Differential cross sections $\frac{{d}^{2}\ensuremath{\sigma}}{\mathrm{dpd}\ensuremath{\Omega}}$ have been measured near 0\ifmmode^\circ\else\textdegree\fi{} for the inclusive reaction $\mathrm{np}\ensuremath{\rightarrow}\mathrm{pX}$, where $X$ represents all possible combinations of pions and nucleons. Proton momentum spectra have been measured at average incident-neutron-momentum values from 950 to 1430 MeV/c in 60-MeV/c steps. Experimental results are compared with a field-theoretical peripheral model based on one-pion and $\ensuremath{\rho}$-meson exchange with nucleon-nucleon and nucleon-$\ensuremath{\Delta}$ intermediate states. The predictions of the model are in excellent agreement with the data, indicative that the $\mathrm{np}\ensuremath{\rightarrow}\mathrm{pX}$ reaction is dominated by the $p{\ensuremath{\Delta}}^{0}$ channel over the whole energy range of measurements.
The dependence of the two-pion-exchange contribution to nucleonnucleon scattering in high partial waves on the model for the swave pi pi yields NN scattering amplitude below threshold for NN production is illustrated by comparing four models. Future improved pp scattering data should be used to reduce the uncertainty in the triplet F and singlet G phase shifts to enable discrimination between the models. (auth)
This model study shows that narrow azimuth acquisition may be adequate for structures which are oriented dip to the acquisition direction but strike components are not well imaged. Wide azimuth acquisition with sufficient cross line offset gives improved results compared to narrow azimuth acquisition for both dip and strike components since this method is actually “directionless”. Also, 3D SRME on narrow azimuth data shot dip gives a good image but narrow azimuth strike data does not yield a comparable uplift from 3D SRME. The application of 3D SRME to wide azimuth data shot either dip or strike yields a very good image which is superior to any of the results without 3D SRME. Results from the datasets with the multiples suppressed shows that dip components are well imaged with narrow azimuth acquisition but strike components may not be. Even if one suppresses all the multiples, wide azimuth is needed to image the strike components of the structure. Ray trace illumination maps can be used to determine the shadow zones in the model and help determine the width and direction of wide azimuth acquisition required to minimize these shadow zones. Finally, a real data comparison of NAZ versus WAZ acquisition and processing shows that the observations seen in the model data are also confirmed in the real data.
Comprehensive analyses of nucleon-nucleon elastic-scattering data below 1100 MeV laboratory kinetic energy are presented. The data base from which an energy-dependent solution and 22 single-energy solutions are obtained consists of 7223 pp and 5474 np data. A resonancelike structure is found to occur in the $^{1}\mathrm{D}_{2}$, $^{3}\mathrm{F}_{3}$, $^{3}\mathrm{P}_{2}$${\mathrm{\ensuremath{-}}}^{3}$${\mathrm{F}}_{2}$, and $^{3}\mathrm{F}_{4}$${\mathrm{\ensuremath{-}}}^{3}$${\mathrm{H}}_{4}$ partial waves; this behavior is associated with poles in the complex energy plane. The pole positions and residues are obtained by analytic continuation of the ``production'' piece of the T matrix obtained in the energy-dependent solution. The new phases differ somewhat from previously published VPI solutions, especially in I=0 waves above 500 MeV, where np data are very sparse. The partial waves are, however, based upon a significantly larger data base and reflect correspondingly smaller errors. The full data base and solution files can be obtained through a computer scattering analysis interactive dial-in (SAID) system at VPI, which also exists at many institutions around the world and which can be transferred to any site with a suitable computer system. The SAID system can be used to modify solutions, plan experiments, and obtain any of the multitude of predictions which derive from partial-wave analyses of the world data base.
Variable-depth streamer acquisition is a solution for broadband marine seismic where the depth profile of the streamer is optimized in order to create receiver ghost diversity, which in turn enables deconvolution of the residual ghost at the imaging stage, either pre-stack or post-stack.
F-36 SUPPRESSING PEG-LEG MULTIPLES WITH PARABOLIC RADON DEMULTIPLE Abstract 1 Parabolic Radon demultiple is one of the standard processing techniques for removing multiple reflection energy from seismic data. In the deep water salt dominated areas of the Gulf of Mexico this technique fails to remove some of the strong salt related multiples. This study will show how an important class of multiples peg-leg multiples can violate the underlying assumptions of parabolic Radon demultiple. This results in a strong near offset residual multiple in the resulting data. This study shows how peg-leg multiples can be removed by expanding the underlying model
This paper derives a unitary model for the coupled $\ensuremath{\pi}NN\ensuremath{-}NN$ problem. Starting from the integral equations obtained by Avishai and Mizutani we introduce an extension of Karlsson's procedure to restate the scattering problem in terms of on-shell transition amplitudes. We obtain a soluble system of Heitler-type integral equations, which unitarize the scattering problem. The model enables the construction of the approximate on-shell transition amplitudes which satisfy both two- and three-particle unitarity constraints.NUCLEAR REACTIONS The coupled $\ensuremath{\pi}NN\ensuremath{-}NN$ problem. Unitary model. Approximation schemes.
