27 research outputs found
Effective T-odd P-even hadronic interactions from quark models
Tests of time reversal symmetry at low and medium energies may be analyzed in
the framework of effective hadronic interactions. Here, we consider the quark
structure of hadrons to make a connection to the more fundamental degrees of
freedom. It turns out that for P-even T-odd interactions hadronic matrix
elements evaluated in terms of quark models give rise to factors of 2 to 5.
Also, it is possible to relate the strength of the anomalous part of the
effective rho-type T-odd P-even tensor coupling to quark structure effects.Comment: 6 pages, 1 figure, RevTe
Initial State Interactions for -Proton Radiative Capture
The effects of the initial state interactions on the radiative
capture branching ratios are examined and found to be quite sizable. A general
coupled-channel formalism for both strong and electromagnetic channels using a
particle basis is presented, and applied to all the low energy data
with the exception of the {\it 1s} atomic level shift. Satisfactory fits are
obtained using vertex coupling constants for the electromagnetic channels that
are close to their expected SU(3) values.Comment: 16 pages, uses revte
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Correlation technique for single- and two-phase pump data
This paper presents a correlation method for single- and two-phase pump data
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Development of nuclear models for higher energy calculations
Two nuclear models for higher energy calculations have been developed in the regions of high and low energy transfer, respectively. In the former, a relativistic hybrid-type preequilibrium model is compared with data ranging from 60 to 800 MeV. Also, the GNASH exciton preequilibrium-model code with higher energy improvements is compared with data at 200 and 318 MeV. In the region of low energy transfer, nucleon-nucleus scattering is predominately a direct reaction involving quasi-elastic collisions with one or more target nucleons. We discuss various aspects of quasi-elastic scattering which are important in understanding features of cross sections and spin observables. These include (1) contributions from multi-step processes; (2) damping of the continuum response from 2p-2h excitations; (3) the ''optimal'' choice of frame in which to evaluate the nucleon-nucleon amplitudes; and (4) the effect of optical and spin-orbit distortions, which are included in a model based on the RPA the DWIA and the eikonal approximation. 33 refs., 15 figs
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Calculated proton-induced thick-target neutron and gamma yield spectra for E sub p le 100 MeV
This paper reviews nuclear data of calculated proton-induced thick-target neutron and gamma yield spectra for energies less than 100 MeV. 15 refs., 1 fig. (LSP
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Preliminary calculations of medium-energy fission cross sections and spectra
Nucleon-induced fission cross sections determined from a statistical preequilibrium model are used in conjunction with a new scission-point model of fission fragment mass, charge and excitation energy distributions to produce evaporation model calculations of particle and gamma spectra and multiplicities from fission. Comparisons are made to experiment for the 14.5-MeV neutron-induced fission of /sup 238/U. In addition, calculated particle and gamma spectra will be compared with the ENDF/B library for 2- and 5-MeV neutron-induced fission of /sup 235/U and /sup 238/U, respectively. Initial predictions for these same quantities for proton-induced fission reactions at energies up to 100 MeV will be presented and discussed. 6 refs., 3 figs
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Transport data libraries for incident proton and neutron energies to 100 MeV
A joint effort between the Applied Nuclear Science and Radiation Transport groups at Los Alamos has begun to develop and implement proton, neutron, and photon transport libraries for incident energies up to 100 MeV. The major steps involved in this effort are: (1) development of evaluated (ENDF/B) data formats appropriate for higher energies; (2) extension of low-energy nuclear physics theoretical models for applicability up to 100 MeV; (3) calculation and evaluation of nuclear data in ENDF/B-VI format for appropriate materials up to 100 MeV; (4) development of processing code capabilities to handle the higher energy data; and (5) development of the appropriate interfaces and code patches for use of data in transport codes such as MCNP. In this paper we mainly discuss the development of the basic transport data library, items (2) and (3) above, and summarize the remaining activities. 14 refs