arXiv subjects

Hui-Feng Fu

Publications and source records attributed to Hui-Feng Fu.

14 recordsLinked to original sources

arXiv2021

Chiral effective Lagrangian for excited heavy-light mesons from QCD

We derive the chiral effective Lagrangian for excited heavy-light mesons from QCD under proper approximations. We focus on the chiral partners with $j_l^P=\frac{3}{2}^+$ and $j_l^P=\frac{3}{2}^-$ which amounts to ($1^+,2^+$) and ($1^-,2^-$) states respectively. The low energy constants including the masses of the chiral partners are calculated. The calculated spectrum for the excited mesons are found roughly consistent with experimental data. In addition, our results indicate that quantum numbers of $B_J(5970)$ can be identified with $1^-$ or $2^-$.

hep-ph↗

arXiv2020

CP violation in non-leptonic $B_c$ decays to excited final states

We study the CP violation in two-body nonleptonic decays of $B_c$ meson. We concentrate on the decay channels which contain at least one excited heavy meson in the final states. Specifically, the following channels are considered: $B_c\to c\bar c(2S, 2P)+\bar cq(1S, 1P)$, $B_c\to c\bar c(1S)+\bar cq(2S, 2P)$, $B_c\to c\bar c(1P)+\bar cq(2S)$, $B_c\to c\bar c(1D)+\bar cq(1S, 1P)$, and $B_c\to c\bar c(3S)+\bar cq(1S)$. The improved Bethe-Salpeter method is applied to calculate the hadronic transition matrix element. Our results show that some decay modes have large branching ratios, which is of the order of $10^{-3}$. The CP violation effect in $B_c \rightarrow \eta_c(1S)+D(2S)$, $B_c \rightarrow \eta_c(1S)+D_0^{*}(2P)$, and $B_c \rightarrow J/\psi+D^{*}(2S)$ are most likely to be found. If the detection precision of the CP asymmetry in such channels can reach the $3\sigma$ level, at least $10^7$ $B_c$ events are needed.

hep-ph↗

arXiv2020

Chiral effective Lagrangian for heavy-light mesons from QCD: $1/m_{Q}$ correction

As a successive work to [Phys.Rev.D 102 (2020), 034034], we derive the $1/m_Q$ corrections to chiral effective Lagrangian for heavy-light mesons from QCD under proper approximations. The low energy constants in the effective Lagrangian are expressed in terms of the light quark self-energy and heavy quark mass $m_Q$. Numerical results of the low energy constants with $1/m_Q$ corrections are given. We find that the results of pion decay constant and the masses of heavy-light mesons are improved coherently compared to that obtained in the heavy quark limit.

hep-ph↗

arXiv2020

Uniqueness of the Observable Leaving Redundant Imprints in the Environment in the Context of Quantum Darwinism

In quantum Darwinism, the pointer observable of a system leaves redundant imprints in its environment after decoherence. Each imprint is recorded in a fraction of the environment, which identifies a particular partition of the environment. An ambiguity situation may occur when another observable noncommuting to the pointer observable also leaves redundant imprints with respect to another partition of the environment. We study this problem based on a uniqueness theorem we proved. We find that within a particular subset of all possible partitions of the environment, the observable of the system leaving redundant and nondegenerately recorded imprints in the environment is unique. And, in a typical situation, the partitions outside this particular subset have no physical significance.

quant-ph↗

arXiv2020

Chiral effective Lagrangian for heavy-light mesons from QCD

We derive the chiral effective Lagrangian for heavy-light mesons in the heavy quark limit from QCD under proper approximations. The low energy constants in the effective Lagrangian are expressed in terms of the light quark self-energy. With typical forms of the running coupling constant of QCD and the quark self-energy obtained from Dyson-Schwinger equations as well as lattice QCD, we estimate the low energy constants in the model and the strong decay widths. A comparison with data and some discussions of the numerical results are presented.

hep-ph↗

arXiv2017

Derivation of the gap and Bethe-Salpeter equations at large $N_c$ limit and symmetry preserving truncations

We develop a framework for deriving Dyson-Schwinger Equations (DSEs) and Bethe-Salpeter Equation (BSE) in QCD at large $N_c$ limit. The starting point is a modified form (with auxiliary fields) of QCD generating functional. This framework provides a natural order-by-order truncation scheme for DSEs and BSE, and the kernels of the equations up to any order are explicitly given. Chiral symmetry (at chiral limit) is preserved in any order truncation, so it exemplifies the symmetry preserving truncation scheme. It provides a method to study DSEs and BSE beyond the Rainbow-Ladder truncation, and is especially useful to study contributions from non-Abelian dynamics (those arise from gluon self-interactions). We also derive the equation for the quark-ghost scattering kernel, and discuss the Slavnov-Taylor identity connecting the quark-gluon vertex, the quark propagator and the quark-ghost scattering kernel.

hep-th↗

arXiv2017

Derivation of the effective Chiral Lagrangian for pseudoscalar, scalar, vector and axial-vector mesons from QCD

A previous formal derivation of the effective chiral Lagrangian for low-lying pseudoscalar mesons from first-principles QCD without approximations [Wang et al., Phys. Rev. D61, (2000) 54011] is generalized to further include scalar, vector, and axial-vector mesons. In the large Nc limit and with an Abelian approximation, we show that the properties of the newly added mesons in our formalism are determined by the corresponding underlying fundamental homogeneous Bethe--Salpeter equation in the ladder approximation, which yields the equations of motion for the scalar, vector, and axial-vector meson fields at the level of an effective chiral Lagrangian. The masses appearing in the equations of motion of the meson fields are those determined by the corresponding Bethe--Salpeter equation.

hep-ph↗

arXiv2016

Annihilation Rates of $^3D_2(2^{--})$ and $^3D_3(3^{--})$ Heavy Quarkonia

We calculate the annihilation decay rates of the $^3D_2(2^{--})$ and $^3D_3(3^{--})$ charmonia and bottomonia by using the instantaneous Bethe-Salpeter method. The wave functions of states with quantum numbers $J^{PC}=2^{--}$ and $3^{--}$ are constructed. By solving the corresponding instantaneous Bethe-Salpeter equations, we obtain the mass spectra and wave functions of the quarkonia. The annihilation amplitude is written within Mandelstam formalism and the relativistic corrections are taken into account properly. This is important, especially for high excited states, since their relativistic corrections are large. The results for the $3g$ channel are as follows: $\Gamma_{^3D_2(c\bar c)\rightarrow ggg} = 9.24$ keV, $\Gamma_{^3D_3(c\bar c)\rightarrow ggg}=25.0$ keV, $\Gamma_{^3D_2(b\bar b)\rightarrow ggg}= 1.87$ keV, and $\Gamma_{^3D_3(b\bar b)\rightarrow ggg}= 0.815$ keV.

hep-ph↗

arXiv2015

Some of semileptonic and nonleptonic decays of $B_c$ meson in a Bethe-Salpeter relativistic quark model

The semileptonic decays $B_c^+\rightarrow P(V) +\ell^++\barν_\ell$ and the nonleptonic decays $B_c^+\rightarrow P(V)+L$, where $P(V)$ denotes a pseudoscalar (vector) charmonium or ($\bar{b}s$)-meson, and $L$ denotes a light meson, are studied in the framework of improved instantaneous Bethe-Salpeter (BS) equation and the Mandelstam formula. The numerical results (width and branching ratio of the decays) are presented in tables, and in order to compare conveniently, those obtained by other approaches are also put in the relevant tables. Based on the fact that the ratio $\frac{\mathcal{BR}(B_c^+\rightarrowψ(2S)π^+)}{\mathcal{BR}(B_c^+\rightarrow J/ψπ^+)}=0.24^{+0.023}_{-0.040}$ estimated here is in good agreement with the observation by the LHCb $\frac{\mathcal{BR}(B_c^+\rightarrow ψ(2S)π^+)}{\mathcal{BR}(B_c^+\rightarrow J/ψπ^+)}=0.250\pm0.068(\mathrm{stat})\pm0.014(\mathrm{syst})\pm0.006(\mathcal{B})$, one may conclude that with respect to the decays the present framework works quite well.

hep-ph↗

arXiv2015

The Quark Propagator in a Truncation Scheme beyond the Rainbow Approximation

The quark propagator is studied under a truncation scheme beyond the rainbow approximation by dressing the quark-gluon vertex non-perturbatively. It is found that, in the chiral limit with dynamical symmetry breaking, the dynamical quark mass and the quark condensate are significantly enhanced due to the non-Abelian contribution arising from the three-gluon interaction compared to those under the rainbow approximation; and the critical strength of the dynamical chiral symmetry breaking is much lowered. The Abelian contribution is much smaller than the non-Abelian contribution. A technical issue on removing the ultraviolet divergences including the overlapping divergences is discussed.

hep-ph↗

arXiv2015

The rare semi-leptonic $B_c$ decays involving orbitally excited final mesons

The rare processes $B_c\to D_{(s)J} ^{(*)}μ\barμ$, where $D_{(s)J}^{(*)}$ stands for the final meson $D_{s0}^*(2317)$, $D_{s1}(2460,2536)$,~$D_{s2}^*(2573)$, $D_0^*(2400)$, $D_{1}(2420,2430)$ or~$D_{2}^*(2460)$, are studied within the Standard Model. The hadronic matrix elements are evaluated in the Bethe-Salpeter approach and furthermore a discussion on the gauge-invariant condition of the annihilation hadronic currents is presented. Considering the penguin, box, annihilation, color-favored cascade and color-suppressed cascade contributions, the observables $\text{d}Br/\text{d}Q^2$, $A_{LPL}$, $A_{FB}$ and $P_L$ are calculated.

hep-ph↗

arXiv2014

The Study of Rare $B_c\rightarrow D^{(*)}_{s,d}l\bar{l}$ Decays

In this paper, we study rare decays $B_c\rightarrow D^{(*)}_{s,d}l\bar{l}$ within the Standard Model. The penguin, box, annihilation, color-favored cascade and color-suppressed cascade contributions are included. Based on our calculation, the annihilation and color-favored cascade diagrams play important roles in the differential branching fractions, forward-backward asymmetries, longitudinal polarizations of the final vector mesons and leptonic longitudinal polarization asymmetries. More importantly, color-favored cascade decays largely enhance the resonance cascade contributions. To avoid the resonance cascade contribution pollution, new cutting regions are put forward.

hep-ph↗

arXiv2013

Two-Body Strong Decay of Z(3930) as the $χ_{c2} (2P)$ State

The new particle Z(3930) found by the Belle and BaBar Collaborations through the $γγ\rightarrow D\bar D$ process is identified to be the $χ_{c2}(2P)$ state. Since the mass of this particle is above the $D\bar D^{(\ast)}$ threshold, the OZI-allowed two-body strong decays are the main decay modes. In this paper, these strong decay modes are studied with two methods. One is the instantaneous Bethe-Salpeter method within Mandelstam formalism. The other is the combination of the $^3P_0$ model and the former formalism. The total decay widths are 26.3 and 27.3 MeV for the methods with or without the $^3P_0$ vertex, respectively. The ratio of $Γ_{D\bar D}$ over $Γ_{D\bar D^\ast}$ which changes along with the mass of the initial meson is also presented.

hep-ph↗

arXiv2012

The Strong Decays of Orbitally Excited $B^{*}_{sJ}$ Mesons by Improved Bethe-Salpeter Method

We calculate the masses and the strong decays of orbitally excited states $B_{s0}$, $B'_{s1}$, $B_{s1}$ and $B_{s2}$ by the improved Bethe-Salpeter method. The predicted masses of $B_{s0}$ and $B'_{s1}$ are $M_{B_{s0}}=5.723\pm0.280 {\rm GeV}$, $M_{B'_{s1}}=5.774\pm0.330 {\rm GeV}$. We calculate the isospin symmetry violating decay processes $B_{s0}\to B_s π$ and $B'_{s1}\to B_s^* π$ through $π^0-η$ mixing and get small widths. Considering the uncertainties of the masses, for $B_{s0}$ and $B'_{s1}$, we also calculate the OZI allowed decay channels: $B_{s0}\to B\bar K$ and $B'_{s1}\to B^*\bar K$. For $B_{s1}$ and $B_{s2}$, the OZI allowed decay channels $B_{s1}\to B^{*}\bar K$, $B_{s2}\to B\bar K$ and $B_{s2}\to B^{*}\bar K$ are studied. In all the decay channels, the reduction formula, PCAC relation and low energy theorem are used to estimate the decay widths. We also obtain the strong coupling constants $G_{B_{s0}B_sπ}$, $G_{B_{s0}B\bar K}$, $G_{B'_{s1}B_s^*π}$, $F_{B'_{s1}B_s^*π}$, $G_{B'_{s1}B^*\bar K}$, $F_{B'_{s1}B^*\bar K}$, $G_{B_{s1}B^{*}\bar K}$, $F_{B_{s1}B^{*}\bar K}$, $G_{B_{s2}B\bar K}$ and $G_{B_{s2}B^{*}\bar K}$.

hep-ph↗