Nuclear masses play a crucial role in both nuclear physics and astrophysics, driving sustained efforts toward their precise experimental determination and reliable theoretical prediction. In this work, we compile the newly measured masses for 296 nuclides from 40 references published between 2021 and 2024, subsequent to the release of the latest Atomic Mass Evaluation. These data are used to benchmark the performance of several relativistic and non-relativistic density functionals, including PC-PK1, TMA, SLy4, SV-min, UNEDF1, and the recently proposed PC-L3R. Results for PC-PK1 and PC-L3R are obtained using the state-of-the-art deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc), while the others are adopted from existing literature. It is found that the DRHBc calculations with PC-PK1 and PC-L3R achieve an accuracy better than 1.5 MeV, outperforming the other functionals, which all exhibit root-mean-square deviations exceeding 2 MeV. The odd-even effects and isospin dependence in these theoretical descriptions are examined. The PC-PK1 and PC-L3R descriptions are qualitatively similar, both exhibiting robust isospin dependence along isotopic chains. Finally, a quantitative comparison between the PC-PK1 and PC-L3R results is presented, with their largest discrepancies analyzed in terms of potential energy curves from constrained DRHBc calculations.
Elastic scattering between $\alpha$-particles and $^{12}\mathrm{C}$ nuclei plays a crucial role in understanding resonance phenomena in light nuclear systems. In this work, we construct inverse potentials for resonant states in $\alpha$-$^{12}\mathrm{C}$ elastic scattering using the variable phase approach, in tandem with a genetic algorithm based optimization technique. The reference function for the potential in the phase equation is chosen as a combination of three smoothly joined Morse-type functions. The parameters of the reference function are genetically evolved to minimize the the mean squared error (MSE) between the numerically obtained scattering phase shifts and the expected values. The resulting inverse potentials accurately reproduce the resonance energies ($E_r$) and the resonance widths ($\Gamma_r$) for the $\ell^{\pi}$ states, $1^-$, $2^+$, $3^-$, and $4^+$, showing excellent agreement with experimental data. This computational approach to constructing inverse potentials serves as a complementary to conventional direct methods for investigating nuclear scattering phenomena.
We investigate the production of the as-yet-undetected true muonium within the quark-gluon plasma formed in relativistic heavy-ion collisions, employing a relativistic Boltzmann transport framework coupled to viscous hydrodynamic simulations. The obtained effective cross sections for central collisions are 1.23~$\mu b$ in AuAu collisions with $\sqrt{s_{\rm NN}}=200$~GeV and 14.2~$\mu b$ in PbPb collisions with $\sqrt{s_{\rm NN}}=5.02$~TeV, resulting in a yield of $\mathcal{O}(10^4)$ and $\mathcal{O}(10^5)$ true muonium per billion $AA$ collisions at RHIC and the LHC, respectively. This establishes heavy-ion collisions as a promising process for detecting true muonium.
The heavy and superheavy elements of the periodic table predominately disintegrate by {\alpha}-decay, facilitating transitions mainly between ground states and occasionally involving isomeric states. This study focuses on estimating the half-lives of {\alpha}-transitions both from and to isomeric states, using a recently refined formula which shows excellent agreement with experimental data when isospin of parent nucleus as well as angular momentum taken away by the {\alpha} particle are incorporated. These findings provide valuable insights for upcoming experimental investigations of isomeric states. Additionally, the study predicts potential {\alpha}-decay in several yet-unobserved isomeric nuclei, contributing to a deeper understanding of nuclear structure in heavy and superheavy elements.
The $\beta$-decay half-lives of nuclei are sensitive to the values of $Q_{\beta}$. For accurate theoretical predictions, it is essential to develop an effective interaction or an energy density functional (EDF) that can systematically reproduce experimental $Q_{\beta}$ values. The challenge lies in identifying an appropriate EDF for an accurate $Q_{\beta}$ prediction. To address this, we focus on the bulk properties of nuclei that have correlations with $Q_{\beta}$. The primary objective of this study is to determine which nuclear bulk properties are sensitive to $Q_{\beta}$, providing information on the key nuclear characteristics that influence $\beta$-decay calculations. We employ the Skyrme energy-density functionals to find correlations between $Q_{\beta}$ and the nuclear bulk properties, assuming spherical symmetry. Using $42$ different Skyrme EDFs, we analyze these correlations by evaluating Pearson linear coefficients, focusing particularly on the relationship between $Q_{\beta}$ and various nuclear properties. We found that the symmetry energy at low densities shows a correlation with the $Q_{\beta}$ value. In particular, this correlation becomes stronger for functionals with an effective mass close to $1$. However, as the nuclear density increases, the correlation weakens. From our analysis, we found that a symmetry energy of $32.8\pm0.7$~MeV and effective mass of $m^{*}/m\ge0.75$ at the saturation density is the most likely to systematically reproduce the experimental data of $Q_{\beta}$ systematically.
We investigate the causality and stability of the relativistic theory of magnetohydrodynamics derived in Phys. Rev. D 109, 096021 (2024) to describe a locally neutral two-component plasma of massless particles. We show that this formalism is linearly causal and stable around global equilibrium, for any value of the magnetic field and discuss its qualitative differences to the traditional Israel-Stewart formalism in the linear regime. Finally, we compare this framework with the magnetohydrodynamic model used in the study of astrophysical plasmas, in which only the longitudinal component of the shear-stress tensor is considered. We discuss the domain of applicability of this type of framework in the context of ultrarelativistic heavy-ion collisions.
The arguably most promising avenue towards testing physics beyond the Standard Model in the anomalous magnetic moment of the $\tau$ proceeds via suitably constructed asymmetries in $e^+e^-\to\tau^+\tau^-$ in the presence of a polarized electron beam. Such a program, as could be realized at Belle II assuming a polarization upgrade of the SuperKEKB $e^+e^-$ collider, crucially relies on a careful consideration of radiative corrections. In this work, we present the complete one-loop result for the fully polarized $e^+e^-\to\tau^+\tau^-$ process and its implementation in the Monte-Carlo integrator McMule. As an application, we discuss projections relevant for measurements at Belle II, both with and without electron polarization, and outline the necessary steps for a generalization to next-to-next-to-leading order.
We perform a comprehensive study of the $3+3$ Type-I seesaw model for a broad range of right-handed mass scales (from keV to 10 TeV). We take into account and, in some cases, update the constraints from a large number of high- and low-energy experiments and study the implications on neutrino-less double beta ($0\nu\beta\beta$) decay experiments. We illustrate our findings through profile likelihood plots for the half-life $T_{1/2}^{0\nu}$ and two-dimensional plots correlating $T_{1/2}^{0\nu}$ to neutrino masses. We find that in this simple class of models for Majorana neutrino masses, current and next-generation $0\nu\beta\beta$ decay experiments have a broad discovery potential in both the normal and inverted orderings of the spectrum of light active neutrinos.
High-spin spectroscopic study of $^{202}$Po ($Z$ = 84, $N$ = 118) has been carried out using the $^{195}$Pt($^{12}$C, 5n)$^{202}$Po fusion-evaporation reaction. An extended level scheme has been proposed up to an excitation energy of $E_x\approx$ 8 MeV and angular momentum of 27$\hbar$, with the addition of 57 newly observed $\gamma$-ray transitions, along with the revisions in the placement of 8 already known transitions and the multipolarities of 4 of these transitions. The energy of the unobserved 8$^+ \rightarrow 6^+$ transition has been proposed to be 9.0(5) keV, which resolves the uncertainty in the excitation energy of the levels above the 6$^{+}$ state. Three new sequences of $M1$ transitions have also been identified in the high excitation energy regime and included in the proposed level scheme. The large-scale shell model calculations for $Z>82$ and $N<126$ valence space have been carried out using PBPOP interaction which explained the overall level scheme for both the positive and negative parity states. The calculations successfully reproduced the purity of the proton $\pi h_{9/2}$ dominated $8^+$ isomeric state, and also explained the missing $E2$ decay of the ${12}^+$ isomeric state in terms of changing nucleonic configurations.
Recent analyses on the properties of the central compact object in the HESS J1731-347 remnant and the PSR J1231-1411 pulsar indicated that these two compact objects are characterized by similar (low) masses and possibly different radii. This paper aims at reconciling the aforementioned measurements by utilizing the widely employed color-flavor locked (CFL) MIT bag model. The main objective is related to the examination of the acceptable values for the color superconducting gap $\Delta$ and the bag parameter $B$. Furthermore, our analysis involves two distinct hypotheses for the nature of compact stars. Firstly, we considered the case of absolute stability for strange quark matter and we found that it is possible to explain both measurements, while also respecting the latest astronomical constraints on the masses and radii of compact stars. Secondly, we studied the case of hybrid stellar matter (transition from hadrons to quarks), and concluded that, when early phase transitions are considered, the simultaneous reconciliation of both measurements leads to results that are inconsistent to the existence of massive compact stars. However, we showed that all current constraints may be satisfied under the consideration that the HESS J1731-347 remnant contains a slow stable hybrid star.