Li Xue-Qian

Possible molecule structure of the newly observed Y(4260)

We suggest that the newly observed resonance Y(4260) is a {chi}{sub c}-{rho}{sup 0} molecule, which is an isovector. In this picture, we can easily interpret why Y(4260){yields}{pi}{sup +}{pi}{sup -}J/{psi} has a larger rate than Y(4260){yields}DD which has not been observed, and we also predict existence of the other two components of the isotriplet and another two possible partner states which may be observed in the future experiments. A direct consequence of this structure is that for this molecular structure Y(4260){yields}{pi}{sup +}{pi}{sup -}J/{psi} mode is more favorable than Y(4260){yields}KKJ/{psi} which may have a larger fraction if other proposed structures prevail.

Study on contributions of hadronic loops to decays of J/ψ → vector + pseudoscalar mesons

In this work, we evaluate the contributions of the hadronic loops to the amplitudes of J/{psi}{yields}PV where P and V denote light pseudoscalar and vector mesons, respectively. By fitting data of two well measured channels of J/{psi}{yields}PV, we obtain the contribution from the pure OZI process to the amplitude which is expressed by a phenomenological quantity |G{sub S}{sup PV}|, and a parameter {alpha} existing in the calculations of the contribution of hadronic loops. In terms of {alpha} and |G{sub S}{sup PV}|, we calculate the branching ratios of other channels and get results which are reasonably consistent with data. Our results show that the contributions from the hadronic loops are of the same order of magnitude as that from the OZI processes and the interference between the two contributions are destructive. The picture can be applied to study other channels such as PP or VV of decays of J/{psi}.

Lifetime of Doubly Charmed Baryons

n this work, we evaluate the lifetimes of the doubly charmed baryons Xi(+)(cc), Xi(++)(cc) and Omega(+)(cc). We carefully calculate the non-spectator contributions at the quark level, where the Cabibbo-suppressed diagrams are also included. The hadronic matrix elements are evaluated in the simple non-relativistic harmonic oscillator model. Our numerical results are generally consistent with that obtained by other authors who used the diquark model. However, all the theoretical predictions on the lifetimes are one order larger than the upper limit set by the recent SELEX measurement. This discrepancy would be clarified by the future experiment. If more accurate experiment still confirms the value of the SELEX collaboration, there must be some unknown mechanism to be explored.

Instantaneous Bethe–Salpeter Equation and Its Exact Solution

We present an approach to solve Bethe-Salpeter (BS) equations exactly without any approximation if the kernel of the BS equations exactly is instantaneous, and take positronium as an example to illustrate the general features of the exact solutions. The key step for the approach is from the BS equations to derive a set of coupled and well-determined integration equations in linear eigenvalue for the components of the BS wave functions equivalenity which may be solvable numerically under a controlled accuracy, even though there is no analytic solution. For positronium, the exact solutions precisely present corrections to those of the corresponding Schrodinger equation in order upsilon(1) (v is the relative velocity) for eigenfunctions, in order upsilon(2) for eigenvalues, and the mixing between S and D components in J(PC) = 1(--) states etc., quantitatively. Moreover, we also point out that there is a questionable step in some existent derivations for the instantaneous BS equations if one is pursuing the exact solutions. Finally, we emphasize that one should take the O(upsilon) corrections emerging in the exact solutions into account accordingly if one is interested in the relativistic corrections for relevant problems to the bound states.

Study of Doubly Heavy Baryon Spectrum via QCD Sum Rules

In this work, we calculate the mass spectrum of doubly heavy baryons with the diquark model in terms of the QCD sum rules. The interpolating currents are composed of a heavy diquark field and a light quark field. Contributions of the operators up to dimension six are taken into account in the operator product expansion. Within a reasonable error tolerance, our numerical results are compatible with other theoretical predictions. This indicates that the diquark picture reflects the reality and is applicable to the study of doubly heavy baryons.

X(1812)in the quarkonia-glueball-hybrid mixing scheme

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Geometrical model for non-zero {theta}{sub 13}

J^{PC}=0^{++}

Members in the 0+ 0(+ +) family

(X(1812)) state with a mass near the threshold of

Spectra of Free Diquark in the Bethe–Salpeter Approach

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Study on Production of Exotic 0+ Meson D*sJ(2317) in Decays of ψ(4415)

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