Pole position of the $a_1(1260)$ resonance in a three-body unitary framework

Abstract

Masses, widths, and branching ratios of hadronic resonances are quantified by their pole positions and residues with respect to transition amplitudes on the Riemann sheets of the complex energy-plane. In this study we discuss the analytic structure in the physical energy region of three-body scattering amplitudes on such manifolds. As an application, we determine the pole position of the $a_1(1260)$ meson from the ALEPH experiment by allowing for $\pi \rho$ coupled channels in S- and D-wave. We find it to be $\sqrt{s_0}=(1232_{-0-11}^{+15+9}-i266_{-22-27}^{+0+15})\text{MeV}$.

17 pages, 13 figures

References in corpus (21)

• The pion-pion scattering amplitude. IV: Improved analysis with once subtracted Roy-like equations up to 1100 MeV
• Three particle quantization condition in a finite volume: 2. general formalism and the analysis of data
• Analytic properties of the scattering amplitude and resonances parameters in a meson exchange model
• Three-body Unitarity in the Finite Volume
• Dispersive analysis of omega --> 3pi and phi --> 3pi decays
• Three body resonances in two meson-one baryon systems
• Three-body Unitarity with Isobars Revisited
• Clues for the existence of two $K_1(1270)$ resonances
• Solution to Faddeev equations with two-body experimental amplitudes as input and application to J^P=1/2^+, S=0 baryon resonances
• The reaction pi+ p --> K+ Sigma+ in a unitary coupled-channels model
• Dynamical coupled-channels analysis of 1H(e,e'pi)N reactions
• Rescattering effects in eta {\to} 3pi decays
• On the radiative decays of light vector and axial-vector mesons
• Pseudocalar meson and vector meson interactions and dynamically generated axial-vector mesons
• Relevance of complex branch points for partial wave analysis
• Extraction of Electromagnetic Transition Form Factors for Nucleon Resonances within a Dynamical Coupled-Channels Model
• The cusp effect in eta' --> eta pi pi decays
• Information on the structure of the a1 from tau decay
• Dalitz-plot decomposition for three-body decays
• Tau decay and the structure of the a1
• Tau decay into ${\nu }_{\tau }$ and $a_1(1260)$, $b_1(1235)$, and two $K_1(1270)$

Cited by in corpus (1)

• Light baryon resonances from a coupled-channel study including $\mathbf{K\Sigma }$ photoproduction