arXiv subjects

Qin-Fang Cao

Publications and source records attributed to Qin-Fang Cao.

3 recordsLinked to original sources

arXiv2021

Some remarks on $X(6900)$

The analysis of the LHCb data on $X(6900)$ found in the di-$\jpsi$ system is performed using a momentum-dependent Flatté-like parameterization. The use of the pole counting rule and spectral density function sum rule give consistent conclusions that both confining states and molecular states are possible, or it is unable to distinguish the nature of $X(6900)$, if only the di-$\jpsi$ experimental data with current statistics are available. Nevertheless, we found that the lowest state in the di-$J/ψ$ system has very likely the same quantum numbers as $X(6900)$, and $X(6900)$ is probably not interpreted as a $J/ψ-ψ(2S)$ molecular state.

hep-ph↗

arXiv2021

On leptonic width of $X(4260)$

New measurements on cross sections in $e^+e^-\to J/ψπ^+π^-$, $h_cπ^+π^-$, $D^0D^{*-}π^++c.c.$, $ψ(2S)π^+π^-$, $ωχ_{c0}$ and $J/ψη$ channels have been carried out by BESIII, Belle and BABAR collaborations, and also in the $D_s^*\bar D_s^*$ channel. We perform extensive numerical analyses by combining all these data available, together with those in $D\bar D^*$ and $D^*\bar D^*$ channels. Though the latter show no evident peak around $\sqrt{s}=4.230$ GeV, the missing $X(4260)$ is explained as that it is concealed by the interference effects of the well established charmonia $ψ(4040)$, $ψ(4160)$ and $ψ(4415)$. Our analyses reveal that the leptonic decay width of $X(4260)$ ranges from $O(10^2)$ eV to $O(1)$ keV, and hence may be explained in the conventional quark model picture. That is, the $X(4260)$ may well be interpreted as a mixture of $4^3S_1$ and $3^3D_1$ states.

hep-ph↗

arXiv2019

Discussions on the Line-shape of $X(4660)$ Resonance

A careful reanalysis is made on $e^+e^-\to X(4660)\to (Λ_c\barΛ_c)/(ψ'ππ)$ processes, aiming at resolving the apparent conflicts between Belle and BESIII data above $Λ_c\barΛ_c$ threshold. We use a model containing a Breit-Wigner resonance and $Λ_c\barΛ_c$ four-point contact interactions, with which the enhancement right above the $Λ_c\barΛ_c$ threshold is well explained by a virtual pole generated by $Λ_c\barΛ_c$ attractive final state interaction, located at $M_V=4.566\pm0.007$ GeV. Meanwhile, $X(4660)$ remains to be a typical Breit-Wigner resonance, and is hence of confinement nature. Our analysis strongly suggests the existence of the virtual pole with statistical significance of $4.2$ standard deviation ($σ$). Nevertheless, the conclusion crucially depends on the line-shape of cross sections which are of limited statistics, hence we urge new experimental analyses from Belle II, BESIII, and LHCb to settle the issue.

hep-ph↗