Survival before annihilation in Psi-prime decays

We extend the simple scenario for $\Psi'$ decays suggested a few years ago. The $c\bar c$ pair in the $\Psi'$ does not annihilate directly into three gluons but rather survives before annihilating. An interesting prediction is that a large fraction of all $\Psi'$ decays could originate from the $\Psi' \to \eta_{c} (3\pi)$ channel which we urge experimentalists to identify. Our model solves the problem of the apparent hadronic excess in $\Psi'$ decays as well as the $\rho\pi$ puzzle since, in our view, the two-body decays of the $\Psi'$ are naturally of electromagnetic origin. Further tests of this picture are proposed, e.g. $J/\Psi \to b_{1}\eta$.Comment: 6 pages, no figur

Scalars in the hadron world: the Higgs sector of the strong interaction

Scalar mesons are a key expression of the strong physics regime of QCD and the role condensates, particularly $$, play in breaking chiral symmetry. What new insights have been provided by recent experiments on $D, D_s$ and $J/\psi$ decays to light hadrons is discussed. We need to establish whether all the claimed scalars $\sigma$, $\kappa$, $f_0(1370)$, etc., really exist and with what parameters before we can meaningfully speculate further about which is transiently ${\bar q}q$, ${\bar{qq}} qq$, multi-meson molecule or largely glue.Comment: 10 pages, 4 figures. Invited talk at the International Conference on QCD and Hadronic Physics, Beijing, June 2005. A shortened version will appear in the Proceeding

Multiquark Hadrons

A number of candidate multiquark hadrons, i.e., particle resonances with substructures that are more complex than the quark-antiquark mesons and three-quark baryons that are prescribed in the textbooks, have recently been observed. In this talk I present: some recent preliminary BESIII results on the near-threshold behavior of sigma(e+e- --> Lambda Lambda-bar) that may or may not be related to multiquark mesons in the light- and strange-quark sectors; results from Belle and LHCb on the electrically charged, charmoniumlike Z(4430)^+ --> pi^+ psi ' resonance that necessarily has a four-quark substructure; and the recent LHCb discovery of the P_c(4380) and P_c(4450) hidden-charm resonances seen as a complex structure in the J/psi p invariant mass distribution for Lambda_b --> K^-J/psi p decays and necessarily have a five-quark substructure and are, therefore, prominent candidates for pentaquark baryons.Comment: 12 pages, 9 figures, summary of a talk presented at the 12th Conference on Hypernuclear and Strange Particle Physics (HYP2015), September 7-12, 2015 Sendai, JAPAN. To appear in the JPS Conference proceeding

Observation of ψ(3686)→ΛΛˉη′\psi(3686) \rightarrow \Lambda \bar{\Lambda} \eta^{\prime} decay

Using a sample of $(27.12\pm 0.14) \times 10^{8}$ $\psi(3686)$ events collected with the BESIII detector, the decay $\psi(3686) \to \Lambda \bar{\Lambda} \eta'$ with $\eta'$ subsequently decaying into $\gamma \pi^+ \pi^-$ and $\eta \pi^+ \pi^-$ is observed for the first time. The branching fraction of $\psi(3686) \to \Lambda \bar{\Lambda}\eta'$ is measured to be $(7.34\pm0.94(stat.)\pm0.43(sys.))\times10^{-6}$. No resonant structures are evident in the $\Lambda\eta'$, $\bar{\Lambda}\eta'$ and $\Lambda\bar{\Lambda}$ mass spectra.Comment: 11 page, 13 Figure

Probing scalar meson structures in χc1\chi_{c1} decays into pseudoscalar and scalar

We evaluate the decay branching ratios of $\chi_{c1}\to PS$, in a quark model parametrization scheme, where $P$ and $S$ stand for pseudoscalar and scalar meson, respectively. An interesting feature of this decay process is that the $c\bar{c}$ annihilate via the pQCD hair-pin diagram is supposed to be dominant. Hence, this decay process should be sensitive to the quark components of the final-state light mesons, and would provide a great opportunity for testing the mixing relations among the scalar mesons, i.e. $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$, by tagging the final state pseudoscalar mesons.Comment: 9 pages and 6 eps figures; Enhanced discussion on the dominance of hair-pin diagram is added. Revised version to appear in IJMP