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Yu-Ji Shi

Publications and source records attributed to Yu-Ji Shi.

At least 19 recordsLinked to original sources

Towards power corrections in the factorization of baryon quasi-distribution amplitudes in LaMET

Light-cone distribution amplitudes (LCDAs) are essential to precision phenomenological studies. They can be accessed from lattice QCD through the large-momentum effective theory (LaMET) via quasi-distribution amplitudes (quasi-DAs). Factorization of quasi-DAs receive power corrections in inverse powers of the hadron momentum, including target-mass and higher-twist corrections. In this work, we present the first systematic analysis of such power corrections for the leading-twist baryon quasi-DA. Establishing the moment relation between the quasi-DA and the LCDA, we derive an exact closed-form relation that resums target-mass correction to all orders at leading twist. This result also applies to heavy baryons and to quasi-transverse-momentum-dependent distributions. We numerically assess these corrections for the $\Lambda$ baryon quasi-DA using existing lattice data, finding that the target-mass correction decreases rapidly with increasing baryon momentum and is almost negligible in the endpoint regions. In addition, we explicitly construct the next-to-leading-twist operators entering the quasi-DA factorization. Our results are a first step toward quantifying the power corrections in future lattice determinations of light or heavy baryon LCDAs.

hep-ph

Heavy quark mass dependence of the $\Lambda_Q$ light-cone distribution amplitude in QCD

We study the heavy quark mass dependence of the leading-twist light-cone distribution amplitude (LCDA) of the $\Lambda_Q$ baryon in QCD. Starting from the factorization formula that relates the QCD LCDA to the boosted heavy-quark effective theory (bHQET) LCDA, we derive a first-order partial differential equation governing this mass dependence in the peak region. The equation is solved analytically, and the explicit factor connecting LCDAs at different heavy quark masses is presented. We further incorporate Borel-resummed perturbative corrections from a renormalon model into the factorization. The impact of these renormalon corrections on the mass dependence is studied, and a numerical analysis using a simple LCDA model is performed to illustrate the behavior and to assess the uncertainties arising from the corrections, thereby providing a numerical estimate of the associated power corrections to the mass dependence. Our results provide an essential tool for extrapolating lattice QCD calculations of heavy-baryon LCDAs from smaller simulated masses to the physical bottom quark mass.

hep-ph

Factorization formula connecting the $\Lambda_Q$ LCDA in QCD and boosted HQET

Light-cone distribution amplitudes (LCDAs) are essential to precision phenomenology in heavy baryon decays. In this work, we derive a factorization formula connecting the leading-twist QCD LCDA to the boosted HQET LCDA of the $\Lambda_Q$ baryon in the peak region. We demonstrate a significant simplification of the matching procedure by applying the method-of-regions to perturbative calculations. With this simplification, we calculate the required one-loop perturbative corrections to the QCD and boosted HQET LCDAs in the $\overline{\rm MS}$ scheme, and thereby obtain the one-loop jet function that serves as the matching kernel in the factorization formula. This result provides a critical step toward lattice QCD calculation of heavy baryon LCDAs in the future.

hep-ph

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

In the work, we study the production of dark baryon $\psi$ with the bottom-baryon decays $\Lambda_b\to M \psi$ 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 $\Lambda_b\to M \psi$ decays. The PQCD approach calculations show these branching ratios reach $\mathcal{O}(10^{-5})$ in both models, with $\mathcal{B}(\Lambda_b\to K\psi)$ 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

On the equivalence of Flavor SU(3) analyses of $B\to PP$ decays

We conduct an SU(3) analysis of $B\to PP$ decays based on reduced matrix elements (RMEs), with $P$ being a light pseudoscalar meson excluding $\eta^{(\prime)}$. We show that a complete basis for the $B\to PP$ decays consists of ten RMEs, where the three RMEs arise from the electroweak penguin operators $O_{7,8}$. In the Standard Model, the relevant Wilson coefficients are small and thus can be neglected. We further demonstrate the equivalence of the RME approach with the irreducible representation amplitude (IRA) and topological diagram amplitude (TDA) methods, and derive relations between the ten RME amplitudes and corresponding IRA/TDA amplitudes. These relations lay a foundation for consistent SU(3) analyses of heavy meson decays.

hep-ph

QCD sum rules study on weak decays $\Omega_c^0\to\Omega^- (\pi^+, \rho^+, l^+\nu_l)$

We study the weak decays of the charmed baryon $\Omega_c^0$ to the $\Omega^-$ baryon within the framework of QCD sum rules. A three-point correlation function is defined for calculating eight form factors governing the $\Omega_c^0 \to \Omega^-$ transition. The cutting rules are employed to extract the double imaginary parts of the correlation functions, enabling their expression in the form of dispersive integrals. These form factors are then used to determine the branching fractions for the hadronic decays $\Omega_c^0 \to \Omega^- \pi^+$ and $\Omega_c^0 \to \Omega^- \rho^+$, as well as the semi-leptonic decay $\Omega_c^0 \to \Omega^- \ell^+ \nu_\ell$. Our results are compared with existing theoretical predictions and experimental data, providing a comprehensive analysis of $\Omega_c^0$ decays and offering valuable insights into the dynamics of charmed baryon decays.

hep-ph

Towards the strong decays of light strange four-quark states with $J^P=1^+$

This thesis considers the decays of fully light four quark exotic as the main subject. In the context, we study the possible decays from general symmetric analysis: $uu\bar d\bar s$, $dd\bar s\bar u$, $ds\bar u \bar u$, and $su\bar d \bar d$. Using the light quark flavor symmetry, we discuss the decay modes of decuplet and 27 multiplet with $J^P=1^+$. Further more, the phenomenological hadronic molecular approach is employed for the calculation of respective decay modes. Our results show that the total decay widths of $T_{\rho K}$ and $S_{\rho K^*}$ can reach several MeV. The two-body and three-body decay widths are further obtained respectively. These are excepted to be fairly valuable supports for future search experiments.

hep-ph

The strong coupling constants of doubly heavy baryons with heavy mesons

In the experiment, only one doubly charmed baryon $\Xi_{cc}^{++}$ was successfully identified. The LHCb collaboration is poised to discover other doubly heavy baryon, $\Xi_{cc}^{+}$ and $\Xi_{bc}^{+}$, 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

SU(3) symmetry analysis in charmed baryon two body decays with penguin diagram contribution

An increasing number of experimental measurements from the BESIII, Belle, and Belle-II collaborations encourage investigations into charmed baryon two-body decay processes. By including contributions from the penguin diagrams that are ignored in previous studies, we perform a global analysis with SU(3) flavor symmetry. Assuming all form factors are real, we achieve a remarkable minimal $\chi^{2}/d.o.f = 0.788$ and find that the contribution of the amplitude proportional to $V_{cb}^*V_{ub}$ is of the order $\sim 0.01$, comparable with the contribution of the tree-level diagram. Additionally, by using the KPW theorem to reduce the number of amplitudes from 13 to 7 in the leading contribution, it becomes possible to consider the complex form factor case for the leading IRA amplitude in the global analysis. However, the analysis of complex form factors significantly conflicts with the experimental data $Br(\Xi_c^0\to\Xi^-\pi^+)$, and by excluding this data, $\chi^2/d.o.f$ is reduced from 5.95 to 1.19. Although the analysis of complex form factors shows a significant central value of the penguin diagram contribution, the large errors from the corresponding form factors make it a challenge to precisely determine its true contribution. Consequently, the direct CP violation in decay processes is predicted to be approximately zero. With more data in future experiments, the penguin diagram contribution with the amplitude proportional to $V_{cb}^*V_{ub}$ will be precisely determined, allowing for a more accurate prediction of CP violation. Our analysis necessitates further theoretical investigations and experimental measurements in the future.

hep-ph

Light-cone sum rules study on the purely non-factorizable $\Lambda_{c}^{+}\to\Xi^{0}K^{+}$ decay

We investigate the purely non-factorizable $\Lambda_{c}^{+}\to\Xi^{0}K^{+}$ decay using light-cone sum rules. To extract the decay amplitudes, a three-point correlation function is defined and calculated at hadron and quark-gluon level, respectively. Both the W-exchange and the W-inward emission diagrams are considered in the quark-gluon level calculation, where the two-particle light-cone distribution amplitudes (LCDAs) of kaon are used as non-perturbative input. We obtain the decay amplitudes contributed from the twist-2 and twist-3 kaon LCDAs, respectively. The obtained P-wave amplitude is consistent with those predicted in the literature, while the S-wave one is much smaller. This significant difference between the S- and P- wave amplitudes leads to small up-down spin asymmetry, closing to the experimental measurement.

hep-ph

Heavy baryon decays into light meson and dark baryon within LCSR

We studied the decays of Heavy baryon into a pseudoscalar meson and a dark baryon in the recently developed $B$-Mesogenesis scenario, where the two types of effective Lagrangians proposed by the scenario are both considered. The decay amplitudes of $Λ_b^0$ are calculated by light-cone sum rules using its light-cone distribution amplitudes. The decay amplitudes of $Ξ_b^{0,\pm}$ are related with those of $Λ_b^0$ through a flavor SU(3) analysis. The uncertainties of threshold parameter and the Borel parameter are both considered in the numerical calculation. The values of effective coupling constants in the $B$-Mesogenesis are taken as their upper limits that obtained from our previous study on the inclusive decay. The upper limits of the decay branching fractions are presented as functions of the dark baryon mass.

hep-ph

Revisiting $Ξ_{Q}-Ξ_{Q}^{\prime}$ mixing in QCD sum rules

In this work, we perform a QCD sum rules analysis on the $Ξ_{Q}-Ξ_{Q}^{\prime}$ mixing. Contributions from up to dimension-6 four-quark operators are considered. However, it turns out that, only dimension-4 and dimension-5 operators contribute, which reveals the non-perturbative nature of mixing. Especially we notice that only the diagrams with the two light quarks participating in gluon exchange contribute to the mixing. Our results indicate that the mixing angle $θ_{c}=(1.2\sim2.8)^{\circ}$ for the $Q=c$ case and $θ_{b}=(0.28\sim0.34)^{\circ}$ for the $Q=b$ case. Our prediction of $θ_{c}$ is consistent with the most recent Lattice QCD result within error. Such a small mixing angle seems unlikely to resolve the tension between the recent experimental measurement from Belle and Lattice QCD calculation for the semileptonic decay $Ξ_{c}^{0}\toΞ^{-} e^{+}ν_{e}$.

hep-ph

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

Revisiting $K_1(1270)- K_1(1400)$ mixing in QCD sum rules

We investigate the $K_1(1270)-K_1(1400)$ mixing caused by the flavor $SU(3)$ symmetry breaking. The mixing angle is expressed by a $K_{1A}\to K_{1B}$ matrix element induced by the operators that breaks flavor $SU(3)$ symmetry. The QCD contribution to this matrix element is assumed to be dominated and calculated by QCD sum rules. A three-point correlation function is defined and handled both at the hadron and quark-gluon levels. The quark-gluon level calculation is based on operator product expansion up to dimension-5 condensates. A detailed numerical analysis is performed to determine the Borel parameters, and the obtained mixing angle is $θ_{K_1}=22^{\circ}\pm 7^{\circ}$ or $θ_{K_1}=68^{\circ}\pm 7^{\circ}$.

hep-ph

QED contributions to the $Ξ_c-Ξ_c'$ mixing

We explore the QED corrections to the $Ξ_c-Ξ_c^{\prime}$ mixing within the framework of light-front quark model (LFQM) in the three-quark picture. After explicitly investigating the relation between the $Ξ_c-Ξ_c^{\prime}$ mixing and the flavor $\rm {SU(3)}$ and heavy quark symmetry breaking, we derive the QED contributions to the mixing angle. Numerical results indicate the QED contribution is smaller than the one from the mass difference between the strange and up/down quark provided by a recent Lattice QCD analysis. Adding these contributions together we find that at this stage the $Ξ_c-Ξ_c^{\prime}$ mixing is small and still incapable to account for the large $\rm {SU(3)}$ symmetry breaking in the semi-leptonic $Ξ_c$ decays.

hep-ph

Semi-inclusive decays of $B$ meson into a dark anti-baryon and baryons

Using the recently developed $B$-Mesogenesis scenario, we studied the semi-inclusive decays of $B$ meson into a dark anti-baryon $ψ$ plus any possible states $X$ containing $u/c$ and $d/s$ quarks with unit baryon number. The two types of effective Lagrangians proposed by the scenario are both considered in the study. The semi-inclusive decay branching fractions of $B\to X ψ$ are calculated by the method of heavy quark expansion, where the non-perturbative contributions from the matrix elements of dimension-5 operators are included. We obtained the branching fractions as functions of the dark anti-baryon mass. Using the experimental upper limits of the branching fractions, we presented the constraints of the coupling constants in the $B$-Mesogenesis scenario.

hep-ph

Heavy flavor conserved semi-leptonic decay of $B_s$ in the covariant light-front approach

We study the heavy flavor conserved semi-leptonic decay $B_s\to B\ellν$ in the covariant light front approach. The covariant light front quark model is used to calculate the transition form factors of $B_s\to B^{(*)}$ as well as $D_s\to D$, which are consistent with the leading power predictions from the heavy quark symmetry. The angular distribution analysis on the $B_s\to B^{(*)}l\barν$ decay is performed by investigating the forward-backward asymmetry of the lepton. We also study the angular distribution of $B_{s}\to B^{*}(\to B γ)l\barν$ decay both through the lepton forward-backward asymmetry and the azimuth angle. The branching fractions of $B_s\to Bl\barν$ and $B_s\to B^{*}l\barν$ are at the order $10^{-8}$ and $10^{-9}$, respectively. The number of $B_s\to B l\barν$ events is estimated to be $1.76$. The branching fraction of $B_{s}\to B^{*}(\to B γ)l\barν$ is at the order $10^{-11}$, which is calculated by introducing Breit-Wigner distribution for the intermediate $B^*$.

hep-ph

Analysis of the interpolating currents of baryons: anomalous dimension

The anomalous dimensions for the interpolating currents of baryons are indispensable inputs in a serious QCD analysis of baryon. However, the results in the literature are vague. In view of this, in this work, we investigate the one-loop anomalous dimensions for some interpolating currents such as those of $Λ_{Q}$ and proton. Under the requirement of precise testing the Standard Model, this study is essential and significant for the QCD analysis in the future.

hep-ph