arXiv subjects

Xiao-Hui Hu

Publications and source records attributed to Xiao-Hui Hu.

15 recordsLinked to original sources

arXiv2026

Final-state rescattering mechanism of doubly-charmed baryon decays: $\mathcal{B}_{cc}\to\mathcal{B}_{c}V$

We study the non-leptonic weak decays of doubly charmed baryons (${\cal B}_{cc}$) into singly charmed baryons (${\cal B}_c$) and vector mesons ($V$), denoted as ${\cal B}_{cc}\to{\cal B}_{c}V$. The short-distance contributions are calculated within the naive factorization hypothesis, while the long-distance final-state interaction effects are modeled via hadronic triangle diagrams. Unlike previous approaches, which compute only the imaginary part using the Cutkosky cutting rule, we evaluate the complete loop integrals to obtain both the real and imaginary parts of the amplitudes. These provide the nontrivial strong phases essential for CP violation. The model parameters are determined using experimental data. With this improved calculation method, we predict the branching ratios and decay asymmetry parameters for various decay channels, as well as $CP$ violations for short-distance dominated and singly Cabibbo-suppressed channels. This strengthens our theoretical framework for future study of doubly charmed baryons. Certain decays, primarily driven by long-distance effects, have been calculated; their observation in future experiments could help clarify the role of final-state interactions in charm baryon decays. Therefore, our calculation of ${\cal B}_{cc}\to{\cal B}_{c}V$ provides crucial predictions for branching ratios, decay asymmetry parameters, and $CP$ violation, which are essential for guiding experimental study at LHCb.

hep-ph↗

arXiv2026

Branching fraction of $Ξ_{bc}^+\to Ξ_{c}^+ J/ψ$ in the final-state-interaction approach

The process of $Ξ_{bc}^{+}\to Ξ_{c}^{+}J/ψ$ is among the most favored modes for searching for bottom-charm baryons. However, its branching fraction has never been studied in theory. In this work, we investigate the branching fraction of $Ξ_{bc}^{+}\to Ξ_{c}^{+}J/ψ$ in the final-state-interaction approach, as it is dominated by the color-suppressed non-factorizable contributions. A similar process, $Λ_{b}^{0}\to Λ^0 J/ψ$, is used as a control mode to fix the model parameter. Consequently, the branching fraction of $Ξ_{bc}^{+}\to Ξ_{c}^{+}J/ψ$ is predicted to be $(1.55_{-0.42}^{+0.50})\times10^{-4}$. With the production rate of bottom-charm baryons and the detection efficiencies of the final states, it is expected for considerable signal events to observe $Ξ_{bc}^+$ in the near future.

hep-ph↗

arXiv2025

New Physics Search at the CEPC: a General Perspective

The Circular Electron-Positron Collider (CEPC), a proposed next-generation Higgs factory, provides new opportunities to explore physics beyond the Standard Model (SM). With its clean electron-positron collision environment and the ability to collect large samples of Higgs, W, and Z bosons, the CEPC enables precision measurements and searches for new physics. This white paper outlines the CEPC's discovery potential, including studies of exotic decays of the Higgs, Z, and top quarks, dark matter and dark sector phenomena, long-lived particles, supersymmetry, and neutrino-related signatures. Advanced detector technologies and reconstruction techniques, such as one-to-one correspondence reconstruction and jet origin identification, significantly improve sensitivity to rare and weakly interacting processes. The CEPC is particularly well suited to probe the electroweak phase transition and test models of electroweak baryogenesis and dark sector interactions. In addition, global fit analyses highlight the CEPC's complementary role in constraining a wide range of new physics scenarios. These features position the CEPC as a powerful tool for exploring the next frontier in fundamental particle physics in the post-Higgs discovery era.

hep-ex↗

arXiv2025

Bottom baryon decays into light meson and dark baryon within perturbative QCD approach

In the work, we study the production of dark baryon $ψ$ with the bottom-baryon decays $Λ_b\to M ψ$ under the perturbative QCD approach. For the Type-I/II models in B-Mesogenesis scenarios, we calculate the form factors for bottom-baryon decays into meson. Using these results, we obtain branching ratios for $Λ_b\to M ψ$ decays. The PQCD approach calculations show these branching ratios reach $\mathcal{O}(10^{-5})$ in both models, with $\mathcal{B}(Λ_b\to Kψ)$ specifically reaching $\mathcal{O}(10^{-4})$ in Type-II. These accessible magnitudes make the predictions testable at the LHCb and B-factories with improved precision.

hep-ph↗

arXiv2025

Final-state rescattering mechanism of double-charm baryon decays: $\mathcal{B}_{cc}\to\mathcal{B}_{c}P$

In this study, we examine the non-leptonic weak decays of doubly charmed baryons, denoted as ${\cal B}_{cc}\to{\cal B}_{c}P$, where ${\cal B}_{cc}$ represents the doubly charmed baryons, specifically $(Ξ_{cc}^{++},Ξ_{cc}^{+},Ω_{cc}^{+})$. The notation ${\cal B}_{c}$ denotes the singly charmed baryons, specifically $({\cal B}_{\bar{3}},{\cal B}_{6})$, while $P$ signifies the light pseudoscalar. These terms are pertinent to the non-leptonic decay modes under discussion. While the short-distance contributions can be precisely estimated through theoretical calculations, addressing the long-distance contributions for final-state-interaction effects presents a significant challenge. In order to address this issue, we utilize the rescattering mechanism of final state interaction effects to compute the long-distance contributions. We initially derive the entire hadronic loop contributions for these two-body nonleptonic decays of doubly charmed baryons. In subsequent analyses, we are able to calculate relative strong phases. As a result, we can provide predictions for their decay asymmetry parameters and CP violations. Furthermore, we employ experimental data from the LHCb collaboration, specifically the ratio $Br(Ξ_{cc}^{++}\toΞ_{c}^{\prime+}π^{+})/Br(Ξ_{cc}^{++}\toΞ_{c}^{+}π^{+})=(1.41\pm0.17\pm0.10)$, to ascertain the model parameters $η=0.9\pm0.2$. Consequently, we present the predictions of branching ratios and decay asymmetry parameters for 67 distinct decay processes and $CP$ violations for the singly Cabibbo suppressed channels. This not only strengthens the validity of our theoretical predictions, but also provides a more comprehensive theoretical framework for the future identification of other doubly charmed baryons.

hep-ph↗

arXiv2025

The strong coupling constants of doubly heavy baryons with heavy mesons

In the experiment, only one doubly charmed baryon $Ξ_{cc}^{++}$ was successfully identified. The LHCb collaboration is poised to discover other doubly heavy baryon, $Ξ_{cc}^{+}$ and $Ξ_{bc}^{+}$, necessitating a comprehensive study of doubly heavy baryons from various perspectives. Such investigations will elucidate the properties of the newly discovered states and facilitate the search for other doubly heavy baryons as predicted in quark model. In this paper, we explore the strong coupling between the doubly heavy baryon, singly heavy baryon, and heavy meson, ${\cal B}_{QQ^{\prime}}{\cal B}_{Q}M_{Q^{\prime}}$, using the light cone QCD sum rules approach. We analytically and numerically calculate the strong coupling, ${\cal B}_{QQ^{\prime}}{\cal B}_{Q}M_{Q^{\prime}}$, utilizing the light-cone distribution amplitudes of the singly heavy baryon ${\cal B}_{Q}$. The numerical predictions for these strong couplings are provided, along with the error analysis. Our theoretical findings can be employed to examine the strong and weak decay dynamics of doubly heavy baryons. Furthermore, our results may offer experimentalists a valuable tool for analyzing data on the strong coupling constants among hadronic multiplets.

hep-ph↗

arXiv2024

The study of the singly anti-charmed pentaquark production in b-factory

The b-factories, such as BelleII, BarBar and LHCb, emphasize the increasing importance of exotic hadron research. In this paper, we discuss the possible production of singly anti-charmed pentaquark states $\bar{c}q qqq$ from $B$ mesons in the b-factory under SU(3) symmetry analysis. Discussions of both possibilities have been driven by the hypothesis that the pentaquark state considered in this work, known as the lowest lying state $P_{\bar c}$, could be bound or unbound. We find the golden channels for the production of the pentaquark ground states, such as $B^0 \to {P}_{\bar{c}sudu}^{(\prime) 0}Σ^0$. We further estimate the branching ratios for the production of the ground states $P_{\bar c}$ from $B$ meson decays. Thus, multiple channels are available for experiments, which may remove certain obstacles to the discovery of new pentaquark states.

hep-ph↗

arXiv2023

Baryons in the light-front approach: The three-quark picture

In this work, a three-quark picture is constructed using a bottom-up approach for baryons in light-front quark model. The shape parameters, which characterize the momentum distribution inside a baryon, are determined with the help of the pole residue of the baryon. The relation between the three-quark picture and the diquark picture is clarified. When building the model, we find that Lorentz boost plays a crucial role, and the bottom-up modeling approach can be generalized to multiquark states. Based on this, a unified theoretical framework for describing multiquark states may be established. As a by-product of model construction, we can easily obtain a newly improved definition of baryon interpolating current. The hadron interpolating currents are the starting point of Lattice QCD and QCD sum rules, and therefore are of great importance.

hep-ph↗

arXiv2023

The Production of Charm Pentaquark from B meson within SU(3) Analysis

We study the masses and production modes of pentaquark with the quark constituent $c\bar qqqq$, by the tridiquark-diquark model and systematical light flavor quark symmetry SU(3) analysis. The mass splittings show that the S-wave singly charm pentaquark $c\bar udds$, $c\bar dusu$, $c\bar sudu$, and $c\bar sudd$ are below their strong decay thresholds, while $c\bar u ds s, c \bar d uss$ with parity $\frac{1}{2}^-$ are near their strong decay thresholds, which imply the possibility of stable states. Furthermore, we discuss the production of the concerned 15 states from $B$ meson, the analysis within SU(3) symmetry yields the golden channels of production process, $\overline B^0_s\!\!\to F_{-1/2}^+ \overline p,\ B^-\!\!\to F_{-3/2}^- \overline Λ^0$, which expected to be work worthily in b-factory.

hep-ph↗

arXiv2022

Light-Cone Sum Rules Analysis of $Ξ_{QQ^{\prime}q}\toΣ_{Q^{\prime}}^{*}$ Weak Decays

In this work, we investigate the semi-leptonic weak decays of spin-1/2 doubly-heavy baryons $Ξ_{QQ^{\prime}}$ into spin-3/2 singly-heavy baryons $Σ_{Q^{\prime}}^*$ within light-cone sum rules. Using the parallel components of the light-cone distribution amplitudes of $Σ_{Q^{\prime}}^*$, the transition form factors for these decays are calculated both analytically and numerically. The numerical results for these semi-leptonic weak decays widths and branching ratios are also predicted, which are compared with the same predictions by other theoretical approaches in the literatures. These phenomenology predictions can be tested by the experiments in the future.

hep-ph↗

arXiv2020

A comprehensive analysis of weak transition form factors for doubly heavy baryons in the light front approach

The transition form factors for doubly heavy baryons into a spin-$1/2$ or spin-$3/2$ ground-state baryon induced by both the charged current and the flavor changing neutral current are systematically studied within the light-front quark model. In the transition the two spectator quarks have two spin configurations and both are considered in this calculation. We use an updated vertex functions, and inspired by the flavor SU(3) symmetry, we also provide a new approach to derive the flavor-spin factors. With the obtained transition form factors, we perform a phenomenological study of the corresponding semi-leptonic decays of doubly heavy baryons induced by the $c\to d/s \ell^+ν$, $b\to c/u\ell^-\bar ν$ and $b\to d/s\ell^+\ell^-$. Results for partial decay widths, branching ratios and the polarization ratios $Γ_{L}/Γ_{T}$s are given. We find that most branching ratios for the semi-leptonic decays induced by the $c\to d,s$ transitions are at the order of $10^{-3}\sim10^{-2}$, which might be useful for the search of other doubly-heavy baryons. Uncertainties in form factors, the flavor SU(3) symmetry and sources of symmetry breaking effects are discussed. We find that the SU(3) symmetry breaking effects could be sizable in charmed baryon decays while in the bottomed case, the SU(3) symmetry breaking effects are less significant. Our results can be examined at the experimental facilities in the future.

hep-ph↗

arXiv2020

Light-Cone Sum Rules Analysis of $Ξ_{QQ^{\prime}}\toΣ_{Q^{\prime}}$ Weak Decays

As a continuation of our previous work, we investigate the weak decays of doubly-heavy baryons $Ξ_{QQ^{\prime}}$ into sextet $Σ_{Q^{\prime}}$ with light-cone sum rules. We calculate the form factors for these decays with the parallel light-cone distribution amplitudes of $Σ_{Q^{\prime}}$. Numerical results of these form factors are used to predict the decay widths and branching ratios of the corresponding semi-leptonic processes. Parametric uncertainties and theoretical analyses are also given in detail. We find that the decay widths of $Ξ_{cc}$ and $Ξ_{bc}$ decays are several orders of magnitude larger than those of $Ξ_{bb}$ decays.

hep-ph↗

arXiv2019

Study of $s\to dν\barν$ rare hyperon decays within the Standard Model and new physics

FCNC processes offer important tools to test the Standard Model (SM), and to search for possible new physics. In this work, we investigate the $s\to dν\barν$ rare hyperon decays in SM and beyond. We find that in SM the branching ratios for these rare hyperon decays range from $10^{-14}$ to $10^{-11}$. When all the errors in the form factors are included, we find that the final branching fractions for most decay modes have an uncertainty of about $5\%$ to $10\%$. After taking into account the contribution from new physics, the generalized SUSY extension of SM and the minimal 331 model, the decay widths for these channels can be enhanced by a factor of $2 \sim 7$.

hep-ph↗

arXiv2018

Weak decays of doubly heavy baryons: "decay constants"

Inspired by the recent observation of the $Ξ_{cc}^{++}$ by LHCb collaboration, we explore the "decay constants" of doubly heavy baryons in the framework of QCD sum rules. With the $Ξ_{cc}, Ξ_{bc}, Ξ_{bb}$, and $Ω_{cc}, Ω_{bc}, Ω_{bb}$ baryons interpolated by three-quark operators, we calculate the correlation functions using the operator product expansion and include the contribution from operators up to dimension six. On the hadron side, we consider both contributions from the lowest-lying states with $J^P=1/2^+$ and from negative parity baryons with $J^P=1/2^-$. We find that the results are stable and the contaminations from negative parity baryons are not severe. These results are ingredients for the QCD study of weak decays and other properties of doubly-heavy baryons.

hep-ph↗

arXiv2016

Study of Nonleptonic $B^{\ast}_{(s)}\to M_1 M_2$ $(M=D$, $D_s$, $π$, $K)$ Weak Decays with Factorization Approach

Motivated by the experiments of heavy flavor physics at running LHC and upgrading SuperKEKB/Belle-II in the future, the nonleptonic $B^{\ast}_{(s)}\to M_1 M_2$ $(M=D$, $D_s$, $π$, $K)$ weak decays are studied in this paper. The amplitudes are calculated with factorization approach, and the transition form factors $A_0^{B^{\ast}_{(s)}\to M_1}(0)$ are evaluated within BSW model. With the reasonable approximation $Γ_{tot}(B^*_{(s)})\simeq Γ(B^*_{(s)}\to B_{(s)}γ)$, our predictions of branching fractions are presented. Numerically, the CKM-favored tree-dominated $\bar{B}^{*0} \to D^+D^-_s$ and $\bar{B}^{*0}_s \to D^+_sD^-_s$ decays have the largest branching fractions of the order $\sim{\cal O}(10^{-8})$, and hence will be firstly observed by forthcoming Belle-II experiment. However, most of the other decay modes have the branching fractions~$<{\cal O}(10^{-9})$ and thus are hardly to be observed soon. Besides, for the possible detectable $B^{\ast}_{(s)}$ decays with branching fractions $\gtrsim{\cal O}(10^{-9})$, some useful ratios, such as $R_D$ {\it et al.,} are presented and discussed in detail.

hep-ph↗