arXiv subjects

Manoj K. Sharma

Publications and source records attributed to Manoj K. Sharma.

7 recordsLinked to original sources

arXiv2026

Exploring $β^+$ decay/EC residues in $^{118}$Sn($^{12}$C,x)$^{130}$Ba reaction

The fusion cross-sections of $^{126}$Ba, $^{127,126,125}$Cs, $^{125,123,122}$Xe and $^{124,123}$I residues, populated via $x$n, p$x$n, $α$$x$n, and $α$p$x$n channels, have been measured in $^{12}$C+$^{118}$Sn system at E$_{\textrm{lab}}$ $\approx$ 65-85 MeV using offline $γ$-spectroscopy. To gain insights into the formation and decay modes of these residues, experimentally measured cross-sections have been analyzed using the statistical model codes PACE4 and EMPIRE. In the analysis, the cross-sections of p$x$n ($^{127,126,125}$Cs), $α$xn ($^{125}$Xe), and $α$p$x$n ($^{123}$I) channels are substantially fed from their higher charge isobars via $β^+$ decay and electron capture. The contribution of $β^+$ decay and electron capture has been calculated using the prescription of Cavinato $et$ $al.$\cite{cavinato1995study} and the independent cross-sections of these residues have been compared with PACE4 and EMPIRE calculations, which fairly reproduce the independent cross-sections of evaporation-residue within the experimental uncertainties. Interestingly, it has been observed that the $α$-emitting channels, contrary to established findings in reactions involving $α$ cluster projectiles (e.g., $^{12}$C, $^{16}$O, etc.) at the studied energy range, display negligible or no contribution of incomplete fusion (ICF) in $^{12}$C+$^{118}$Sn system. The absence of ICF has been verified through a complementary experiment in which the forward recoil ranges of $^{126}$Ba(4n) and $^{125}$Xe($α$n) channels have been measured. Present measurements reveal anomalous suppression of ICF in the $^{12}$C+$^{118}$Sn system, providing new constraints on entrance-channel mass-asymmetry systematics absent in prior data.

nucl-ex↗

arXiv2019

Role of Neutron Transfer in Sub-Barrier Fusion

Fusion excitation function of $^{35}$Cl + $^{130}$Te system is measured in the energy range around the Coulomb barrier and analyzed in the framework of the coupled-channels approach. The role of projectile deformation, nuclear structure, and the couplings of inelastic excitations and positive Q$-$value neutron transfer channels in sub-barrier fusion are investigated through the comparison of reduced fusion excitation functions of $^{35,37}$Cl +$^{130}$Te systems. The reduced fusion excitation function of $^{35}$Cl + $^{130}$Te system shows substantial enhancement over $^{37}$Cl + $^{130}$Te system in sub-barrier energy region which is attributed to the presence of positive Q-value neutron transfer channels in $^{35}$Cl + $^{130}$Te system. Findings of this work strongly suggest the importance of +2$n$ - transfer coupling in sub-barrier fusion apart from the simple inclusion of inelastic excitations of interacting partners, and are in stark contrast with the results presented by Kohley \textit{et al.}, [Phys. Rev. Lett. 107, 202701 (2011)].

nucl-ex↗

arXiv2017

Restoration of Topological Surface State by Vacuum Annealing in Magnetically Doped Topological Insulator

The introduction of magnetic order on the surface of topological insulators in general breaks the two-dimensional character of topological surface state (TSS). Once the TSS disappears, it is improbable to restore the topological surface properties. In this report, we demonstrate that it is possible to restore the inherent TSS by ultra-high vacuum annealing. Starting from an antiferromagnetic Gd-doped Bi2Te3, that has surface state gap without TSS properties, after annealing we observed the gap closing as well as typical TSS features in physical properties. The microscopic mechanism of atomic migration and TSS restoration by annealing process is unraveled by the combination of scanning tunneling microscopy measurements and density functional theory calculations. This approach to control the surface of topological insulators and stabilize the TSS simply by vacuum annealing provides a new platform towards the exploitation of their topological properties.

cond-mat.mtrl-sci↗

arXiv2015

Decay analysis of compound nuclei with mass A$\sim 30-200$ formed in the reactions involving loosely bound projectiles

The dynamics of the reactions forming compound nuclei using loosely bound projectiles is analysed within the framework of dynamical cluster decay model (DCM) of Gupta and Collaborators. We have analysed different reactions with $^{7}Li$, $^{9}Be$ and $^{7}Be$ as neutron rich and neutron deficient projectiles, respectively, on different targets at the three $E_{lab}$ values, forming compound nuclei within the mass region A$\sim 30-200$. The contributions of light particles LPs ($A\le4$) cross sections $σ_{LP}$, energetically favoured intermediate mass fragments IMFs ($5 \le A_2 \le 20$) cross sections $σ_{IMF}$ as well as fusion-fission $\it{ff}$ cross sections $σ_{ff}$ constitute the $σ_{fus}$ (=$σ_{LP}$+$σ_{IMF}$+$σ_{ff}$) for these reactions. The contribution of the emitted LPs, IMFs and ff fragments is added for all the angular momentum upto the $\ell_{max}$ value, for the resepctive reactions. Interestingly, we find that the $ΔR^{emp}$, the only parameter of model and uniquely fixed to address the $σ_{fus}$ for all other reactions having $\it same$ loosely bound projectile at the chosen incident energy. It may be noted that the dynamical collective mass motion of preformed LPs, IMFs and ff fragments or clusters through the modified interaction potential barrier are treated on parallel footing. We see that the values of modified interaction barrier heights $ΔV_{B}^{emp}$ for such reactions are almost of the same amount specifically at the respective $\ell_{max}$ values.

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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.

nucl-th↗

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.

nucl-th↗

arXiv2011

Temeprature-dependent Seeger's liquid drop energy for nuclei up to Z=118

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 (g.s.) binding energies of nuclei within a precision of <1.5 MeV and for nuclei up to Z=118. The aim is to include the temperature T-dependence on experimental binding energies, and not to obtain the new parameter set of Seeger's liquid drop energy VLDM . Our proceedure is to define the g.s. binding energy B = V_{LDM} + δU, as per Strutinsky renormalization procedure, and using the empirical shell corrections δU of Myers and Swiatecki, fit the constants of V_{LDM} to obtain the experimental binding energy Bexpt or theoretically calculated Btheo if data were not available. The T-dependence of the constants of V_{LDM}, is introduced as per the work of Davidson et al., where the pairing energy δ(T) is modified as per new calculations on compound nucleus decays. The newly fitted constants of V_{LDM} at T=0 are made available here for use of other workers interested in nuclear dynamics of hot and rotating nuclei.

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