Related papers: Survival before annihilation in Psi-prime decays
In this talk a short overview of $\eta$ and $\eta'$ decays is given with an emphasis on what can be learned for the strong interaction from them. The talk consists of a short introduction to ChPT, a discussion of $\eta\to3\pi$ beyond $p^4$…
Results are reported based on samples of 58 million $\jpsi$ and 14 million $\psip$ decays obtained by the BESII experiment. Improved branching fraction measurements are determined, including branching fractions for $\jpsi\to\ppp$, $\psip\ra…
The two-particle hadronic decays of B_c meson into S-wave and P-wave charmonium states X_cc are considered in the framework of hard gluon exchange model. It is shown that decay width of B_c meson into S-wave charmonium states doubly exceeds…
From inclusive measurements it is known that about 7% of all $B$ mesons decay into final states with baryons. In these decays, some striking features become visible compared to mesonic decays. The largest branching fractions come with quite…
There are two apparent puzzles connected with the two-body and three-body doubly charmed baryonic B decays. First, earlier calculations based on QCD sum rules or the diquark model predict $Br(\bar B^0\to\Xi_c^+\bar\Lambda_c^-)\approx…
We compute the strangeness-conserving double beta decay of $\Sigma^-$ hyperons, which is the only hadronic system that can undergo such decays. We consider both, the lepton number conserving %$\Sigma^-\go \Sigma^++2e^-+2 \bar{\nu}$…
We address the problem of observed charmonium decays which should be forbidden in perturbative QCD. We examine the model in which these decays proceed through a gluonic component of the $J/\Psi$ and the $\eta_c$, arising from a mixing of…
We report the observation of prompt J/psi via double ccbar production from the e+e- continuum. In this process one ccbar pair fragments into a J/psi meson while the remaining pair either produces a bound charmonium state or fragments into…
Vector charmonium states $J/\Psi$ and $\Psi'$ are copiously produced by $e^+e^-$ annihilations at the Beijing Electron Positron Collider (BEPC). Their decays provide an excellent place for studying excited nucleons and hyperons -- $N^*$,…
Based on $(2712.4\pm14.1)\times10^{6}$ $\psi(3686)$ events collected with the BESIII detector, we study the decays $h_{c}\to3(\pi^{+}\pi^{-})\pi^{0}$, $h_{c}\to2(\pi^{+}\pi^{-})\omega$, $h_{c}\to2(\pi^{+}\pi^{-})\pi^{0}\eta$,…
We survey various U_A(1) problems and attempt to resolve the two puzzles related to the eta mesons that have experimental verification. Specifically, we first explore the Goldstone structure of the eta and eta' mesons in the context of…
The $J/{\psi}$ weak decays are rare but possible within the standard model of elementary particles. Inspired by the potential prospects at the future intensity frontier, the $C$ parity violating $J/{\psi}$ ${\to}$…
In a sample of 58 million $J/\psi$ events collected with the BES II detector, the process J/$\psi\to\gamma\eta_c$ is observed in five decay channels: $\eta_c \to K^+K^-\pi^+\pi^-$, $\pi^+\pi^-\pi^+\pi^-$, $K^\pm K^0_S \pi^\mp$ (with…
The decay of $J/\psi$ to three photons is studied using $\psi(3686)\to\pi^+\pi^-J/\psi$ in a sample of $1.0641\times10^8$ $\psi(3686)$ events collected with the BESIII detector. Evidence of the direct decay of $\eta_c$ to two photons,…
We present the three-body decays for the resonances $\pi_{2}(1670)$ and $ \rho_3(1690)$. We use an effective model based on the flavor symmetry and have assumed the Sill distribution for describing the lie-shape of intermediate unstable…
To avoid the impact from the background events directly from $e^+e^-$ annihilations or $J/\psi$ decays, we propose a novel approach to investigate $\eta$ decays, in particular for its rare or forbidden decays, by using…
Based on 5.8x10^7 J/psi events detected in BESII, the branching fractions of J/psi--> phi eta and phi eta^prime are measured for different eta and eta^prime decay modes. The results are significantly higher than previous measurements. An…
We calculate the branching ratios of the yet unmeasured eta' decays into four pions, based on a combination of chiral perturbation theory and vector-meson dominance. The decays eta' --> 2(pi+ pi-) and eta' --> pi+ pi- 2pi0 are P-wave…
We have observed new channels for $\tau$ decays with an $\eta$ in the final state. We study 3-prong tau decays, using the $\eta\to\gamma\gamma$ and $\eta\to 3\piz$ decay modes and 1-prong decays with two $\piz$'s using the…
In view of the recent diboson resonant excesses reported by both ATLAS and CMS Collaborations, we suggest that a new weak singlet pseudo-scalar particle, $\eta_W$, may decay into two weak bosons while being produced in gluon fusion at the…