Annual Report on Contract AEC AT(11-1) 34 p107B

Work that has been carried out in several areas of High Energy Physics is described. Visual techniques are used. For the study of the three-pion decay of the K/sup +/ meson, bubble chamber and emulsion methods are used to complement each other, particularly for the tau' mode. Several separate bubble chamber experiments in ..pi../sup +/p, anti pp and K/sup -/p interactions are also described, and the large effort devoted to computer reprogramming for the data analysis indicated. Two emulsion research projects are also described which have for their purpose the study of electromagnetic processes induced by 16 BeV electrons and the study of hypernuclei by K/sup -/ mesons. For the latter work high speed computer methods have been successfully applied to the analysis of the product hypernuclei. These programs of work have not been under way long enough for the main results yet to be available, but some preliminary data have been published and several reports on data analysis and related subjects have been prepared

Physics of ion beam cancer therapy: a multi-scale approach

We propose a multi-scale approach to understand the physics related to ion-beam cancer therapy. It allows the calculation of the probability of DNA damage as a result of irradiation of tissues with energetic ions, up to 430 MeV/u. This approach covers different scales, starting from the large scale, defined by the ion stopping, followed by a smaller scale, defined by secondary electrons and radicals, and ending with the shortest scale, defined by interactions of secondaries with the DNA. We present calculations of the probabilities of single and double strand breaks of DNA, suggest a way to further expand such calculations, and also make some estimates for glial cells exposed to radiation.Comment: 18 pag,5 fig, submitted to PR

Data for Elementary-Particle Physics

These data are provided: Masses and .Mean Lives of Elementary Particles; Atomic and Nuclear Properties of Materials; Particle Scattering; Atomic and Nuclear Constants; Particle Decay and Reaction Dynamics; Tentative Data on Strongly lnteracting Particles and Resonances; and Clebsch-Gordan Coefficients and Spherical Harmonics

Nonlinear energy-loss straggling of protons and antiprotons in an electron gas

The electronic energy-loss straggling of protons and antiprotons moving at arbitrary nonrelativistic velocities in a homogeneous electron gas are evaluated within a quadratic response theory and the random-phase approximation (RPA). These results show that at low and intermediate velocities quadratic corrections reduce significantly the energy-loss straggling of antiprotons, these corrections being, at low-velocities, more important than in the evaluation of the stopping power.Comment: 4 pages, 3 figures, to appear in Phys. Rev.

The Antiproton-Nucleon Annihilation Process (AntiprotonCollaboration Experiment)

In the exposure to a 7 0 0-MeV/c negative particle beam, 35 antiproton stars have been found. Of these antiprotons, 21 annihilate in flight and three give large-angle scatters ( {Theta} > 15 , T{sub P-} > 50 Mev), while 14 annihilate at rest. From the interactions in flight we obtain the total c r o s s section for antiproton interactio