arXiv subjects

Sukhjeet Singh

Publications and source records attributed to Sukhjeet Singh.

3 recordsLinked to original sources

arXiv2025

Features of Two-Quasiparticle Rotational Bands in Deformed Odd-Odd Nuclei, $156 \le A \le 168$

In present work, we evaluated the experimental data pertains to two quasiparticle rotational structures in deformed odd-odd nuclei in rare earth mass region. The compilation includes total 234 rotational bands among which 173 are rotational bands and 61 bandhead states. Gallagher Moszkowski doublets are identified for 63 two quasiparticle configurations which provide a good testing ground for np residual interaction systematics. The highest excitation energies reach approximately 18 MeV in 164Lu and 168Lu nuclide. The triplet configuration becomes ground state in case of 22 nuclides namely 156-170Ho, 156-176Tm and 162-168Lu. Signature splitting is reported for 76 bands and signature inversion is identified in 29 bands which indicate the presence of Coriolis couplings and evolving configuration mixing with spin. The average signature splitting amplitudes lies between 12 to 300 keV. Band crossings have been observed in case of 10 bands, often accompanying changes in the kinematic and dynamic moments of inertia as paired high-j quasiparticles align with the rotational axis. Halflife information is available for 58 bandhead. The branching ratios and effective gfactors remain scares. In total, 137 bands display regular level sequences of energy levels whereas 8 exhibit irregular patterns. The present evaluation of two quasiparticle rotational bands reveals substantial gaps in the experimental data and highlight the need of fresh measurements to support rigorous calculations and reliable systematics.

nucl-th↗

arXiv2025

Modelling and Systematics of $\tfrac{1}{2}[521]\,ν$ Quasiparticle Rotational Bands in $N = 99,\;101,\;103$ Isotonic Chains

We analyze the $\tfrac{1}{2}[521]\,ν$ quasiparticle rotational bands along the $N = 99,\;101,\;103$ isotonic chains using semi-empirical model in which first and higher order Coriolis terms are treated perturbatively. A dedicated Python routine optimizes five parameters bandhead energy, inertia A, decoupling a, and Coriolis coefficients B and C for each nucleus. The calculations match experimental level spacings to within 5 keV. Staggering keeps a common phase across the three chains yet grows with spin and, on average, with both neutron and proton number. The inertia parameter rises smoothly with Z (e.g., A for N = 99: 10.6 to 12.4 keV), signaling a decrease in the moment of inertia as axial deformation weakens. Decoupling parameter a increases and then saturates for N = 99 and 103, indicating purer K = 1/2 structure at high Z; the N = 101 chain shows the opposite trend, pointing to stronger configuration mixing. The first order Coriolis term B becomes increasingly negative with Z, whereas the higher order term C shows chain specific sign changes. The present work, explore the dynamics of various physical parameters associated with ν1/2[521] quasiparticle rotational bands and helps to understand observed signature effects.

nucl-th↗

arXiv2025

Review of magnetic- and antimagnetic-rotational structures in nuclei

This work is an update of the 2000 publication of magnetic-rotational bands by Amita et al. [1], followed by an unpublished update of 2006 [2], and reviews detailed experimental data extracted from original publications for 228 magnetic-rotational (MR or Shears) structures spread over 117 nuclides, and 40 antimagnetic-rotational (AMR) structures in 28 nuclei, with a brief commentary about each band. Many of these nuclei are located at or near the semi-magic nucleon numbers, mostly for protons. For example, 88 MR bands are currently known for the Pb (Z=82) nuclei, and 29 AMR band in Pd, Cd and In nuclei. It is interesting that the proton magic numbers appear to play a major role in the MR phenomenon, which seems less well understood. A brief discussion of the salient features of the MR and AMR bands and their theoretical interpretation has been presented in the present review. The tables contain gamma-ray energies, associated level energies with spins and parities, level lifetimes, B(M1), B(E2), and B(M1)/B(E2) ratios and probable spherical quasiparticle configurations. We find that many bands claimed in the literature as MR and AMR bands still have tentative assignments, as level lifetimes, thus B(M1) and B(E2) values, for a large number of MR and AMR bands, which can potentially provide critical criteria for firm identification of such structures, are lacking. Additionally, theoretical model calculations for many of these bands, which could provide insight for a better description of nuclear structure, are also lacking in literature. While this review is mainly based on original research articles, nuclear structure databases ENSDF [3], XUNDL [4], and NSR [5] have been consulted for completeness. The literature cut-off date March 31, 2025.

nucl-th↗