Probing strong-gravity chaos and stability of circular photon orbits around the Kerr–Sen black holePradeep Singh, Hemwati Nandan, Shubham Kala, Nidhi Handa, Lokesh Kumar Joshi and G. MustafaEur. Phys. J. C, 86 3 (2026) 286DOI: https://doi.org/10.1140/epjc/s10052-026-15505-6