abstract

Neutron-induced reactions on \(^{60}\)Ni were examined to study nuclear reaction mechanisms and provide a comparison with nuclear models. The analysis is based entirely on previously published experimental data, from charged-particle detection at Peking University to \(\gamma \)-ray spectroscopy at the Los Alamos Neutron Science Center/Weapons Neutron Research (LANSCE/WNR) facility. Charged-particle detection provides direct insight into \(\alpha \)-particle cross sections at lower energies, while the \(\gamma \)-ray measurements allow for a reliable determination of total cross sections for residual even–even isotopes at higher energy ranges. Experimental cross sections for the \(^{60}\)Ni\((n, X)^{54,55,56,57}\)Fe reactions were collected from the Experimental Nuclear Reaction Data (EXFOR) database and compared with the newest Evaluated Nuclear Data Files (ENDF): JENDL-5, ENDF/B-VIII.1, TENDL-2023, and theoretical predictions from TALYS 2.0 extended to intermediate energies \(\sim 240\) MeV. TALYS 2.0 successfully reproduces the shape of the energy dependence of the total cross section for selected \(\alpha \)-emission channels within the theoretical uncertainty band, except for the \(^{60}\)Ni\((n, 4n2p)^{55}\)Fe channel, while the multi-nucleon emission channels at high incident-neutron energies are also in good agreement with the TALYS 2.0 predictions above \(\sim 180\) MeV.

abstract

We argue that modular classes of \(Q\)-manifolds provide an efficient method for addressing the existence of supersymmetric Berezin volumes in the supergeometric representation theory of the \(\mathcal {N}=2\) \(d=1\) supertranslation algebra. We establish a cohomological coherence criterion for the existence of a Berezin volume that is invariant under both of the supercharges.

abstract

We develop a unified microcanonical formulation for \(N\) noninteracting particles with an arbitrary number \(p\) of equally spaced local energy levels, \(0,\varepsilon ,2\varepsilon ,\dots ,(p-1)\varepsilon \). The exact microcanonical multiplicity is expressed as a coefficient of a local generating function, providing a finite-\(N\) representation that can also be systematically analyzed in the thermodynamic limit. By converting this coefficient extraction into a contour integral and applying saddle-point analysis, we obtain analytical expressions for the entropy per particle \(s(u,p)\) and the inverse temperature \(\beta (u,p)\), where \(u=E/(N\varepsilon )\in \left [ 0,p-1\right ] \). The main result is a single arbitrary-\(p\) solution that contains the two-level and three-level systems as special cases and connects them continuously to the unbounded limit \(p\rightarrow \infty \). For every finite \(p\), the upper spectral bound produces an entropy maximum at \(u_\mathrm {c}=(p-1)/2\), where the inverse temperature vanishes and the positive-temperature branch changes into a negative-temperature branch. As \(p \) increases, this characteristic energy is displaced toward higher values, and in the limit \(p\rightarrow \infty \) the upper bound is removed, the finite-energy entropy maximum disappears, and only positive temperatures remain. The formulation therefore provides an analytically controlled description of the crossover between bounded- and unbounded-spectrum thermodynamics. Beyond the present model, the method supplies an exact microcanonical template for discrete additive systems whose local spectra can be encoded by generating functions, including finite-level quantum and spin systems.

abstract

In this paper, the properties of Quark–Gluon Plasma (QGP) are investigated by studying the production rate of diphotons as a function of their invariant mass. Since diphotons are non-interactive constituents and carry information from initial phase to final phase, they are treated as a special probe. The current work is an extension of Kumar et al. [Phys. Scr. 96, 124060 (2021)], in which thermal quark mass is utilized. Considering parton’s thermal interactions, we use a phenomenological quasi-particle approach which combines a thermally generated mass, the current mass, and a term connecting the two, which is used as effective quark mass. The effective quark mass replaces the role of the thermal quark mass, and the resulting diphoton production rate spectra are in good agreement with those obtained in previous theoretical studies. The model results serve as a benchmark for evaluating diphoton yields across different quasi-particle treatments. Therefore, the modified quasi-particle model does not invalidate the calculation of the diphoton production rate and helps us better understand the evolution of the QGP through its electromagnetic signals by providing a framework for studying experimental data from heavy-ion collisions at RHIC and the LHC.

abstract

We examine spin-polarized Strange Quark Matter and the complex structure of Strange Quark Stars in the presence of a strong magnetic field. Our framework uses a quasiparticle model, enhanced by a QCD-informed effective quark mass dependent on both chemical potential value and magnetic field strength. The resulting Equation of State yields an energy per baryon below the iron limit, supporting the hypothesis that the actual ground state of matter is a strange matter. By solving the Tolman–Oppenheimer–Volkoff expressions, we find that the maximum stellar mass decreases with the degree of spin polarization, reaching as high as \(2.35~M_\odot \) with a related radius 12.33 km. Furthermore, the model’s predictions for mass, radius, and surface redshift are in excellent conformance to observational limitations for the massive pulsar PSR J0952-0607. These results highlight the crucial role of quasiparticle medium effects and strong magnetic fields in describing dense matter.