structure of the Proton

Chambers, E.E. ; Hofstadter, R. ;
Phys.Rev. 103 (1956) 1454-1463, 1956.
Inspire Record 945003 DOI 10.17182/hepdata.26939

The structure and size of the proton have been studied by means of high-energy electron scattering. The elastic scattering of electrons from protons in polyethylene has been investigated at the following energies in the laboratory system: 200, 300, 400, 500, and 550 Mev. The range of laboratory angles examined has been 30° to 135°. At the largest angles and the highest energy, the cross section for scattering shows a deviation below that expected from a point proton by a factor of about nine. The magnitude and variation with angle of the deviations determine a structure factor for the proton, and thereby determine the size and shape of the charge and magnetic-moment distributions within the proton. An interpretation, consistent at all energies and angles and agreeing with earlier results from this laboratory, fixes the rms radius at (0.77±0.10) ×10−13 cm for each of the charge and moment distributions. The shape of the density function is not far from a Gaussian with rms radius 0.70×10−13 cm or an exponential with rms radius 0.80×10−13 cm. An equivalent interpretation of the experiments would ascribe the apparent size to a breakdown of the Coulomb law and the conventional theory of electromagnetism.

1 data table

In the experiment just relative cross sections were measured. The absolute values were ascribed at each energy after multiplying experimental data by a co nstant factor to obtain the best fit with theory assuming the diffuse proton model with charge and magnetic moment rms radii 0.08 fm.. The values in the table are extracted from the graphs (see figs. 6 - 9) byZOV.


p-p Interactions at 3 Bev

Cester, R. ; Hoang, T.F. ; Kernan, A. ;
Phys.Rev. 103 (1956) 1443-1449, 1956.
Inspire Record 945004 DOI 10.17182/hepdata.26958

Interactions initiated by 3-Bev protons of the Brookhaven Cosmotron were studied by photoemulsion technique. With appropriate criteria, 115 events are attributed to interactions of the incident beam protons with hydrogen nuclei (∼55%) and with bound protons of other nuclei (∼45%). A detailed analysis allowed the subdivision of the 115 events in categories, according to the number of π mesons (N>~0) produced in the collision. The ratio of elastic scattering to the total number of events was estimated to be σelσtotal=0.20−0.07+0.04. The observed cross section for pure elastic scattering is σel=8.9±1.0 mb. The percentages of single, double, triple, and quadruple π-meson production are respectively: 34−20+22; 35.6−23+20; 9.6−4+6; ∼1.0+3.5. Among the 20 most probable cases of single π-meson production—the estimated ratio of π+ to π0 is σπ+σπ0=5.3−1.4+0.3. The experimental results are not in agreement with the Fermi statistical-model theory (in particular the lower limit for the experimental ratio of triple to single production is given by σ3σ1>∼110 in contrast with the predicted ratio σ3σ1=167) but are not inconsistent with the Peaslee excited-state-model theory.

1 data table

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Cross Sections for Antiprotons in Hydrogen, Beryllium, Carbon, and Lead

Cork, Bruce ; Lambertson, Glen R. ; Piccioni, Oreste ; et al.
Phys.Rev. 107 (1957) 248-256, 1957.
Inspire Record 944999 DOI 10.17182/hepdata.26942

A strong-focusing momentum channel has been arranged to form a beam from antiprotons produced by 6.0-Bev protons striking an internal target of the Bevatron. The channel consists of five 4-inch-diameter magnetic quadrupole lenses and two deflecting magnets adjusted to give a ±5% momentum interval. The antiprotons were selected from a large background of mesons by a scintillation counter telescope with a time-of-flight coincidence circuit having a resolution of ±2×10−9 second. This system allowed detection of approximately 400 antiprotons per hour. With a liquid hydrogen attenuator, the total antiproton-proton cross section at four different energies, 190, 300, 500, and 700 Mev, has been observed to be 135, 104, 97, and 94 mb, respectively. Also, the total cross sections for antiprotons incident on Be and C have been measured at two energies. The inelastic cross sections for carbon have been measured by observing the pulse heights produced by the interactions in a target of liquid scintillator. To measure the inelastic cross section for a high-Z element, lead wafers were immersed in the liquid scintillator, and to select inelastic events the pulse heights were measured.

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Antiproton-Proton Cross Sections at 1.0, 1.25, and 2.0 Bev

Armenteros, Rafael ; Coombes, Charles A. ; Cork, Bruce ; et al.
Phys.Rev. 119 (1960) 2068-2073, 1960.
Inspire Record 46744 DOI 10.17182/hepdata.813

The interaction of 1.0-, 1.25-, and 2.0-Bev antiprotons with protons has been studied with the aid of a 4π solid-angle scintillation-counter detector system. The measured total cross sections at the above energies are 100, 89, and 80 mb, respectively. At each energy, the charge-exchange cross section is approximately 5 mb. The total elastic cross sections are 33, 28, and 25 mb, respectively, at the three energies. The angular distribution of elastic scattering has been fitted with a simple optical-model calculation.

3 data tables

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Total Cross Sections for p, \bar{p}, K + /-, and pi + /- on Hydrogen Between 3 and 10 Gev/c

von Dardel, G. ; Frisch, D.H. ; Mermod, R. ; et al.
Phys.Rev.Lett. 5 (1960) 333-336, 1960.
Inspire Record 944910 DOI 10.17182/hepdata.197

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2 data tables

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Electromagnetic Form Factors of the Proton

Bumiller, F. ; Croissiaux, M. ; Dally, E. ; et al.
Phys.Rev. 124 (1961) 1623-1631, 1961.
Inspire Record 47220 DOI 10.17182/hepdata.26853

This paper reports experimental findings on the Dirac (F1) and Pauli (F2) form factors of the proton. The form factors have been obtained by using the Rosenbluth formula and the method of intersecting ellipses in analyzing the elastic electron-proton scattering cross sections. A range of energies covering the interval 200-1000 Mev for the incident electrons is explored. Scattering angles vary from 35° to 145°. Values as high as q2≅31 f−2 (q=energy−momentumtransfer) are investigated, but form factors can be reliably determined only up to about q2=25 f−2. Splitting of the form factors is confirmed. The newly measured data are in good agreement with earlier Stanford data on the form factors and also with the predictions of a recent theoretical model of the proton. Consistency in determining the values of the form factors at different energies and angles gives support to the techniques of quantum electrodynamics up to q2≅25 f−2. At the extreme conditions of this experiment (975 Mev, 145°) the behavior of the form factors may be exhibiting some anomaly.

24 data tables

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Polarization of the Recoil Proton from the Neutral Photoproduction at 800 and 910 Mev

Mencuccini, C. ; Querzoli, R. ; Salvini, G. ;
Phys.Rev. 126 (1962) 1181-1182, 1962.
Inspire Record 944983 DOI 10.17182/hepdata.26790

The measurements on the polarization of the recoil protons from the process γ+p→π0+p have been extended to higher γ-ray energies, at 90° in the center-of-mass system. We have found at 910 Mev a polarization, P=−0.45±0.07; at 800 Mev, P=−0.42±0.10. The rather high values of P agree with the hypothesis that the neutral photoproduction in the 500-1000 Mev range can be described by the well-known three resonant states, and strongly indicate that the second and third resonance have opposite parity. The probable quantum numbers are: T=12, J=32, D pion wave for the second resonance; T=12, J=52, F wave for the third resonance.

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Evidence for Vector-Meson Effects on pi0 Photoproduction From Hydrogen

Talman, R.M. ; Clinesmith, C.R. ; Gomez, R. ; et al.
Phys.Rev.Lett. 9 (1962) 177-180, 1962.
Inspire Record 944904 DOI 10.17182/hepdata.19353

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3 data tables

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Elastic scattering in pi- p collisions at 604 MeV

Riley, Benny R. ;
PhD Thesis, U. Kentucky, Lexington, 1963.
Inspire Record 1408826 DOI 10.17182/hepdata.70524

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