K − p elastic scattering at 10 GeV/ c is studied on ∼3600 bubble chamber events. The elastic cross section is found to be σ el = (3.20 ± 0.14)mb and the ratio σ el σ tot = (0.142 ± 0.006) , that is below the upper limit of 0.185 suggested in a model by Van Hove. The value of the forward differential cross section is consistent with zero real part to the scattering amplitude. The slope of d σ d t is similar to that for π ± and greater than that of K + , with no evidence for shrinkage of the diffraction peak. No events of backward scattering were observed. The Regge-pole model of Phillips and Rarita gives a good fit to the data.
No description provided.
The single-pion production reactions $pp\to d\pi^+$, $pp\to np\pi^+$ and $pp\to pp\pi^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p \approx$ 400 MeV) using the short version of the COSY-TOF spectrometer. The implementation of a central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements. Thus all pion production channels were recorded with 1-4 overconstraints. The total and differential cross sections obtained are compared to previous data and theoretical calculations. Main emphasis is put on the discussion of the $pp\pi^0$ channel, where we obtain angular distributions different from previous experimental results, however, partly in good agreement with recent phenomenological and theoretical predictions. In particular we observe very large anisotropies for the $\pi^0$ angular distributions in the kinematical region of small relative proton momenta revealing there a dominance of proton spinflip transitions associated with $\pi^0$ $s$- and $d$-partial waves and emphasizing the important role of $\pi^0$ d-waves.
Measured angular distribution for elastic P P scattering in the CM system normalised to the data in the SAID database (Arndt et al. PR C62,034005(2000). This measurement is made to determine the luminosity.
Analyzing powers of pion-proton elastic scattering have been measured at PSI with the Low Energy Pion Spectrometer LEPS as well as a novel polarized scintillator target. Angular distributions between 40 and 120 deg (c.m.) were taken at 45.2, 51.2, 57.2, 68.5, 77.2, and 87.2 MeV incoming pion kinetic energy for pi+ p scattering, and at 67.3 and 87.2 MeV for pi- p scattering. These new measurements constitute a substantial extension of the polarization data base at low energies. Predictions from phase shift analyses are compared with the experimental results, and deviations are observed at low energies.
Analyzing power for PI+ P elastic scattering at incidient kinetic energy 87.2 MeV from the data set 1.
Analyzing power for PI+ P elastic scattering at incidient kinetic energy 68.4 MeV from the data set 1.
Analyzing power for PI+ P elastic scattering at incidient kinetic energy 57.2 MeV from the data set 1.
We have made, for the first time, a direct reconstruction of the pp elastic-scattering matrix at 579 MeV from a series of experiments performed at the Schweizerisches Institut für Nuklearforschung polarized-beam line. Fifteen observables consisting of the polarization, two-spin correlation and transfer parameters, and three-spin parameters were measured at seven angles between 66° and 90° (c. m.). The experimental results and reconstructed amplitudes are presented and compared to phase shift analysis.
No description provided.
A measurement of the spin correlation parameters A xx (90° cm) and A yy (90° cm) of 47.5 MeV proton-proton scattering has been performed by means of polarized beam and a polarized target.
No description provided.
We have measured the difference between the pp total cross-sections for parallel and anti-parallel longitudinal spin states at beam momenta of 3 and 6 GeV/ c . These results, combined with our previous measurements, at lower momenta, are useful in clarifying a striking structure appearing at around 1.5 GeV/ c . We have also measured for the first time, the spin-spin correlation parameter C LL ( t ) in pp elastic scattering at 6 GeV/ c . We observe evidence for an exchange with A 1 -like quantum-numbers.
NOTE: HIGHER -T DATA ARE BEING ANALYSED. PUBLISHED GRAPH HAS LARGER ERRORS.
THESE NUMBERS APPEAR TO UPDATE THOSE REPORTED IN I. P. AUER ET AL., PRL 37, 1727 (76). NOTE: DATA MAY HAVE SMALLER ERROR BARS IN THE FINAL ANALYSIS.
NOTE: MORE DATA ARE BEING ANALYSED. SINCE THE POLARIZED TARGET MAGNETIC FIELD WAS TILTED AT 18 DEG AWAY FROM THE BEAM DIRECTION, THE MEASURED CSL CONTAINS AN ADMIXTURE OF CSS. THE CSL VALUES QUOTED HERE HAVE BEEN CORRECTED FOR THIS EFFECT USING THE EXPERIMENTAL VALUES OF CSS.
Analyzing powers for πp elastic scattering at bombarding energies below the Δ(1232) resonance were measured at TRIUMF using the CHAOS spectrometer and a polarized spin target. This work presents π− data at six incident energies of 57, 67, 87, 98, 117, and 139 MeV, and a single π+ data set at 139 MeV. The higher energy measurements cover an angular range of 72°<~θc.m.<~180° while the lower energies were limited to 101°<~θc.m.<~180°. There is a high degree of consistency between this work and the predictions of the VPI/GWU group’s SM95 partial wave analysis.
Analysing power measurements for a 139 GeV PI+ beam (standard track).
Analysing power measurements for a 139 GeV PI- beam (standard track).
Analysing power measurements for a 117 GeV PI- beam (standard track).
Angular distributions of the analyzing powers for π+p→ and π−p→ elastic scattering have been measured in a single-scattering experiment employing a polarized proton target. Measurements were obtained for pion energies of 98, 139, 166, 215, and 263 MeV. The addition of these data to the existing πp database significantly reduces the uncertainties in all S and P phase shifts for πp reactions over the delta resonance.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 98 MeV.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 139 MeV.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 166 MeV.
pp-elastic differential cross sections are reported at 492 MeV from 40° to 90°, and at 576, 642, 728, and 793 MeV from 75° to 90° c.m., with an absolute accuracy of less than 1%. These data, obtained with polyethylene targets, agree with recent measurements at the same energies obtained with a liquid-hydrogen target. © 1996 The American Physical Society.
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Absolute pp-elastic-differential cross sections were measured at incident energies 492, 576, 642, 728, and 793 MeV from about 30° to 90° c.m. The total uncertainty was determined to be less than 1%, made possible by particle counting for beam normalization and extensive cross-checks of systematic effects. These new data are consistent with previous data above 600 MeV but have uncertainties about a factor of 10 smaller. Near 500 MeV these data are consistent with 90° data from TRIUMF, but differ significantly from similar data from PSI; the cause of this discrepancy is discussed.
No description provided.
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