200 research outputs found
Comment on "Tetraquarks as diquark-antidiquark bound systems"
The author argues that the calculated masses of heavy tetraquarks obtained by
solution of the spin-independent homogeneous Lippmann-Schwinger integral
equation in a diquark-antidiquark picture reported by M. Monemzadeh et al.,
Phys. Lett. B {\bf741}, 124 (2015), are incorrect. We have reexamined all of
the published results and we believe that not only the reported tetraquark
masses for states with zero total angular momentum are incorrect, the reported
masses for states with non-zero total angular momentum are quite misleading,
because these states cannot be predicted by a spin-independent formalism
Toward the Application of Three-Dimensional Approach to Few-body Atomic Bound States
The first step toward the application of an effective non partial wave (PW)
numerical approach to few-body atomic bound states has been taken. The two-body
transition amplitude which appears in the kernel of three-dimensional
Faddeev-Yakubovsky integral equations is calculated as function of two-body
Jacobi momentum vectors, i.e. as a function of the magnitude of initial and
final momentum vectors and the angle between them. For numerical calculation
the realistic interatomic interactions HFDHE2, HFD-B, LM2M2 and TTY are used.
The angular and momentum dependence of the fully off-shell transition amplitude
is studied at negative energies. It has been numerically shown that, similar to
the nuclear case, the transition amplitude exhibits a characteristic angular
behavior in the vicinity of 4He dimer pole.Comment: 8 pages, 6 figures, 4 tables. Oral contribution to the 19th
International IUPAP Conference on Few-Body Problems In Physics, 31 Aug-5 Sep
2009, Bonn, German
Three-Nucleon Bound State in a Spin-Isospin Dependent Three Dimensional Approach
A spin-isospin dependent Three-Dimensional approach based on momentum vectors
for formulation of the three-nucleon bound state is presented in this paper.
The three-nucleon Faddeev equations with two-nucleon interactions are
formulated as a function of vector Jacobi momenta, specifically the magnitudes
of the momenta and the angle between them with the inclusion of the
spin-isospin quantum numbers, without employing a partial wave decomposition.
As an application the spin-isospin dependent Faddeev integral equations are
solved with Bonn-B potential. Our result for the Triton binding energy with the
value of -8.152 MeV is in good agreement with the achievements of the other
partial wave based methods.Comment: 24 pages, 1 figure, 7 tables. Major changes; version to appear in
Physical Review
Solution of Two-Body Bound State Problems with Confining Potentials
The homogeneous Lippmann-Schwinger integral equation is solved in momentum
space by using confining potentials. Since the confining potentials are
unbounded at large distances, they lead to a singularity at small momentum. In
order to remove the singularity of the kernel of the integral equation, a
regularized form of the potentials is used. As an application of the method,
the mass spectra of heavy quarkonia, mesons consisting from heavy quark and
antiquark , are calculated for linear and
quadratic confining potentials. The results are in good agreement with
configuration space and experimental results.Comment: 6 pages, 5 table
Four-Body Bound State Formulation in Three-Dimensional Approach (Without Angular Momentum Decomposition)
The four-body bound state with two-body forces is formulated by the
Three-Dimensional approach, which greatly simplifies the numerical calculations
of few-body systems without performing the Partial Wave components. We have
obtained the Yakubovsky equations directly as three dimensional integral
equations.Comment: Talk given at the Third Asia-Pacific Conference on Few-Body Problems
in Physics. Nakhon Ratchasima, Thailand. July 200
Bound State Calculations of the Three-Dimensional Yakubovsky Equations with the inclusion of Three-Body Forces
The four-body Yakubovsky equations in a Three-Dimensional approach with the
inclusion of the three-body forces is proposed. The four-body bound state with
two- and three-body interactions is formulated in Three-Dimensional approach
for identical particles as function of vector Jacobi momenta, specifically the
magnitudes of the momenta and the angles between them. The modified three
dimensional Yakubovsky integral equations is successfully solved with the
scalar two-meson exchange three-body force where the Malfliet-Tjon-type
two-body force is implemented. The three-body force effects on the energy
eigenvalue and the four-body wave function, as well as accuracy of our
numerical calculations are presented.The four-body Yakubovsky equations in a
Three-Dimensional approach with the inclusion of the three-body forces is
proposed. The four-body bound state with two- and three-body interactions is
formulated in Three-Dimensional approach for identical particles as function of
vector Jacobi momenta, specifically the magnitudes of the momenta and the
angles between them. The modified three dimensional Yakubovsky integral
equations is successfully solved with the scalar two-meson exchange three-body
force where the Malfliet-Tjon-type two-body force is implemented. The
three-body force effects on the energy eigenvalue and the four-body wave
function, as well as accuracy of our numerical calculations are presented.Comment: 23 pages, 2 eps figures, 5 tables. Major changes; version to appear
in European Physical Journal
Calculation of Relativistic Nucleon-Nucleon Potentials in Three-Dimensions
In this paper, we have applied a three-dimensional approach for calculation
of the relativistic nucleon-nucleon potential. The quadratic operator relation
between the non-relativistic and the relativistic nucleon-nucleon interactions
is formulated as a function of relative two-nucleon momentum vectors, which
leads to a three-dimensional integral equation. The integral equation is solved
by the iteration method, and the matrix elements of the relativistic potential
are calculated from non-relativistic ones. Spin-independent Malfliet-Tjon
potential is employed in the numerical calculations, and the numerical tests
indicate that the two-nucleon observables calculated by the relativistic
potential are preserved with high accuracy
Heavy Tetraquarks in the Diquark-Antidiquark Picture
The homogeneous Lippmann-Schwinger integral equation is solved in momentum
space to calculate the masses of heavy tetraquarks with hidden charm and
bottom. The tetraquark bound states are studied in the diquark-antidiquark
picture as a two-body problem. A regularized form of the diquark-antidiquark
potential is used to overcome the singularity of the confining potential at
large distances or small momenta. Our numerical results indicate that the
relativistic effect leads to a small reduction in the mass of heavy
tetraquarks, which is less than for charm and less than for
bottom tetraquarks. The calculated masses of heavy tetraquarks for , ,
, and states are in good agreement with other theoretical
calculations and experimental data. Our numerical analysis predict the masses
of heavy tetraquarks for , and states for the first time, and we
are not aware of any other theoretical results or experimental data for these
states
R-Matrix Calculations for Few-Quark Bound States
The R--matrix method is implemented to study the heavy charm and bottom
diquark, triquark, tetraquark and pentaquarks in configuration space, as the
bound states of quark--antiquark, diquark--quark, diquark--antidiquark and
diquark--antitriquark systems, respectively. The mass spectrum and the size of
these systems are calculated for different partial wave channels. The
calculated masses are compared with recent theoretical results obtained by
other methods in momentum and configuration spaces and also by available
experimental data
- …