Reboud, M.
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Publication Access status: Metadata only , Analysis of the {\psi (3770)} resonance in line with unitarity and analyticity constraints(2024); ; ; We study the inclusive and exclusive cross sections of $e^+e^-\rightarrow \text {hadrons}$ for center-of-mass energies between 3.70 and $3.83\,\,\textrm{GeV}$ to infer the mass, width, and couplings of the $\psi (3770)$ 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 $\psi (2S)$ and the $\psi (3770)$, no further pole is required to describe the $\psi (3770)$ line shape. In particular we derive from the pole location $M_{\psi (3770)}~=~3778.8~\pm ~0.3~\,\textrm{MeV}$ and $\varGamma _{\psi (3770)}~=~25.0~\pm ~0.5~\,\textrm{MeV}$. Moreover, we find the decay to $D^+D^-$ and $D^0\bar{D}^0$ to be consistent with isospin symmetry and derive an upper bound on the branching ratio ${\mathcal {B}}(\psi (3770) \rightarrow \text {non-}D\bar{D}) < 6\%$ at $90\%$ probability.Source Type:Article1 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Dispersive analysis of B → K(*) and Bs → ϕ form factors(2023); ; ; We propose a stronger formulation of the dispersive (or unitarity) bounds à la Boyd-Grinstein-Lebed (BGL), which are commonly applied in analyses of the hadronic form factors for B decays. In our approach, the existing bounds are split into several new bounds, thereby disentangling form factors that are jointly bounded in the common approach. This leads to stronger constraints for these objects, to a significant simplification of our numerical analysis, and to the removal of spurious correlations among the form factors. We apply these novel bounds to $$ \overline{B}\to {\overline{K}}^{\left(\ast \right)} $$ and $$ {\overline{B}}_s\to \phi $$ form factors by fitting them to purely theoretical constraints. Using a suitable parametrization, we take into account the form factors’ below-threshold branch cuts arising from on-shell $$ {\overline{B}}_s{\pi}^0 $$ and $$ {\overline{B}}_s{\pi}^0{\pi}^0 $$ states, which so-far have been ignored in the literature. In this way, we eliminate a source of hard-to-quantify systematic uncertainties. We provide machine readable files to obtain the full set of the $$ \overline{B}\to {\overline{K}}^{\left(\ast \right)} $$ and $$ {\overline{B}}_s\to \phi $$ form factors in and beyond the entire semileptonic phase space.Source Type:Article2
