The low-lying level structure of 80Se was investigated via the 76Ge(9Be,2p3n) reaction at Elab ≈ 31 MeV using a Compton-suppressed HPGe clover array, and level lifetimes were measured with the Doppler-shift attenuation method. Measured excitation energies and B(E2) transition strengths are reasonably well reproduced by Interacting Boson Approximation (IBA) calculations. The observed excitation-energy and transition-strength patterns associated with the σ=5 and σ=3 representations, together with candidate members of the σ=1 representation, exhibit pronounced O(6)-like collective behavior in this five-boson system. The combined experimental observables and finite-boson IBA calculations indicate a surprisingly good correspondence with O(6) expectations for these selected collective structures. At the same time, the presence of low-lying 02+ and 23+ states that are not consistently accommodated within the same classification, together with a finite B(E2;03+→21+) strength, demonstrates that the O(6) limit does not provide a complete description of the low-energy spectrum. We therefore interpret the present results as evidence for pronounced O(6)-like collective structures embedded within a more complex nuclear structure of 80Se.
In this paper we test Non-Conservative Conformal Killing Gravity (NC-CKG), a geometric extension of general relativity in which the cosmological constant arises as a constant of integration and the energy-momentum tensor is allowed to deviate from covariant conservation through an effective coupling parameter, τ. We constrain the model with a Bayesian MCMC analysis combining Cosmic Chronometers, DESI DR2 baryon acoustic oscillations, and three Type Ia supernova compilations (Pantheon+, Union3, and DES-Dovekie). Across all dataset combinations, τ remains consistent with zero, with only a mild tendency toward negative values. A negative τ corresponds to a faster dilution of the pressureless matter density than the standard a−3 scaling, while the current data do not provide statistically significant evidence for a departure from matter conservation. The conformal-Killing density parameter ΩD is negative in all dataset combinations, while the resulting expansion history gives transition redshifts in the range zt ≈ 0.68–0.74. When the SH0ES local distance-ladder calibration is included, the model gives H0=72.85±0.98kms−1Mpc−1. This high value is not driven by the additional freedom in τ, since flat ΛCDM and conservative CKG give comparable constraints under the same calibration. Model selection via AIC and BIC generally favours the conservative limit (τ=0) or ΛCDM over the full non-conservative model. Overall, NC-CKG remains a geometrically motivated alternative to dark energy, although current background-expansion data do not require non-conservation. Future observations will provide stronger tests of the model.
The growing evidence for nanohertz gravitational waves, from NANOGrav and other observations, may be pointing to a cosmological first-order phase transition at temperatures of O(10−100)MeV. Such an interpretation requires beyond the Standard Model dynamics in this energy range. If so, it may well be the case that galactic core-collapse supernova explosions would produce the key components related to the first-order phase transition, leaving detectable imprints on the spectrum of neutrinos emitted in the initial few seconds of the collapse. This might provide further evidence in support of the early universe interpretation of the nanohertz gravitational wave signal. The scenario proposed here is also suggestive of a low-mass seesaw mechanism to explain neutrino masses. We outline the prospects for future observations of Galactic supernovae to uncover the signals of this scenario, with further confirmation from future pulsar timing array measurements of primordial nanohertz gravitational waves.
We solve the radical-square reflection residual of the symmetric elliptic free-fermion eight-vertex model in a minimal four-dimensional local coefficient algebra. Two parity-odd tangent channels generate an ordered product in the square of the radical, and the reflection equation fixes its parity-even completion within the trace-fixed sector whose radical-square term starts at order u2. The resulting regular boundary object enters a double-row transfer construction. Its scalar quotient yields the open anisotropic XY Hamiltonian with diagonal boundary fields, while the full transfer object retains the non-semisimple boundary channels. Finite-chain audits through N=12 accompany the analytic construction.
A new measurement of the 2H(15C,3He)14B reaction was conducted to investigate proton shell evolution in neutron-rich carbon and boron isotopes. The experiment employed a radioactive beam of 15C with a higher energy at 28.3 MeV/u and a large acceptance charged particle detector array LACPU, enabling coincident measurement of high-lying unbound states in 14B that include π0p1/2-π0p3/2 transitions. A newly observed 3.45(35)-MeV resonance with a statistical significance of 3.1σ in 14B exhibits π0p1/2- rather than π0p3/2-dominant character according to structural model predictions. The extracted proton spectroscopic factor of 0.16 ± 0.06 for 15Cg.s. not only follows the systematic decreasing trend in neutron-rich carbon isotopes but also agrees with theoretical predictions, providing clear evidence for the Z = 6 magicity in 15C. Furthermore, systematic analysis of the energy splitting between the π0p3/2 and π0p1/2 orbitals in 12−14B reinforces the robustness of this magic number in neutron-rich nuclei systems.
We investigate the gravitational deflection of charged massive particles by a charged galactic wormhole supported by the Sofue dark matter density profile [56], ρ(r)=ρ0e−r/r0, where ρ0 and r0 denote the central dark matter density and the characteristic scale radius, respectively. This phenomenological profile models the dark matter distribution in galactic halos and acts as the matter source sustaining the wormhole geometry. Extending our previous investigation of light rays and neutral massive particles in this spacetime [57], we study the combined effects of gravitational and electromagnetic interactions on the motion of charged massive particles. The deflection angle is computed independently using the Rindler–Ishak method based on the Jacobi metric and the Gauss–Bonnet theorem, enabling a systematic comparison between the two approaches. We find that the predictions of the two methods become nearly indistinguishable in the relativistic regime, whereas the differences at lower velocities arise from the velocity-dependent correction terms proportional to (1−v2) in the trajectory equation. We further perform backward relativistic ray tracing of optically thin accretion flows around the charged galactic wormhole to investigate its shadow and photon-ring structure. Although the shadow remains circular because of the spacetime’s spherical symmetry, its radius, photon-ring structure, and intensity distribution exhibit a nontrivial dependence on the wormhole charge, providing potential observational signatures of charged galactic wormholes. These results provide new insights into the interplay between gravitational and electromagnetic interactions in charged wormhole spacetimes and their observational manifestations.
In this paper, we investigate the Krylov complexity of the massless scalar field in the massive Bañados-Teitelboim-Zanelli (BTZ) black hole with quantum fluctuation. This fluctuation is considered to be triggered by the Hawking radiation, which indeed influences the behavior of the time evolution of Krylov complexity. Our results show that Lanczos coefficients bn exhibit a black hole mass M-dependent staggering, ΔbN‾∼M, inducing oscillatory complexity dynamics that intensify with lower mass black holes. Moreover, the graviton mass m is found to suppress the oscillations but accelerate the late-time exponential growth K(t)∼eλKt. This study indicates that the Krylov complexity could be a sensitive probe to distinguish massless and massive gravity via operator growth signatures.
We investigate X(6900) as a hadronic realization of a gluonic portal between a dark sector and QCD. The analysis is updated using the 2026 CMS observation of a family of all-charm structures and a recent combined LHCb–ATLAS–CMS analysis of the di-J/ψ spectrum. The CMS angular analysis favors JPC=2++, motivating a spin-two mediator rather than the scalar ansatz used in earlier versions of this study. The combined analysis also demonstrates that the extracted X(6900) mass and width are significantly model dependent because of interference. We therefore use MX=6.919GeV and ΓX=70.3MeV as a reference benchmark, corresponding to the narrow-width, weak-interference Model I of the combined analysis, while treating the spread among interference models as a systematic theoretical uncertainty. The interaction isLint=−cχΛXμνTχμν−cgΛXμνTgμν.Using the standard spin-two normalization,Γ(X→gg)=cg2MX310πΛ2,and the gluonic gravitational form factor Ag(0), the leading spin-independent nucleon cross section isσχNSI=μχN2mχ2mN2π(cχcgΛ2MX2)2Ag(0)2.For Ag(0)=0.42, Bgg=0.10, and mχ=100GeV, the benchmark reference-scale estimate implies cχ/Λ≲1.87×10−8GeV−1 when the 90% C.L. XENONnT reference scale is imposed. The annihilation channel χχ¯→X*→gg is p-wave suppressed and resonantly enhanced at mχ≃MX/2=3.46GeV. We show that the most important phenomenological uncertainty is no longer the existence of X(6900), which is now highly significant, but the interpretation of its line shape and hence the extraction of its mass, width, and gluonic coupling. We argue that a small set of numerical figures is essential for a publication-quality presentation: the direct-detection exclusion plane, the resonance line shape, and the resonant annihilation line shape.
We study a quantum-corrected version of the Oppenheimer–Snyder (OS) spacetime in which classical collapse is modified by a single effective parameter α, representing small quantum gravitational effects in a phenomenologically rescaled form. Although the correction enters through a term proportional to αM2/r4, it produces noticeable changes in the strong-field region while leaving weak-field physics almost unchanged. One of the main results is the appearance of a minimum mass for horizon formation, Mmin∼(0.5−1.2)M⊙ for the effective parameter α ≈ 0.22. We emphasize that this Mmin is expressed in terms of the effective parameter α; in terms of the bare loop quantum gravity (LQG) parameter, Mmin∼MPl∼10−5 g, consistent with the theoretical expectation. Orbital properties are also slightly modified, with the innermost stable circular orbit (ISCO) shifting to rISCO=6M−α/(12M), giving corrections of order ∼10−4 for stellar black holes and ∼10−10 for Sgr A*. In the same region, radial epicyclic frequencies change by about 5%−10% near r ∼ 5M, while vertical modes are less affected, leading to small but structured shifts in quasi-periodic oscillation (QPO) behavior. Using four X-ray binaries (GRS 1915+105, XTE J1550-564, XTE J1859+226, GRO J1655-40), we find a consistent range α=0.22±0.10, with masses between 5.4−12.4M⊙ and emission radii r/M∼5.5−8.6. The observed QPO frequencies, lying in the range 100−450 Hz, are well reproduced within this framework. Weak-field tests such as S2 and Mercury still allow fsp=1.10±0.19, leaving room for these small strong-gravity corrections. This work demonstrates that while bare Planck-scale corrections are unobservable, effective rescaled parameters that encode the collective effect of quantum gravity can be constrained by current astrophysical observations.
A stationary surface response is formulated for an isolated, settled disk galaxy as a possible endpoint of deformation memory. The response is described by a scalar field coupled to the projected baryonic density, with a positive quadratic Hamiltonian and a finite range Green function constructed from the modified Bessel function K0. SPARC selects the long range regime, where the additional circular support follows the enclosed projected mass. Its normalization is fixed by the baryonic Tully–Fisher relation through a single acceleration scale. For 153 primary SPARC galaxies, the model gives a median relative rotation curve residual of 0.166, compared with 0.159 for the radial acceleration relation and 0.081 for NFW fits with two parameters for each galaxy. The inferred acceleration scale agrees with the canonical galactic value. Bootstrap resampling places the response and radial acceleration relation within the same population interval. Their predictions separate through their dependences on baryonic concentration, source mass, surface brightness, and gas fraction. These relations provide observational tests of an enclosed mass response as a description of galactic dynamics.
Inspired by the studies of Rahaman et al. [Eur. Phys. J. C (2018) 78, 948] and Chen et al. [Phys. Rev. D (2024) 109, 024010] which adopted dyon black hole and covariant loop quantum black hole solutions as effective descriptions of the solar exterior gravitational field and performed gravitational tests via Solar System planetary orbital motions, we adopt the exterior solution of a Schwarzschild black hole in modified gravity (MOG), which incorporates a dimensionless coupling parameter α, to describe the gravitational field of spherical celestial bodies and constrain this key parameter. We calculate the first-order post-Newtonian periastron precession of a timelike particle in this spacetime. Using observational data from five binary pulsars and Solar System measurements, we obtain small-scale constraints on the MOG coupling parameter at the α∼10−6−10−5 level, which provide independent weak-field tests of the Schwarzschild–MOG spacetime complementary to large-scale galactic gravity probes.
In the framework of modified teleparallel gravity, we study the neutrino flavor conversion. We show how the presence of spacetime torsion modifies both neutrino flavor oscillation and the matter-enhanced Mikheyev-Smirnov-Wolfenstein (MSW) resonance. Using data from solar neutrino experiments, we perform an analysis to place new bounds on the modified teleparallel model parameters and neutrino-torsion coupling. Our numerical results indicate that the resulting modifications to the neutrino survival probability may explain potential observational discrepancies in current and future observatories without invoking new physics or non-standard interactions.
Exactly elastic partial-wave constructions omit multiparticle flux. We compute the complete leading four-Goldstone cut generated by the O(p2) 2 → 4 amplitude in the massless, parity-even O(4)/O(3) Goldstone effective field theory (EFT); it enters elastic partial-wave unitarity at O(p8). For the custodial-vector wave the result is the consistency condition −Im(1/t11)=1+(5.0349±0.0003)×10−7(E/v)4+O(p6), where E is the center-of-mass energy, v the Goldstone decay constant, and the quoted uncertainty is numerical only. Any inelastic completion matching this massless pure-Goldstone EFT through O(p8) must reproduce this condition. Writing I and J for custodial isospin and angular momentum, four-body unitarity also gives the exact leading-order positive partial-wave sum rule AI=32π∑J(2J+1)CIJ, with CIJ ≥ 0 and I+J even; in the isovector channel, J=1 carries 88.17% of the production rate and J ≤ 3 carries 96.88%. Each AI is quoted for one normalized component of its custodial multiplet. Independent factorized-Sobol quasi-Monte Carlo and RAMBO phase-space Monte Carlo calculations agree for the custodial coefficients, the resolved odd-spin spectrum through J=15, and all ten representative charge-channel rates. Finite-mass electroweak observables and O(p10) production corrections lie beyond this calculation.
We formulate a unified theoretical framework for the fractional dynamics of graphene Dirac quasiparticles within the Riemann-Liouville (RL) fractional calculus approach. In this case, by starting from the fractional graphene Dirac equation, we derive an exact hydrodynamic formulation through the systematic construction of the density, current, and pseudospin evolution equations without applying perturbative assumptions or phenomenological approximations. Moreover, the fractional relativistic Langevin description is subsequently established to incorporate stochastic contributions into the relativistic hydrodynamic dynamics, allowing a consistent treatment of fluctuations in fractional quantum systems. Within this formulation, the corresponding fractional Fokker-Planck equation and relativistic stochastic Hamilton-Jacobi equation are derived, providing a complete statistical framework for analyzing fractional quantum transport processes. Also, the resulting hydrodynamic variables are then used to reconstruct the fractional graphene Dirac equation exactly, confirming the equivalence between the original spinor representation and the hydrodynamic description at the mathematical level. Furthermore, we introduce a fractional geometric hydrodynamic reconstruction operator and extend the developed formalism to curved spacetime in the RL framework, leading to a covariant description of fractional graphene dynamics in nontrivial geometries. In this context, this formulation provides a systematic theoretical structure connecting fractional relativistic quantum dynamics, stochastic transport mechanisms, and geometric hydrodynamic methods, enabling the investigation of nonlocal transport behavior and anomalous diffusion effects in graphene and other Dirac materials.
Symmetric Macdonald polynomials of N variables provide eigenfunctions of the N-body trigonometric Ruijsenaars-Schneider integrable system at particular eigenvalues. In order to construct eigenfunctions with arbitrary eigenvalues, M. Noumi and J. Shiraishi used a recursion in N (branching rule) for the symmetric Macdonald polynomials and analytically continued them. This generated a power series, which is a part of triad (universal solution). In the present paper, we demonstrate that a similar procedure is available for another integrable system, N-body Cherednik integrable system inspired by the DAHA of type A, which has non-symmetric Macdonald polynomials as its polynomial eigenfunctions. However, in this system, the generic eigenfunction is more complicated: it is not just a simple power series as in the Noumi-Shiraishi case, but has an involved structure with N! branches, each of them being a sum over the Weyl chambers of power series of the Noumi-Shiraishi type. As an illustration, we also provide explicit formulas for particular cases.
In this work, we investigate the dynamics of a relativistic spinless particle in a static charged black hole surrounded by quintessence (dark energy). We show that the radial equation can be written as a Heun-type equation and determine the quasibound states and energy quasispectrum. We find that a stronger quintessence field suppresses the radiation observed outside the event horizon, while lower the particle energy values ω and black hole mass M, or higher black hole charge Q, enhance the emission rate of positively charged particles. We also show that superradiance can occur under appropriate conditions. Furthermore, quintessence acts as an effective mass for the scalar field, causing the quintessence horizon to behave as a confining barrier. As a result, the radial modes become trapped, leading to the black hole bomb instability and/or the formation of stationary scalar clouds. Finally, in the limit α → 0, our results recover those of the Reissner–Nordström black hole.
We perform an observational and thermodynamic analysis of four cosmological models—ΛCDM, CPL, MPL, and the three-parameter MmAH parametrization. All dynamical models improve the fit relative to ΛCDM, with Δχ2 ∼ 6–6.5, with MPL providing the best fit, while MmAH remains viable. Although Bayesian evidence mildly favors ΛCDM due to its lower complexity, the dynamical dark-energy models remain competitive alternatives given current observations. We then reconstruct thermodynamic quantities within observationally constrained cosmological models, extending previous theoretical studies. The best-fit heat-capacity reconstruction indicates that the divergence associated with a second-order thermodynamic phase transition coincides with the deceleration-acceleration transition only in ΛCDM, whereas for the dynamical dark-energy models it occurs at distinct redshifts, suggesting that this coincidence is not universal. The generalized second law is satisfied for all models over 0 ≤ z ≤ 1, while the Hessian analysis reveals a transient instability at the phase transition; however, the late-time thermodynamic stability is model dependent, with CPL and MPL remaining stable and ΛCDM and MmAH failing to satisfy both stability conditions simultaneously. These results show that thermodynamic properties reconstructed within observationally constrained cosmological models provide a complementary probe of dark energy, with the thermodynamic phase transition emerging as an intrinsically model-dependent phenomenon.
In the synthesis of superheavy element (SHE) via heavy-ion fusion reactions, quasifission is one of the major factors hindering superheavy nuclei (SHN) formation and the mechanism behind this process is intricate. We investigate dynamics of quasifission in hot fusion reactions synthesizing SHN with Z=112–120 using microscopic time-dependent Hartree-Fock theory in a total of 18 reactions. Remarkably, the nucleon numbers of heavy fragments distribute closely around certain quantum shells in these reactions, highlighting the crucial role of shell effects in fragment formation. In the reactions with 48Ca, 45Sc, 50Ti and 51V projectiles, the formation of heavy fragment is dominantly driven by the double spherical shells of 208Pb. In contrast, the influence of the double octupole deformed shells at Z=88 and N=136 is more pronounced in 54Cr-induced reactions, resulting in a tendency of producing pear-shaped 224Ra heavy fragment. Moreover, in the reaction with a heavier projectile, the colliding system tends to undergo a more rapid quasifission. This may be responsible for significantly reduced fusion probability and synthesis cross section observed in the reactions with projectiles heavier than 48Ca. These results elucidate quasifission mechanisms behind the reactions for synthesizing new SHEs Z=119 and Z=120.
In this work, we explore the evolution of non-static, radiating, shearing, and hyperbolically symmetric stellar configurations within the framework of general relativity by imposing the Euclidean condition. To model the interior spacetime, we consider a non-static hyperbolically symmetric fluid distribution undergoing gravitational collapse in the presence of anisotropic stresses and heat dissipation. We derive the corresponding gravitational field equations for the anisotropic matter content. We use the Euclidean condition, which simplifies the equations of motion by establishing a direct relationship between the metric functions and allows the construction of exact analytic stellar models. By smoothly matching the interior spacetime to the hyperbolic Vaidya geometry across the boundary hypersurface, the appropriate boundary conditions are obtained. Explicit expressions for the physical variables are derived, including the energy density, radial and tangential pressures, heat flux, anisotropic factor, and hyperbolic mass function. The effects of density inhomogeneity, dissipative heat flux, and pressure anisotropies on the dynamical evolution of hyperbolic stellar matter are analyzed in detail. The presented analytical solution may provide a useful application of the complexity factor in the dynamics of non-static hyperbolically symmetric matter distributions.
