Mahdi Radin

K.N.Toosi University of Technology | KNTU · Nuclear physics

In this study, we focus on the radiative capture process of the deuteron on alpha particle leading to the formation of $^6{\textrm{Li}}$ in the two-body formalism through the cluster effective field theory~(CEFT). It was the primitive nuclear reaction to produce ${^6 \textrm{Li}}$ in a few minutes after the Big Bang. In detail, we outline the calcu...

This paper explores a novel revision of the Faddeev equation for three-body (3B) bound states, as initially proposed in Ref. [1]. This innovative approach, referred to as t −matrix-free in this paper, directly incorporates two-body (2B) interactions and completely avoids the 2B transition matrices. We extend this formalism to relativistic 3B bound...

This study presents a solution to the Yakubovsky equations for four-body bound states in momentum space, bypassing the common use of two-body t−matrices. Typically, such solutions are dependent on the fully-off-shell two-body t−matrices, which are obtained from the Lippmann-Schwinger integral equation for two-body subsystem energies controlled by t...

In this paper, we study the low-energy d−α elastic scattering within the two-body cluster effective field theory (EFT) framework. The importance of the d(α, α)d scattering in the 6 Li production reaction leads us to study this system in an effective way. In the beginning, the scattering amplitudes of each channel are written in a cluster EFT with t...

The matrix elements of relativistic nucleon-nucleon $(NN)$ potentials are calculated directly from the nonrelativistic potentials as a function of relative $NN$ momentum vectors, without using a partial wave decomposition. To this aim, the quadratic operator relation between the relativistic and nonrelativistic $NN$ potentials is formulated in mome...

The matrix elements of relativistic nucleon-nucleon $(NN)$ potentials are calculated directly from the nonrelativistic potentials as a function of relative $NN$ momentum vectors, without using a partial wave decomposition. To this aim, the quadratic operator relation between the relativistic and nonrelativistic $NN$ potentials is formulated in mome...

Partial wave (PW) decomposition approaches have been widely used in the few-body calculation. After truncation, a PW representation leads to coupled equations on angular momentum quantum numbers. The complexity of modern few-nucleon interactions with a different spin, isospin, and angular momentum combinations, demands avoiding a partial wave repre...

We propose a new regularization scheme to study the bound state of two-nucleon systems in lattice effective field theory. Inspired by a continuum effective field theory calculation, we study an exponential regulator acting on the leading-order and next-to-leading order interactions, consisting of local contact terms. By fitting the low-energy coeff...

We propose a new regularization scheme to study the bound state of two-nucleon systems in Lattice Effective Field Theory. Inspired by continuum EFT calculation, we study an exponential regulator acting on the leading-order (LO) and next-to-leading order (NLO) interactions, consisting of local contact terms. By fitting the low-energy coefficients (L...

In this paper, we study the relativistic effects in a three-body bound state. For this purpose, the relativistic form of the Faddeev equations is solved in momentum space as a function of the Jacobi momentum vectors without using a partial wave decomposition. The inputs for the three-dimensional Faddeev integral equation are the off-shell boost two...

In this paper, we study the relativistic effects in a three-body bound state. For this purpose, the relativistic form of the Faddeev equations is solved in momentum space as a function of the Jacobi momentum vectors without using a partial wave decomposition. The inputs for the three-dimensional Faddeev integral equation are the off-shell boost two...

The authors argue that $^5$He binding energies reported by E. Ahmadi Pouya and A. A. Rajabi [Karbala International Journal of Modern Science {\bf 3}, 287 (2017)] are completely meaningless and should be discarded. The formalism of the paper has serious mistakes and the numerical results obtained from the coupled Yakubovsky integral equations in a...

https://absuploads.aps.org/presentation.cfm?pid=13936

In this paper we develop a three-dimensional approach for describing meson bound states based on the momentum-helicity basis. To this end, we formulate the relativistic form of Lippmann-Schwinger equation in the momentum-helicity basis which leads to two sets of integral equations. Then we have solved these integral equations by inserting a spin de...

The authors argue that the five-body binding energies obtained from the solution of the coupled Yakubovsky integral equations by E. Ahmadi Pouya and A.A. Rajabi [Acta Phys. Pol. B, 48, 1279 (2017)] are incorrect and should be discarded. The theory and formalism of the paper have serious mistakes and the numerical results are not trustable and canno...

In this paper, we solve the coupled Yakubovsky integral equations for four-body (4B) bound state using the low-momentum effective two-body interaction (Formula presented.) in a three-dimensional (3D) approach, without using a partial wave (PW) decomposition. The renormalization group (RG) evolved interaction is constructed from spin-independent Mal...

reaction n + n + α → 6 He + γ is studied by the effective field theory approach. For this purpose, as a first step, we introduce the Faddeev equation of the particle–dimer scattering amplitudes in the 2 × 2 cluster configuration space using the formalism based on the halo effective field theory in the channel J π = 1 −. In the next step, the normal...

The authors argue that the calculated $^6$He binding energies by the solution of the coupled Yakubovsky integral equation in a partial wave decomposition reported by E. Ahmadi Pouya and A. A. Rajabi [Eur. Phys. J. Plus (2016) 131: 240] are incorrect. The formalism of the paper has serious mistakes and the numerical results are not reproducible and...

The authors argue that the calculated $^6$He binding energies by the solution of the coupled Faddeev-Yakubovsky integral equation in a Three-dimensional scheme reported by E. Ahmadi Pouya and A. A. Rajabi [Int. J. Mod. Phys. E 25, 9 (2016) 1650072] are incorrect. The formalism of the paper has serious mistakes and the numerical results are quite mi...

The authors argue that the calculated $^6$He binding energies by the solution of the coupled Faddeev-Yakubovsky integral equation in a Three-dimensional scheme reported by E. Ahmadi Pouya and A. A. Rajabi [Int. J. Mod. Phys. E 25, 9 (2016) 1650072] are incorrect. The formalism of the paper has serious mistakes and the numerical results are quite mi...

In this paper we have solved the nonrelativistic form of the Lippmann-Schwinger equation in the momentum-helicity space by inserting a spin-dependent quark-antiquark potential model numerically. To this end, we have used the momentum-helicity basis states for describing a nonrelativistic reduction of one gluon exchange potential. Then we have calcu...

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 eq...

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 eq...

In this paper we have extended a three-dimensional approach for describing quark-antiquark bound states based on a momentum-helicity representation. To this end we have formulated the relativistic form of the Lippmann-Schwinger equation in the momentum-helicity space which leads to integral equations with one variable. Then we have solved these int...

In this paper, we have extended a three-dimensional Faddeev scheme for three-quark bound state calculations in momentum space. To this end, we have solved Faddeev integral equation by inserting a screened quark-quark potential numerically. Finally, we have obtained binding energy and mass of triply heavy baryons Ωccc++ and Ωbbb−.

A spin-isospin dependent three-dimensional approach has been applied for the formulation of the three-nucleon bound state, and a new expression for Faddeev equation based on three-nucleon free basis states has been obtained. The advantage of this new expression is that the Faddeev integral equation has been simpler for numerical calculation.

We have introduced a spin-isospin dependent three-dimensional approach for formulation of the three-nucleon scattering. Faddeev equation is expressed in terms of vector Jacobi momenta and spin-isospin quantum numbers of each nucleon. Our formalism is based on connecting the transition amplitude $T$ to momentum-helicity representations of the two-bo...

The low-momentum effective interaction Vlowk has been formulated in the three-dimensional momentum-helicity representation as a function of the magnitude of momentum vectors and the angle between them. As an application, AV18 potential has been used in the model space of Lee–Suzuki method and it has been shown that the low-momentum effective intera...

Recently developed three-dimensional Faddeev integral equations for the three-nucleon bound state with two-nucleon interactions have been solved in momentum space for the Bonn-B potential.

The formulation of the low-momentum effective interaction in the model space Lee-Suzuki and the renormalization group methods is implemented in the three-dimensional approach. In this approach the low-momentum effective interaction V_{low k} has been formulated as a function of the magnitude of momentum vectors and the angle between them. As an app...

Linear perturbation of the MHD equation in the flux coordinate system is derived for non-circular cross section of tokamak plasma. The coefficients of derived equation are functions of cross-section geometrical parameters such as elongation, triangularity, Shafranov shift, etc. This equation is solved for non-circular cross section of Damavand toka...

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...

In this work we study the Damavand tokamak plasma equilibrium with an elongated ross section and fixed boundary conditions. These equilibria are characterized by three parameters such as elongation, triangularity and magnetic axis shift. An iterative scheme f the moment’s method is used to solve the Grad-Shafranov equation in flux coordinate system...