First exclusive data for the $pp \to nn\pi^+\pi^+$ reaction have been obtained at CELSIUS with the WASA detector setup at a beam energy of $T_p$ = 1.1 GeV. Total and differential cross sections disagree with theoretical calculations, which predict the $\Delta\Delta$ excitation to be the dominant process at this beam energy. Instead the data require the excitation of a higher-lying $\Delta$ state, most likely the $\Delta(1600)$, to be the leading process.
Total cross section.
Distribution of the invariant mass of the PI+PI+ system.
Distribution of the cosine of the PI+_PI+ opening angle DELTA at an incident kinetic energy of 1.1 GeV.
We have measured inclusive data on $K^+$-meson production in $pp$ collisions at COSY J\"ulich close to the hyperon production threshold and determined the hyperon-nucleon invariant mass spectra. The spectra were decomposed into three parts: $\Lambda p$, $\Sigma^0p$ and $\Sigma^+n$. The cross section for the $\Sigma^+n$ channel was found to be much smaller than a previous measurement in that excess energy region. The data together with previous results at higher energies are compatible with a phase space dependence.
Total cross section for P P --> K+ SIGMA+ N. Errors are combined statistics and systematics.
Deduced total cross section for P P --> K+ P LAMBDA.
Deduced total cross section for P P --> K+ SIGMA0 P.
The production of neutral strange particles (K0, Λ) inp Ar,pXe and\(\bar p\)Xe collisions at 200 GeV is investigated in the NA5 experiment using a streamer chamber at the CERN SPS. Results are presented on inclusive cross sections, average multiplicities, and on rapidity and transverse momentum distributions of neutral strange particles.
No description provided.
No description provided.
No description provided.