Analysis of binary-lens microlensing events typically requires intensive computation because of the multimodal and complex posterior distributions. With the recent development of the JAX-based differentiable binary-lensing modeling package microlux, we present an analysis of two microlensing events with planet/brown-dwarf candidates, KMT-2025-BLG-1314 and KMT-2025-BLG-1392. Both events exhibit the "Close/Wide" degeneracy, and KMT-2025-BLG-1314 suffers from the "Planet/Binary" degeneracy and a recently recognized "Point/Finite" degeneracy among the planetary solutions. For KMT-2025-BLG-1314, the binary mass ratio is logq∼−3.5 for the planetary solutions and logq>−1.5 for the binary solutions, while for KMT-2025-BLG-1392, we find logq∼−1.3. We show that for the analysis of KMT-2025-BLG-1314, Hamiltonian Monte Carlo (HMC), enabled by microlux, provides robust parameter inference and outperforms traditional Markov chain Monte Carlo (MCMC) methods in the presence of bimodal posteriors.
@article{arxiv.2603.01735,
title = {KMT-2025-BLG-1314 and KMT-2025-BLG-1392: two microlensing planetary/brown-dwarf candidates analyzed with differentiable code},
author = {Haibin Ren and Weicheng Zang and Wei Zhu and Yoon-Hyun Ryu and Yuchen Tang and Jiyuan Zhang and Michael D. Albrow and Sun-Ju Chung and Andrew Gould and Cheongho Han and Kyu-Ha Hwang and Youn Kil Jung and In-Gu Shin and Yossi Shvartzvald and Hongjing Yang and Jennifer C. Yee and Dong-Jin Kim and Chung-Uk Lee and Byeong-Gon Park and Yunyi Tang and Dan Maoz and Shude Mao and Qiyue Qian},
journal= {arXiv preprint arXiv:2603.01735},
year = {2026}
}