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RE/IM MEASUREMENTS TAKEN FROM TABLE 1 OF KIRILLOVA 65.
TABLE 1 (REF. 1 ).
RE/IM MEASUREMENTS TAKEN FROM TABLE 1 OF KIRILLOVA 65.
The elastic scattering of 3.55 GeV/ c π + and π − mesons by protons was measured at centre-of-mass angles between 165° and 177°. The angular distributions for 864 events show a steeply rising backward peak for π + p, while the shape is less clear for π − p.
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Extrapolations.
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.
A phase shift analysis of the K<sup loc="post">+</sup>p elastic scattering at 780 MeV/c has been performed. The experimental differential cross section is best explained by a solution with dominant s wave, negative s wave phase shift (−42.7 ± 1 deg.) and small contributions of p and d waves.
Corrected for PI+ P events and scanning efficiency.
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.
Absolute π±p elastic scattering differential cross sections have been measured at five incident pion energies between 87 and 139 MeV. An active target of scintillator material (CH1.1) was used to detect recoil protons in coincidence with scattered pions. Pions were detected at forward angles between 27 and 98°c.m. where the low-energy recoil protons stop in the target. The cross sections, typically 5–10% lower than phase shift predictions for π+p and 10–20% lower for the π−p cross sections, are consistent with earlier measurements by this group.
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NAME=THEORY DENOTES THE MONTE-CARLO GENERATED CROSS SECTIONS.
Differential cross sections have been measured for π+p and π−p elastic scattering at 378, 408, 427, 471, 509, 547, 586, 625, 657, and 687 MeV/c in the angular range -0.8<cosθc.m.<0.8. The scattered pion and recoil proton were detected in coincidence using scintillation-counter hodoscopes. A liquid-hydrogen target was used except for measurements at forward angles, in which a CH2 target was used. Statistical uncertainties in the data are typically less than 1%. Systematic uncertainties in acceptance and detection efficiency are estimated to be 1%. Absolute normalization uncertainties are 2–3 % for most of the data. The measurements are compared with previous data and with the results of recent partial-wave analyses. The data are fit with Legendre expansions from which total elastic cross sections are obtained.
Normalisation uncertainty = 3.1 pct.
Normalisation uncertainty = 4.1 pct.
Normalisation uncertainty = 2.1 pct.
New high-statistics measurements of π + p elastic scattering differential cross sections are presented at 30 momentum points between 1.282 and 2.472 GeV/ c , covering most of the angular distribution outside the forward diffractive peak. These data show significant disagreements at some momenta with previous high-statistics experiments and with current partial wave analyses.
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We have measured differential cross sections for both π+p and π−p elastic scattering at incident-pion kinetic energies of 30, 50, 70, and 90 MeV in the center-of-mass angular range between 50° and 150°. The experiment detected pions scattered from a liquid-hydrogen target with multiwire proportional chambers and scintillation-counter range telescopes. The relative accuracy of each angular distribution is better than 5%, while the absolute cross sections have uncertainties of 4% to 25%. Our results for the absolute cross section for π+p scattering at 30 and 90 MeV are inconsistent with previous measurements. Our π−p measurements comprise the first extensive set of precision differential cross sections below 90 MeV.
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