arXiv subjects

M. Bhuyan

Publications and source records attributed to M. Bhuyan.

72 records · Page 4Linked to original sources

arXiv2014

Search of double shell closure in the superheavy nuclei using a simple effective interaction

This paper refers to an another attempt to search for spherical double shell closure nu- clei beyond Z=82, N=126. All calculations and results are based on a newly developed approach entitled as simple effective interaction. Our results predict the combination of magic nucleus occurs at N=182 (Z=114,120,126). All possible evidences for the oc- currence of magic nuclei are discussed systematically. And, the obtained results for all observables compared with the relativistic mean field theory for NL3 parameter.

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arXiv2014

$Λ-$hyperon interaction with nucleons

We study the interaction of $Λ-$hyperon with proton and neutron inside a nucleus within the framework of relativistic mean field formalism. The single particle energy levels for some of the specific proton and neutron orbits are analyzed with the addition of $Λ-$successively. We found that the interaction of $Λ$ with neutron is more stronger than proton.

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arXiv2013

Gravitational wave from rotating neutron star

Using the nuclear equation of states for a large variety of relativistic and non-relativistic force parameters, we calculate the static and rotating masses and radii of neutron stars. From these equation of states, we also evaluate the properties of rotating neutron stars, such as rotational and gravitational frequencies, moment of inertia, quadrupole deformation parameter, rotational ellipcity and gravitational wave strain amplitude. The estimated gravitational wave strain amplitude of the star is found to be $\sim 10^{-23}$.

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arXiv2013

The evaporation residue in the fission state of Barium nuclei within relativistic mean-field theory

The evaporation residue of Barium isotopes are investigated in a microscopic study using relativistic mean field theory. The investigation includes the isotopes of Barium from the valley of stability to exotic proton-rich region. The ground as well as neck configurations for these nuclei are generated from their total nucleonic density distributions of the corresponding state. We have estimated the constituents (number of nucleons) in the elongated neck region of the fission state. We found the $α$-particle as the constituent of neck of Ba-isotopes, referred to as the evaporated residue in heavy-ion reaction studies. A strong correlation between the neutron and proton is observed throughout the isotopic chain.

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arXiv2013

The Oxygen core inside the Magnesium isotopes

We have studied the ground state bulk properties of magnesium isotopes using axially symmetric relativistic mean field formalism. The BCS pairing approach is employed to take care of the pairing correlation for the open shell nuclei. The contour plot of the nucleons distribution are analyzed at various parts of the nucleus, where clusters are located. The presence of an $^{16}$O core along bubble like $α$-particle(s) and few {\it nucleons} are found in the Mg isotopes.

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arXiv2013

Effect of isospin asymmetry in nuclear system

The effect of $δ-$ and $ω-ρ-$meson cross couplings on asymmetry nuclear systems are analyzed in the frame-work of an effective Field theory motivated relativistic mean field formalism. The calculations are done on top of the G2 parameter set, where these contributions are absent. We calculate the root mean square radius, binding energy, single particle energy (for the $1^{st}$ and last occupied orbits), density and spin-orbit interaction potential for some selected nuclei and evaluate the $L_{sym}-$ and $E_{sym}-$ coefficients for nuclear matter as function of $δ-$ and $ω-ρ-$meson coupling strengths. As expected, the influence of these effects are negligible for symmetry nuclear system and these effects are very important for systems with large isospin asymmetry.

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arXiv2013

Simple effective interaction: Infinite nuclear matter and finite nuclei

The mean field properties and equation of state for asymmetric nuclear matter are studied by using a simple effective interaction which has a single finite range Gaussian term. The study of finite nuclei with this effective interaction is done by means of constructing a quasilocal energy density functional for which the single particle equations take the form of Skryme-Hartree-Fock equations. The predictions of binding energies and charge radii of spherical nuclei are found to be compatible with the results of standard models as well as experimental data.

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arXiv2012

The effect of isoscalar-isovector coupling in infinite nuclear matter

Working on the framework of Relativistic Mean Field theory, we exposed the effect of nonlinear isoscalar-isovector coupling on G2 parameter set on the density dependence of nuclear symmetry energy in infinite nuclear matter. The observables like symmetric energy and few related coefficients are studied systematically. We presented the results of stiff symmetry energy at sub-saturation densities and a soft variation at normal densities. Correlation between the symmetric energy and the isoscalar-isovector coupling parameter fully demonstrated for wide range of density. The work further extended to the octet system and showed the effect of coupling over the equation of state.

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arXiv2012

Properties of Z=120 nuclei and the α-decay chains of the (292,304)120 isotopes using relativistic and non-relativistic formalisms

The ground state and first intrinsic excited state of superheavy nuclei with Z=120 and N=160-204 are investigated using both non-relativistic Skyrme-Hartree-Fock and the axially deformed Relativistic Mean Field formalisms. We employ a simple BCS pairing approach for calculating the energy contribution from pairing interaction. The results for isotopic chain of binding energy, quadrupole deformation parameter, two neutron separation energies and some other observables are compared with the FRDM and some recent macroscopic-microscopic calculations. We predict superdeformed ground state solutions for almost all the isotopes. Considering the possibility of magic neutron number, two different mode of α-decay chains (292)120 and (304)120 are also studied within these frameworks. The Q_α-values and the half-life T^α_{1/2} for these two different mode of decay chains are compared with FRDM and recent macroscopic-microscopic calculations. The calculation is extended for the α-decay chains of 292120 and 304120 from their exited state configuration to respective configuration, which predicts long half-life T^α_{1/2}(sec.).

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arXiv2012

An effective Nuclear Model: from Nuclear Matter to Finite Nuclei

The momentum and density dependence of mean fields in symmetric and asymmetric nuclear matter are analysed using the simple density dependent finite range effective interaction containing a single Gaussian term alongwith the zero-range terms. Within the formalism developed, it is possible to reproduce the various diverging predictions on the momentum and density dependence of isovector part of the mean field in asymmetric matter. The finite nucleus calculation is formulated for the simple Gaussian interaction in the framework of quasilocal density functional theory. The prediction of energies and charge radii of the interaction for the spherical nuclei compares well with the results of other effective theories.

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arXiv2011

Magic nuclei in superheavy valley

An extensive theoretical search for the proton magic number in the superheavy valley beyond $Z=$82 and corresponding neutron magic number after $N=$126 is carried out. For this we scanned a wide range of elements $Z=112-130$ and their isotopes. The well established non-relativistic Skryme-Hartree-Fock and Relativistic Mean Field formalisms with various force parameters are used. Based on the calculated systematics of pairing gap, two neutron separation energy and the shell correction energy for these nuclei, we find $Z=$120 as the next proton magic and N=172, 182/184, 208 and 258 the subsequent neutron magic numbers.

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arXiv2011

The α-Decay Chains of the $^{287, 288}115$ Isotopes using Relativistic Mean Field Theory

We study the binding energy, root-mean-square radius and quadrupole deformation parameter for the synthesized superheavy element Z = 115, within the formalism of relativistic mean field theory. The calculation is dones for various isotopes of Z = 115 element, starting from A = 272 to A = 292. A systematic comparison between the binding energies and experimental data is made.The calculated binding energies are in good agreement with experimental result. The results show the prolate deformation for the ground state of these nuclei. The most stable isotope is found to be 282115 nucleus (N = 167) in the isotopic chain. We have also studied Qα and Tα for the α-decay chains of $^{287, 288}$115.

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arXiv2011

A new microscopic nucleon-nucleon interaction derived from relativistic mean field theory

A new microscopic nucleon-nucleon (NN) interaction has been derived for the first time from the popular relativistic mean field theory (RMFT) Lagrangian. The NN interaction so obtained remarkably relate to the inbuilt fundamental parameters of RMFT. Furthermore, by folding it with the RMFT-densities of cluster and daughter nuclei to obtain the optical potential, it's application is also examined to study the exotic cluster radioactive decays, and results obtained found comparable with the successfully used M3Y phenomenological effective NN interactions. The presently derived NN-interaction can also be used to calculate a number of other nuclear observables.

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arXiv2010

Application of relativistic mean field and effective field theory density to calculate scattering observables for Ca isotopes

In the frame work of relativistic mean field (RMF) theory, we calculate the density distribution of protons and neutrons for $^{40,42, 44,48}Ca$ with NL3 and G2 parameter sets. The microscopic proton-nucleus optical potential for $p+^{40,42,44,48}Ca$ system is evaluated from Dirac NN-scattering amplitude and the density of the target nucleus using Relativistic-Love-Franey and McNeil-Ray-Wallace parametrizations. Then we estimate the scattering observables, such as elastic differential scattering cross-section, analyzing power and the spin observables with relativistic impulse approximation. We compare the results with the experimental data for some selective cases and found that the use of density as well as the scattering matrix parametrization is crucial for the theoretical prediction.

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arXiv2010

Relativistic mean field study of the properties of Z=117 nucleus and the decay chains of $^{293,294}$117 isotopes

We have calculated the binding energy, root-mean-square radius and quadrupole deformation parameter for the recently synthesized superheavy element Z=117, using the axially deformed relativistic mean field (RMF) model. The calculation is extended to various isotopes of Z=117 element, strarting from A=286 till A=310. We predict almost spherical structures in the ground state for almost all the isotopes. A shape transition appears at about A=292 from prolate to a oblate shape structures of Z=117 nucleus in our mean field approach. The most stable isotope (largest binding energy per nucleon) is found to be the $^{288}$117 nucleus. Also, the Q-value of $α$-decay $Q_α$ and the half-lives $T_α$ are calculated for the $α$-decay chains of $^{293}$117 and $^{294}$117, supporting the magic numbers at N=172 and/ or 184.

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arXiv2010

Effects of density and parametrization on scattering observables

We calculate the density distribution of protons and neutrons for $^{40,42, 44,48}Ca$ in the frame-work of relativistic mean field (RMF) theory with NL3 and G2 parameter sets. The microscopic proton-nucleus optical potential for $p+^{40}Ca$ system is evaluted from Dirac NN-scattering amplitude and the density of the target nucleus using Relativistic-Love-Franey and McNeil-Ray-Wallace parametrizations. Then we estimate the scattering observables, such as elastic differential scattering cross-section, analysing power and the spin observables with relativistic impulse approximation. We compare the results with the experimental data for some selective cases and found that the use of density as well as the scattering matrix parametrization is crucial for the theoretical prediction.

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arXiv2009

Internal stucture of clusters in $^{112-122}$Ba nuclei within relativistic mean field theory

We study the clustering structure and the internal or sub-structure of clusters in $^{112-122}$Ba nuclei within the framework of relativistic mean field theory in an axially deformed cylindrical co-ordinate. We calculate the total density distribution, and the individual neutrons and protons density distributions. From the analysis of the clustering confugurations of the density distributions of various shapes, we find different sub-structures inside the Ba nuclei considered here. The important step, carried out for the first time, is the counting of number of protons and neutrons present in the clustering region(s). $^{12}$C is shown to consitute the cluster configuration of Ba nuclei in most cases, with $^{2,3}$H and $^4$He constituting the neck between two fissioning symmetrical fragments.

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arXiv2009

Superdeformed and Hyperdeformed States in Z=122 Isotopes

We calculate the binding energy, root-mean-square radius and quadrupole deformation parameter for the recent, possibly discovered superheavey element Z=122, using the axially deformed relativistic mean field (RMF) and non-relativistic Skyrme Hartree-Fock (SHF) formalisms. The calculation is extended to include various isotopes of Z=122 element, strarting from A=282 to A=320. We predict highly deformed structures in the ground state for all the isotopes. A shape transition appears at about A=290 from a highly oblate to a large prolate shape, which may be considered as the superdeformed and hyperdeformed structures of Z=122 nucleus in the mean field approaches. The most stable isotope (largest binding energy per nucleon) is found to be $^{302}$122, instead of the experimentally observed $^{292}$122.

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