物理最新文献

Neutrino mass origin remains one of the central unsolved puzzles in particle physics. Leading mechanisms were established by the early 2000s, with limited essential breakthroughs observed in the past twenty years. These approaches often rely on the unobserved Higgs triplet field, non-renormalizable operators or the hypothetical coupling of the left-handed and right-handed neutrinos. In this work, we address these fundamental challenges by proposing a novel low-scale mechanism where neutrino masses are generated through a renormalizable, Higgs doublet-mediated interaction between the SU(2) lepton doublet and the CP conjugate singlet, distinct from the conventional Higgs–Yukawa coupling formed between the lepton doublet and singlet. Through a fresh extension of the Standard Model (SM) where the SU(2) doublet and singlet representations of neutrinos are slightly misaligned with their chiral fields, we were able to provide a theoretically coherent explanation for the Majorana neutrino mass generation without a priori assumption that neutrinos are their own antiparticles. Our model further eliminates the coupling of the left-handed and right-handed neutrinos and meanwhile substantially reduces the fine-tuning of Yukawa couplings. We conclude by highlighting the key implications of our findings, including the minimal mixing between active and sterile neutrinos (consistent with current experiments) and the potential of the present SM extension in decoding the flavor mixing and CP-violating phases.

Beginning with a 2D linear model with the Lagrangian action consisting of the sum between that of a topological field theory of BF-type and that of a system of massless real scalar fields, one determines the general interaction vertex that can be added to the initial theory, while preserving the field spectrum and the range of independent degrees of freedom. The analysis is performed using the deformation technique within the framework of antifield-BRST symmetry, aided by specific techniques of local (co-)homology. In the considered space-time dimension, it is shown that the scalar fields from the BF field spectrum ’generate’ some ’gravitational potential facet’ in the context of the interaction with the considered matter fields.

We present a systematic investigation of the thermodynamic topology for a broad class of asymptotically charged Anti-de Sitter (AdS) black holes in Einstein–Maxwell-Dilaton (EMD) theories, examining how scalar coupling parameters and spacetime dimensions influence black hole thermodynamics. Employing a topological approach that utilizes the torsion number of vector fields constructed from the generalized free energy, we characterize black hole states as topological defects within the thermodynamic parameter space. Through analytical solutions spanning dimensions (d = 4,) (d=5,) and (d=6,) including the Gubser–Rocha model, we demonstrate that variations in the dilaton coupling constant (delta ,) particularly near its critical value (delta _c,) induce transitions between distinct thermodynamic topological phases. Our analysis reveals that certain black hole solutions constitute a novel class designated as (W^{0-leftrightarrow 1+},) characterized by a torsion number (W = 1) that corresponds to a unique stability structure. We establish that Gubser–Rocha models belong to this topological classification. These results significantly expand the existing classification framework while reinforcing thermodynamic topology as a robust analytical tool for probing the universal properties of black holes in both gravitational and holographic contexts. The findings provide new insights into the relationship between microscopic couplings and macroscopic thermodynamic behavior in extended gravity theories.

Among different additive manufacturing (AM) technologies, laser-induced forward transfer (LIFT) has been widely investigated, owing to the eco-friendly rapid processing and the compatibility with a broad range of materials. In this work, the combination of the LIFT of solder materials (Gold-tin (AuSn) thin film and solder paste) and of a laser-based bonding station comprising a vacuum-assisted pick-and-place tool, and a laser soldering setup is reported for the bonding of small dimension optoelectronic components onto test silicon substrates. The findings of this study determined the optimal laser soldering parameters for integrating resistors and LEDs onto test substrates comprising LIFT printed solder patterns of solder paste with particles’ size of 2–11 μm and AuSn thin film materials. Optimal conditions for solder paste and AuSn thin film bonding were determined, ensuring reliable attachment of components and consistent process performance. The proposed methodology enables thermally localized, non-contact bonding with high positional accuracy and reproducibility. Initial experimental results validate the robustness and repeatability of the process, demonstrating its potential as a scalable solution for heterogeneous integration in advanced photonic and microelectronic packaging architectures.

The transverse momentum spectra of particles coming from high-energy collisions can generally be divided into the lower and higher p_T parts, where mostly the soft and hard processes contribute, respectively. In this paper, we have presented the new combined Tsallis-Hagedorn function with transverse flow in an attempt to describe better the longer range of p_T spectra of hadrons. This new model function combines thermodynamically consistent Tsallis distribution with embedded transverse flow and QCD inspired Hagedorn function, assuming independence of the soft and hard processes, which contribute to the lower and higher parts of p_T distribution. In order to study an influence of the p_T fit range on the values of the parameters and quality of fits, the experimental midrapidity transverse momentum distributions of the charged pions and kaons, protons and antiprotons in ten centrality classes in Pb + Pb collisions at (sqrt {s_{nn} }) = 5.02 TeV, measured by the ALICE Collaboration, have been analyzed using simultaneous minimum χ² fits by the introduced combined Tsallis-Hagedorn function with transverse flow in two p_T fit ranges up to 5 and 8 GeV/c. The results obtained using combined Tsallis-Hagedorn function with transverse flow for kinetic freeze-out temperature and average transverse flow velocity as well as non-extensivity parameter q, and dependencies of these parameters on collision centrality, have been compared systematically with those obtained using thermodynamically consistent Tsallis function with embedded transverse flow. On the whole, both functions have resulted in comparably good fit qualities and similar trends of collision centrality dependencies of the extracted kinetic freeze-out parameters, confirming the important findings of the earlier work in both shorter and longer p_T fit ranges.

In this article, we performed Simpson–Visser (SV)-regularization scheme to Anti-de Sitter (AdS) black holes and then studied thermal properties of the resulting spacetime geometry. We considered the validity of the first law of black hole thermodynamics in this case and derived an entropy formula consistent with this new regular geometry. Next, we carried out the free energy analysis and studied the phase structure of these black holes. We discovered non-trivial phase transition properties dependent on the SV-regularization parameter. We also considered the validity of the second law of black hole thermodynamics and analyzed a merger scenario of two equal mass SV-regular black holes. In particular, we investigated the impact of the SV-regularization parameter on the constraints on post-merger black hole mass. Interestingly, we found that the bounds initially increase and then fall sharply with increasing the SV-regularization parameter. All results are compared with standard black holes for vanishing SV-regularization parameter.

To improve the high-quality drilling capability of 2.5D-Cf/SiC ceramic matrix composites (CMCs) for high-temperature structural applications, this study systematically investigates the drilling quality and efficiency characteristics of millisecond pulse laser under varying hole diameters (0.6 mm to 1.7 mm). Key metrics such as hole geometry accuracy, sidewall roughness, taper angle, and machining time were evaluated using optical microscopy, scanning electron microscopy (SEM), and laser confocal microscopy. Results reveal a consistent entrance-export diameter mismatch during laser drilling, resulting in positive tapers ranging from 3.2° to 4.2°. Smaller holes (< 1 mm) exhibited more pronounced export deformation, while larger holes significantly increased machining time. The constituent materials showed distinct responses to laser ablation: carbon fibers exhibited anisotropic ablation with transverse scratches on the hole walls, whereas the SiC matrix developed regular vertical striations, leading to notable roughness variations. The 1.2 mm hole diameter demonstrated the poorest surface quality across roughness parameters, indicating a nonlinear mismatch between laser energy and hole size. This study confirms the potential of millisecond pulse laser for efficient drilling in Cf/SiC CMCs and elucidates the critical coupling relationship between hole diameter and process parameters. These findings provide theoretical insight and experimental evidence supporting the application of laser precision machining in high-performance ceramic structures.

Maps of cosmic microwave background (CMB) are extracted from multi-frequency observations using a variety of cleaning procedures. However, in regions of strong microwave emission, particularly in the galactic plane from our own galaxy Milky Way and some extended or point sources, the recovered CMB signal is not reliable. Thus, a galactic mask is provided along with the cleaned CMB sky for use with that CMB map which excises sky regions that may still be potentially contaminated even after cleaning. So, to avoid bias in our inferences, we impose such a foreground mask. In this paper, we analyze a cleaned CMB map from Planck public release 3 to probe for any foreground residuals that may still be present outside the galactic mask where the derived CMB sky is considered clean. To that end, we employ a local cross-correlation coefficient statistic where we cross-correlate widely used foreground templates that trace galactic synchrotron, free-free, and thermal dust emission from our galaxy with the cleaned CMB sky. Using simulations, we find that few regions of the derived CMB sky are still contaminated and have to be omitted. Based on this study, we derived a mask that could be used in conjugation with the standard mask to further improve the purpose of galactic masks.

The interaction of energetic ions with semiconductor heterojunctions can significantly influence interfacial states and charge transport, thereby impacting device performance and long-term reliability. In this study, ZnO/p-Si heterojunctions were irradiated with 120 MeV Ag⁸⁺ ions at fluences ranging from 1 × 10¹¹ to 5 × 10¹² ions·cm⁻², and their current-voltage characteristics were systematically examined. Swift heavy-ion irradiation generated lattice disorder, point defects, and interface traps, which reduced the barrier height from 0.82 eV for the pristine diode to 0.68 eV at 5 × 10¹² ions·cm⁻² and increased the reverse leakage current. At low fluence, transient thermal-spike effects slightly improved junction quality, whereas higher fluences produced defect-dominated transport. Under UV illumination, the irradiated heterostructure showed enhanced photocurrent, but its sensitivity decreased due to the irradiation-induced increase in dark current. These results provide important insights into radiation-driven modifications in oxide/semiconductor heterojunctions and emphasize the need to account for such effects while developing devices for radiation environments.

The dependence of (textrm{f}_{0})(980) production on the final-state charged-particle multiplicity is reported for proton–proton (pp) collisions at the centre-of-mass energy, (sqrt{s}=) 13 TeV. The production of (textrm{f}_{0})(980) is measured with the ALICE detector via the (textrm{f}_0 (980) rightarrow pi ^{+}pi ^{-}) decay channel in a midrapidity region of (|y|<) 0.5. The evolution of the integrated yields and mean transverse momentum of f(_{0})(980) as a function of charged-particle multiplicity measured in pp at (sqrt{s}=) 13 TeV follows the trends observed in pp at (sqrt{s}=) 5.02 TeV and in proton–lead (p–Pb) collisions at (sqrt{s_{textrm{NN}}}=) 5.02 TeV. Particle yield ratios of (textrm{f}_{0})(980) to (pi ^{pm }) and (textrm{K}^{*})(892)(^{0}) are found to decrease with increasing charged-particle multiplicity. These particle ratios are compared with calculations from the canonical statistical thermal model as a function of charged-particle multiplicity. The thermal model calculations provide a better description of the decreasing trend of particle ratios when no strange or antistrange quark composition for f(_{0})(980) is assumed, which suggests that the data do not support significant hidden strangeness in the (textrm{f}_{0} (980)).