abstract

The study of the process of particle creation in high-energy nucleon–nucleon and nucleus–nucleus collisions heavily relies on the pseudorapidity distribution (PD) of charged particles. Several theoretical theories and concepts may frequently be tested using the multiplicity distributions (MD) and PD of final-state particles. In this work, we have utilized PD to investigate potential processes that might produce the fast target protons (FTP) released from the interactions of \(^{84}\mathrm {Kr}\) with emulsion at 1 \(A\) GeV. In order to examine the properties of the FTP emitted system for various targets (such as AgBr, CNO, and Em) of the nuclear emulsion detector (NED), the angular distribution (AD) and PD of the generated FTP were examined.

abstract

In this article, we propose a unified framework for cosmological expansion and inflation at the level of background dynamics, by modeling both the inflaton field and dark energy as a four-dimensional continuous medium, whose elastic deformation is described by a covariant vector field. Focusing on homogeneous and isotropic background cosmology, we show that for a bulk modulus \(K = 1.64 \times 10^{109}~\mathrm {N}\,\mathrm {m}^{-2}\), the dark-energy density decreases by a factor of \(\sim 10^{122}\), while the scale factor expands \(10^{28}\) times over \(\sim 10^{-42}\) seconds during primordial inflation. For illustrative parameter values, our analysis suggests three potential new physical phenomena for future investigation, including longitudinal elastic modes, frequency redshifts in early-universe light, and improved fits to supernova curves. At the end of the paper, we discuss the challenges of applying the framework to inflationary perturbations, particularly the need for a consistent theory capable of producing a nearly scale-invariant power spectrum, as well as of addressing reheating, and identifying these as key directions for future work.

abstract

The Leggett–Garg inequality (LGI), an analogue of Bell’s inequality involving correlations of measurements of one observable on a system at different times, stands as one of the hallmark tests of quantum mechanics against classical predictions. In this work, we investigate its implications in the context of neutrino flavour (\(\nu _{e}^{\rm L}\leftrightarrow \nu _{\mu }^{\rm L}\)) and spin (\(\nu _{e}^{\rm L}\leftrightarrow \nu _{e}^{\rm R}\)) oscillations in the presence of a constant transverse magnetic field. For systems with strong magnetic fields, we show that, for both cases, there are length regions \(\Delta L\) where the LGI is violated, as quantified by the correlator functions \(K_3\) and \(K_4\).

abstract

In this study, we present an improved formulation for calculating (\(p,n\)) reaction cross sections at a proton energy of 12.4 MeV. This new approach is based on updated experimental data (EXFOR 2026), a revised compilation of non-elastic cross sections using the TALYS nuclear reaction code, and a re-evaluation of the empirical adjustment parameters. The proposed model builds upon the work of Broeders and Konobeyev (2008) and integrates key theoretical elements of the compound nucleus regime, including the semi-empirical mass formula and the statistical evaporation model. Comparisons with TALYS calculations, which include both statistical and pre-equilibrium contributions, demonstrate the validity of our approach at 12.4 MeV, where compound nucleus mechanisms dominate. The revised six-parameter formulation demonstrates excellent agreement with the latest experimental data and yields significantly reduced values for the statistical deviation metrics \({\mit \Sigma }\) and \(\chi ^2\). This work contributes to the refinement of nuclear reaction models and provides a reliable tool for cross-section prediction in applied and fundamental nuclear science.

abstract

We study the thermodynamics of the quark–gluon plasma using an effective 2-flavor Polyakov–Nambu–Jona-Lasinio (PNJL) model extended by a quasiparticle description for quarks and gluons, incorporating temperature-dependent quark masses within the PNJL framework. Two variants, Quasiparticle Model-I and Quasiparticle Model-II, are implemented to investigate bulk thermodynamic observables such as pressure, energy density, entropy density, specific heat, and the speed of sound. The combined framework yields a robust baseline for the description of hot QGP dynamics in the high-temperature regime at vanishing chemical potential and zero magnetic field. Systematic comparison with lattice QCD results shows excellent agreement and a clear improvement over conventional PNJL implementations. We observe that both variants complement each other, offering mutually consistent insight into quasiparticle mass effects and medium response in the deconfined phase. This mutual consistency validates the physical foundation of the overall quasiparticle mechanism, reinforcing the credibility of the calculated Equation of State. Finally, the quasiparticle model extension improves PNJL from a descriptive tool to a more qualitative phenomenological approach, enabling an improved description of the strongly interacting quark–gluon plasma.

abstract

We study free open fermionic strings on a non-commutative phase-space. Modified super-Virasoro algebras in both the Ramond and Neveu–Schwarz sectors acquire non-commutativity anomalies, and this non-commtativity breaks also the Lorentz symmetry and give a non-diagonal mass operator. Redefining the Fock space diagonalizes the mass operator. Extra constraints on non-commutativity parameters cancel the anomalies, restore the standard spectrum, and make the GSO projection possible.