No Arabic abstract
Using the soft-pion theorem and the assumption on the final-state interactions, we include the contribution of $DK$ continuum into the QCD sum rules for $D_{sJ}(2317)$ meson. We find that this contribution can significantly lower the mass and the decay constant of $D_s(0^+)$ state. For the value of the current quark mass $m_c(m_c)=1.286 {rm GeV}$, we obtain the mass of $D_s(0^+)$ $M=2.33 pm 0.02 {rm GeV}$ in the interval $s_0=7.5-8.0 {rm GeV}^2$, being in agreement with the experimental data, and the vector current decay constant of $D_s(0^+)$ $f_0=0.128 pm 0.013 {rm GeV}$, much lower than those obtained in previous literature.
Production of $D_{sJ}$(2317) mesons in relativistic heavy ion collisions at RHIC is studied. Using the quark coalescence model, we first determine the initial number of $D_{sJ}$(2317) mesons produced during hadronization of created quark-gluon plasma. The predicted $D_{sJ}$(2317) abundance depends sensitively on the quark structure of the $D_{sJ}$(2317) meson. An order-of-magnitude larger yield is obtained for a conventional two-quark than for an exotic four-quark $D_{sJ}$(2317) meson. To include the hadronic effect on the $D_{sJ}$(2317) meson yield, we have evaluated the absorption cross sections of the $D_{sJ}$(2317) meson by pion, rho, anti-kaon, and vector anti-kaon in a phenomenological hadronic model. Taking into consideration the absorption and production of $D_{sJ}$(2317) mesons during the hadronic stage of heavy ion collisions via a kinetic model, we find that the final yield of $D_{sJ}$(2317) mesons remains sensitive to its initial number produced from the quark-gluon plasma, providing thus the possibility of studying the quark structure of the $D_{sJ}$(2317) meson and its production mechanism in relativistic heavy ion collisions.
We derive a new QCD sum rule for $D(0^+)$ which has only the $Dpi$ continuum with a resonance in the hadron side, using the assumption similar to that has been successfully used in our previous work to the mass of $D_s(0^+)(2317)$. For the value of the pole mass $M_c=1.38 $ GeV as used in the $D_s(0^+)$ case we find that the mass of $D(0^+)$ derived from this sum rule is significantly lower than that derived from the sum rule with the pole approximation. Our result is in agreement with the experimental dada from Belle.
Using three point QCD sum rules method, the form factors relevant to the semileptonic $B_{s}to D_{sJ}(2460)ell u$ decay are calculated. The $q^2$ dependencies of these form factors are evaluated. The dependence of the asymmetry parameter $alpha$, characterizing the polarization of $D_{sJ}$ meson, on $q^2$ is studied. This study gives useful information about the structure of the $D_{sJ}$ meson. Finally the branching ratio of this decay is also estimated and is shown that it can be easily detected at LHC.
We analyze various possible interpretations of the narrow state $D_{sJ}(2632)$ which lies 100 MeV above threshold. This interesting state decays mainly into $D_s eta$ instead of $D^0 K^+$. If this relative branching ratio is further confirmed by other experimental groups, we point out that the identification of $D_{sJ}(2632)$ either as a $cbar s$ state or more generally as a ${bf {bar 3}}$ state in the $SU(3)_F$ representation is probably problematic. Instead, such an anomalous decay pattern strongly indicates $D_{sJ}(2632)$ is a four quark state in the $SU(3)_F$ ${bf 15}$ representation with the quark content ${1over 2sqrt{2}} (dsbar{d}+sdbar{d}+subar{u}+usbar{u}-2ssbar{s})bar{c}$. We discuss its partners in the same multiplet, and the similar four-quark states composed of a bottom quark $B_{sJ}^0(5832)$. Experimental searches of other members especially those exotic ones are strongly called for.
We have studied the charmonium and bottomonium hybrid states with various $J^{PC}$ quantum numbers in QCD sum rules. At leading order in $alpha_s$, the two-point correlation functions have been calculated up to dimension six including the tri-gluon condensate and four-quark condensate. After performing the QCD sum rule analysis, we have confirmed that the dimension six condensates can stabilize the hybrid sum rules and allow the reliable mass predictions. We have updated the mass spectra of the charmonium and bottomonium hybrid states and identified that the negative-parity states with $J^{PC}=(0, 1, 2)^{-+}, 1^{--}$ form the lightest hybrid supermultiplet while the positive-parity states with $J^{PC}=(0, 1)^{+-}, (0, 1, 2)^{++}$ belong to a heavier hybrid supermultiplet.