Production of $pi^0$ Mesons by gamma-Rays on Hydrogen

Silverman, A. ; Stearns, M. ;
Phys.Rev. 88 (1952) 1225-1230, 1952.
Inspire Record 944938 DOI 10.17182/hepdata.26460

The production of π∘ mesons in the reaction γ+p→π∘+p is investigated as a function of the incident γ-ray energy in the region from 200 Mev to 300 Mev. For the π∘ emitted at approximately 90° laboratory angle, the differential cross section can be represented by (dσπ∘dΩ)π2=C(K−145)1.9±0.4, where K= energy of incident γ-ray in Mev. The approximate threshold for the reaction is 145 Mev. The ratio of the cross section at 60° laboratory angle to that at 90° laboratory angle, for γ-rays between 250 Mev and 300 Mev, is 1.45±0.25.

1 data table

No description provided.


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

No description provided.


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.

4 data tables
More…

Elastic Proton-Proton Scattering at 2.24, 4.40, and 6.15 Bev

Cork, Bruce ; Wenzel, William A. ; Causey, Charles W. ;
Phys.Rev. 107 (1957) 859-867, 1957.
Inspire Record 944998 DOI 10.17182/hepdata.26883

Protons of the internal circulating beam of the Bevatron were scattered in a polyethylene target. Both scattered and recoil protons were detected by scintillation counters at angles which define elastic proton-proton events. An internal counter was located within a few inches of the beam to permit measurements at laboratory scattering angles as low as 2°. Absolute values are based on the calibration of the induction electrode that monitors the circulating beam. Total elastic cross sections obtained by integrating the differential spectra are 17, 10, and 8 mb at 2.24, 4.40, and 6.15 Bev, respectively. The experimental angular distributions are consistent with the prediction of a simple optical model with a complex index of refraction at short range.

1 data table

'ALL'.


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

No description provided.

No description provided.


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

No description provided.

No description provided.


Photoproduction of Neutral Pions at Forward Angles

Berkelman, Karl ; Waggoner, James A. ;
Phys.Rev. 117 (1960) 1364-1375, 1960.
Inspire Record 46817 DOI 10.17182/hepdata.26899

The bremsstrahlung beam of the Cornell Bev electron synchrotron has been used to study the reaction γ+p→π0+p over the photon energy range 250 Mev to 1 Bev, and for center-of-mass pion angles between 20° and 70°. The recoil protons, of energies between 10 and 60 Mev, were identified and their energies determined using a range telescope of eight thin plastic scintillators enclosed in a vacuum chamber with the thin liquid hydrogen target. Correlated pulse-height information was obtained by photographing an oscilloscope display and was used to sort out the protons from mesons and electrons. Corrections were made for the background of photoprotons from the Mylar target cup, the energy loss of the protons in the liquid hydrogen, absorption and scattering in the counter telescope, and the variation of beam intensity profile with energy. Compared with previous experiments and extrapolations the results show a somewhat smaller forward differential cross section above 400 Mev. The angular distributions obtained from a least-squares fit to all existing data indicate a d32 assignment for the 760-Mev resonance level. Other implications of the data are also discussed.

1 data table

No description provided.


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

No description provided.

No description provided.

No description provided.


Total Cross Sections of Protons with Momentum Between 10 and 28 Gev/c

Ashmore, A. ; Cocconi, G. ; Diddens, A.N. ; et al.
Phys.Rev.Lett. 5 (1960) 576-578, 1960.
Inspire Record 944909 DOI 10.17182/hepdata.192

None

2 data tables

No description provided.

No description provided.


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

No description provided.

No description provided.

No description provided.

More…