arXiv subjects

M. Uroić

Publications and source records attributed to M. Uroić.

5 recordsLinked to original sources

arXiv2026

How elastic unitarity governs resonance peaks and residue phases

Imposing elastic unitarity on resonant amplitudes yields a geometric rule connecting the reaction threshold, S-matrix pole, and Breit-Wigner peak. Validated across six orders of magnitude in energy, from $^5\text{He}$ to the Higgs boson, this rule predicts currently unknown residue phases: $-44(12)^\circ$ for $^5\mathrm{He}$, $-24(7)^\circ$ for $Σ(1385)^+$, and $-7(13)^\circ$ for $Ξ(1530)^0$. By inverting this formalism, we determine the $Υ(4S)$ pole from its empirical peak to be $10575(1)-i\,8.3(13)$ MeV, with a $-52(6)^\circ$ phase.

hep-ph↗

arXiv2026

Rethinking Partial Widths: Unitary Mixing and the $Δ(1232)$ Pole Residue

The extracted $πN$ partial decay width of the $Δ(1232)$ systematically exceeds its total width ($2|r|>Γ$). We demonstrate this anomaly is a natural consequence of S-matrix unitary mixing. Because exact multi-channel shadow poles are distant and model-dependent, we utilize a heuristic elastic model -- treating the overlapping $Δ(1600)$ as fully elastic -- to isolate the core mechanism. We show that evaluating a perturbing S-matrix at a state's complex pole systematically inflates the residue magnitude. This proof of principle confirms complex residues reflect global amplitude topology rather than isolated intrinsic properties, challenging naive interpretations of branching fractions.

hep-ph↗

arXiv2026

Elastic phase shift analysis reveals the geometric origin of the residue phase

We show that the complex-plane structure of light hadron resonances is governed by a unified geometric framework where the threshold position plays a decisive role. By applying this framework to $ππ$, $πK$, and $πN$ phase shifts, we show that the residue phase $θ$ is primarily determined by the geometric phase $δ_0$ (the angle between pole and real axis seen from the threshold). While vector resonances exhibit excellent alignment with this geometric baseline, scalar resonances show systematic deviations of $10^\circ$--$15^\circ$, which we identify as the dynamical imprint of Adler zeros.

hep-ph↗

arXiv2026

Geometric Constraint on Residue Phases: Resolving the N(2190) Anomaly and Diagnosing Exotic States

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 it yields a phase of $-28^\circ\pm10^\circ$, 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.

hep-ph↗

arXiv2025

No hidden physics in resonance pole residue phase

In hadron resonant scattering, there are four fundamental resonant parameters: real and imaginary part of the pole position, and the magnitude and the phase of the residue. Out of the four, the last one is the least understood. The search for the residue phase's physical meaning has focused on model-independent phases of the majority of the lowest-mass resonances. Here, we apply a simple mathematical identity to the amplitude in the complex plane to reveal the exact reason for the noticed regularity and show that there is no room for hidden physical variables in the residue phase.

hep-ph↗