arXiv subjects

Chong-Chung Lih

Publications and source records attributed to Chong-Chung Lih.

18 recordsLinked to original sources

arXiv2026

Weak Decays of the $Λ_{b}$ Baryon in Light-Front Dynamics

We investigate the exclusive semileptonic and nonleptonic $Λ_{b} \to Λ_{c}(p)$ decays within the Standard Model by using the light-front quark model. To determine the behavior of the $Λ_{b} \to Λ_{c}(p)$ transition form factors, we employ the Bethe-Salpeter formalism in the timelike region, effectively accounting for both valence and nonvalence contributions. Using these form factors, including nonvalence contributions, we obtain branching fractions of $Λ_b \to Λ_c\,\ell\,\barν_{\ell}$, $Λ_b \to Λ_c\,τ\,\barν_τ$, $Λ_b \to p\,\ell\,\barν_{\ell}$ and $Λ_b \to p\,τ\,\barν_τ$~($\ell=e$ or $μ$) are found to be around $5.39\%$, $1.41\%$, $3.33\times 10^{-4}$ and $2.08\times 10^{-4}$, respectively, which are consistent with the experimental measurements. The ratios of $R^{\ellτ}(Λ_{c})=\frac{{\cal B}({Λ_b}\to {Λ_c}\,τ\,\barν_τ)} {{\cal B}({Λ_b}\to {Λ_c}\,\ell\,\barν_l)}$ and $R^{\ellτ}(p)=\frac{{\cal B}({Λ_b}\to p\,τ\,\barν_τ)} {{\cal B}({Λ_b}\to p\,\ell\,\barν_l)}$, are given by $0.261^{+0.097}_{-0.117}$ and $0.624^{+0.119}_{-0.129}$, respectively. The forward-backward asymmetries in the above semilepton decays are also examined. Our results indicate that, within the light-front framework, the nonvalence contributions to the asymmetries are negligible compared to the $β$-induced uncertainties. In addition, we calculate the branching ratios for the nonleptonic decays of $Λ_{b}\to Λ_{c}(p)\,M$ with $M$ being the pseudo scalar and vector mesons with the results found to be consistent with the current experimental data.

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arXiv2026

Semileptonic Decays of $Λ\to p \ell^{-} \barν_{\ell}$ in the Light-Front Dynamics

We investigate the exclusive semileptonic decays of $Λ\to p \ell^{-} \barν_{\ell}~(\ell=e,μ)$ within the Standard Model using the light-front quark model. The transition form factor behaviors of $Λ\to p$ are obtained from the effective treatment of nonvalence contributions in addition to the valence ones in the Drell-Yan-West frame due to the Bethe-Salpeter formalism. Based on these form factors, we obtain that the branching ratios of $Λ\to p e^{-} \barν_{e}$ and $p μ^{-} \barν_μ$, including nonvalence contributions, are around $8.32\times 10^{-4}$ and $1.31\times 10^{-4}$, which are consistent with the latest measurements from the BESIII Collaboration, respectively. Our results indicate that nonvalence contributions can play a non-negligible role in the semileptonic baryon decays within the light-front framework.

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arXiv2026

Time-like electromagnetic form factors of $Λ,~Σ$ and $Ξ^{+}$ in a light-front quark model

We use the light front quark model to investigate the form factors in the $e^{+}e^{-} \to B\bar{B}$ collision proceses with $B=Λ,~Σ$ and $Ξ$. These form factor behaviors are calculated based on the Bethe-Salpeter formalism with $q^{+} > 0$ to effectively account for non-valence contributions. We show that our results of the $q^2$-dependent form factors closely match the BESIII data. In particalar, we obtain that $|G_{eff}| = (0.921,~0.098,~0.189$) and $R =|$$G_E\over G_M$$|= (0.97,~0.89$,~$0.936$) for $e^{+} e^{-}\to Λ\barΛ$,~$Σ^{+} Σ^{-},~Ξ^{+} Ξ^{+})$ which $q^2 = (5.74,~6.0,~7.0)$ GeV$^2$.

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arXiv2025

Semileptonic decays of $Λ^{+}_{c}$ in light-front quark model with nonvalence contributions

We investigate the exclusive semilpetonic decays of $Λ^{+}_{c}\to (Λ/n) \ell^{+} ν_{\ell}~(\ell=e,μ)$ within the standard model by using the light-front quark model (LFQM). The form factor behaviors are obtained from the effective treatment of nonvalence contributions in addition to the valence ones in the Drell-Yan-West frame due to the Bethe-Salpeter formalism. Based on these form factors, we find that the decay branching ratios of $Λ^{+}_{c}\to (Λe^{+} ν_{e},\,Λμ^{+} ν_{e} ,\, n e^{+} ν_{e},\, n μ^{+} ν_{e})$ are about $ (3.39,\,3.21,\,0.36,\,0.35)\%$ with the non-valence contributions, which are consistent with the recent experimental measurements at BESIII. Furthermore, we use the experimental data to fit the $β$ parameters in the baryonic distribution amplitudes under the LFQM, resulting in ($β_{Λ_{c}},β_Λ, β_{n})= (0.58\pm0.08, 0.52\pm0.08,0.44\pm0.04)$.

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arXiv2025

Charmful two-body $Ω_b$ decays in the light-front quark model

We investigate the singly and doubly charmful two-body $Ω_b^-$ decays using the light-front quark model. Our findings reveal that most branching fractions calculated in this study, such as ${\cal B}(Ω_b^-\toΞ^- D^0,Ξ^{-}D^{*0})$, can be ten to one hundred times larger than those reported in previous calculations. Additionally, we interpret the ratio ${\cal B}(Ω_b^-\toΩ^- J/ψ)/{\cal B}(Ω_b^-\toΩ^- η_c)\simeq 3.4$ within the helicity framework. While the decay involving external $W$-boson emission appears to be suppressed by the $b\to u \bar c s$ weak transition, it still yields a significant branching fraction. For instance, ${\cal B}(Ω_b^-\toΞ^0 D_s^{*-})=(5.9-14.2)\times 10^{-5}$, ${\cal B}(Ω_b^-\toΞ^{*0}D_s^{-})=(6.7-12.1)\times10^{-5}$, and ${\cal B}(Ω_b^-\toΞ^{*0}D_s^{*-})=(12.8-26.7)\times10^{-5}$, with values reaching as large as $10^{-4}$. These predictions are well within the experimental reach of LHCb.

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arXiv2022

Fragmentation fraction $f_{Ω_b}$ and the $Ω_b\to ΩJ/ψ$ decay in the light-front formalism

One has measured $f_{Ω_b}{\cal B}(Ω_b^-\to Ω^- J/Ψ)$ at the level of $10^{-6}$, where the fragmentation faction $f_{Ω_b}$ is to evaluate the $b$-quark to $Ω_b^-$ production rate. Using the $Ω_b\to Ω$ transition form factors calculated in the light-front quark model, we predict ${\cal B}(Ω_b^-\to Ω^- J/Ψ) =(5.3^{+3.3+3.8}_{-2.1-2.7})\times 10^{-4}$. In particular, we extract $f_{Ω_b}=(0.54^{+0.34+0.39+0.21}_{-0.22-0.28-0.15})\times 10^{-2}$, demonstrating that the $b$ to $Ω_b$ productions are much more difficult than the $b$ to $Λ_b(Ξ_b)$ ones. Since $f_{Ω_b}$ has not been determined experimentally, $f_{Ω_b}$ added to theoretical branching fractions can be compared to future measurements of the $Ω_b$ decays.

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arXiv2020

Charmed $Ω_c$ weak decays into $Ω$ in the light-front quark model

More than ten $Ω_c^0$ weak decay modes have been measured with the branching fractions relative to that of $Ω^0_c\toΩ^-π^+$. In order to extract the absolute branching fractions, the study of $Ω^0_c\toΩ^-π^+$ is needed. In this work, we predict ${\cal B}_π\equiv {\cal B}(Ω_c^0\toΩ^-π^+)=(5.1\pm 0.7)\times 10^{-3}$ with the $Ω_c^0\toΩ^-$ transition form factors calculated in the light-front quark model. We also predict ${\cal B}_ρ\equiv {\cal B}(Ω_c^0\toΩ^-ρ^+)=(14.4\pm 0.4)\times 10^{-3}$ and ${\cal B}_e\equiv{\cal B}(Ω_c^0\toΩ^-e^+ν_e)=(5.4\pm 0.2)\times 10^{-3}$. The previous values for ${\cal B}_ρ/{\cal B}_π$ have been found to deviate from the most recent observation. Nonetheless, our ${\cal B}_ρ/{\cal B}_π=2.8\pm 0.4$ is able to alleviate the deviation. Moreover, we obtain ${\cal B}_e/{\cal B}_π=1.1\pm 0.2$, which is consistent with the current data.

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arXiv2020

Semileptonic decays of $Λ_c^+$ in dynamical approaches

We study the semileptonic decays of $Λ_c^+ \to Λ(n)\ell^+ ν_{\ell}$ in two relativistic dynamical approaches of the light-front constituent quark model (LFCQM) and MIT bag model (MBM). By considering the Fermi statistic between quarks and determining spin-flavor structures in baryons along with the helicity formalism in the two different dynamical models, we calculate the branching ratios (${\cal B}$s) and averaged asymmetry parameters ($α$s) in the decays. Explicitly, we find that ${\cal B}( Λ_c^+ \to Λe^+ ν_{e})=(3.36\pm0.87,3.48)\%$ and $α( Λ_c^+ \to Λe^+ ν_{e})=(-0.97\pm0.03,-0.83)$ in (LFCQM, MBM), in comparison with the data of ${\cal B}( Λ_c^+ \to Λe^+ ν_{e})=(3.6\pm0.4)\%$ and $α( Λ_c^+ \to Λe^+ ν_{e})=-0.86\pm 0.04$ given by the Particle Data Group, respectively. We also predict that ${\cal B}( Λ_c^+ \to n e^+ ν_{e})=(0.57\pm0.15, 3.6\pm1.5)\times 10^{-3}$ and $α( Λ_c^+ \to n e^+ ν_{e})=(-0.98\pm0.02,-0.96\pm0.04)$ in LFCQM with two different scenarios for the momentum distributions of quarks in the neutron, and ${\cal B}( Λ_c^+ \to n e^+ ν_{e})= 0.279\times 10^{-2}$ and $α( Λ_c^+ \to n e^+ ν_{e})=-0.87$ in MBM, which could be tested by the ongoing experiments at BESIII, LHCb and BELLEII.

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arXiv2020

Testing the W-exchange mechanism with two-body baryonic B decays

The role of $W$-exchange diagrams in baryonic $B$ decays is poorly understood, and often taken as insignificant and neglected. We show that charmful two-body baryonic $B\to {\bf B}_c \bar {\bf B}'$ decays provide a good test-bed for the study of the $W$-exchange topology, whose contribution is found to be non-negligible; here ${\bf B}_c$ is an anti-triplet or a sextet charmed baryon, and ${\bf \bar B}'$ an octet charmless (anti-)baryon. In particular, we calculate that ${\cal B}(\bar B^0\toΣ_c^{+}\bar p)=(2.9^{+0.8}_{-0.9})\times 10^{-6}$ in good agreement with the experimental upper bound. Its cousin $\bar B_s^0$ mode, $\bar B_s^0\toΛ^+_c\bar p$, is a purely $W$-exchange decay, hence is naturally suited for the study of the role of the $W$-exchange topology. We predict ${\cal B}(\bar B_s^0\toΛ^+_c\bar p)=(0.8\pm 0.3)\times 10^{-6}$, a relatively large branching ratio to be tested with a future measurement by the LHCb collaboration. Other predictions, such as ${\cal B}(\bar B^0\toΞ_c^+\barΣ^-)=(1.1\pm 0.4)\times 10^{-5}$, can be tested with future Belle II measurements.

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arXiv2016

Some heavy vector and tensor meson decay constants in light-front quark model

We study the decay constants ($f_M$) of the heavy vector ($D^{*}$, $D^{*}_{s}$, $B^{*}$, $B^{*}_{s}$, $B^{*}_{c}$) and tensor ($D_{2}^{*}$, $D_{s2}^{*}$, $B^{*}_{2}$, $B^{*}_{s2}$) mesons in the light front quark model. With the known pseudoscalar meson decay constants of $f_D$, $f_{D_s}$, $f_B$, $f_{B_s}$, and $f_{B_c}$ as the input parameters to determine the light-front meson wave functions, we obtain that $f_{D^{*}, D^{*}_{s}, B^{*},B^{*}_s,B^{*}_c} = (252.0^{+13.8}_{-11.6}$, $318.3^{+15.3}_{-12.6}$ , $201.9^{+43.2}_{-41.4}$, $244.2\pm7.0$, $473.4\pm18.2$) and $(264.9^{+10.2}_{-9.5}$, $330.9^{+9.9}_{-9.0}$, $220.2^{+49.1}_{-46.2}$, $265.7\pm8.0$, $487.6\pm19.2$) MeV with Gaussian and power-law wave functions, respectively, while $f_{D_{2}^{*},D_{s2}^{*},B^{*}_{2},B^{*}_{s2}}$= ($143.6^{+24.9}_{-21.8}$, $209.5^{+29.1}_{-24.2}$, $80.9^{+33.8}_{-27.7}$, $109.7^{+15.7}_{-15.0}$) MeV with only Gaussian wave functions.

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arXiv2014

Semi-dileptonic decays of the light vector mesons in Light Front Quark Model

We study the transition form factors of the light vector to pseudoscalar mesons as functions of the momentum transfer $q^2$ within the light-front quark model. With these form factors, we calculate the decay branching ratios of all possible modes for $V\to P\ell^+\ell^-$ ($V=ω$ and $ϕ$, $P=π^0$, $η$ and $η^{\prime}$ and $\ell=e$ and $μ$). We find that our numerical results fit with the data, such as those of $ω\to π^0 \ell^+\ell^-$ and $ϕ\to π^0 e^+e^-$ by NA60 and $ϕ\toηe^+e^-$ by SND. We also predict that the branching ratios of $ϕ\to π^0 μ^+μ^-$, $ω\to ηe^+e^-$, $ω\to ημ^+μ^-$, $ϕ\to ημ^+μ^-$ and $ϕ\to η^{\prime} e^+e^-$ to be aroud $3.48\times 10^{-6}$, $3.22\times 10^{-6}$, $1.81\times 10^{-9}$, $6.86\times 10^{-6}$ $2.97\times 10^{-7}$, respectively.

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arXiv2013

Form factors of $η_c$ in light front quark model

We study the form factors of the $η_c$ meson in the light-front quark model. We explicitly show that the transition form factor of $η_c \to γ^* γ$ as a function of the momentum transfer is consistent with the experimental data by the BaBar collaboration, while the decay constant of $η_c$ is found to be $f_{η_{c}}=230.5^{+52.2}_{-61.0}$ and $303.6^{+115.2}_{-116.4}$ MeV for $η_c\sim c\bar{c}$ by using two $η_c \to γγ$ decay widths of $5.3\pm 0.5$ and $7.2\pm2.1$ keV, given by Particle Data Group and Lattice QCD calculation, respectively.

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arXiv2012

Study of pesudoscalar transition form factors within light front quark model

We study the transition form factors of the pesudoscalar mesons ($π,η$ and $η^{\prime}$) as functions of the momentum transfer $Q^2$ within the light-front quark model. We compare our results with the recent experimental data by CELLO, CLEO, BaBar and Belle. By considering the possible uncertainties from the quark masses, we illustrate that our predicted form factors can fit with all the data, including those at the large $Q^2$ regions.

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arXiv2012

$π^0\toγ^*γ$ transition form factor within Light Front Quark Model

We study the transition form factor of $π^0\toγ^* γ$ as a function of the momentum transfer $Q^2$ within the light-front quark model (LFQM). We compare our result with the experimental data by BaBar as well as other calculations based on the LFQM in the literature. We show that our predicted form factor fits well with the experimental data, particularly those at the large $Q^2$ region.

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arXiv2011

Study of the Radivative Pion Decay

We study the radiative pion decay of $π^{+} \to e^{+}ν_{e}γ$ in the chiral perturbation theory (ChPT) and light front quark model (LFQM). The vector and axial-vector hadronic form factors ($F_{V,A}$) for the $π\toγ$ transition are evaluated in the whole allowed momentum transfer. In terms of these momentum dependent form factors, we calculate the decay branching ratio and compare our results with the experimental data and other theoretical predictions in the literature. We also constrain the possible size of the tensor interaction in the LFQM.

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arXiv2010

Study of $π^{0}$ and $η$ decays containing dilepton

We calculate the momentum dependent form factors of $P \to γ^* γ^*$($P=π^{0}, η$) within the light-front quark model. Using the form factors, we examine the decays of $P \to l^+ l^-$, $P \to l^+ l^- γ$ and $P \to l^+ l^- l^+ l^-$($l=e$ or $μ$) and compare our results with the experimental data and other theoretical predictions. In particular, for $π^0 \to e^+e^-$, we find that the decay branching ratio is $6.68\times 10^{-8}$, which is consistent with the recent measurement of $(7.48\pm0.29\pm0.25)\times 10^{-8}$ by E799 of KTeV/Fermilab.

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arXiv2007

Analysis of $K^+ \to e^+ ν_{e}γ$ in light-front quark model and chiral perturbation theory of order $p^6$

Within the frameworks of the light-front quark model (LFQM) and chiral perturbation theory (ChPT) of $O(p^6)$, we reevaluate the form factors of the $K^+ \to γ$ transition. We use these form factors to study the decay of $K^+ \to e^+ ν_{e}γ$, which is dominated by the structure dependent contribution. We show the differential decay branching ratio as a function of $x=2E_γ/m_K$, where $E_γ$ ($m_K$) is the photon energy (kaon mass). Explicitly, we find that, in the standard model with the cut of $x=0.01$ (0.1), the decay branching ratio of $K^+ \to e^+ ν_{e}γ$ is $1.54 (1.44)\times 10^{-5}$ and $1.57 (1.47)\times 10^{-5}$ in the LFQM and ChPT, respectively.

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arXiv2007

Study of $B \to K_0^* (1430)\ell\bar{\ell} $ Decays

We examine the exclusive rare decays of $B \to K_{0}^*(1430)\ell\bar{\ell} $ with $K_{0}^*(1430)$ being the p-wave scalar meson and $\ell=ν,e,μ,τ$ in the standard model. The form factors for the $B\to K_{0}^{*}$ transition matrix elements are evaluated in the light front quark model. For the decays of $B \to K_{0}^*\ell\bar{\ell}$, the branching ratios are found to be $(11.6,1.63,1.62,0.029)\times 10^{-7}$ with $\ell=(ν,e,μ,τ)$ and the integrated longitudinal lepton polarization asymmetries $(-0.97,-0.95,-0.03)$ with $\ell=(e,μ,τ)$, respectively.

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