Forward differential cross sections for π − p elastic scattering at 1.0, 1.5 and 2.0 GeV/ c show that the square of the imaginary parts of the nuclear scattering agrees with the optical theorem prediction within ±3%, when averaged over the three momenta.
No description provided.
The angular distribution of π + p elastic scattering has been measured at an incident momentum of 10 GeV/ c . Nearly the whole angular range was covered in one experimental set-up. The pronounced dip at − t = 2.8 (GeV/ c ) 2 , observed at lower momenta, has diminished and is essentially a shoulder at 10 GeV/ c . The other structure at larger momentum transfers are also different in detail from what we observed at 5 GeV/ c . In the 90° c.m. region the differential cross-section is approximately one nb/(GeV/ c ) 2 , which is more than two orders of magnitude lower than at 5 GeV/ c .
THESE DATA ARE REPORTED MORE FULLY IN C. BAGLIN ET AL., NP B98, 365 (1975).
We have measured dσ du for π − p elastic scattering at 3 and 4 GeV c in the ranges −0.119⩽ u ⩽0.113 and −0.233⩽ u ⩽0.088, respectively. A fit of the form d σ /d u = A exp ( Bu + Cu 2 ) gives B = 4.34±0.42 and C = 7.0±3.5 at 4 GeV c with χ 2 = 5.7 for 9 degrees of freedom; the simpler form d σ /d u = A exp( Bu ) gives B = 3.7 ± 0.3 with χ 2 = 9.6. At 3 GeV c we confirm with high statistics the structures already observed.
No description provided.
No description provided.
The differential cross-section in proton-proton scattering at 144 ± 1.5 MeV has been measured over the Coulomb-nuclear interference region. When the present data are included in a phase-shift analysis the resultant phas-shifts are only slightly changed from their previous values.
No description provided.
The asymmetry parameter A in π−p elastic scattering at incident pion laboratory kinetic energies Tπ of 98, 238, and 2922 MeV and in π−p charge-exchange scattering π−p→π0n at Tπ=238, 292, and 310 MeV have been measured over a wide range of scattering angles (typically from about 60° to 130° c.m.) with a polarized proton target. The data have been used in an energy-independent phase-shift analysis to improve the precision of the pion-nucleon phase shifts, to set new limits on violation of isospin conservation in the pion-nucleon S wave, and to confirm significant charge dependence in the P32 wave.
Axis error includes +- 0.0/0.0 contribution (?////BACKGROUND SUBTRACTION SMALL).
Axis error includes +- 0.0/0.0 contribution (?////BACKGROUND SUBTRACTION SMALL).
Axis error includes +- 0.0/0.0 contribution (?////BACKGROUND SUBTRACTION SMALL).
Backward elastic scattering has been measured for π + p at 2.85 and 3.30 GeV/ c and for π − p at 3.30 GeV/ c . The π + p angular distributions show steep backward peaks, whereas the π − p distribution is flatter. At 2.85 GeV/ c the π + p differential cross section close to 180° is more than twice that at 3.30 GeV/ c , supporting the assignment J P = 11 2 + for Δ δ (2420) resonance. The π + p data at 2.85 GeV/ c indicate the onset of a dip at cos θ c.m. ≈ −0.97.
The data for cos(theta) = 1 is the extrapolation.
The data for cos(theta) = 1 and U = 0 are the extrapolations.
The data for cos(theta) = 1 and U = 0 are the extrapolations.
Measurements of the differential elastic cross sections for π − p scattering at incident momenta of 20 and 50 GeV c and π + p at 50 GeV c in the momentum transfer range 0.7 < |t|; < 8.0 ( GeV c ) 2 are presented. The data are compared with various models of elastic scattering.
No description provided.
No description provided.
No description provided.
We present results on .~--p seattering at kinetic energies in the laboratory of 516, 616, 710, 887 and 1085MeV. The data were obtained by exposing a liquid hydrogen bubble chamber to a pion beam from the Saelay proton synchrotron Saturne. The chamber had a diameter of 20 cm and a depth of 10 cm. There was no magnetic field. Two cameras, 15 em apart, were situated at 84 cm from the center- of the chamber. A triple quadrnpole lens looking at an internal target, and a bending magnet, defined the beam, whose momentum spread was less than 2%. The value of the momentum was measured by the wire-orbit method and by time of flight technique, and the computed momentum spread was checked by means of a Cerenkov counter. The pictures were scanned twice for all pion interactions. 0nly those events with primaries at most 3 ~ off from the mean beam direction and with vertices inside a well defined fiducial volume, were considered. All not obviously inelastic events were measured and computed by means of a Mercury Ferranti computer. The elasticity of the event was established by eoplanarity and angular correlation of the outgoing tracks. We checked that no bias was introduced for elastic events with dip angles for the scattering plane of less than 80 ~ and with cosines of the scattering angles in the C.M.S. of less than 0.95. Figs. 1 to 5 show the angular distributions for elastic scattering, for all events with dip angles for the scattering plane less than 80 ~ . The solid curves represent a best fit to the differential cross section. The ratio of charged inelastic to elastic events, was obtained by comparing the number of inelastic scatterings to the areas under the solid curves which give the number of elastic seatterings.
No description provided.
No description provided.
No description provided.
A description is given of an experiment to study elastic scattering of π ± , K ± and p on protons at c.m. scattering angles from 45° to 100° at incident laboratory momenta 20 GeV/ c and 30 GeV/ c . The corresponding t range is from −6.2 (GeV/ c ) 2 to −28 (GeV/ c ) 2 . There are no previous observations for these reactions in this t range. High intensity and large geometrical acceptance were required in order to measure the low cross sections. The experiment used a double-arm spectrometer. MWPCs were used for reconstruction, and threshold and differential Čerenkov counters for identification. Scintillation counters, Čerenkov counters and a hadron calorimeter were used in the trigger. The trigger logic utilized specially designed matrices and a hard wired microprocessor. The π − p elastic scattering cross sections follow approximately the dimensional counting rule from 3.5 GeV/ c .and up to 30 GeV/ c . The cross sections decrease by seven orders of magnitude in this energy range. The data is compared to quark models. None of these models give a comprehensive description of the results. However, some modifications to these models improve their consistency with the data.
EARLIER RESULTS GIVEN IN 'A'.
No description provided.
EARLIER RESULTS GIVEN IN 'A'.
The analyzing power A N of proton-proton, proton-hydrocarbon, and antiproton-hydrocarbon, scattering in the Coulomb-nuclear interference region has been measured using thhe 185 GeV/ c Fermilab polarized-proton and -antiproton beams. The results are found to be consistent with theoretical predictions within statistical uncertainties.
No description provided.
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