Some insights into the newly observed Zc(4100)Z_c(4100) in B0→ηcK+π−B^0\to \eta_c K^+ \pi^- by LHCb

The newly reported exotic signal $Z_c(4100)$ by the LHCb Collaboration in the invariant mass spectrum of $\eta_c\pi^-$ in $B^0\to \eta_c K^+ \pi^-$ has been a new experimental evidence for an exotic meson containing four constituent quarks. Although the present experimental information is very limited, we show that its correlations with some existing exotic candidates can be recognized. This signal can be either caused by final state interaction effects or a $P$-wave resonance state arising from the $D^*\bar{D}^*$ interaction. For the latter option its neutral partner will have exotic quantum numbers of $I^G(J^{PC})=1^-(1^{-+})$. This signal, if confirmed, would provide important clues for dynamics for producing multiquark systems in $B$ meson decays and $e^+e^-$ annihilations.Comment: 6 pages, 2 eps figure

Charmonium hadronic decays and the OZI rule violation effects

We discuss the scalar meson mixing scenario and present an OZI rule violation mechanism for understanding the scalar productions in charmoium hadronic decays. We stress that the OZI violation could play a key role in disentangling the structure of the scalars: $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$.Comment: Proceeding of the International Workshop on Tau-Charm Physics, Beijing, China, June 5-7, 200

Quarks, diquarks and QCD mixing in the N∗N^* resonance spectrum

We identify a "$\Lambda$ selection rule" for $N^*$ resonances in the presence of QCD mixing effects. We quantify these mixing effects from existing data and predict amplitudes for exciting {\bf 20} representations in SU(6), which are forbidden in strict diquark models. By classifying Particle-Data-Group (PDG) states at N=2, we show that $\gamma N\to K\Lambda$, $K^*\Lambda$, $K\Sigma$, $K^*\Sigma$, and $J/\psi \to \bar{p}N^*$ are ideal probes of baryon dynamics and for establishing whether strongly correlated diquarks survive for $L > 0$.Comment: Extended version accepted by PR