arXiv subjects
Publications and source records attributed to Peng-Zhi Huang.
We calculate the $ρ$ meson couplings between the heavy hybrid doublets H^h/S^h/M^h/T^h and the ordinary q\bar{Q} doublets in the framework of the light-cone QCD sum rule. The sum rules obtained rely mildly on the Borel parameters in their working regions. The resulting coupling constants are rather small in most cases.
We study the spectra of the hybrid mesons containing one heavy quark ($q\bar{Q}g$) within the framework of QCD sum rules in the heavy quark limit. The derived sum rules are stable with the variation of the Borel parameter within their corresponding working ranges. The extracted binding energy for the heavy hybrid doublets $H^h(S^h)$ and $M^h(T^h)$ is almost degenerate. We also calculate the pionic couplings between these heavy hybrid and the conventional heavy meson doublets using the light-cone QCD sum rule method. The extracted coupling constants are rather small as a whole. With these couplings we make a rough estimate of the partial widths of these pionic decay channels.
Within the framework of the QCD sum rules, we consider the three-point correlation function, work at the limit q^2 -> 0 and m_π-> 0, and pick out the singular term ~ {1\over q^2} to extract the pionic coupling constants of the 1^{-+} hybrid meson. Then we calculate the decay widths of different modes. The decay width of the S-wave modes b_1 π, f_1πincreases quickly as the hybrid meson mass and decay momentum increase. But for the low mass hybrid meson around 1.6 GeV, the P-wave decay mode ρπis very important and its width is around 180 MeV, while the widths of ηπand η^\prime πare strongly suppressed. We suggest the experimental search of π_1(1600) through the decay chains at BESIII: e^+e^- -> J/ψ(ψ') -> π_1 +γor e^+e^- -> J/ψ(ψ') -> π_1 +ρwhere the π_1 state can be reconstructed through the decay modes π_1 -> ρπ-> π^+π^-π^0 or π_1 -> f_1(1285)π^0. It is also interesting to look for π_1 using the available BELLE/BABAR data through the process e^+e^- -> γ^\ast -> ρπ_1, b_1π_1, γπ_1 etc.
We calculate the coupling constants of the decay modes $1^{-+}\rightarrowρπ, f_1π, b_1π, ηπ, η'π, a_1π, f_1η$ within the framework of the light-cone QCD sum rule. Then we calculate the partial width of these decay channels, which differ greatly from the existing calculations using phenomenological models. For the isovector $1^{-+}$ state, the dominant decay modes are $ρπ, f_1π$. For its isoscalar partner, its dominant decay mode is $a_1π$. We also discuss the possible search of the $1^{-+}$ state at BESIII, for example through the decay chains $J/ψ(ψ')\to π_1 +γ$ or $J/ψ(ψ')\to π_1 +ρ$ where $π_1$ can be reconstructed through the decay modes $π_1\to ρπ\to π^+π^-π^0$ or $π_1\to f_1(1285)π^0$. Hopefully the present work will be helpful to the experimental establishment of the $1^{-+}$ hybrid meson.
The P-wave charm-strange mesons $D_{s0}(2317)$ and $D_{s1}(2460)$ lie below the $DK$ and $D^\ast K$ threshold respectively. They are extremely narrow because their strong decays violate the isospin symmetry. We study the possible heavy molecular states composed of a pair of excited charm strange mesons. As a byproduct, we also present the numerical results for the bottonium-like analogue.
We study the possible heavy molecular states composed of a pair of charm mesons in the H and S doublets. Since the P-wave charm-strange mesons $D_{s0}(2317)$ and $D_{s1}(2460)$ are extremely narrow, the future experimental observation of the possible heavy molecular states composed of $D_s/D_s^\ast$ and $D_{s0}(2317)/D_{s1}(2460)$ may be feasible if they really exist. Especially the possible $J^{PC}=1^{--}$ states may be searched for via the initial state radiation technique.
We calculate the $π$, $ρ$, $ω$, and $γ$ coupling constants between the heavy meson doublets $(1^-,2^-)$ and (0^-,1^-)/(0^+,1^+) within the framework of the light-cone QCD sum rule at the leading order of heavy quark effective theory. Most of the sum rules are stable with the variations of the Borel parameter and the continuum threshold. Then we calculate the strong and electromagnetic decay widths of the $(1^-,2^-)$ D-wave heavy mesons. Their total widths are around several tens of MeV, which is helpful in the future experimental search.
We calculate the coupling constants between the light vector mesons and heavy baryons within the framework of the light-cone QCD sum rule in the leading order of heavy quark effective theory. Most resulting sum rules are stable with the variations of the Borel parameter and the continuum threshold. The extracted couplings will be useful in the study of the possible heavy baryon molecular states.
We calculate the coupling constants between the light vector mesons and heavy mesons within the framework of the light-cone QCD sum rule in the leading order of heavy quark effective theory. The sum rules are very stable with the variations of the Borel parameter and the continuum threshold. The extracted couplings will be useful in the study of the possible heavy meson molecular states. They may also helpful in the interpretation of the proximity of X(3872), Y(4260) and Z(4430) to the threshold of two charmed mesons through the couple-channel mechanism.
With the identification of ($D_{sJ}(2317), D_{sJ}(2460)$) as the ($0^+$, $1^+$) doublet in the heavy quark effective field theory, we derive the light cone QCD sum rule for the coupling of eta meson with $D_{sJ}(2317) D_s $ and $D_{sJ}(2460) D_s^{*} $. Through $η-π^0$ mixing we calculate their pionic decay widths, which are consistent with the experimental values (or upper limits). Combining the radiative decay widths derived by Colangelo, Fazio and Ozpineci in the same framework, we conclude that the decay patterns of $D_{sJ}(2317, 2460)$ strongly support their interpretation as ordinary $c \bar s$ mesons.
We have calculated the magnetic moment of the recently observed $Θ^+$ pentaquark in the framework of the light cone QCD sum rules using the photon distribution amplitudes. We find that $μ_{Θ^+}=(0.12\pm 0.06) μ_N$, which is quite small. We also compare our result with predictions of other groups.