arXiv subjects

S. K. Patra

Publications and source records attributed to S. K. Patra.

At least 91 records · Page 5Linked to original sources

arXiv2015

Examining the stability of thermally fissile Th and U isotopes

The properties of recently predicted thermally fissile Th and U isotopes are studied within the framework of relativistic mean field (RMF) approach using axially deformed basis. We calculated the ground, first intrinsic excited state and matter density for highly neutron-rich thorium and uranium isotopes. The possible modes of decay like $α$-decay and $β$-decay are analyzed. We found that the neutron-rich isotopes are stable against $α$-decay, however they are very much unstable against $β$-decay. The life time of these nuclei predicted to be tens of second against $β$-decay. If these nuclei utilize before their decay time, a lots of energy can be produced within the help of multi-fragmentation fission. Also, these nuclei have a great implication in astrophysical point of view. The total nucleonic densities distribution are calculated, from which the clusters inside the parent nuclei are determined. %Most of the thorium isotopes are $α$ emitters, where as some %of them have short half-lives. In some cases, we found the isomeric states with energy range from 2 to 3 MeV and three minima in the potential energy surface of $^{228-230}$Th and $^{228-234}$U isotopes.

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arXiv2015

Properties of superheavy nuclei with Z = 124

We employ Relativistic Mean Field (RMF) model with NL3 parametrization to investigate the ground state properties of superheavy nucleus, Z = 124. The nuclei selected (from among complete isotopic series) for detailed investigation show that the nucleon density at the center is very low and therefore, these nuclei can be treated as semi-bubble nuclei. The considerable shell gap appears at neutron numbers N = 172, 184 and 198 showing the magicity corresponding to these numbers. The results are compared with the macro-microscopic Finite Range Droplet Model (FRDM) wherever possible.

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arXiv2015

Effects of $NN$ potentials on $p$ nuclides in the A$\sim$100-120 region

Microscopic optical potentials for low energy proton reactions have been obtained by folding density dependent M3Y interaction derived from nuclear matter calculation with densities from mean field approach to study astrophysically important proton rich nuclei in mass 100-120 region. We compare S factors for low-energy $(p,γ)$ reactions with available experimental data and further calculate astrophysical reaction rates for $(p,γ)$ and $(p,n)$ reactions. Again we choose some nonlinear R3Y interactions from RMF calculation and folded them with corresponding RMF densities to reproduce experimental S factor values in this mass region. Finally the effect of nonlinearity on our result is discussed.

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arXiv2015

Quest of $^{37}Mg$ halo structure using Glauber model and microscopic relativistic mean field densities

We have studied the ground state properties (binding energy and charge radius) using relativistic mean filed formalism (RMF) for Mg-isotopes in the valley of stability to drip line region. The RMF densities have been analyzed in context of reaction dynamics. The calculated results of $^{24-40}$Mg+$^{12}$C reactions at projectile energy 240 AMeV using Glauber model with the conjunction of densities from relativistic mean field formalism are compared with experimental data. We found remarkable agreement of estimated values of reaction cross sections with experimental data except for $^{37}$Mg isotope. In view of this, the halo status of $^{37}$Mg is examined through higher magnitude of rms radius and small value of longitudinal momentum distribution. Finally, an effort is made to explore the structure of $^{37}$Mg halo candidate using Glauber few body formalism.

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arXiv2014

A relativistic mean field study of multi-strange system

We study the binding energies, radii, single-particle energies, spin-orbit potential and density profile for multi-strange hypernuclei in the range of light mass to superheavy region within the relativistic mean field (RMF) theory. The stability of multi-strange hypernuclei as a function of introduced hyperons ($Λ$ and $Σ$) is investigated. The neutron, lambda and sigma mean potentials are presented for light to superheavy hypernuclei. The inclusion of hyperons affects the nucleon, lambda and sigma spin-orbit potentials significantly. The bubble structure of nuclei and corresponding hypernuclei is studied. The nucleon and lambda halo structure are also investigated. A large class of bound multi-strange systems formed from the combination of nucleons and hyperons (n, p, $Λ$, $Σ^+$ and n, p, $Λ$, $Σ^-$) is suggested in the region of superheavy hypernuclei which might be stable against the strong decay. These multi-strange systems might be produced in heavy-ion reactions.

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arXiv2014

The effect of self interacting isoscalar-vector meson on finite nuclei and infinite nuclear matter

A detailed study is made for the nucleon-nucleon interaction based on relativistic mean field theory in which the potential is explicitly expressed in terms of mass and the coupling constant of the meson fields. A unified treatment for self-coupling of isoscalar-scalar $σ-$, isoscalar-vector $ω$-mesons and their coupling constant are given with a complete analytic form. The present investigation is focused on the effect of self-interacting higher order $σ$ and $ω$ field on nuclear properties. An attempt is made to explain the collapsing stage of nucleon by higher order $ω$-field. Both infinite nuclear matter and the finite nuclear properties are included in the present study to observe the behaviour or sensitivity of this self interacting terms.

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arXiv2014

Softness of Sn isotopes in relativistic semi-classical approximation

Within the frame-work of relativistic Thomas-Fermi and relativistic extended Thomas-Fermi approximations, we calculate the giant monopole resonance (GMR) excitation energies for Sn and related nuclei. A large number of non-linear relativistic force parameters are used in this calculations. We find that a parameter set is capable to reproduce the experimental monopole energy of Sn isotopes, when its nuclear matter compressibility lies within $210-230$ MeV, however fails to reproduce the GMR energy of other related nuclei. That means, simultaneously a parameter set can not reproduce the GMR values of Sn and other nuclei.

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arXiv2014

Anatomy of nuclear matter fundamentals

The bridge between finite and infinite nuclear system is analyzed for the fundamental quantities like binding energy, density, compressibility, giant monopole excitation energy and effective mass of both nuclear matter and finite nuclei systems. It is shown quantitatively that by knowing one of the fundamental property of one system one can estimate the same in its counter part, only approximately

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arXiv2014

Superdeformed structures and low $Ω$ parity doublet in Ne$-$S nuclei near neutron drip-line

The structure of Ne, Na, Mg, Al, Si, P and S nuclei near the neutron drip-line region is investigated in the frame-work of relativistic mean field theory and non-relativistic Skyrme Hartree-Fock formalism. The recently discovered nuclei $^{40}$Mg and $^{42}$Al, which are beyond the drip-line predicted by various mass formulae are located within these models. We find many largely deformed neutron-rich nuclei, whose structures are analyzed. From the structure anatomy, we find that at large deformation, low $Ω$ orbits of opposite parities (e.g. $\frac{1}{2}^+$ and $\frac{1}{2}^-$) occur close to each other in energy.

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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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arXiv2014

Effects of isovector scalar $δ$-meson on hypernuclei

We analyze the effects of $δ-$ meson on hypernuclei within the frame-work of relativistic mean field theory. The $δ-$ meson is included into the Lagrangian for hypernuclei. The extra nucleon-meson coupling ($g_δ$) affects the every piece of physical observables, like binding energy, radii and single particle energy of hypernuclei. The lambda mean field potential is investigated which is consistent with other predictions. Flipping of single particle energy levels are observed with the strength of $g_δ$ in the considered hypernuclei as well as normal nuclei. The spin-orbit potentials are observed for considered hypernuclei and the effect of $g_δ$ on spin-orbit potentials is also analyzed. The calculated single-$Λ$ binding energies ($B_Λ$) are quite agreeable with the experimental data.

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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

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

Reaction and structure effects of light mass nuclei using Glauber model with relativistic and non relativistic simple effective interaction densities

We study the structural properties of some nuclei in the region of light mass using simple effective interaction in the frame work of microscopic non relativistic Hartree-Fock and relativistic mean field formalism. For the reaction dynamics, well known Glauber model is used with the conjunctions of the densities obtained from these formalism. We observe good agreement of results by both the formalism in comparison to the experimental values. These two different approaches seems to be equally capable to reproduce the ground state properties of nuclei in this region. A careful study of reaction dynamics suggest the superiority of relativistic mean field over the Hartree-Fock with simple effective interaction densities. But good agreement of reaction cross section is appeared with simple effective interaction density for halo nuclear systems. The possibility of existence of bubble nuclei are also studied using both the formalism.

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arXiv2013

Nuclear Structure and Reaction Properties of Ne, Mg and Si Isotopes with RMF Densities

We have studied nuclear structure and reaction properties of Ne, Mg and Si isotopes, using relativistic mean field densities, in the frame work of Glauber model. Total reaction cross section $σ_R$ for Ne isotopes on 12C target have been calculated at incident energy 240 MeV. The results are compared with the experimental data and with the recent theoretical study [W. Horiuchi et al., Phys. Rev. C, 86, 024614 (2012)]. Study of $σ_R$ using deformed densities have shown a good agreement with the data. We have also predicted total reaction cross section $σ_R$ for Ne, Mg and Si isotopes as projectiles and 12C as target at different incident energies.

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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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