arXiv subjects

Wei-Han Tan

Publications and source records attributed to Wei-Han Tan.

9 recordsLinked to original sources

arXiv2026

The decay properties of two- and three- gluon glueballs

We previously studied the decay properties of two- and three-gluon glueballs using the Fierz rearrangement method and obtained their relative branching ratios in Ref.~\cite{Tan:2026uue}. In this work, we extend and develop this analysis by providing a more complete treatment of two-gluon glueball decays and by considering the tensor and pseudotensor states with $J^{PC}=2^{++}$ and $2^{-+}$. We also perform an independent QCD sum rule analysis of the $0^{++}$ two-gluon glueball decay. The consistency between the two approaches provides a useful check of the Fierz analysis. Our results support a sizable gluon component in the $f_0(1710)$ and favor the $0^{-+}$ glueball interpretation of the $\eta(2370)$. For the tensor glueball, the vector--vector ($VV$) decay channels, especially $K^{*}(892)\bar{K}^{*}(892)$, are found to be favorable for experimental searches. We also study three-gluon glueballs with $J^{PC}=0^{++}$ and $1^{+-}$ and identify several potentially favorable three-meson decay channels, including $\pi\pi\omega$ and $K\bar K\phi$. These results provide possible guidance for future experimental searches for glueball states.

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arXiv2026

Fierz analyses on the decay properties of two- and three-gluon glueballs

The Fierz rearrangement, based on the various internal symmetries of hadrons, can be used to study their decay properties in a largely model-independent way. In this Letter we apply this method to calculate the relative branching ratios of two-gluon glueballs with $J^{PC} = 0^{++}/0^{-+}$ and three-gluon glueballs with $J^{PC} = 0^{++}/1^{+-}$. In total, we derive nearly one hundred ratios for these glueballs. Our results suggest that the $f_0(1710)$ and $\eta(2370)$ likely contain a significant gluon component, whereas the gluon component in $f_0(1500)$ appears to be small. Furthermore, we propose observing the three-gluon glueball with $J^{PC} = 0^{++}$ in the $\pi\pi\omega$ and $K\bar{K}\phi$ channels, and the three-gluon glueball with $J^{PC} = 1^{+-}$ in the $\pi\pi\omega$, $\pi\pi\phi$, and $K\bar{K}\phi$ channels. This study enhances our understanding of the gluonic structure of exotic hadrons and will assist future experimental searches in high-energy physics.

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arXiv2025

Topped baryons from QCD sum rules

The recent CMS observation of a near-threshold enhancement in top quark pair production provides the first experimental indication of a short-lived pseudoscalar $t\bar{t}$ bound state, commonly referred to as toponium. While most existing studies focus on toponium using perturbative QCD near threshold, baryonic configurations containing a single top quark -- singly topped baryons -- offer a complementary nonperturbative perspective. Notably, singly topped baryons are expected to exhibit a longer lifetime and a narrower decay width than toponium, since only one top quark decays rather than two. The heavy quark effective theory provides a natural and powerful framework for analyzing such systems, allowing the separation of heavy and light quark dynamics. In this work we employ heavy quark effective theory to investigate the internal structure of ground-state singly topped baryons. We construct their interpolating currents and analyze them using QCD sum rules. The resulting masses of the ground-state singly topped baryons are found to lie around 174 GeV, approximately $1.1$-$1.5$ GeV above the pole mass of the top quark.

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arXiv2025

QCD sum rule study on excited light meson operators

We apply the QCD sum rule method to systematically study excited light meson operators and calculate their decay constants. These operators are constructed by explicitly adding one covariant derivative to the quark-antiquark pair. In total, twelve such operators are constructed, among which ten are subjected to detailed numerical analyses. The considered quark contents include $\bar{q}q$, $\bar{q}s$, and $\bar{s}s$ ($q = u/d$), allowing the formation of various $SU(3)$ flavor nonets. For instance, our results support the interpretation that the $a_2(1320)$, $f_2(1270)$, $f_2^\prime(1525)$, and $K_2^*(1430)$ constitute a flavor nonet with quantum numbers $J^{P(C)} = 2^{+(+)}$. In addition, we predict several excited meson states, whose masses and decay constants are determined using the QCD sum rule method.

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arXiv2024

Strong decay properties of P-wave single bottom baryons of the SU(3) flavor antitriplet $\bf\bar 3_F$

We study the $P$-wave bottom baryons of the $SU(3)$ flavor antitriplet and systematically calculate their strong decay properties, including their $D$-wave decays into ground-state bottom baryons with light pseudoscalar mesons and $S$-wave decays into ground-state bottom baryons with light vector mesons. Together with Refs.~\cite{Tan:2023opd,Yang:2019cvw,Yang:2020zrh,Luo:2024jov}, a rather complete investigation has been performed to study their mass spectra and strong/radiative decay properties, through the methods of QCD sum rules and light-cone sum rules within the framework of heavy quark effective theory. Among various possibilities, we identify four $\Lambda_b$ and four $\Xi_b$ baryons, with limited decay widths and so capable of being observed in experiments. Their masses, mass splittings within the same multiplets, and strong/radiative decay widths are summarized in Table~\ref{tab:decayb3f} for future experimental searching.

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arXiv2024

Light single-gluon hybrid states with various (exotic) quantum numbers

We apply the QCD sum rule method to study the light single-gluon hybrid states with various (exotic) quantum numbers. We construct twenty-four single-gluon hybrid currents, and use eighteen of them to calculate the masses of forty-four single-gluon hybrid states with the quark-gluon contents $\bar q q g$ ($q=u/d$) and $\bar s s g$. We concentrate on the hybrid states with the exotic quantum number $J^{PC} = 1^{-+}$, whose masses and widths are calculated to be $M_{|\bar q q g;1^-1^{-+}\rangle} =1.67^{+0.15}_{-0.17}$ GeV, $\Gamma_{|\bar q q g;1^-1^{-+}\rangle} = 530^{+540}_{-330}$ MeV, $M_{|\bar q q g;0^+1^{-+}\rangle} = 1.67^{+0.15}_{-0.17}$ GeV, $\Gamma_{|\bar q q g;0^+1^{-+}\rangle} = 120^{+160}_{-110}$ MeV, $M_{|\bar s s g;0^+1^{-+}\rangle} = 1.84^{+0.14}_{-0.15}$ GeV, and $\Gamma_{|\bar s s g;0^+1^{-+}\rangle} = 100^{+110}_{-~80}$ MeV. Our results support the interpretations of the $\pi_1(1600)$ and $\eta_1(1855)$ as the hybrid states $|\bar q q g;1^-1^{-+}\rangle$ and $|\bar s s g;0^+1^{-+}\rangle$, respectively. Considering the uncertainties, our results suggest that the $\pi_1(1600)$ and $\eta_1(1855)$ may also be interpreted as the hybrid states $|\bar q q g;1^-1^{-+}\rangle$ and $|\bar q q g;0^+1^{-+}\rangle$, respectively. To differentiate these two assignments and to verify whether they are hybrid states or not, we propose to examine the $a_1(1260) \pi$ decay channel in future experiments.

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arXiv2023

Predicted $\Xi_b(6087)^0$ and further predictions

The methods of QCD sum rules and light-cone sum rules within the framework of heavy quark effective theory have been widely applied to study the singly heavy baryons, and especially, we have applied these methods to predict not only the mass and width of the $\Xi_b(6087)^0$ recently discovered by LHCb, but also its observation channel and its mass difference from the $\Xi_b(6100)^-$. We apply the same approach to perform a complete study on the $P$-wave bottom baryons of the $SU(3)$ flavor $\mathbf{\bar 3}_F$ and investigate their fine structure. Besides the $\Lambda_b(5912)^0$, $\Lambda_b(5920)^0$, $\Xi_b(6087)^0$, and $\Xi_b(6100)^-$, our results suggest the existence of the other two $\Lambda_b$ and two $\Xi_b$ baryons, whose widths are limited. They are the $\Lambda_b(J^P = 3/2^-)$ with the mass and width about $(5.93^{+0.13}_{-0.13}~{\rm GeV},\,0.0^{+12.0}_{-~0.0}~{\rm MeV})$, the $\Lambda_b(5/2^-)$ with $(5.94^{+0.13}_{-0.13}~{\rm GeV},\,\approx0~{\rm MeV})$, the $\Xi_b(3/2^-)$ with $(6.10^{+0.15}_{-0.10}~{\rm GeV},\,1.4{^{+11.6}_{-~1.4}}~{\rm MeV})$, and the $\Xi_b(5/2^-)$ with $(6.11^{+0.15}_{-0.10}~{\rm GeV},\,1.0{^{+7.4}_{-1.0}}~{\rm MeV})$. Their mass splittings are calculated to be $M_{\Lambda_b(5/2^-)} - M_{\Lambda_b(3/2^-)} = 17\pm7~{\rm MeV}$ and $M_{\Xi_b(5/2^-)} - M_{\Xi_b(3/2^-)} = 14\pm7~{\rm MeV}$. All these baryons are explained as the $P$-wave bottom baryons of the $\rho$-mode, where the orbital excitation is between the two light quarks. However, the existence of this mode is still controversial, so their experimental searches can verify both our approach and the existence of the $\rho$-mode, which can significantly improve our understanding on the internal structure of hadrons.

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arXiv2023

Strong decays of the $ϕ(2170)$ as a fully-strange tetraquark state

We study strong decays of the $ϕ(2170)$, along with its possible partner $X(2436)$, as two fully-strange tetraquark states of $J^{PC} = 1^{--}$. We consider seven decay channels: $ϕη$, $ϕη^\prime$, $ϕf_0(980)$, $ϕf_1(1420)$, $h_1(1415) η$, $h_1(1415) η^\prime$, and $h_1(1415) f_1(1420)$. Some of these channels are kinematically possible, and we calculate their relative branching ratios through the Fierz rearrangement. Future experimental measurements on these ratios can be useful in determining the nature of the $ϕ(2170)$ and $X(2436)$. The $ϕ(2170)$ has been observed in the $ϕf_0(980)$, $ϕη$, and $ϕη^\prime$ channels, and we propose to further examine it in the $h_1(1415) η$ channel. Evidences of the $X(2436)$ have been observed in the $ϕf_0(980)$ channel, and we propose to verify whether this structure exists or not in the $ϕη$, $ϕη^\prime$, $h_1(1415) η$, and $h_1(1415) η^\prime$ channels.

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arXiv2023

Light double-gluon hybrid states with the exotic quantum numbers $J^{PC} = 1^{-+}$ and $3^{-+}$

We apply the QCD sum rule method to study the double-gluon hybrid states with the quark-gluon contents $\bar q q gg$ ($q=u/d$) and $\bar s s gg$. We construct twenty-eight double-gluon hybrid currents, eleven of which are found to be zero due to some internal symmetries between the two gluons fields. We concentrate on the non-vanishing currents with the exotic quantum numbers $J^{PC} = 1^{-+}$ and $3^{-+}$. Their masses are calculated to be $M_{|\bar q q gg;1^{-+}\rangle} = 4.35^{+0.26}_{-0.30}$ GeV, $M_{|\bar s s gg;1^{-+}\rangle} = 4.49^{+0.25}_{-0.30}$ GeV, $M_{|\bar q q gg;3^{-+}\rangle} = 3.02^{+0.24}_{-0.31}$ GeV, and $M_{|\bar s s gg;3^{-+}\rangle} = 3.16^{+0.22}_{-0.28}$ GeV. The decay behaviors of the $J^{PC} = 3^{-+}$ states are studied, and we propose to search for them in the $πa_1(1260)/ρω/ϕϕ$ channels in future particle experiments.

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