Inclusive <math altimg="si2.gif" display="inline" overflow="scroll"><msup><mi>K</mi><mo>+</mo></msup></math> production in proton–proton collisions has been measured at a beam energy of 2.16 GeV using the COSY-ANKE magnetic spectrometer. The resulting spectrum, as well as those corresponding to <math altimg="si3.gif" display="inline" overflow="scroll"><msup><mi>K</mi><mo>+</mo></msup><mi>p</mi></math> and <math altimg="si4.gif" display="inline" overflow="scroll"><msup><mi>K</mi><mo>+</mo></msup><msup><mi>π</mi><mo>+</mo></msup></math> correlated pairs, can all be well described using consistent values of the total cross sections for the <math altimg="si5.gif" display="inline" overflow="scroll"><mi>p</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>p</mi><mi>Λ</mi></math>, <math altimg="si6.gif" display="inline" overflow="scroll"><mi>p</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>p</mi><msup><mi>Σ</mi><mn>0</mn></msup></math>, and <math altimg="si7.gif" display="inline" overflow="scroll"><mi>p</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>n</mi><msup><mi>Σ</mi><mo>+</mo></msup></math> reactions. While the resulting values for Λ and <math altimg="si8.gif" display="inline" overflow="scroll"><msup><mi>Σ</mi><mn>0</mn></msup></math> production are in good agreement with world data, our value for the total <math altimg="si9.gif" display="inline" overflow="scroll"><msup><mi>Σ</mi><mo>+</mo></msup></math> production cross section, <math altimg="si10.gif" display="inline" overflow="scroll"><mi>σ</mi><mo stretchy="false">(</mo><mi>p</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>n</mi><msup><mi>Σ</mi><mo>+</mo></msup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>2.5</mn><mo>±</mo><msub><mn>0.6</mn><mi mathvariant="normal">stat</mi></msub><mo>±</mo><msub><mn>0.4</mn><mi mathvariant="normal">syst</mi></msub><mo stretchy="false">)</mo><mtext> μb</mtext></math> at an excess energy of <math altimg="si11.gif" display="inline" overflow="scroll"><mi>ε</mi><mo>=</mo><mn>129</mn><mtext> MeV</mtext></math>, could only be reconciled with other recently published data if there were a highly unusual near threshold behaviour.
We have measured the differential cross section d2σdΩdTπ and the polarization parameter P for the production of π+ and π− in various target nuclei (H1, H2, Be, C, O, Al, Ni, Cu, Mo, and Pb) by protons with a kinetic energy of 585 MeV, for production angles θπ=22.5°, 45°, 60°, 90°, and 135°, and for pion kinetic energies Tπ of 24, 35, 46, 88, 151, 192, and 254 MeV (all quantities in the laboratory system). Our data disagree strongly with recent data for 580-MeV protons. On the other hand, for pion energies up to 150 MeV, our cross sections differ little from those measured for a proton energy of 730 MeV. For nuclei with A>20, the total production cross sections σ(π+) and σ(π−) show the Z13 and N23 proportionality expected from theoretical arguments. There is evidence in our data of a shift of the π+ energy distributions compared to the π− distributions due to the effects of the Coulomb field of the nuclear protons on the emitted pions. NUCLEAR REACTIONS H1, H2, Be, C, O, Al, Ni, Cu, Mo, Pb p, π±, Tp=585 MeV; measured σ(Tπ, θπ) and asymmetry parameter P(Tπ, θπ).
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Inclusive measurements of pion production in proton--proton collisions in the forward direction were undertaken at 400 and 600 MeV at COSY using the Big Karl spectrograph. The high resolution in the $\pi^+$ momentum ensured that there was an unambiguous separation of the $pp\to {\pi}^+d/\pi^+pn$ channels. Using these and earlier data, the ratio of the production cross sections could be followed through the $\Delta$ region and compared with the predictions of final state interaction theory. Deviations are strongly influenced by long-range terms in the production operator and the tensor force in the final $pn$ system. These have been investigated in a realistic $pp\to\pi^+d/\pi^+pn$ calculation that includes $S \rightleftharpoons D$ channel coupling between the final nucleons. A semi-quantitative understanding of the observed effects is achieved.
The emission of protons from targets of Li6, Li, C12, Al27, Ca40, V51, Zr90, and Pb under bombardment from 800 MeV protons has been studied using a high resolution proton spectrometer. Spectra were measured at laboratory scattering angles of 5°, 7°, 9°, 11°, 13°, 15°, 20°, 25°, and 30° with special emphasis on the quasifree region. Outgoing momenta corresponding to the region of pion production were examined at 11° and 15°. Absolute cross sections have been derived by reference to known (p,p) scattering data at 800 MeV. The quasifree scattering has been compared to a distorted-wave impulse approximation analysis by summing over the unobserved (struck) nucleon. The systematics of proton production and the applicability of the distorted-wave impulse approximation analyses are discussed. NUCLEAR REACTIONS (p,p′) on Li6, Li, C12, Al27, Ca40, V51, Zr90, Pb; Ep=800 MeV, θL=5° to 30°; quasielastic scattering, DWIA analysis.
APPROXIMATE SYSTEMATIC CROSS SECTION ERROR IS EQUAL TO +-5.9%.
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