arXiv subjects

Ke-Wei Wei

Publications and source records attributed to Ke-Wei Wei.

At least 19 recordsLinked to original sources

arXiv2024

Probing the soft rescattering parameters in $B$ decays involving a scalar meson with QCD factorization

In this work, the soft rescattering parameters in the $B^\pm\rightarrow π^\pmπ^+π^-$ and $B^\pm\rightarrow K^\pmπ^+π^-$ decays with the light scalar meson $f_0(500)$ as the intermediate resonance are studied within the QCD factorization. Considering the interference effect between $ρ(770)^0$ and $f_0(500)$, we utilize the experimentally more direct event yields for fitting and get the soft rescattering parameters $|ρ_k^{SP}|=3.29\pm1.01$ and $|ρ_k^{PS}|=2.33\pm0.73$ in $B\rightarrow PS$ and $B\rightarrow SP$ decays ($P$ and $S$ denote pseudoscalar and scalar mesons, respectively), respectively. We also study the branching ratios and $CP$ asymmetries in the decay modes involving other scalar mesons, including $f_0(980)$, $a_0(980)$, $a_0(1450)$ and $K_0^*(1430)$, to test the rationality of the values of $|ρ_k^{SP}|$ and $|ρ_k^{PS}|$. Meanwhile, the wealth of experimental data facilitate the examination of the forward-backward asymmetry induced $CP$ asymmetries (FB-CPAs), and the localized $CP$ asymmetries (LACPs). We investigate these asymmetries resulting from the interference between $ρ(770)^0$ and $f_0(500)$ for $B^\pm\rightarrow π^\pmπ^+π^-$ and $B^\pm\rightarrow K^\pmπ^+π^-$ decays when the invariant mass of $π^+π^-$ locates in the low-energy region $0.445\mathrm{GeV}<m_{ππ}<0.795\mathrm{GeV}$. Our theoretical results of FB-CPAs and LACPs align with the experimental findings. We propose that the interference between $ρ(770)^0$ and $f_0(500)$ can be extended to other beauty and charmed mesons decays.

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arXiv2023

Mass and decay of the $s\bar{s}$ member of the $1^{3}F_{4}$ meson nonet

The mass and decay of the $s\bar{s}$ member of the $1^{3}F_{4}$ meson nonet are investigated in the framework of the Regge phenomenology and the $^{3}P_{0}$ model. We propose, based on the results, that the assignment of the $s\bar{s}$ member of the $1^{3}F_{4}$ meson nonet will require additional testing in the future. Our results also provide information for future studies of the $1^{3}F_{4}$ meson nonet.

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arXiv2023

Mass spectrum and decays of the first radial excitation axial vector meson nonet

In this work, the mass spectrum of the first radial excitation axial vector meson nonet is considered in the framework of the nonrelativistic constituent quark model and Regge phenomenology. After that, we investigate the strong decay characteristics of these states within the $^{3}P_{0}$ model. The results are compared to values from other phenomenological models, and they may be beneficial in the prospective search for $2^{3}P_{1}$ meson nonets.

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arXiv2022

Revisiting the assignment of $1^{3}D_{1}$ meson nonet

Based on the mass relations from the Regge phenomenology, we revisit the mass spectrum of $1^{3}D_{1}$ meson nonet. The masses of kaon and $s\bar{s}$ member of $1^{3}D_{1}$ ($1^{3}D_{1}(s\bar{s})$) meson nonet are obtained and the results are compared with the values from different theoretical models. Moreover, the strong decay properties of the kaon and $1^{3}D_{1}(s\bar{s})$ are presented in the $^{3}P_{0}$ model. On the basis of results, we suggest the assignment of $1^{3}D_{1}$ meson nonet need further tested in the new experiment in the future. Our results also provide mass constraints for the study of these states.

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arXiv2022

Re-evaluation of the isoscalar mixing angle within selected mesonic nonets

Based on the relations from the meson-meson mass mixing matrix, the mixing angles of isoscalar state have been re-evaluated via mass relations and latest experimental results. The results in the present work are compared with the values from different theoretical models, meanwhile, the quarkonia content of isoscalar state are presented. In order to check the validity of analysis, some predictions on the decays of the isoscalar state are presented. These predictions may be useful for the phenomenological analysis for meson nonet in future experiments.

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arXiv2022

$b$-hadron spectroscopy study based on the similarity of double bottom baryon and bottom meson

The dynamical similarity which exists between the $λ$-mode excited $bbq$ baryons ($q$ refers to the $u$, $d$, and $s$ quarks) and the $\bar{b}q$ mesons inspires us to carry out a combined study of their spectroscopy. In this work, the masses and strong decays of these low-lying $b\bar{q}$ and $bbq$ states are studied by the same theoretical methods, and the dynamical similarity which is implied in their mass spectra and strong decays are also discussed. The recent discovered $\bar{b}q$ states, including the $B_J(5840)$, $B_J(5970)$, $B_{sJ}(6064)$, and $B_{sJ}(6114)$, are analyzed. According to our result, the $B_J(5840)$ could be assigned as a 2$S$ state, while the $B_J(5970)$ could be regarded as a member of the $1D(2^-,~3^-)_{j_q=5/2}$ doublet. The $B_{sJ}(6064)$ and $B_{sJ}(6114)$ are probably the $D$-wave states. Especially, they could be explained as the members of the $1D(1^-,~2^-)_{j_q=3/2}$ and $1D(2^-,~3^-)_{j_q=5/2}$ doublets, respectively. The predicted masses and decay properties of other unknown $\bar{b}q/bbq$ states may provide useful clues to the future experiment.

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arXiv2018

Role of newly discovered $Ξ_b(6227)^-$ for constructing excited bottom baryon family

Selecting the newly observed $Ξ_b(6227)^-$ by LHCb as a study example, we decode its inner structure by giving the mass spectrum analysis and the investigation of its two-body strong decay behaviors. Our result indicates that the $Ξ_b(6227)^-$ is a good candidate of the $P$-wave $Ξ_b^{\prime}$ state with $J^P=3/2^-$ or $5/2^-$. In addition, we further provide the information of the properties of the partners of the $Ξ_b(6227)^-$. These predicted states include three $2S$ states and the remaining $1P$ states in the bottom-strange baryon family. The calculated sizable Okubo-Zweig-Iizuka$-$allowed decay widths of these partners show that the experimental search for them becomes possible via LHCb. We have a reason to believe that the present study can be treated as a start point for constructing the highly excited bottom baryon spectroscopy.

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arXiv2017

Spectra of charmed and bottom baryons with hyperfine interaction

Up to now, the excited charmed and bottom baryon states are still not well studied both experimentally and theoretically. In the present paper, we predict the mass of $Ω_b^*$, the only $L = 0$ baryon state which has not been observed, to be 6069.2 MeV. The spectra of charmed and bottom baryons with the orbital angular momentum $L = 1$ are studied in two popular constituent quark models, the Goldstone boson exchange (GBE) and the one gluon exchange (OGE) hyperfine interaction models, respectively. Inserting the latest experimental data from the "Review of Particle Physics", we find that in the GBE model, there exist some multiplets ($Σ_{c(b)}$, $Ξ'_{c(b)}$ and $Ω_{c(b)}$) which total spins of three quarks in their lowest energy states are 3/2, but in the OGE model there is no such phenomenon. This is the most important difference between the GBE and OGE models. These results can be tested in the near future. We suggest more efforts to study the excited charmed and bottom baryons both theoretically and experimentally, not only for the abundance of baryon spectra, but also for determining which hyperfine interaction model is realized in nature.

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arXiv2017

Spectroscopy of singly, doubly, and triply bottom baryons

Recently, some singly bottom baryons have been established experimentally, but none of doubly or triply bottom baryons has been observed. Under the Regge phenomenology, the mass of a ground state unobserved doubly or triply bottom baryon is expressed as a function of masses of the well established light baryons and singly bottom baryons. Then, the values of Regge slopes and Regge intercepts for baryons containing one, two, or three bottom quarks are calculated. After that, masses of the orbitally excited singly, doubly, and triply bottom baryons are estimated. Our predictions may be useful for the discovery of these baryons and the $J^P$ assignment of them.

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arXiv2017

Low-lying charmed and charmed-strange baryon states

In this work, we systematically study the mass spectra and strong decays of $1P$ and $2S$ charmed and charmed-strange baryons in the framework of nonrelativistic constituent quark models. With the light quark cluster-heavy quark picture, the masses are simply calculated by a potential model. The strong decays are studied by the Eichten-Hill-Quigg decay formula. Masses and decay properties of the well-established $1S$ and $1P$ states can be reproduced by our method. $Σ_c(2800)^{0,+,++}$ can be assigned as a $Σ_{c2}(3/2^-)$ or $Σ_{c2}(5/2^-)$ state. We prefer to interpret the signal $Σ_c(2850)^0$ as a $2S(1/2^+)$ state although at present we cannot thoroughly exclude the possibility that this is the same state as $Σ_c(2800)^0$. $Λ_c(2765)^+$ or $Σ_c(2765)^+$ could be explained as the $Λ_c^+(2S)$ state or $Σ^+_{c1}(1/2^-)$ state, respectively. We propose to measure the branching ratio of $\mathcal{B}(Σ_c(2455)π)/\mathcal{B}(Σ_c(2520)π)$ in future, which may disentangle the puzzle of this state. Our results support $Ξ_c(2980)^{0,+}$ as the first radial excited state of $Ξ_c(2470)^{0,+}$ with $J^P=1/2^+$. The assignment of $Ξ_c(2930)^0$ is analogous to $Σ_c(2800)^{0,+,++}$, \emph{i.e.}, a $Ξ^\prime_{c2}(3/2^-)$ or $Ξ^\prime_{c2}(5/2^-)$ state. In addition, we predict some typical ratios among partial decay widths, which are valuable for experimental search for these missing charmed and charmed-strange baryons.

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arXiv2016

Is the Regge Trajectory Quasi-linear or Square-root Form?

There are many orbital excited mesons discovered in recent years. In this work we attempt to study whether the Regge trajectory is quasi-linear or square-root form. In the framework of the quasi-linear Regge trajectory and square-root Regge trajectory, the masses of the states lying on the well established 11S0, 13S1, and 13P2 trajectories are estimated. Comparison of the results given by the two trajectories with the existing experimental data illustrates that both of them can give a reasonable description for the ground mesons. For the orbital excited states, the quasi-linear trajectory describes the existing meson spectrum to be more reasonable.

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arXiv2015

Masses of doubly and triply charmed baryons

Until now, the first reported doubly charmed baryon $Ξ_{cc}^{+}(3520)$ is still a puzzle. It was discovered and confirmed by SELEX collaboration, but not confirmed by LHCb, BABAR, BELLE, FOCUS, or any other collaboration. In the present paper, by employing Regge phenomenology, we first express the mass of the ground state ($L$=0) doubly charmed baryon $Ω_{cc}^{*+}$ as a function of masses of the well established light baryons and singly charmed baryons. Inserting the recent experimental data, the mass of $Ω_{cc}^{*+}$ is given to be 3809$\pm$36 MeV, which is independent of any unobservable parameters. Then, with the quadratic mass relations, we calculate the masses of the ground state triply charmed baryon $Ω_{ccc}^{++}$ and doubly charmed baryons $Ξ_{cc}^{(*)++}$, $Ξ_{cc}^{(*)+}$, and $Ω_{cc}^{+}$ (the mass of $Ξ_{cc}^{+}$ is determined as 3520$^{+41}_{-40}$ MeV, which agrees with the mass of $Ξ_{cc}^{+}(3520)$). The isospin splitting $M_{Ξ_{cc}^{++}} - M_{Ξ_{cc}^{+}} = 0.4 \pm 0.3$ MeV. After that, masses of the orbitally excited ($L$=1,2,3) doubly and triply charmed baryons are estimated. The results are reasonable comparing with those extracted in many other approaches. We suggest more efforts to study doubly and triply charmed baryons both theoretically and experimentally, not only for the abundance of baryon spectra, but also for numerically examining whether the linear mass relations or the quadratic mass relations are realized in nature. Our predictions are useful for the discovery of unobserved doubly and triply charmed baryon states and the $J^P$ assignment of these states.

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arXiv2015

Assignments of $Λ_Q$ and $Ξ_Q$ baryons in the heavy quark-light diquark picture

We apply a new mass formula which is derived analytically in the relativistic flux tube model to the mass spectra of $Λ_Q$ and $Ξ_Q$ (\emph{Q} = \emph{c} or \emph{b} quark) baryons. To this end, the heavy quark-light diquark picture is employed. We find that all masses of the available $Λ_Q$ and $Ξ_Q$ states can be understood well. The assignments to these states do not appear to contradict the strong decay properties. $Λ_c(2760)^+$ and $Ξ_c(2980)$ are assigned to the first radial excitations with $J^P = 1/2^+$. $Λ_c(2940)^+$ and $Ξ_c(3123)$ might be the 2\emph{P} states. The $Λ_c(2880)^+$ and $Ξ_c(3080)$ are the good 1\emph{D} candidates with $J^P = 5/2^+$. $Ξ_c(3055)$ is likely to be a 1\emph{D} state with $J^P = 3/2^+$. $Λ_b(5912)^0$ and $Λ_b(5920)^0$ favor the 1\emph{P} assignments with $J^P = 1/2^-$ and $3/2^-$, respectively. We propose a search for the $\tildeΛ_{c2}(5/2^-)$ state which can help to distinguish the diquark and three-body schemes.

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arXiv2014

$CP$ violation for $B^{0}\rightarrow ρ^{0}(ω)ρ^{0}(ω) \rightarrow π^+π^-π^+π^-$ in QCD factorization

In the QCD factorization (QCDF) approach we study the direct $CP$ violation in $\bar{B}^{0}\rightarrowρ^0(ω)ρ^0(ω)\rightarrowπ^+π^-π^+π^-$ via the $ρ-ω$ mixing mechanism. We find that the $CP$ violation can be enhanced by double $ρ-ω$ mixing when the masses of the $π^+π^-$ pairs are in the vicinity of the $ω$ resonance, and the maximum $CP$ violation can reach 28{\%}. We also compare the results from the naive factorization and the QCD factorization.

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arXiv2013

X(1870) and $η_2(1870)$: Which can be assigned as a hybrid state?

The mass spectrum and strong decays of the X(1870) and $η_2(1870)$ are analyzed. Our results indicate that X(1870) and $η_2(1870)$ are the two different resonances. The narrower X(1870) seems likely a good hybrid candidate. We support the $η_2(1870)$ as the $η_2(2^1D_2)$ quarkonium. We suggest to search the isospin partner of X(1870) in the channels of $J/ψ\rightarrowρf_0(980)π$ and $J/ψ\rightarrowρb_1(1235)π$ in the future. The latter channel is very important for testing the hybrid scenario.

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arXiv2010

Direct CP violation for $\bar{B}_{s}^{0}\to K^{0}π^{+}π^{-}$ decay in QCD factorization

In the framework of QCD factorization, based on the first order of isospin violation, we study direct CP violation in the decay of $\bar{B}_{s}^{0} \to K^{0}ρ^{0}(ω)\to K^{0}π^{+}π^{-}$ including the effect of $ρ-ω$ mixing. We find that the CP violating asymmetry is large via $ρ-ω$ mixing mechanism when the invariant mass of the $π^{+}π^{-}$ pair is in the vicinity of the $ω$ resonance. For the decay of $\bar{B}_{s}^{0} \to K^{0}ρ^{0}(ω)\to K^{0}π^{+}π^{-}$, the maximum CP violating asymmetries can reach about 46%. We also discuss the possibility to observe the predicted CP violating asymmetries at the LHC.

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arXiv2008

Some mass relations for mesons and baryons in Regge phenomenology

In the quasilinear Regge trajectory ansatz, some useful linear mass inequalities, quadratic mass inequalities and quadratic mass equalities are derived for mesons and baryons. Based on these relations, mass ranges of some mesons and baryons are given. The masses of bc-bar and ss-bar belonging to the pseudoscalar, vector and tensor meson multiplets are also extracted. The J^P of the baryon Xi_cc(3520) is assigned to be 1/2^+. The numerical values for Regge slopes and intercepts of the 1/2^+ and 3/2^+ SU(4) baryon trajectories are extracted and the masses of the orbital excited baryons lying on the 1/2^+ and 3/2^+ trajectories are estimated. The J^P assignments of baryons Xi_c(2980), Xi_c(3055), Xi_c(3077) and Xi_c(3123) are discussed. The predictions are in reasonable agreement with the existing experimental data and those suggested in many other different approaches. The mass relations and the predictions may be useful for the discovery of the unobserved meson and baryon states and the J^P assignment of these states.

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arXiv2008

Strong decays of heavy baryons in Bethe-Salpeter formalism

In this paper we study the properties of diquarks (composed of $u$ and/or $d$ quarks) in the Bethe-Salpeter formalism under the covariant instantaneous approximation. We calculate their BS wave functions and study their effective interaction with the pion. Using the effective coupling constant among the diquarks and the pion, in the heavy quark limit $m_Q\to\infty$, we calculate the decay widths of $Σ_Q^{(*)}$ ($Q=c,b$) in the BS formalism under the covariant instantaneous approximation and then give predictions of the decay widths $Γ(Σ_b^{(*)}\toΛ_b+π)$.

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