Search for exotic mesons at SLAC
The theoretical justification and results from recent experimental searches for backward-produced exotic mesons including two experiments carried out by the collaboration at SLAC are reviewed. The first experiment put upper limits of about 1 to 2 $mu$b for X$sup ++$ $Yields$ (2$pi$, 4$pi$, 6$pi$)$sup ++$ and anti pp$pi$$sup +$$pi$$sup +$ in the reaction $pi$$sup +$ + p $Yields$ X$sup ++$ + n/sub forward/ at 8.4 GeV/c studied with the SLAC 14 inch rapid cycling bubble chamber triggered by a downstream neutron detector. Also the important features of the recently completed second experiment with the SLAC streamer chamber to study the reaction $pi$$sup -$ + p $Yields$ X$sup --$ + p/sub forward/ at 14 GeV/c are discussed. (auth)
Search for exotics produced opposite a forward Λ in 15 GeV/c π+p interactions
We have carried out a search for exotic meson resonances produced in the reaction π+p→K++ + Λ (forward) at 15 GeV/c. We have found no evidence for the existence of resonance-like states in the K++ system, and have obtained 95% confidence level upper limits of 1.7 μb on their production with masses <2.8 GeV, and 2.6 μb with masses between 2.8 GeV and 4 GeV.
Denitrification of PVA-immobilized denitrifying photosynthetic bacterium, Rhodobacter sphaeroides
Abstract A newly isolated denitrifying strain, Rhodobacter sphaeroides NII2 was immobilized in polyvinyl alcohol (PVA) gel, and the properties of the cells in the gel were examined. The immobilized cells had low or almost no denitrification activity, but the cells were activated by incubation in light with culture medium for denitrification containing 0.5% nitrate and no other nitrogen source. Cells grown in the dark were activated by incubation at an earlier stage and to a higher rate than the light-grown cells. The activation was markedly enhanced in the PVA gel with a low cell concentration. The immobilized cells consumed nitrate with a temporary accumulation of NO 2 and evolved nitrogen gas. The immobilized cells could use various organic compounds as electron donors for denitrification. Thus, the immobilized cells were applied to a continuous treatment of synthetic wastewater using an aparatus devised by this laboratory. The results showed an efficient removal of NO 3 -N from the test water.