Liaoning Normal University

Abstract We consider the constraints of the purely leptonic decays of charged pseudoscalar mesons $P$ (being $\pi^\pm$, $K^\pm$, $D_{(s)}^\pm$ or $B^\pm$) and the gauge boson $W$, $P \to \ell \nu_\ell$, $P \to \ell \nu_\ell \nu \bar{\nu}$, $P \to \ell \nu_\ell e^+ e^-$ and $W \to \ell \nu_\ell$, on the leptophilic axion-like particles ($\ell$ALPs, denoted as $a$) with masses in the range $10 MeV \sim 100 MeV$ via the decays $P \to \ell \nu_\ell a$ and $W \to \ell \nu_\ell a$, where $a$ is assumed to escape the detector as missing energy or to decay into a pair of charged leptons. Comparing our numerical results with the latest experimental data, we find that some of these decay processes for $P$ being $\pi^\pm$ and $K^\pm$ can give meaningful constraints on the flavor-diagonal (FD) coupling parameter $g_\ell/f_a$ with the $\ell$ALP mass in the range considered in this paper. The strongest constraints come from the decay $K^+\to \mu^+\nu_{\mu}\nu\bar{\nu} $, which set upper limits of $7.60 \times 10^{-2} GeV^{-1}$ $\sim$ $1.03 \times 10^{-1} GeV^{-1}$ on $g_\ell/f_a$ at the 90$\%$ C.L..

The evolution of pulsed discharge behavior inside a preformed air bubble in water from the first to subsequent pulses was experimentally investigated using a synchronized needle–bubble system. A positive nanosecond high-voltage pulsed power supply, together with a pulse valve and ICCD imaging, was employed to generate reproducible preformed bubbles and to record the corresponding discharge development with good temporal synchronization. The results show that, although the preformed bubbles exhibit good repeatability in size and morphology under identical conditions, the first-pulse discharge inside the bubble remains highly stochastic. The first discharge is predominantly corona-like and is not significantly affected by bubble size once the electrode is covered by the bubble. By varying the pulse width, the discharge inside the bubble was observed to evolve progressively from corona-like emission to streamer discharge, accompanied by increasing instability of the bubble interface. At sufficiently large pulse width and pulse number, bubble wrinkling and even rupture were induced. The effect of solution conductivity was also examined. Increasing conductivity significantly enhanced discharge intensity, enlarged the luminous region, and promoted streamer propagation along the inner bubble surface. At sufficiently high conductivity, the first pulse already produced strong discharge and rapid bubble rupture. In addition, the current amplitude and the energy dissipated per pulse increased with conductivity and pulse number. These results demonstrate that the discharge evolution inside a preformed bubble is jointly governed by pulse history, pulse width, and solution conductivity, and that residual effects from previous pulses play an important role in the transition from the first pulse to subsequent discharges.

Introduction: The altruistic behavior of left-behind children, a vulnerable population, plays a crucial role in their moral and social development, yet it remains understudied. This study investigated how group identity influences altruistic behavior in children, examining the moderating roles of left-behind status and self-esteem.

A bstract Within the framework of nonrelativistic quantum chromodynamics (NRQCD) factorization, we compute the $$ \mathcal{O}\left({v}^4\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> <mml:mfenced> <mml:msup> <mml:mi>v</mml:mi> <mml:mn>4</mml:mn> </mml:msup> </mml:mfenced> </mml:math> relativistic corrections to the fragmentation of a heavy quark into the color-singlet $$ {}^1{S}_0^{\left[1\right]} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:msubsup> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> <mml:mfenced> <mml:mn>1</mml:mn> </mml:mfenced> </mml:msubsup> <mml:mprescripts/> <mml:none/> <mml:mn>1</mml:mn> </mml:mmultiscripts> </mml:math> and $$ {}^3{S}_1^{\left[1\right]} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:msubsup> <mml:mi>S</mml:mi> <mml:mn>1</mml:mn> <mml:mfenced> <mml:mn>1</mml:mn> </mml:mfenced> </mml:msubsup> <mml:mprescripts/> <mml:none/> <mml:mn>3</mml:mn> </mml:mmultiscripts> </mml:math> quarkonium states. Using the Collins-Soper definition of the fragmentation function, we reproduce the known $$ \mathcal{O}\left({v}^2\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> <mml:mfenced> <mml:msup> <mml:mi>v</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:mfenced> </mml:math> results. We find that the $$ \mathcal{O}\left({v}^4\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> <mml:mfenced> <mml:msup> <mml:mi>v</mml:mi> <mml:mn>4</mml:mn> </mml:msup> </mml:mfenced> </mml:math> correction gives a positive contribution relative to the leading order result over a wide range of the light-cone momentum fraction z , while its magnitude remains much smaller than that of the $$ \mathcal{O}\left({v}^2\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> <mml:mfenced> <mml:msup> <mml:mi>v</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:mfenced> </mml:math> correction. This behavior indicates a good convergence of the NRQCD relativistic expansion in this process. We further extend the calculation to the fragmentation functions in the unequal-mass case at $$ \mathcal{O}\left({v}^4\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> <mml:mfenced> <mml:msup> <mml:mi>v</mml:mi> <mml:mn>4</mml:mn> </mml:msup> </mml:mfenced> </mml:math> and obtain the corresponding analytical expressions.

In software quality assurance, Just-In-Time Defect Prediction (JIT-DP) and Just-In-Time Defect Localization (JIT-DL) automate the identification of potential defective code and localization of defect lines by analyzing program change characteristics and code commit contexts. These techniques enables just-in-time quality monitoring and defect prevention during development, while also reducing manual costs and improving reliability. Due to the high dynamism and unstructured noise in code change data within agile development scenarios, as well as the difficulty in capturing complex nonlinear synergistic effects of multidimensional expert features, existing work faces dual challenges: lack of data robustness and lack of fine-grained modeling of expert features. To address these challenges, we propose a multi-task interaction technology JIT-DCK , which contains three core components: defect feature preprocessing component, defect prediction component, and defect localization component. The defect feature preprocessing component creates a subword vocabulary, controls extreme values and removes interference to generate data with three aspects, sending the line-level structure to the defect localization component and the semantic aggregation and expert features to the defect prediction component. The defect prediction component is structured with a three-layer cooperative architecture. It works on fusing semantic and line-level features and also models the complex nonlinear relationships of 14-dimensional expert features to achieve effective defect prediction. The defect localization component builds a closed-loop decision chain. It integrates commit-level global features and line-level local semantics through multi-level encoding and dynamic attention mechanisms for accurately localizing defects. Experiments show that JIT-DCK significantly outperforms SOTA models in defect prediction and localization metrics such as F1-Score +2.76%, AUC +1.79%, CodeChurn@20%Recall +2.88%, Top5-Acc +3.10%, Top10-Acc +2.55%, Recall@20%CodeChurn l +6.46%, CodeChurn@20%Recall l +18.58%, and IFA +3.57%, demonstrating its competence in code defect prediction and localization tasks.