446494 research outputs found
Sort by
Resonant leptogenesis in inverse see-saw framework with modular
No full textWe introduce a lepton mass generation and flavor mixing model, realized through a (2,3) inverse seesaw structure based on modular symmetry. The model employs modular forms to construct the lepton Yukawa couplings, significantly simplifying the framework by reducing redundant parameters. A detailed numerical analysis demonstrates consistency with current neutrino oscillation data, yielding specific outputs for the mixing angles and CP-violating phases. The Dirac CP phase is predicted to lie near , corresponding to near-maximal leptonic CP violation. The total neutrino mass lies within eV, and the effective Majorana mass eV, within reach of upcoming neutrinoless double beta decay experiments such as nEXO and AMoRE-II. The model also remains consistent with current bounds on charged lepton flavor violating processes from MEG and BaBar. We further explore resonant leptogenesis enabled by quasi-degenerate heavy neutrino states and show that the observed baryon asymmetry of the universe can be successfully generated in this scenario. The combined treatment of low-energy observables and high-scale baryogenesis demonstrates the predictivity and testability of the modular -based ISS(2,3) framework
Regular black hole’s impact on the gravitational waveforms from periodic orbits
No full textIn this paper, we investigate periodic orbits exhibiting zoom-whirl behavior around a magnetically charged black hole (MCBH) within the framework of the regular black hole. We examine how the magnetic charge influences orbital dynamics by modifying the background spacetime geometry, thereby affecting the energy and angular momentum of particles. In particular, we calculate the radii of the marginally bound orbits (MBOs) and innermost stable circular orbits (ISCOs), demonstrating that the magnetic charge parameter reduces both radii. This provides valuable insight into the role of the charge parameter in shaping orbital behavior and altering spacetime geometry. We model the complex motion of a stellar-mass object as a timelike particle, inspiraling into a supermassive black hole (SMBH) in the MCBH background, with its trajectory described using periodic geodesic orbits. Based on this analysis of such periodic orbits, we further analyze the gravitational waveforms generated by extreme mass ratio inspirals (EMRIs), in which the SMBH’s spacetime dominates the dynamics of the stellar-mass object. By combining particle trajectory analysis with waveform modeling in a semi-analytical approach, we show that the charge parameter significantly alters the zoom-whirl orbital dynamics and induces notable changes in the waveform structure. These results illustrate that future gravitational wave (GW) observations may constrain the properties of MCBHs, thereby deepening our understanding of the gravitational imprint of regular black holes
Robust topological invariants of timelike circular orbits for spinning test particles in black hole spacetimes
No full textThe spin-curvature coupling in the Mathisson–Papapetrou–Dixon (MPD) formalism induces non-geodesic motion, shifting the orbital parameters of spinning test particles in black hole spacetimes. We investigate whether these quantitative shifts alter the qualitative, global structure of the orbit manifold. Using a topological approach, we study timelike circular orbits (TCOs) for spinning particles in static, spherically symmetric spacetimes. By constructing an auxiliary vector field, we compute the topological winding number W in horizon-bounded regions of asymptotically flat, anti-de Sitter (AdS), and de Sitter (dS) backgrounds. We find that W is robust against both the magnitude and direction of the particle’s spin: between two horizons, guaranteeing at least one unstable TCO; outside the outermost horizon in asymptotically flat and AdS spacetimes, enforcing that TCOs must appear in stable–unstable pairs or be absent. This spin independence reveals that the fundamental orbital structure is a property of spacetime geometry itself, not of the particle’s spin. We validate this with quantitative examples in Schwarzschild, Schwarzschild–AdS, and Schwarzschild–dS spacetimes, showing explicit spin-induced TCO shifts while confirming the invariant topology. This result provides a topological foundation for interpreting gravitational waveforms from extreme mass-ratio inspirals involving spinning secondaries
Approaching stable quark matter
No full textThe determination of whether the ground state of baryon matter in Quantum Chromodynamics (QCD) is the ordinary nucleus or a quark matter state remains a long-standing question in physics. A critical parameter in this investigation is the bag parameter B, which quantifies the QCD vacuum energy and can be computed using nonperturbative methods such as Lattice QCD (LQCD). By combining the equation of state derived from perturbative QCD (pQCD) with the bag parameter to fit the LQCD-simulated data for isospin-dense matter, we address the stability of quark matter within the LQCD+pQCD framework. Our findings suggest that the current data imposes an upper bound on MeV, approaching a conclusive statement on quark matter stability. Given the lower bound on B from the quark condensate contribution to the vacuum energy, the stable 2-flavor quark matter remains possible, whereas the stable 2+1-flavor quark matter is excluded, assuming complete deconfinement and chiral-symmetry restoration and the reliability of pQCD at baryon chemical potentials around the proton mass. Additionally, we derive more general thermodynamic bounds on the quark matter energy-per-baryon and B, which, while weaker, provide complementary insights
Nitrogen abundances in star-forming galaxies 2.2 Gyr after the Big Bang are not elevated
No full textUsing deep, medium-resolution, JWST rest-optical spectra of a sample of typical star-forming galaxies (Lyman-break galaxies and Lyman-α emitters) from the LyC22 survey at z ∼ 3, we determined the nebular abundances of N, O, and Ne relative to H for a subsample of 25 objects with a direct method based on auroral )=-1.29^ line detections. Our measurements increased the number of accurate N/O determinations at z ∼ 2-4 using a homogeneous approach. We found a mean value of łog( ̊m N/O +0.25 _ -0.21 over a metallicity range of oh=7.56 to 8.44. The observed N/O ratio and scatter are indistinguishable from that observed in low-z galaxies and regions over the same metallicity range, thus showing no redshift evolution of N/O for typical galaxies over a significant fraction of cosmic time. We also show that typical z ∼ 3 galaxies have a similar offset in the BPT diagram to galaxies from the low-z Lyman Continuum Survey (LzLCS) when compared to the average of SDSS galaxies, and we demonstrate that this offset is not due to enhanced nitrogen abundances. Our results establish a basis for future studies of the evolution of N and O at higher redshifts
Sustainable innovation in plant-based protein: Development and optimization of champignon mushroom-TVP meatloaf as a nutritious meat alternative
No full textThis study developed a champignon mushroom–based meatloaf as a plant-based meat substitute using textured vegetable protein (TVP) to improve texture and sensory quality. Three formulations containing 8%, 11%, and 14% TVP were prepared and evaluated through descriptive sensory analysis conducted by 10 trained panelists and hedonic preference testing involving 100 untrained and semi-trained consumers. The sensory attributes assessed included color, aroma, flavor, and texture. Results from descriptive analysis indicated that the 8% TVP formulation most closely resembled conventional meatloaf, particularly in terms of softness and natural mushroom flavor, while higher TVP levels produced firmer and more elastic textures. Hedonic testing showed that consumer preferences varied according to texture, with some respondents favoring the denser structure of higher TVP formulations. Based on the combined results of both sensory evaluations, the 8% TVP formulation was selected for nutritional analysis. Proximate analysis revealed that the mushroom-based meatloaf contained lower fat (5.30 g/100 g) and energy (140 kcal/100 g) compared to the meat-based control (9.17 g fat and 190 kcal/100 g), while providing moderate protein content (8.65 g/100 g) and higher moisture levels. These findings demonstrate that champignon mushrooms combined with TVP can produce a nutritionally adequate, lower-fat, and lower-calorie plant-based meat alternative with favorable sensory characteristics
Hydrophilicity controls thermodiffusion in alkylammonium chlorides
No full textIn this study, we examine the Soret effect of ammonium chloride (Cl) and its alkyl-substituted derivatives: dimethylammonium chloride (DMACl), ethylammonium chloride (EACl), and trimethylammonium chloride (TMACl) in aqueous solution using infrared thermal diffusion forced Rayleigh scattering. The Soret coefficient, , increases systematically with alkyl substitution, following the trend Cl DMACl < EACl TMACl, while hydrophilicity decreases correspondingly. Across the investigated temperature range (C) and concentrations (1–4 mol/kg), increases with both temperature and the degree of alkyl substitution. However, the concentration dependence varies among the salts. DMACl, EACl, and TMACl exhibit decreasing with increasing concentration and are predominantly thermophobic; TMACl remains thermophobic under all conditions. In contrast, Cl shows a non-monotonic concentration dependence above C and is largely thermophilic. We discuss the origin of this minimum at elevated temperatures in relation to other aqueous salt systems that exhibit non-monotonic behavior of with respect to concentration. Overall, each additional alkyl substitution decreases the temperature sensitivity of the Soret coefficient, , consistent with reduced solute hydrophilicity. Furthermore, we observe a clear correlation between the thermal diffusion coefficient and the thermal expansion coefficient in these aqueous electrolyte solutions. This is consistent with the trends reported for nonpolar organic mixtures and aqueous solutions of non-ionic solutes. These findings highlight thermodiffusion as a sensitive probe for understanding how hydrophilicity and ion-specific interactions govern molecular transport in aqueous environments
Heavy quark potential and thermal charm production in heavy-ion collisions
No full textThe effective mass of heavy quark in QGP is related to the heavy quark potential at a large distance. In this study we test different heavy quark potentials, namely, the screened potential such as the free energy and the internal energy of the heavy quark pair in QGP, and the unscreened potential, which was recently proposed by the HotQCD Collaboration, through the thermal production of charm quarks in heavy-ion collisions at the LHC. We find that the free energy potential overestimates charm production in heavy-ion collisions at the LHC, while the unscreened potential produces results closest to the experimental data from the ALICE Collaboration among the three potentials
Neutron stars in minimal dilatonic gravity
No full textWe study the structure of neutron stars within the framework of minimal dilatonic gravity (MDG), a scalar–tensor theory related to Brans–Dicke gravity with . Using three realistic unified equations of state (EOSs), LOCV1804, LOCV1811, and LOCV1815, enabling us to investigate the sensitivity of MDG predictions to the stiffness of dense matter, we analyze stellar configurations for different values of the dilaton field mass . Our results show that a dilaton halo forms around the neutron star, contributing significantly to the total mass. The halo mass fraction reaches 20–30% in neutron stars with masses greater than , leading to total masses that exceed those predicted by General Relativity. These results are consistent with mass measurements from recent gravitational wave and NICER (Neutron Star Interior Composition Explorer) observations. We also find that smaller dilaton field masses yield more massive neutron star–halo systems. For high-density stars, the dilaton pressure becomes negative at the center and behaves like dark energy, modifying the radial profile of the dilaton field