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Higher twist contributions to lepton-pair production and other QCD processes

Description: A general discussion of the calculations and phenomenological consequences of power-law suppressed QCD processes is given with emphasis on tests in massive lepton pair production. Absolutely normalized predictions are given for the leading twist (transverse current) and higher twist (longitudinal current) contributions to the meson structure function in the region of large x.
Date: December 1, 1982
Creator: Brodsky, S.J.; Berger, E.L. & Lepage, G.P.
Partner: UNT Libraries Government Documents Department

Introduction to conformal field theory and string theory

Description: These lectures are meant to provide a brief introduction to conformal field theory (CFT) and string theory for those with no prior exposure to the subjects. There are many excellent reviews already available, and most of these go in to much more detail than I will be able to here. 52 refs., 11 figs.
Date: December 1, 1989
Creator: Dixon, L.J.
Partner: UNT Libraries Government Documents Department

Theoretical Atomic Physics code development IV: LINES, A code for computing atomic line spectra

Description: A new computer program, LINES, has been developed for simulating atomic line emission and absorption spectra using the accurate fine structure energy levels and transition strengths calculated by the (CATS) Cowan Atomic Structure code. Population distributions for the ion stages are obtained in LINES by using the Local Thermodynamic Equilibrium (LTE) model. LINES is also useful for displaying the pertinent atomic data generated by CATS. This report describes the use of LINES. Both CATS and LINES are part of the Theoretical Atomic PhysicS (TAPS) code development effort at Los Alamos. 11 refs., 9 figs., 1 tab.
Date: December 1, 1988
Creator: Abdallah, J. Jr. & Clark, R.E.H.
Partner: UNT Libraries Government Documents Department

Nuclear decay studies far-from-stability

Description: Nuclear decay studies far-from-stability are performed not merely to characterize new isotopes, but to establish an experimental footing for improving our theoretical understanding of nuclear structure and decay. Although progress has been made in explaining low-lying level structure for a broad range of nuclei, transition probabilities are not yet quantitatively understood. The ability to understand nuclei far-from-stability is important to astrophysics for extending r- and s-process calculations to unknown nuclei, and to nuclear engineering for decay-heat calculations. Finally, by studying nuclei far-from-stability, we probe extremes of both decay energy and proton-neutron ratios where unforeseen and important new nuclear properties may be exhibited. The decays of nearly 100 isotopes and isomers have been studied with the OASIS mass-separation facility on-line at the Lawrence Berkeley Laboratory SuperHILAC. These studies have concentrated on neutron-deficient nuclei with 55{le}Z{le}71 up to A=157 and neutron-rich nuclei with 166{le}A{le}174. The results of these experiments are combined in this paper with those from many other laboratories to provide insight into systematic trends of beta- and {gamma}-ray transition probabilities near N=82. It is hoped that the smooth systematic trends in these transition probabilities will provide clues towards interpreting the underlying nuclear structure. Nuclei near N=82 and Z=64 are expected to be spherical and should be described by simple Shell Model considerations. Away from the shell closures, deformation sets in which should exhibit itself in the transition probabilities. The Z=64 shell closure is expected to disappear near N=78. The qualitative nature of these phenomena will be discussed.
Date: December 1, 1989
Creator: Firestone, R.B.; Nitschke, J.M.; Wilmarth, P.A.; Vierinen, K.S.; Chasteler, R.M.; Gilat, J. et al.
Partner: UNT Libraries Government Documents Department

Kaon decay amplitudes using staggered fermions

Description: A status report is given of an attempt, using staggered fermions to calculate the real and imaginary parts of the amplitudes for K ..-->.. ..pi pi..,. Semi-quantitative results are found for the imaginary parts, and these suggest that epsilon' might be smaller than previously expected in the standard model.
Date: December 1, 1986
Creator: Sharpe, S.R.
Partner: UNT Libraries Government Documents Department