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ANNIHILATION INTO CHARGED PION OR KAON PAIRS. THE SEPARATE CROSS SECTIONS FOR PIONS AND KAONS ARE CALCULATED ASSUMING SIG(K+K-)/SIG(PI+PI-) IS 0.33 +- 0.05 FROM INTERPOLATION OF OTHER EXPERIMENTS.
The results on total channel cross-sections obtained in the 2 m HBC exposed to a separated K− beam at the CERN PS are presented here. The total cross-sections for each channel are given at seven incident K− momenta between 1.934 and 2.516 GeV/c.
CORRECTED FOR ALL POSSIBLE V DECAY MODES. STATISTICAL ERRORS ONLY.
The quasi-elastic cross-sectionsσeltot and dσ/dq2 for the reactions 1) νn → μ−p and 2)\(\overline v \) → μ+n have been measured by using the data of the ν Gargamelle collaboration. 687 ν events, candidates for reaction 1), and 476\(\overline v \) events, candidates for the reactions 2), have been used for the analysis. Because the ν and\(\overline v \) interactions are on nuclei, suitable corrections for nuclear effects have been taken into account. In the framework of the «usual»V −A theory, by assuming for the axial form factor the dipolar formFA(q2)=1.23/(1 +q2/MA/2)2, our data have been fitted to the differential cross-section dσ/dq2 integrated over the ν and\(\overline v \) energy spectra and to the total cross-sectionσeltot as a function of the ν,\(\overline v \) energy to determine the best value for the parameterMA.
Measured Quasi-Elastic total cross section.
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T-DEPENDENCE OF TWO-BODY PROTON DIFFRACTION DISSOCIATION FOR VARIOUS MASS BINS. FOR IDENTIFICATION OF POSSIBLE <P PI0> AND <N PI+> RESONANCES, SEE THE PREVIOUS LETTER, R. R. APPLE ET AL., NCL 18, 167 (1977).
The angular distribution of the inclusive reaction 4 He + p → 3 He + X was measured with 6.85 GeV/ c incident alphas. At large angles, the observed kinematics corresponds to the elastic scattering on the target proton of an 3 He present in the incoming 4 He, the remaining neutron being a spectator. This shows the presence of an important component of 3 He in 4 He. The integrated cross section for 3 He production is σ 3He = 24.1 ± 1.9 mb.
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The ωπ − mass spectrum, in the reaction π −p → ωπ − pat 11.2 GeV/ c , shows the production of the B − meson with a cross section of 27 ± 5 μb as well as a clear enhancement around 1670 MeV. In the differential cross section for B − production, there is a strong forward peak and a change of slope at t ' t 0.2 GeV 2 .
CORRECTED FOR BACKGROUND AND OMEGA TAILS.
No description provided.
ABS(D-WAVE/S-WAVE) = 0.4 +- 0.1 FOR B DECAY.
The production of the f 0 (1270) has been studied in the reaction π − p → π + π − n at 12 and 15 GeV/ c in the momentum transfer range 0.02 to 0.80 GeV 2 . Differential and total cross sections for the reaction π − p → f 0 n have been determined. The f 0 decay density matrix elements have been evaluated requiring all the matrix eigenvalues to be non-negative. The relative unnatural and natural parity exchange contributions to the f 0 production have been studied. The results are compared with a Regge exchange model formulated in terms of the pion and A 2 exchanges including cut contributions.
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Three- and four-body final states with strange particles are studied in π + p and π − p interactions at 16 GeV/ c . We present cross sections and investigate their energy dependence. Production mechanism, resonance production and quantum number transfer are discussed. Strong Y ∗ (1385) production is found in the reaction π + p → Λ K + π + , while the corresponding π − p reaction is dominated by production of K ∗ (890). In the NK K π channels, the K and K are produced mainly at the same vertex, i.e. non-strangeness exchange ΔS = 0 is dominant (about 75% of the cases), whereas in the Λ K ππ channels, the Λ and K are more frequently produced at opposite vertices, i.e. | ΔS | = 1 exchange is important (about 60% of the cases). Results on the polarization of the lambdas produced in the π + p reactions are given.
No description provided.
The dominant partial waves of the diffractively produced N π system at low Nπ masses (⩽ 1.4 GeV) are determined in the reactions π ± p → π (N π ) at 16 GeV/ c . A satisfactory description of our data can only be obtained by strong contributions of both a 1 2 − S-wave and a 3 2 + P-wave, violating the Gribov-Morrison rule. Spin and parity of the diffractively produced states are found from the interference between diffraction and Δ (1236) production. The interference term is obtained by an isospin analysis.
No description provided.
<NUCLEON PION> MASS DEPENDENCE.
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