M. Soyeur | Searcharxiv

arXiv2008

Radiative and isospin-violating decays of Ds mesons in the hadrogenesis conjecture

The masses and decays of the scalar D_{s0}^*(2317) and axial-vector D_{s1}^*(2460) charmed strange mesons are calculated consistently in the hadrogenesis conjecture. These mesons decay either strongly into the isospin-violating pi^0 D_s and pi^0 D_s^* channels or electromagnetically. They are generated by coupled-channel dynamics based on the leading order chiral Lagrangian. The effect of chiral corrections to chiral order Q_χ^2 is investigated. We show that taking into account large-N_c relations to determine the strength of these correction terms implies a measurable signal for an exotic axial-vector state in the eta D* invariant mass distribution. The one-loop contribution to the electromagnetic decay amplitudes of scalar and axial-vector states is calculated. The Lagrangian describing electromagnetic interactions is obtained by gauging the chiral Lagrangian for hadronic interactions and adding gauge-invariant correction terms to chiral order Q_chi^2. In addition the role of light vector meson degrees of freedom is explored. We confront our results with measured branching ratios. Once the light vector mesons are included, a natural explanation of all radiative decay parameters is achieved.

hep-ph↗

arXiv2002

Quantum interference of rho0- and omega-mesons in the pi N -> e+e- N reaction

The study of the $πN\to ρ^0 N$ and $πN \to ωN$ amplitudes below and close to the vector meson production threshold ($1.4<\sqrt s <1.8$ GeV)reveals a rich structure arising from the presence of baryon resonances in this energy range. These resonances are reflected in the interference pattern of the $e^+e^-$ decays of the $ρ^0$- and $ω$-mesons produced in $π^- p$ and $π^+ n$ reactions. We discuss the shape and magnitude of the $ρ^0$-$ω$ interference in the $π^-p \to e^+e^- n$ and $π^+n \to e^+e^- p$ reaction cross sections as functions of the total center of mass energy $\sqrt s$. We find contrasted results: the interference is largely destructive for the $π^-p \to e^+e^- n$ cross section but constructive for the $π^+n \to e^+e^- p$ cross section. An experimental study of these reactions would provide significant constraints on the coupling of vector meson-nucleon channels to low-lying baryon resonances.

nucl-th↗