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Register a new userPossible Interpretations of $D_{sJ}^+(2632)$ If It Really Exists
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We analyze various possible interpretations of the narrow state $D_{sJ}^+(2632)$ observed by SELEX Collaboration recently, which lies above threshold and has abnormal decay pattern. These interpretations include: (1) sever
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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.
The resonance $D_{sJ}(2632)$ observed by SELEX, has attracted great interests and meanwhile brought up serious dispute. Its spin-parity, so far has not finally determined and if it exists, its quark-structure might be exotic. Following the previous literature where $D_{sJ}(2632)$ is assumed to be a radial-excited state of $1^-$, we consider the possibilities that it might be a $qbar q$ ground state of $2^+$ or the first radial-excited state of $0^+$ $D_{sJ}(2317)$ and re-calculate its strong decay widths in terms of the Bethe-Salpeter equation. Our results indicate that there still is a sharp discrepancy between the theoretical evaluation and data.
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We consider possible assignments for the D$_{sJ}^+(2632)$, which was recently reported in D$_s^+eta$ and D$^0$K$^+$ final states by the SELEX Collaboration at Fermilab. The most plausible quark model assignment for this state is the first radial excitation ($2^3S_1$) of the $cbar s$ D$_s^*(2112)$, although the predicted mass and strong decay branching fractions for this assignment are not in agreement with the SELEX data. The reported dominance of D$_seta$ over DK appears especially problematic. An intriguing similarity to the K$^*(1414)$ is noted. $2^3S_1$--$^3D_1$ configuration mixing is also considered, and we find that this effect is unlikely to resolve the branching fraction discrepancy. Other interpretations as a $cbar s$-hybrid or a two-meson molecule are also considered, but appear unlikely. Thus, if this state is confirmed, it will require reconsideration of the systematics of charmed meson spectroscopy and strong decays.
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.
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