A study of the reaction K+n → K+π−p at 2–3 GeV/c

Results are given from a study of 15 518 events of the reaction K⁺d → K⁺π^?pp. The K⁺π^? spin density matrix and the constraints imposed on it by positivity have been studied. Analyses of K⁺π^? → K⁺π^? elastic scattering have been carried out using methods developed by Estabrooks and Martin and Ochs and Wagner for the analogous case of ππ scattering. Results are found to be in agreement with earlier Kπ scattering studies using the reaction K⁺p → K⁺π^?Δ⁺⁺ at much higher energies. The S-wave scattering length is found to be in agreement with the prediction of current algebra.     

Normal stresses in flow through tubes of non-circular cross-section

Zusammenfassung Eine visko-elastische Flüssigkeit fliesst durch ein zylindrisches Rohr von nichtkreisförmigem Querschnitt. Die Theorie zweiter Ordnung der visko-elastischen Flüssigkeiten wird auf die Bestimmung der Variation der auf die Rohrwandung ausgeübten Normalspannungen angewandt. Explizite Lösungen für elliptische, dreieckige und rechteckige Querschnitte werden angegeben.     

Repulsive effect of low frequency phonons on superconductivity

The Eliashberg integral equations are investigated to determine the effect of low frequency phonons on the superconducting transition temperature T_c. It is found that phonons of frequency less than T_c are repulsive (diminish T_c) while phonons of higher frequency have a diminished attraction unless the frequency is substantially above T_c. Various implications are discussed concerning observed values of T_c and predicted mechanisms for raising T_c.     

Non-statistical effects in neutron capture γ-ray spectra

A search for non-statistical effects in γ-ray spectra following neutron capture has been made for incident neutron energies in the range 40 keV to 1 MeV. The experiments were performed using a 20 cm × 15 cm Nal detector; thirty elements ranging from calcium to uranium were examined. Marked non-statistical effects were found in the spectra from elements in the mass regions where the 3s, 3p and 4s neutron strength functions maximize. Results from the first two regions could often be explained in terms of enhanced transition strengths to final states with a strong single-particle nature.     

Resonance and background interference in 54Fe neutron capture

Asymmetric s-wave resonances observed in the neutron capture cross section of ⁵⁴Fe can be explained by interference between resonance valence components. An upper limit is obtained for the background capture cross section which is much smaller than that expected from the large correlation observed between s-wave reduced neutron widths and radiative widths.