Direct photons as a potential probe of the triangle -resonance in compressed nuclear matter

Pions are trapped in the compressed hadronic matter formed in relativistic heavy-ion collisions for the time periods of 15 fm/c. Such time scales are long compared to the width of the #DELTA#-resonance and result in an enhancement of the #DELTA#/#pi#"o #gamma#-ratio over the free value. Simulations for the acceptance of the photon spectrometer TAPS indicate that the photon signal from the #DELTA#-resonance might be observable. (orig.)Available from TIB Hannover: RO 801(94-22) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Secondary pion beams at GSI

Protons and "1"2C ions from the 18 Tm synchrotron have been used to irradiate a production target of beryllium, with the resulting pion beams being transported to the nearest downstream experimental area. The beam line accomodates pion momenta up to 2.8 GeV/c and has a momentum acceptance of 8%. For "1"2C projectiles with the maximum energy of 2A GeV the negative pion yields reach values of 1 x 10"7/spill near the peak of the momentum distribution around 1 GeV/c, if extrapolated to the space charge limit of the synchrotron. The corresponding p-induced yields at 3.5 GeV are smaller except for hard pions for which the production exceeds the "1"2C-induced intensities because of the higher energy per nucleon. (orig.)4 refs.Available from TIB Hannover: RO 801(99-13) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Flow effects in Bi + Pb collisions at 1 GeV/u

We report particle-exclusive measurements of triple-differential cross sections for positive pions, nucleons and light nuclear fragments in multiplicity-selected collisions of 1 GeV/u "2"0"9Bi+"2"0"8Pb. The dependence upon the azimuthal angle with respect to the reaction plane is studied as a function of the particle rapidity and transverse momentum. Flow and squeeze-out are clearly established. For the baryonic component both effects increase with increasing mass of the particle. The meson flow is anticorrelated to the baryon flow. (orig.)Available from TIB Hannover: RO 801(93-75) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Pion reabsorption in heavy-ion collisions interpreted in terms of the #DELTA# capture process

We have measured energy-differential cross sections for #pi#"0 production in "3"6Ar+"1"9"7Au collisions at 95 MeV/u. From an analysis of spectral features due to pion final-state interactions we have estimated the cross section of the capture process #DELTA#+N#->#N+N in the center-of-mass energy range #sq root#s#approx =#2.05-2.25 GeV. Within the frame of BUU calculations, our results support the extension of the detailed-balance principle to broad-width resonances. (orig.)23 refs.SIGLEAvailable from TIB Hannover: RO 801(95-67) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Investigation of polar and azimuthal distributions of subthreshold pions at intermediate energies

SIGLEAvailable from TIB Hannover: RO 801(94-20) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Evidence for stopping in heavy-ion collisions from a study of hard-photon source velocities

SIGLEAvailable from TIB Hannover: RO 801(94-19) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman