2,653 research outputs found
The Relativistic Three-Body Bound State in Three-Dimensions
Studying of the relativistic three-body bound state in a three-dimensional
(3D) approach is a necessary first step in a process to eventually perform
scattering calculations at GeV energies, where partial-wave expansions are not
useful. To this aim we recently studied relativistic effects in the binding
energy and for the first time, obtained the relativistic 3B wave function
\cite{Hadizadeh_PRC90}. The relativistic Faddeev integral equations for the
bound state are formulated in terms of momentum vectors, and relativistic
invariance is incorporated within the framework of Poincar\'e invariant quantum
mechanics.Comment: Contribution to the 21st International Conference on Few-Body
Problems in Physics, Chicago, Illinois, US
The Proton-Deuteron Break-Up Process in a Three-Dimensional Approach
The pd break-up amplitude in the Faddeev scheme is calculated by employing a
three-dimensional method without partial wave decomposition (PWD). In a first
step and in view of higher energies only the leading term is evaluated and this
for the process d(p,n)pp. A comparison with the results based on PWD reveals
discrepancies in the cross section around 200 MeV. This indicates the onset of
a limitation of the partial wave scheme. Also, around 200 MeV relativistic
effects are clearly visible and the use of relativistic kinematics shifts the
cross section peak to where the experimental peak is located. The theoretical
peak height, however, is wrong and calls first of all for the inclusion of
rescattering terms, which are shown to be important in a nonrelativistic full
Faddeev calculation in PWD.Comment: 4 pages, 5 figures, Proceeding of the Second Asia-Pasific Conference
on Few-Body Problem in Physics, August 2002, Shanghai, Chin
Nucleon-Nucleon Scattering in a Three Dimensional Approach
The nucleon-nucleon (NN) t-matrix is calculated directly as function of two
vector momenta for different realistic NN potentials. To facilitate this a
formalism is developed for solving the two-nucleon Lippmann-Schwinger equation
in momentum space without employing a partial wave decomposition. The total
spin is treated in a helicity representation. Two different realistic NN
interactions, one defined in momentum space and one in coordinate space, are
presented in a form suited for this formulation. The angular and momentum
dependence of the full amplitude is studied and displayed. A partial wave
decomposition of the full amplitude it carried out to compare the presented
results with the well known phase shifts provided by those interactions.Comment: 26 pages plus 10 jpg figure
Understanding contextualised rational action - author's response
Understanding contextualised rational action - author's respons
Treatment of Two Nucleons in Three Dimensions
We extend a new treatment proposed for two-nucleon (2N) and three-nucleon
(3N) bound states to 2N scattering. This technique takes momentum vectors as
variables, thus, avoiding partial wave decomposition, and handles spin
operators analytically. We apply the general operator structure of a
nucleon-nucleon (NN) potential to the NN T-matrix, which becomes a sum of six
terms, each term being scalar products of spin operators and momentum vectors
multiplied with scalar functions of vector momenta. Inserting this expansions
of the NN force and T-matrix into the Lippmann-Schwinger equation allows to
remove the spin dependence by taking traces and yields a set of six coupled
equations for the scalar functions found in the expansion of the T-matrix.Comment: 4 pages, Contribution to The 19th International IUPAP Conference on
Few-Body Problems in Physics, 31.08 - 05.09.2009, Bonn, German
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