Related papers: Theoretical analysis of the $\gamma\gamma \to \pi^…
We study the $D^+ \to \pi^+ \eta \eta $ and $D^+ \to \pi^+ \pi^0 \eta$ reactions, which are single Cabibbo suppressed and can proceed both through internal and external emission. The primary mechanisms at quark level are considered,…
The radiative decays of the pseudoscalar mesons $P=(\pi^0,\eta,\eta')$ are of special interest as they provide an experimental window on the electromagnetic and colour chiral $U_A(1)$ anomalies. $\pi^0\to\gamma\gamma$ is well described by…
A prediction for the contributions of chiral loops and the L$\sigma$M model to the radiative $\phi\to\pi^0\eta\gamma$ decay mode is presented. The L$\sigma$M is used as an appropriate framework for describing the pole effects of the…
The scalar contributions to the radiative decays of light vector mesons into a pair of neutral pseudoscalars, $V\to P^0P^0\gamma$, are studied within the framework of the Linear Sigma Model. This model has the advantage of incorporating not…
A high statistics study of the reaction $\gamma\gamma\to \pi^+\pi^-\pi^0$ has been performed with the Belle detector using a data sample of 26 fb$^{-1}$ collected at $\sqrt{s}=10.58\GeVcsq$. A spin-parity analysis shows dominance of the…
The decay $\psi(3686)\to\gamma\pi^+\pi^-\pi^0$ is studied using a sample of $(2712.4\pm14.3)\times10^6$ $\psi(3686)$ events collected with the BESIII detector. The decay $\eta(1405)\to\pi^+\pi^-\pi^0$ is observed for the first time in…
We study the radiative $\rho$, $\omega$ and $\phi$ decay into $\pi^0 \pi^0 \gamma$ and $\pi^0 \eta \gamma $ taking into account mechanisms in which there are two sequential vector-vector-pseudoscalar or axial-vector--vector--pseudoscalar…
We study the $D_s^+\to \pi^+(a_0(980)^0\to)\pi^0\eta$, $\pi^0(a_0(980)^+\to)\pi^+\eta$ decays, which have been recently measured by the BESIII collaboration. We propose that $D_s^+\to \pi^{+(0)}(a_0(980)^{0(+)}\to)\pi^{0(+)}\eta$ receives…
The $\gamma p \to K^+ \pi^0 \Lambda$ and $\gamma p \to K^+ \pi \Sigma $ reactions are studied in the kinematic region where the $\pi^0 \Lambda$(1116) and $\pi\Sigma$(1192) pairs originate dominantly from the decay of the $\Sigma$(1385) and…
We observe a narrow enhancement near 2m_p in the invariant mass spectrum of p\bar{p} pairs from radiative J/psi-->gamma p\bar{p} decays. No similar structure is seen in J/psi-->pi0 p\bar{p} decays. The results are based on an analysis of a…
The decays of $J/\psi\to \eta\phi f_0(980) (\eta\to \gamma\gamma, \phi \to K^+K^-, f_0(980)\to\pi^+\pi^-)$ are analyzed using a sample of $5.8 \times 10^{7}$ $J/\psi$ events collected with the BESII detector at the Beijing Electron-Positron…
We present a calculation of $P\to \gamma^{(\ast)}\gamma^{(\ast)}$ processes, where $P=\pi^0,\ \eta,\ \eta'$, at the one-loop level up to and including next-to-next-to-leading order (NNLO) in large-$N_c$ chiral perturbation theory. The…
We investigate the scalar resonances in the processes of $D^{0} \rightarrow \pi^{0}\pi^{0}\pi^{0}, \pi^{0}\pi^{0}\eta, \pi^{0}\eta\eta$ decays based on the chiral unitary approach for the final state interaction. We start from singly…
We have made a thorough study of the $D^+ \to \pi^+ \eta \eta $ reaction, recently measured by the BESIII collaboration, which shows an abnormal strength at high invariant masses in the $\pi\eta$ mass distribution. We studied in detail the…
We reexamine the $\omega \to \pi^{0} \pi^{0} \gamma $ decay, adding the effect of $\omega-\rho$ mixing to the amplitude calculated with the aid of chiral perturbation theory and vector meson dominance. We predict the neutral decay to occur…
The $e^+e^- \to \omega \pi^0 \to \pi^0 \pi^0 \gamma$ process was investigated in the SND experiment at the VEPP-2M collider. A narrow energy interval near the $\phi$-meson was scanned. The observed cross-section reveals, at the level of…
In this paper, we first review the theoretical and experimental studies of the process $\Lambda_c^+ \to \pi^+ \eta \Lambda$. Motivated by the recent BESIII and Belle measurements, we have conducted a theoretical study of the process…
This paper is focused on two issues: the K\pi spectrum near threshold - the kappa problem -, and the pi\pi spectrum between 1.2 and 1.5 GeV/(c^2) -- the f_0(1370) problem. Both problems will be analysed from the perspective of the $D$ meson…
To investigate the interaction between the nucleon $N$ and nucleon resonance $N(1535)1/2^-$, the $\eta d$ threshold structure connected to the isoscalar $S$-wave $N$-$N(1535)1/2^-$ system has been experimentally studied in the…
Using a large acceptance calorimeter and a stopped pion beam we have made a precise measurement of the rare Pi+ -> Pi0 e+ Nu,(pi_beta) decay branching ratio. We have evaluated the branching ratio by normalizing the number of observed…