Related papers: Pole Analysis of Unitarized One Loop $\chi$PT Ampl…
We revisit the classification of polarization observables of the cosmic microwave background. There exists a unified approach to the $3 \times 3$ density matrix by which intensity, linear and circular polarization are treated on an equal…
A linear CKM relation, $\bar\eta= \tan\Phi_{3/2}(\bar\rho-0.24\pm 0.03)$, involving a $1\sigma$ range for $\Phi_{3/2}$, $20^\circ < \Phi_{3/2} < 115^\circ$, is obtained from $B^0\to K^*\pi$ amplitudes measured recently in Dalitz plot…
We investigate the relation between different three-dimensional reductions of the Bethe-Salpeter equation and the analytic structure of the resultant amplitudes in the energy plane. This correlation is studied for both the $\phi^2\sigma$…
By simultaneously analyzing the cross section data of $e^+e^-\rightarrow D\bar D, D\bar D^*, D^*\bar D^*, D\bar D\pi$ in a coupled-channel scheme with unitarity, we found that, in contrast to the conventional wisdom, the pole of…
It is analysed the triple-cut of one-loop amplitudes in dimensional regularisation within spinor-helicity representation. The triple-cut is defined as a difference of two double-cuts with the same particle content, and a same propagator…
This article provides a pedagogical exploration of coupled-channel scattering in hadronic physics, focusing on theoretical methodologies, and practical applications. It covers key concepts such as the $N/D$ method, Castillejo-Dalitz-Dyson…
A recent analysis of data on the two photon production of the $\eta_c$ and its decay to $K(K\pi)$ has determined the $K\pi$ $S$-wave amplitude in a "model-independent" way assuming primarily that the additional kaon is a spectator in this…
We discuss unitarity constraints on the dynamics of a system of three interacting particles. We show how the short-range interaction that describes three-body resonances can be separated from the long-range exchange processes, in particular…
Using an interaction extracted from the local hidden gauge Lagrangians, which brings together vector and pseudoscalar mesons, and the coupled channels $\rho N$ (s-wave), $\pi N$ (d-wave), $\pi \Delta$ (s-wave) and $\pi \Delta$ (d-wave), we…
Coupled-channel $\pi K$ and $\eta K$ scattering amplitudes are determined by studying the finite-volume energy spectra obtained from dynamical lattice QCD calculations. Using a large basis of interpolating operators, including both those…
We set up a general framework to describe $\pi\pi$ scattering below 1 GeV based on chiral low-energy expansion with possible spin-0 and 1 resonances. Partial wave amplitudes are obtained with the $N/D$ method, which satisfy unitarity,…
In a series of previous papers the present authors and collaborators have shown strong evidence for existence of the long-sought sigma-particle by analyzing the pi pi-scattering and pi pi-production processes, applying, respectively, the IA…
We present results of a new multichannel partial-wave analysis for $\bar K N$ scattering in the c.m.\ energy range 1480 to 2100 MeV. Resonance parameters were extracted by fitting partial-wave amplitudes from all considered channels using a…
We study $S$-wave interactions of the baryon decuplet with the octet of pseudoscalar mesons using the lowest order chiral Lagrangian. In the S=1 sector, we find an attractive interaction in the $\Delta K$ channel with I=1 while it is…
We perform a rigorous analysis of the $\pi K$ scattering at an unphysical pion mass 391 MeV using the Roy-Steiner equations, which satisfy unitarity, analyticity and crossing symmetry, for the first time. Stable solutions of the Roy-Steiner…
One has to study multivariable scattering amplitudes to extract properties of the three-body states from the generalizations of the L\"uscher finite-volume formalism. In particular, a three-body amplitude obtained from a Lattice QCD…
A general expression resembling Breit-Wigner formulae is derived for the description of resonances which appear in meson-meson scattering. Starting point is a unitarised meson model, but reduced to a simpler form and freed from the specific…
Motivated by the continuous experimental investigations of $X(1835)$ in three-body decay channels like $\eta^\prime \pi^+ \pi^-$, we investigate the $\eta^\prime K \bar K$ system with the aim of searching for bound states and/or resonances…
We present results following from the coupled channel model of two a0 resonances decaying into the pi-eta and K anti-K mesons. The a0(980) resonance can be described by two distinct poles. It is shown that the discrepancy in the a0(980)…
Data on the reaction $\gamma p\to K^+\Lambda$ from the CLAS experiments are used to derive the leading multipoles, $E_{0+}$, $M_{1-}$, $E_{1+}$, and $M_{1+}$, from the production threshold to 2180\,MeV in 24 slices of the invariant mass.…