We have conducted a search for bound states of a negative pion and a number of neutrons (pineuts) using the E814 spectrometer. A beam of Si28 at a momentum of 14.6A GeV/c was used to bombard targets of Al, Cu, Sn, and Pb. We describe our experimental technique, present measured upper limits for pineut production, and discuss the significance of our results.
AUTHORS NAMED CHARGED- BY PINEUT. Here ALL means the total number of interactions.
We have investigated the fragmentation of 3.65 GeV/nucleon O16, Mg24, and S32 projectiles on C, Al, Cu, Ag, and Pb targets using solid state nuclear track detectors. Track counting was performed by an automatic measuring system. Total charge changing and the partial cross sections for the production of fragments with charges 9≤Z≤15 for S32 projectiles and of charge 6≤Z≤11 for Mg24 were determined. Comparison with theoretical models and other experimental data is made.
No description provided.
We have measured a complete isotope distribution of projectile-like nuclear-charge pickup products, formed by bombarding a Al17 target with 790A MeV Xe129 ions. The shape of the cross-section distribution indicates a dominant influence of evaporation processes during the formation of the final cesium fragments observed, thus masking to a large extent the primary processes involved in the charge exchange. We can show, however, that an intranuclear-cascade-plus-evaporation calculation can reproduce the observed yields, and that the effect of Δ-formation during the first stage of the reaction is visible even in the inclusive cross sections. The same model can explain the strong increase in total charge-pickup cross sections with increasing projectile mass noted previously by other authors. It is therefore not necessary to invoke coherent processes to explain this increase as has been suggested previously.
No description provided.
The total cross section for γp→ηp near threshold has been measured using the PHOENICS tagging system at the ELSA electron facility of the Physikalisches Institut der Universität Bonn. The photons are created by bremsstrahlung, and are tagged by measuring the momentum of each electron after the photon has been emitted. The recoil proton from γp→ηp is detected by the AMADEUS counter setup in coincidence with the tagging system. Data were taken with AMADEUS at 3.3° in the laboratory, where the large Jacobian increases our event rate so that we obtain the cross section from threshold (Eγ=707.2 MeV) to Eγ≃720 MeV with adequate statistics. The γp→ηp events are identified by kinematics, dE/dx, and timing information. We find that in our energy region the production cross section is consistent with S-wave production.
No description provided.
Pion-induced double charge exchange (π+,π−) on Se76,78,80,82, leading to the double isobaric analog states (DIAS) and the ground states of Kr76,78,80,82, has been studied at a laboratory angle of 50 and incident pion kinetic energy of 293.2 MeV. Cross sections for these transitions have been extracted, and those for the DIAS are compared to two simple models of pion double charge exchange.
No description provided.
The vector analyzing power iT11 and the composite observable τ22=T22+T20/ √6 were measured at 10 incident pion energies between 100 and 294 MeV, in an angular range between 50° and 120°. Two different techniques were applied, the detection of the pion with a magnet spectrometer, and the πd coincidence method with scintillation counters. In the case of the first technique also two different target materials were used. Consistency among all data was obtained. The experimental data are compared to Faddeev calculations from one of us (H.G.). The discrepancies between theory and experiment are discussed, and an outlook for further research is given.
Vector analyzing power iT11 and composite observale TAU22 = T22 + T20/sqrt(6). LiDeut target.
Vector analyzing power iT11 and composite observale TAU22 = T22 + T20/sqrt(6). LiDeut target.
Vector analyzing power iT11 and composite observale TAU22 = T22 + T20/sqrt(6). LiDeut target.
The ITEP-PNPI collaboration presents the first results of the spin rotation parameter A + measurements in the second resonance region. The experiment was performed at the ITEP accelerator at a positive pion beam momentum 1.43 GeV/c for scattering angles θ cm = 127° and 133°. The setup was based on a polarized proton target and a carbon-plate polarimeter. The obtained data is compared with the predictions of the existing partial-wave analyses.
No description provided.
The polarization transfer κ 0 and the tensor analyzing power T 20 for the 1 H d p)d reaction have been measured up to an internal momentum of k = 0.58 GeV/c. Comparison of the same observables obtained in recent studies for 1 H d p)d reaction, as a function of k , show different behavior. However the data from these two reactions are almost identical when compared in T 20 versus κ 0 correlation plots. We discuss similarities and differences observed in the two reactions.
The authors use the Infinite Momentum Frame variable K= M( proton) * sqrt(1/(4*a*(1-a)) - 1), where a = (E(proton)+P_long(proton))/(E(deut)+P(deut)).
The annihilation p p → Φγ has been investigated with the Crystal Barrel detector at LEAR for antiprotons stopped in liquid hydrogen. The observed branching ratio BR ( p p → Φγ = (1.7 ± 0.4) · 10 −5 is almost two orders of magnitude higher than expected from the OZI-rule. As a by-product, the branching ratios BR ( p p → K L K S ) = (9.0 ± 0.6) · 10 −4 and BR ( p p → Φπ 0 ) = (5.5 ± 0.7) · 10 −4 have been measured.
No description provided.
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No description provided.
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