Related papers: Some Developments in Light Quark Spectroscopy
Radiative decays of heavy baryons are analyzed within the Heavy Quark Symmetry (HQS). It is shown that employing the light-diquark symmetries, the number of electromagnetic couplings among S-wave and P-wave states as well as those between…
Based on a sample of $(1310.6 \pm 10.5) \times 10^{6}$ $J/\psi$ events collected with the BESIII detector operating at the BEPCII storage ring, a partial wave analysis of the decay $J/\psi\rightarrow \gamma \phi \phi$ is performed in order…
Recent results from BES-II experiment on hadron spectroscopy using $\jpsi$ and $\psi^\prime$ data samples collected in $e^+e^-$ annihilation are presented, including study of the scalar particles in $\jpsi$ radiative and hadronic decays,…
We describe the $B^0$ and $B^0_s$ decays into $J/\psi$ $f_0(500)$ and $J/\psi$ $f_0(980)$ by taking into account the dominant process for the weak decay of $B^0$ and $B^0_s$ into $J/\psi$ and a $q \bar q$ component. After hadronization of…
Recent reports of the observation of the decay $\tau \rarrow \nu_{\tau} + K + \pi + \pi$ raise interesting questions. The $u-s$ quark mass difference can induce an effective second-class current in the strange sector and enhance decays to…
Half a century of work on the light scalar mesons $f_0(500)$, $f_0(980)$, $K_0^\star(700)$, and $a_0(980)$ is briefly reviewed. After summarising all light scalar candidates in the Review of Particle Physics since 1963, a selection of…
The $\psi$ decays provide a novel way to explore baryon spectroscopy and baryon structure. The baryon resonances observed from $\psi$ decays at BES are reviewed. The implications and prospects at upgraded BESIII/BEPCII are discussed.
We review recent studies of light scalar meson properties by means of unitarization techniques, obtained from dispersion theory, and applied to the Chiral Perturbation Theory expansion. In particular, light scalars do not follow the N_c…
The experimental status of stable bound states made out of heavy quarks is reviewed. The need for a way to deal with the non-perturbative transitions involved calls for precision measurements on one hand, and for discovery of as yet…
We review the physics of purely leptonic decays of $\pi^\pm$, $K^\pm$, $D^{\pm}$, $D_s^\pm$, and $B^\pm$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of…
We review the physics of purely leptonic decays of $\pi^\pm$, $K^\pm$, $D^{\pm}$, $D_s^\pm$, and $B^\pm$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of…
The fundamental nature of mass is one of the greatest mysteries in physics. The Higgs mechanism is a theoretically appealing way to account for the different masses of elementary particles and implies the existence of a new, yet unseen…
The tetraquark assignement for light scalar states below 1 GeV is discussed on the light of strong decays. The next-to-leading order in the large-N expansion for the strong decays is considered. Mixing with quarkonia states above 1 GeV is…
I present a mini-review of the masses and couplings of the bare (unmixed) light scalar mesons : $\bar qq, (\overline{qq})(qq), (\bar qq)(\bar qq), gg$ from QCD spectral sum rules (QSSR) and low-energy theorems (LET) which we compare with…
The KLOE measurement of phi radiative decays and of the ratio Gamma(Ks->pi+pi-(gamma))/Gamma(Ks->pi0pi0) are discussed. The first measurement aims at understanding the real nature of the scalar mesons a0 and f0, whose possible compositions…
Decays of B mesons offer interesting probes to search for physics beyond the Standard Model. Thanks to the data taking at the LHC, we are at the beginning of a new era of precision B physics. I will discuss recent developments concerning…
With usage of obvious mechanisms of quark currents the amplitudes of leptonic decaies of pseudoscalar mesons are investigated. The estimation for a constant of leptonic decay of the D+ meson is obtained, f_D+ ~ 0.23 GeV.
The low and approximately equal masses of the scalar mesons $f_0(980)$ and $a_0(980)$, as well as their relatively small decay widths, are impossible to understand in terms of standard $P$-wave quark-antiquark states. Here, these mesons are…
We propose an explanation of the new resonances observed in $D_s^{(*)+} \pi^0$ decays. We suggest that the data can be explained by the mixing of conventional p-wave excited $D_s^+$ mesons with 4-quark states. The narrow states observed in…
Recent experimental improvements on K-decay data allow for a precise extraction of the strangeness-changing scalar K pi form factor and the related strange scalar spectral function. On the basis of this scalar as well as the corresponding…