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An analysis of three pion production data at 23 GeV/c is described; these reactions are of the form pi- -> pi+pi-pi-A where A is one of the nuclear targets: carbon, aluminum, copper, silver, or lead. Total and differential cross-sections are quoted, and the method of their computation is outlined. The spin-parity composition of the three-pion system has been analyzed using the Illinois method of partial wave analysis. The partial wave structure of the data is remarkably similar to that of the data from hydrogen, excepting the distributions in momentum transfer, which exhibit the usual coherent and incoherent contributions of nuclear scattering. The partial~wave results have been fitted with an optical model for three-pion production, with very good results. With this model the absorptions of the three-pion system (in nuclear matter) tu...
The data presented and discussed in this report were obtained from K-p interactions at 4.1 GeV/c and 5.5 GeV/c in the MURA thirty-inch hydrogen bubble chamber. K track lengths equivalent to 0.95 IJ.b per event and 0.27 IJb per event have been analyzed at 4.1 GeV/c and 5.5 GeV/c, respectively. Differential cross sections are given for the ~rr+ final states, and the results obtained in this experiment agree well with extrapolated results from lower energies. The data for Sigma+pi- is interpreted in terms of the Regge pole model. A search for the existence of hyperorin resonances in the mass region above 1900 MeV/c2 is made in the Sigma±pi±K+K- data, but no evidence for such resonances is found. Consistent with results from lower energies, this reaction appears to be dominated by quasi-,three-body processes in which either the Y * (1405),...
The 72" Bubble Chamber at the Lawrence Radiation Laboratory has been exposed to a beam of 5 Bev/c pi- mesons and 150,000 photographs have been taken. As a part of this experiment, the interactions producing four charged particles in the final states have been measured and the reaction pi-p -> ppi+pi-pi- has been studied, with the emphasis placed on the three pions system. The cross section for this reaction was found to be 1.80±0.45 mba For the final analysis 6300 events (.286 ± .071 pb/event) were selected. The mass spectra of the different particle combinations have been investigated. The reaction has been found to be characterized by the following features: (1) Strong production of well-known resonances, in particular the p (35% of the events), N1236 (30%) and various N IS. (2) A broad enhancement in the pi+pi-pi- and in the popi ma...
The results of a spin parity analysis of the nv-decay mode of the A-meson produced in the reaction A2-p -A2-pare presented. Data for the analysis are drawn from bubble chamber experiments between 3.9 and 16 GeV/c. The analysis favors JP=Z+ for both the upper and lower regions of the AZ' Possible evidence for a weakly produced JP=l daughter state is also presented. The evidence comes largely from an interference effect observed in the lower AZ region. Using the A-nv-data along with data on the decay channel A2- -> p0pi -at 5.0,7.5 and l1.Z GeV/c, the production mechanism of A2 the A-in the reaction A2-p -A2-P is investigated. Assuming that this reaction is dominated by a t channel exchange mechanism the isospin and J parity of the exchange are investigated. The sand t cross section dependence of the data are compared with a simple Regge...
Charmonium production in 190 GeV/c pi--Be interactions has been observed. The states 1(3510) and X(3555) are seen through their radiative decay into J/psi , and are found to correspond to 0.29 +- 0.09 of total J/psi' production for J/psi's with xf > 0.2. The rate of production for the two X states appears as Ba(X(3555)/Bc(X(3510) = 0.60 + 0.35. The fraction of J/~'s produced through X decay appears to rise with higher xf . For J/psi's wf > 0 42, X decay 1"th x f X is responsible for 0.345 + 0.09 of the total J/, sample, with the two states produced at the rate Bc(X(3555)/Ba(X(3510) = 0.82 +- 0.45.
v-Jun accelerates G1 progression and shares the capacity of the Myc, E2F, and E1A oncoproteins to sustain S-phase entry in the absence of mitogens; however, how it does so is unknown. To gain insight into the mechanism, we investigated how v-Jun affects mitogen-dependent processes which control the G1/S transition. We show that v-Jun enables cells to express cyclin A and cyclin A-cdk2 kinase activity in the absence of growth factors and that deregulation of cdk2 is required for S-phase entry. Cyclin A expression is repressed in quiescent cells by E2F acting in conjunction with its pocket protein partners Rb, p107, and p130; however, v-Jun overrides this control, causing phosphorylated Rb and proliferation-specific E2F-p107 complexes to persist after mitogen withdrawal. Dephosphorylation of Rb and destruction of cyclin A nevertheless oc...
The Ski oncoprotein has been found to bind non-specifically to DNA in association with unindentified nuclear factors. In addition, Ski has been shown to activate transcription of muscle-specific and viral promoters/enhancers. The present study was undertaken to identify Ski's DNA binding and transcriptional activation partners by identifying specific DNA binding sites. We used nuclear extracts from a v-Ski-transduced mouse L-cell line and selected Ski-bound sequences from a pool of degenerate oligonucleotides with anti-Ski monoclonal antibodies. Two sequences were identified by this technique. The first (TGGC/ANNNNNT/GCCAA) is the previously identified binding site of the nuclear factor I (NFI) family of transcription factors. The second (TCCCNNGGGA) is the binding site of Olf-1/EBF. By electophoretic mobility shift assays we find that...
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