The production of η′ (958) and φ (1020) mesons has been studied very close to threshold in the inclusive p d → 3He X reaction. The complicated phase space acceptance problem caused by rapidly changing kinematics close to threshold has been carefully treated. The measured averaged squared amplitudes |f|2 at threshold are 0.9 and 2.4 nb/sr for the η′ and φ meso Our results are in remarkable agreement with predictions of a two-step model, which uses existing π− p → n X data as input. However the ratio of φ to ω production seems at variance with naïve expectations based on the Okubo-Zweig-Iizuka rule.

The reaction pd-->He-3 pi(+)pi(-) was measured at 1150 MeV/c proton beam momentum using MOMO instalation at COSY.

The production of eta' (958) and phi (1020) mesons has been studied very close to threshold in the inclusive p d --> He-3 X reaction. The complicated phase space acceptance problem caused by rapidly changing kinematics close to threshold has been carefully treated. The measured averaged squared amplitudes \f\(2) at threshold are 0.9 and 2.4 nb/sr for the eta' and phi meson. Our results are in remarkable agreement with predictions of a two-step model, which uses existing pi(-)p --> n X data as input. However the ratio of phi to omega production seems at variance with naive expectations based on the Okubo-Zweig-Iizuka rule.

We report a new calibration of the polarimeter POMME for energies between 1.05 and 2.40 GeV using polarized proton beams at the Laboratoire National Saturne. A 16 parameter and a new 14 parameter empirical formula have been used to fit both the angular and energy dependencies of the inclusive proton-carbon analyzing power data between 0.80 and 2.40 GeV. Both fits have very good chi-square, 1.20 per degree of freedom for the former, and 1.05 for the latter. The parameters from these fits can be used to predict the angular distribution of the pC analyzing power at any energy within the energy range of the fits.

This experimental program focuses on meson production near threshold via the reaction p + d → 3He + X. The incident beam energy and the 3He momentum are matched in such a way that the mesons are produced at rest in the c.m. system. Clear signals can be observed at the ω,ή, K \(\bar K\) and φ thresholds.

The associated strangeness production in pp collisions was studied at bombarding energies of 2.3 and 2.7 GeV by detecting the outgoing K+ particles with a high resolution magnetic spectrometer at forward angles up to 23.5° laboratory angle. The kaons were separated from an immense background of protons and pions by a highly resolving TOF electronics addition to vetoes from Čerenkov detectors utilizing either β differing Čerenkov light cones in lucite or different thresholds for light production in aerogel. The hyperon-nucleon missing mass spectra obtained show strong deviations from pure phase space which is ascribed to final state interactions of the pΛ and the Nσ systems. The structures found are discussed and compared with results from K−d → π−YN experiments, with theoretical calculations in the frame of OBE models, and with the prediction of sharp strange dibaryon resonances from several quark-bag models.

A new threshold Cherenkov detector to discriminate pions from kaons in the momentum range from 1.2 GeV/c to 1.73 GeV/c is discussed. Silica aerogel is used as radiator. A method for developing such detectors by the aid of Monte Carlo simulations is presented. A rejection rate for π+ of 99.8±0.2% has been reached. The production of fast secondary electrons by subthreshold particles is considered.

The analyzing power ${\mathit{T}}_{20}$ in the inclusive $^{1}\mathrm{H}$${(}^{6}$Li,d or \ensuremath{\alpha} or t)X reaction with 4.5 GeV tensor polarized $^{6}\mathrm{Li}$ nuclei has been measured at an angle of 0.8\ifmmode^\circ\else\textdegree\fi{}. The kinematics chosen favor the detection of spectator fragments; in the impulse approximation the laboratory momentum of such a fragment is then the Lorentz boosted internal momentum. Nonzero ${\mathit{T}}_{20}$ values have been observed, in agreement with the known nonsphericity of $^{6}\mathrm{Li}$ indicated by its quadrupole moment. The sign of ${\mathit{T}}_{20}$ in the d channel suggests that near q=0 the D state in $^{6}\mathrm{Li}$ has the same sign as in the deuteron; an abrupt change of sign near q=0.12 GeV/c is in agreement with theoretical expectation of a node in the \ensuremath{\alpha}d position wave function. The \ensuremath{\alpha}-channel data show larger ${\mathit{T}}_{20}$ values than the d channel; in this case the small-q-region has not been explored enough to establish a similar node. A few data points in the t channel might suggest that ${\mathit{T}}_{20}$ becomes positive above q=0.4 GeV/c in this case.

The analyzing power T20 in the inclusive H-1(Li-6,d or alpha or t)X reaction with 4.5 GeV tensor polarized Li-6 nuclei has been measured at an angle of 0.8-degrees. The kinematics chosen favor the detection of spectator fragments; in the impulse approximation the laboratory momentum of such a fragment is then the Lorentz boosted internal momentum. Nonzero T20 values have been observed, in agreement with the known nonsphericity of Li-6 indicated by its quadrupole moment. The sign of T20 in the d channel suggests that near q = 0 the D state in Li-6 has the same sign as in the deuteron; an abrupt change of sign near q = 0.12 GeV/c is in agreement with theoretical expectation of a node in the alpha-d position wave function. The alpha-channel data show larger T20 values than the d channel; in this case the small-q-region has not been explored enough to establish a similar node. A few data points in the t channel might suggest that T20 becomes positive above q = 0.4 GeV/c in this case.

The polarization of the proton from the inclusive breakup reaction 1H(d, p)X at 2.1 GeV was measured at 0°. The results are expressed as the ratio of the proton polarization, Pp, to the deuteron beam polarization, Pd, κ0=Pp/Pd. The measured values of κ0 range from +0.983 to -0.305 and are in general agreement with the expected behavior arising from the D state in the deuteron wave function.

The polarization of the proton from the inclusive breakup reaction H-1 (d-->, p-->) X at 2.1 GeV was measured at 0-degrees. The results are expressed as the ratio of the proton polarization, P(p), to the deuteron beam polarization, P(d), kappa-0=P(p)/P(d). The measured values of kappa-0 range from +0.983 to -0.305 and are in general agreement with the expected behavior arising from the D skate in the deuteron wave function.

The energy region from the pi-threshold up to the Roper resonance N(1440) has been investigated in inelastic alpha-scattering on hydrogen using alpha-particles from SATURNE with a beam momentum of 7 GeV/c. In addition to projectile excitation, excitation of the P11(1440 MeV) resonance has been observed for the proton, indicating a strong monopole excitation. From this a value of the nucleon compressibility of 1.4 +/- 0.3 GeV is extracted.

Coincidences between inelastically scattered alpha-particles and fission products from U-238 have been measured with a 172 MeV a beam. Inelastically scattered alpha-particles were measured at angles between 0-degrees and 4-degrees. The fission decay of the giant resonances, in particular, of the giant quadrupole resonance, is clearly observed in the coincidence data. Experimental fission probabilities are well described within the statistical model. The multipole strength, extracted from the angular distribution, is consistent with that obtained from singles (alpha, alpha') measurements if a background due to multistep processes is taken into account.

Total cross sections for the reaction p+p→p+p+π0 have been measured for proton incident energies ranging from 480 to 560 MeV in 20 MeV steps, by detecting the decay γ-rays of the π0 emitted at forward angles. Isoscalar partial cross sections (σ01) are extracted by comparison to the known total cross sections of the n+p→n+n+π+ measured at the same incident energies. No signal in the energy dependence of the π0 production excitation function due to possible narrow, isovector dibaryon resonance is noticeable in the data.