Publications (58)
Preformation Probability and Kinematics of Clusters Emission yielding Pb-daughters
Joshua T. Majekodunmi, M. Bhuyan, K. Anwar +2
In the present study, the newly established preformation formula is applied for the first time to study the kinematics of the cluster emission from various radioactive nuclei, espe…
Very High-energy Gamma-Ray Episodic Activity of Radio Galaxy NGC 1275 in 2022-2023 Measured with MACE
S. Godambe, N. Mankuzhiyil, C. Borwankar +37
The radio galaxy NGC 1275, located at the central region of Perseus cluster, is a well-known very high-energy (VHE) gamma-ray emitter. The Major Atmospheric Cherenkov Experiment Te…
Exploring the ground state bulk and decay properties of the nuclei in superheavy island
Nishu Jain, Raj Kumar, M. Bhuyan
The -decay half-lives of 204 superheavy nuclei covering the range have been investigated using the relativistic mean-field model (RMF) for NL3 paramet…
Black hole spin estimation of XTE J2012+381 using simultaneous observations of Swift/XRT and NuSTAR
Raj Kumar
A sufficiently precise measurement of black hole spin is required to carry out quantitative tests of the Kerr metric and to understand several phenomena related to astrophysical bl…
Exploring the extended density-dependent Skyrme effective forces for normal and isospin-rich nuclei to neutron stars
B. K. Agrawal, Shashi K. Dhiman, Raj Kumar
We parameterize the recently proposed generalized Skyrme effective force (GSEF) containing extended density dependence. The parameters of the GSEF are determined by the fit to seve…
Study of Solar Energetic Particles: their Source Regions, Flares and CMEs during Solar Cycles 23-24
Raj Kumar, Ramesh Chandra, Bimal Pande +1
In this work, we examine the association between solar active regions and 152 solar flares, coronal mass ejections, and solar energetic particle (SEP) events over solar cycles 23-2…
An application of Cohn's rule to convolutions of univalent harmonic mappings
Raj Kumar, Sushma Gupta, Sukhjit Singh +1
Dorff et al. [4], proved that the harmonic convolution of right half-plane mapping with dilatation -z and mapping f_β= h_β+ \bar{g}_β, where f_βis obtained by shearing of analy…
Chandrayaan-2 Dual-Frequency SAR (DFSAR): Performance Characterization and Initial Results
Sriram S. Bhiravarasu, Tathagata Chakraborty, Deepak Putrevu +14
The Dual-Frequency synthetic aperture radar (DFSAR) system manifested on the Chandrayaan-2 spacecraft represents a significant step forward in radar exploration of solid solar syst…
Sudden- or Frozen-density approximation in Semi-classical extended Thomas Fermi model for Wong formula used in 64Ni+64Ni reaction
Raj Kumar, Raj K. Gupta
The {\ell}-summed Wong expression is applied in the semiclassical extended Thomas Fermi (ETF) method of Skyrme energy density formalism (SEDF), using both the sudden and frozen-den…
Convolution properties of univalent harmonic mappings convex in one direction
Raj Kumar, Sushma Gupta, Sukhjit Singh
Let and denote the convolution of two analytic maps and that of an analytic map and a harmonic map respectively. Pokhrel [1] proved that if $f = h+\overl…
Barrier modification in sub-barrier fusion reactions using Dynamical cluster-decay and extended-Wong models
Raj Kumar, Manie Bansal, Raj K. Gupta
Fusion-evaporation cross-sections Ïevr in reactions known for fusion hindrance phenomenon in coupled-channels calculations at below-barrier energies, are studied in terms of the d…
Temeprature-dependent Seeger's liquid drop energy for nuclei up to Z=118
BirBikram Singh, Manoj K. Sharma, Raj Kumar +2
Seeger's semi-empirical mass formula is revisited for two of its constants (bulk constant α(0) and neutron-proton asymmetry constant a_{a}) readjusted to obtain the ground-state (…
Exploring the role of low-lying intrinsic degrees of freedom and their impact on fusion cross-sections
Nishu Jain, M. Bhuyan, Raj Kumar
The present work focuses on examining the low-lying intrinsic degrees of freedom and their impact on fusion dynamics. Fusion cross-sections were calculated using the coupled-channe…
Relativistic approach for the determination of nuclear and neutron star properties in consideration of PREX-II results
Virender Thakur, Raj Kumar, Pankaj Kumar +6
The bulk properties of nuclear matter and neutron stars with the newly generated relativistic interaction DBHP are investigated which provides an opportunity to modify the coupling…
X-ray spectral and temporal evolution of atoll source 4U 1820-30 with AstroSat: detection of high frequency quasi-periodic oscillation
Subhasish Das, Vivek Kumar Agrawal, Parijat Thakur +4
AstroSat/LAXPC and SXT observed the persistent neutron star low-mass X-ray binary 4U 1820-30 between 2016 and 2022. During these observations, the hardness-intensity diagram (HID)…
Persistence of the N = 50 shell closure over the isotopic chains of Sc, Ti, V and Cr nuclei using relativistic energy density functional
Praveen K. Yadav, Raj Kumar, M. Bhuyan
The analytical expression of the density-dependent binding energy per nucleon for the relativistic mean field (RMF), also known as the relativistic energy density functional (Relat…
Quest for a Universal Cluster Preformation Formula: A new paradigm for estimating the cluster formation energy
Joshua T. Majekodunmi, Raj Kumar, M. Bhuyan
This study presents a holistic picture of the preformation of nuclear clusters with credence to the kinematics of their emissions. Besides the fitting of the preformation formula t…
Correlations in the properties of static and rapidly rotating compact stars
B. K. Agrawal, Raj Kumar, S. K. Dhiman
Correlations in the properties of the static compact stars (CSs) and the ones rotating with the highest observed frequency of 1122Hz are studied using a large set of equations of s…
Cluster decay dynamics of Actinides yielding non-Pb-daughter
Joshua T. Majekodunmi, M. Bhuyan, Raj Kumar
The cluster dynamics of radioactive nuclei decaying to neighbouring daughter nuclei of the double magic Sn and Pb is investigated using the relativistic mean-field…
An Electrical Spinning Particle In Einstein's Unified Field Theory
S. N. Pandey, B. K. Sinha, Raj Kumar
Previous work on exact solutions has been shown that sources need to be appended to the field equation of Einstein's unified field theory in order to achieve physically meaningful…
Fusion cross section of the superheavy = 120 nuclei within the relativistic mean-field formalism
Shilpa Rana, Raj Kumar, M. Bhuyan
Present theoretical investigations aim to explore the fusion characteristics of various isotopes of Z=120 within the relativistic mean-field (RMF) formalism. We predict the most su…
Relativistic mean-field study of alpha decay in superheavy isotopes with 100 \texorpdfstring{ Z }-120
Nishu Jain, M. Bhuyan, Raj Kumar
The -decay half-lives of superheavy nuclei with are comprehensively analyzed using the axially deformed relativistic mean field (RMF) formalism for the NL…
Study of type-B QPOs observed in black hole X-ray binary Swift J1728.9-3613
Raj Kumar
We report the detection of type-B quasi-periodic oscillation (QPO) of the black hole X-ray binary Swift J1728.9-3613 observed by NICER during the 2019 outburst. A type- B QPO was o…
Nuclear fusion as a probe for octupole deformation in Ra
Raj Kumar, J. A. Lay, A. Vitturi
: Nuclear fusion has been shown to be a perfect probe to study the different nuclear shapes. However, the possibility of testing octupole deformation of a nucl…
On Retro Frame Associated With Measurable Space
Raj Kumar, Ashok K. Sah, Satyapriya +1
Frames are redundant system which are useful in the reconstruction of certain classes of spaces. Duffin and Schaeffer introduced frames for Hilbert spaces, while addressing some de…
Linear combinations of univalent harmonic mappings convex in the direction of the imaginary axis
Raj Kumar, Sushma Gupta, Sukhjit Singh
In the present paper, we introduce a family of univalent harmonic functions, which map the unit disk onto domains convex in the direction of the imaginary axis. We find conditions…
Variability study of classical supergiant X-ray binary 4U 1907+09 using NuSTAR
Raj Kumar, Sayantan Bhattacharya, Sudip Bhattacharyya +1
We investigate the X-ray variability of the supergiant X-ray binary 4U 1907+09 using the new NuSTAR observation of 2024. The source had a relatively stable flux level during previo…
Observational constraint from the heaviest pulsar PSR J0952-0607 on the equation of state of dense matter in relativistic mean field model
Raj Kumar, Mukul Kumar, Virender Thakur +5
In the present work, we constrain the equation of the state of dense matter in the context of heaviest observed neutron star mass M = 2.35 M for the bla…
Medium dependent relativistic NN potential: Application to the fusion dynamics
Mrutunjaya Bhuyan, Shilpa Rana, Nishu Jain +3
In-medium effects are introduced in the microscopic description of the effective nucleon-nucleon (NN) interaction potential entitled DDR3Y in terms of the density-dependent nucleon…
Structural and decay properties of nuclei appearing in the -decay chains of 120 within the relativistic mean-field formalism
N. Biswal, Nishu Jain, Raj Kumar +2
An extensive study of -decay half-lives for various decay chains of isotopes of = 120 is performed within the axially deformed relativistic mean-field (RMF) formalism by em…
Fusion cross-section for Ni-based reactions within the relativistic mean field formalism
M. Bhuyan, Raj Kumar
In this theoretical study, we establish an interrelationship between the nucleon-nucleon interaction potential and the nuclear fusion reaction cross-sections at low energies. The a…
Nuclear incompressibility and its enduring impact on fusion cross-section
Shilpa Rana, M. Bhuyan, S. K. Patra +1
The fusion mechanism of reactions involving even-even Sn, doubly magic Sn, Pb as targets, and Ni as the projectile is explored within the relativ…
Relativistic Mean Field Model parameterizations in the light of GW170817, GW190814, and PSR J0740 + 6620
Virender Thakur, Raj Kumar, Pankaj Kumar +3
Three parameterizations DOPS1, DOPS2, and DOPS3 (named after the Department of Physics Shimla) of the Relativistic Mean Field (RMF) model have been proposed with the inclusion of a…
Relativistic energy density functional from momentum space to coordinate space within a coherent density fluctuation model
Praveen K. Yadav, Raj Kumar, M. Bhuyan
In this theoretical study, we have derived a simplified analytical expression for the binding energy per nucleon as a function of density and isospin asymmetry within the relativis…
Convolution properties of some harmonic mappings in the right-half plane
Raj Kumar, Michael Dorff, Sushma Gupta +1
Dorff, proved in [2] that the convolution of two harmonic right-half plane mappings is convex in the direction of real axis provided that the convolution is locally univalent and s…
Characteristics of SEPs during Solar Cycle 21-24
Raj Kumar, Ramesh Chandra, Bimal Pande +1
The study of the solar energetic particle events (SEPs) and their association with solar flares and other activities are very crucial to understand the space weather. Keeping this…
Effects of meson self-coupling on the properties of finite nuclei and neutron stars
Raj Kumar, B. K. Agrawal, Shashi K. Dhiman
The effects of meson self-coupling (OMSC) on the properties of finite nuclei and neutron stars are investigated within the framework of effective field theory based relativist…
CREX- and PREX-II-motivated relativistic interactions and their implications for the bulk properties of nuclear matter and neutron stars
Mukul Kumar, Sunil Kumar, Virender Thakur +3
We investigate the implications of parity-violating electron scattering experiment on neutron skin thickness of Ca (CREX) and Pb (PREX-II) data on the bulk propertie…
Skyrme-force dependence of fusion cross-sections using Wong formula in semiclassical formalism
Raj Kumar, Raj K Gupta
we use the nuclear proximity potential obtained recently for the Skyrme nucleus-nucleus interaction in the semiclassical extended Thomas Fermi (ETF) approach using Skyrme energy de…
Systematic study of fusion barrier characteristics within the relativistic mean-field formalism
Shilpa Rana, Mrutunjaya Bhuyan, Raj Kumar
Background: The nuclear interaction potential and hence the fusion barrier formed between the interacting nuclei are the keys to understanding the complex fusion process dynamics.…
Barrier modification in sub-barrier fusion reactions using Wong formula with Skyrme forces in semiclassical formalism
Raj Kumar, Raj K. Gupta
We obtain the nuclear proximity potential by using semiclassical extended Thomas Fermi (ETF) approach in Skyrme energy density formalism (SEDF), and use it in the extended -s…
Implementation of the microscopic nuclear potential in the coupled channels calculations to study the fusion dynamics of Oxygen based reactions
N. Jain, M. Bhuyan, Raj Kumar
In the present work, we have incorporated the microscopic relativistic nuclear potential obtained from recently developed relativistic R3Y NN potential in the coupled channels code…
Gate-controlled skyrmion and domain wall chirality
Charles-Elie Fillion, Johanna Fischer, Raj Kumar +14
Magnetic skyrmions are localized chiral spin textures, which offer great promise to store and process information at the nanoscale. In the presence of asymmetric exchange interacti…
Competing decay modes and stability analysis of superheavy nuclei with Z = 120 using relativistic mean-field approach
Nishu Jain, M. Bhuyan, P. Mohr +1
We systematically study the competition between α-decay and spontaneous fission in even-even superheavy nuclei with (Z=120) and 256 \leq A \leq 304 within the preformed cluster-de…
On Weyl-Heisenberg Frames
Satyapriya, Raj Kumar, Ashok K. Sah +1
In this paper we have generalized and studied the -Weyl-Heisenberg frames, where is a bounded linear operator on . We have obtained necessary and sufficie…
Non-rotating and rotating neutron stars in the extended field theoretical model
Shashi K. Dhiman, Raj Kumar, B. K. Agrawal
We study the properties of non-rotating and rotating neutron stars for a new set of equations of state (EOSs) with different high density behaviour obtained using the extended fiel…
Systematic study of the effect of individual rotational energy levels on the fusion cross-section of \texorpdfstring{}--based reactions of range
Nishu Jain, M. Bhuyan, Raj Kumar
The present work aims to investigate the effect of individual rotational energy levels on the fusion cross-sections for O-based reaction systems, namely, O + $^{182,1…
Enhanced subbarrier fusion for proton halo nuclei
Raj Kumar, J. A. Lay, A. Vitturi
In this short note we use a simple model to describe the dynamical effects of break-up processes in the subbarrier fusion involving weakly bound nuclei. We model two similar cases…
Influence of effective interactions and nuclear densities on the dynamics of heavy-ion fusion
Shilpa Rana, Raj Kumar, M. Bhuyan
The study aims to explore the mechanism of heavy-ion fusion using various effective nucleon-nucleon (NN) interactions and nuclear density distributions. The nuclear potentials are…
Spectro-Polarimetric Study of Weakly Magnetized Neutron Star X-ray binary GX 349+2
Raj Kumar, Subhasish Das
We report the first spectro-polarimetric investigation of the bright Z-type source GX 349+2 using simultaneous observations of \textit{IXPE}, \textit{NuSTAR} and \textit{Swift/XRT}…
On harmonic convolutions involving a vertical strip mapping
Raj Kumar, Sushma Gupta, Sukhjit Singh +1
Let f_β= h_β+\bar{g}_βand F_a = H_a +\bar{G}_a be harmonic mappings obtained by shearing of analytic mappings h_β+g_β= 1/(2i\sinβ)log((1 + ze^{iβ})/(1 + ze^{-iβ})), 0<β<υ
Reply to the "Comment on `Effect of density and nucleon-nucleon potential on the fusion cross section within the relativistic mean field formalism'"
M. Bhuyan, Raj Kumar, Shilpa Rana +3
In reply to the Comment made by M. V. Chushnyakova et al. on our paper [Phys. Rev. C 101, 044603 (2020)], we argue that the calculations, results and conclusions of our paper remai…
Fusion dynamics of C+C reaction: An astrophysical interest within the relativistic mean-field approach
Shilpa Rana, Raj Kumar, M. Bhuyan
The C+C fusion reaction plays a significant role in the later phases of stellar evolution. For a better understanding of the evolution involved, one must understand t…
Exploring the effect of positive Q-value neutron transfer in coupled-channels calculations using microscopic nuclear potentials
N. Jain, M. Bhuyan, P. Mohr +1
We investigated the effect of the degree of freedom of neutron transfer on the cross section of heavy-ion fusion reactions, using the relativistic mean-field formalism within the c…
Effect of isovector scalar meson on equation of state of dense matter within relativistic mean field model
Virender Thakur, Raj Kumar, Pankaj Kumar +5
The effects of the isovector-scalar -meson field on the properties of finite nuclei, infinite nuclear matter and neutron stars are investigated within the Relativistic Mean Fie…
Role of nuclear deformation and orientation about symmetry axis of target nucleus on heavy-ion fusion dynamics
Shilpa Rana, M. Bhuyan, Raj Kumar +1
Nuclear shape and orientation degrees of freedom are incorporated into the calculation of the double-folding nuclear potential within the relativistic mean-field (RMF) formalism. T…
Control of skyrmion chirality in Ta/FeCoB/TaOx trilayers by TaOx oxidation and FeCoB thickness
Raj Kumar, Charles-Elie Fillion, Bertrand Lovery +10
Skyrmions are magnetic bubbles with nontrivial topology envisioned as data bits for ultrafast and power-efficient spintronic memory and logic devices. They may be stabilized in hea…
Isospin dependent properties of the isotopic chain of Scandium and Titanium nuclei within the relativistic mean-field formalism
Praveen K. Yadav, Raj Kumar, M. Bhuyan
The density-dependent nuclear symmetry energy is directly related to the isospin asymmetry for finite and infinite nuclear systems. It is critical to determine the coefficients of…