https://doi.org/10.1140/epjc/s10052-024-12785-8
Regular Article - Theoretical Physics
Analysis of the 
resonance in line with unitarity and analyticity constraints
1
Institute for Advanced Simulation and Institut für Kernphysik, Forschungszentrum Jülich, 52425, Jülich, Germany
2
Physik Department T31, Technische Universität München, 85748, Garching, Germany
3
Helmholtz-Institut für Strahlen- und Kernphysik (Theorie), Bethe Center for Theoretical Physics, Universität Bonn, 53115, Bonn, Germany
4
Theoretische Physik 1, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068, Siegen, Germany
5
Institute for Particle Physics Phenomenology and Department of Physics, Durham University, DH1 3LE, Durham, UK
Received:
11
January
2024
Accepted:
8
April
2024
Published online:
9
May
2024
We study the inclusive and exclusive cross sections of 
for center-of-mass energies between 3.70 and 
to infer the mass, width, and couplings of the 
resonance. By using a coupled-channel K-matrix approach, we setup our analysis to respect unitarity and the analyticity properties of the underlying scattering amplitudes. We fit several models to the full dataset and identify our nominal results through a statistical model comparison. We find that, accounting for the interplay between the 
and the , no further pole is required to describe the line shape. In particular we derive from the pole location 
and 
. Moreover, we find the decay to 
and 
to be consistent with isospin symmetry and derive an upper bound on the branching ratio 
at 
probability.
© The Author(s) 2024
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Funded by SCOAP3.
