S. Ceci, R. Omerović, H. Osmanović, M. Uroić, M. Vukšić, B. Zauner, Geometric constraint on residue phases: resolving the N(2190) anomaly and implications for exotic states, Physics Letters B, Volume 875, 2026, 140332, ISSN 0370-2693, https://doi.org/10.1016/j.physletb.2026.140332.
(https://www.sciencedirect.com/science/article/pii/S0370269326001863)
Abstract: We derive a parameter-free geometric constraint on residue phases dictated by the pole-threshold angle. Using the N(2190) anomaly as a test case, this constraint reveals a sign ambiguity in prior data; correcting the sign ambiguity yields a phase of −28∘±10∘, matching our prediction. This consistency validates the method as a model-independent diagnostic for distinguishing compact from molecular states, offering a rigorous tool for exotic spectroscopy.
Keywords: Unitary S-matrix; Baryon and meson resonances; Resonant properties
