Researchers have directly observed Weyl nodes in TaAs using soft X-ray angle-resolved photoemission spectroscopy (ARPES). Weyl nodes are points in momentum space where two non-degenerate bands cross, and they represent Weyl fermions, which are massless particles predicted by the Dirac equation. The observation confirms the existence of Weyl fermions in TaAs, a noncentrosymmetric and non-magnetic transition-metal monoarsenide. The study shows that TaAs is a Weyl semimetal with twelve pairs of Weyl nodes in its 3D Brillouin zone. The Weyl nodes are located near the Fermi energy and are protected by broken inversion or time-reversal symmetry. The experimental results match well with first-principles calculations, confirming the presence of Weyl nodes in TaAs. The study also demonstrates the relationship between bulk Weyl nodes and surface Fermi arcs, providing evidence for the existence of Weyl fermions in TaAs. The results are significant as they confirm the long-sought-after Weyl nodes in a real material, opening new avenues for studying Weyl semimetals.Researchers have directly observed Weyl nodes in TaAs using soft X-ray angle-resolved photoemission spectroscopy (ARPES). Weyl nodes are points in momentum space where two non-degenerate bands cross, and they represent Weyl fermions, which are massless particles predicted by the Dirac equation. The observation confirms the existence of Weyl fermions in TaAs, a noncentrosymmetric and non-magnetic transition-metal monoarsenide. The study shows that TaAs is a Weyl semimetal with twelve pairs of Weyl nodes in its 3D Brillouin zone. The Weyl nodes are located near the Fermi energy and are protected by broken inversion or time-reversal symmetry. The experimental results match well with first-principles calculations, confirming the presence of Weyl nodes in TaAs. The study also demonstrates the relationship between bulk Weyl nodes and surface Fermi arcs, providing evidence for the existence of Weyl fermions in TaAs. The results are significant as they confirm the long-sought-after Weyl nodes in a real material, opening new avenues for studying Weyl semimetals.