Pseudo point nodal superconducting gap in spin-triplet UTe₂

UTe₂ is an unconventional heavy-fermion superconductor discussed as a candidate for spin-triplet pairing. However, conflicting reports on gap structure, particularly regarding point nodes, have hindered understanding of the order parameter symmetry. Here, we report b-axis thermal conductivity κ_b/T measurements on high-quality UTe₂ single crystals down to  ~ 50 mK that definitively resolve the gap anisotropy. κ_b/T shows negligible residual conductivity as T → 0, while magnetic fields induce only weak enhancement of the residual term. Remarkably, a threshold-like field scale is observed at low fields for H∥a, characterized by a kink signaling a change in quasiparticle transport normal to the field. Above this threshold, strong anisotropy develops for transport along and normal to the field. These results strongly suggest that UTe₂ hosts a fully gapped state with pseudo point nodes, where the gap minima approach but never reach zero, placing strong constraints on the order parameter and exotic pairing mechanism.