We have performed a numerical analysis of branching ratios and direct CP-asymmetries of B meson decays to two light pseudoscalar nonets with deltaS=1 using QCD improved factorization. The parameters related to B meson including its semileptonic form factors, strange quark mass and the CKM phase angle have been varied over a limited range and phenomenological parameters used to parameterize divergences in hard spectator scattering and weak annihilation have been varied over a wide range simultaneously with an aim to achieve a fit of branching ratios and some direct CP-asymmetries. A good fit for the majority of the parameters has been achieved indicating that the standard model is quite satisfactory in accounting for these processes.
Stimulated by the BESIII observation of $X(2100)$, $X(2500)$, and $η(2225)$, we try to pin down new pseudoscalar meson nonets including these states. The analysis of mass spectra and the study of strong decays indicate that $X(2120)$ and $η(2225)$ associated with $π(2070)$ and the predicted kaon $K(2150)$ may form a new pseudoscalar meson nonet. In addition, more experimental data for $X(2100)$ are necessary to determine its structure of nonets. Then, $X(2500)$, $X(2370)$, $π(2360)$, and the predicted kaon $K(2414)$ can be grouped into another new nonet. These assignments to the discussed pseu…
Within the context of a generalized linear sigma model that includes two nonets of scalar mesons (a two-quark nonet and a four-quark nonet) and two nonets of pseudoscalar mesons (a two-quark nonet and a four-quark nonet) a collective description of scalar and pseudoscalar mesons below and above 1 GeV is studied. The quark contents of these states are probed; estimates on their quark components are extracted; and prediction for pi pi scattering amplitude is made. An overview of these studies is presented here.
由于标量介子的九元态可能被描述为"两夸克"和"四夸克"组分的混合物，我们进一步研究了一个玩具模型，在这个模型中相应的手征九元态（也包含赝标伙伴）相互作用.虽然"二夸克"和"四夸克"手征场在SU（3）$_L \times$ SU（3）$_R$变换下的变换是相同的，但它们在U（1）$_A$变换下的变换是不同的，U（1）$_A$变换实质上是计算介子的总含量（夸克+反夸克）。为了实现这一点，我们制定了一个有效的拉格朗日模拟的U（1）$_A$行为的基础QCD。我们推导出生成方程产生沃德恒等式型关系的基础上，只假设的对称结构。这是适用于质量谱的低躺pseudoscalar和标量。以及他们的"兴奋"。假设同位旋不变性，就有可能解开"双夸克"与"双夸克"的纠缠。赝标$π, K ,η$型态和标量$κ$型态中的"四夸克"含量。发现最轻赝标量中的小"四夸克"含量与最轻标量$κ$介子中的大"四夸克"含量是一致的。目前的玩具模型还允许人们容易地估计“四夸克”真空凝聚的强度。似乎有一个丰富而有趣的结构。
Two-body decay widths of lowest lying and next-to-lowest lying scalar and pseudoscalar mesons are studied in Generalized Linear Sigma Model (GLSM) of low-energy QCD. This model which considers mixing between "two quark" and "four quark" chiral nonets has been employed to investigate various decays and scatterings in low energy region of QCD. In this paper, $Γ[f_0(980) \rightarrow K \bar{K}]$ and $Γ[a_0(980) \rightarrow K \bar{K}]$ are obtained and it is shown that two-body decay widths of lowest lying mesons are well predicted by this model while for the next-to-lowest lying mesons, only some …
First part of the paper is devoted to applying the confinement mechanism proposed earlier by the author to estimate the possible parameters of the confining SU(3)-gluonic field in neutral kaons. The estimates obtained are consistent with the widths of the electromagnetic decays $K^0,\bar{K}^0\to2γ$ too. The corresponding estimates of the gluon concentrations, electric and magnetic colour field strengths are also adduced for the mentioned field at the scales of the mesons under consideration. The second part of the paper takes into account the results obtained previously by the author to estima…
We analyze quark-mass and $1/N_c$ corrections to all of the radiative transitions between the vector-meson nonet and the pseudoscalar-meson nonet within a chiral effective Lagrangian approach. We perform fits of the available coupling constants to experimental data and discuss the corresponding approximations. In terms of five (six) coupling constants, we obtain a reasonably good description of the 12 experimental decay rates.
We analyze the restoration pattern of the members of the scalar and pseudoscalar meson nonets under chiral $O(4)$ and $U(1)_A$ symmetries. For that purpose, we exploit QCD Ward Identities (WI), which allow one to relate susceptibilities with quark condensates, as well as susceptibility differences with meson vertices. In addition, we consider the low-energy realization of QCD provided by $U(3)$ Chiral Perturbation Theory (ChPT) at finite temperature to perform a full analysis of the different correlators involved. Our analysis suggests $U(1)_A$ partner restoration if chiral symmetry partners a…
The contributions of one-loop diagrams with dynamical vector mesons to masses and decay constants of pseudoscalar mesons are determined. Hereby, a relativistic Lagrangian for both the pseudoscalar-meson octet and the vector-meson nonet is used. The vector mesons are given in the antisymmetric tensor representation. Both the differences between static and dynamical vector mesons and the differences between calculations with and without vector mesons are studied as functions of the light quark mass.
We study the SU(3) linear sigma model for the pseudoscalar mesons in the Gaussian Functional Approximation (GFA). We use the SU(3) linear sigma model Lagrangian with nonet scalar and pseudo-scalar mesons including symmetry breaking terms. In the GFA, we take the Gaussian Ansatz for the ground state wave function and apply the variational method to minimize the ground state energy. We derive the gap equations for the dressed meson masses, which are actually just variational parameters in the GFA method. We use the Bethe-Salpeter equation for meson-meson scattering which provides the masses of t…
Underlying mixing of scalar mesons is studied in $η'\rightarrow ηππ$ decay within a generalized linear sigma model of low-energy QCD which contains two nonets of scalar mesons and two nonets of pseudoscalar mesons (a quark-antiquark nonet and a four quark nonet). The model has been previously employed in various investigations of the underlying mixings among scalar mesons below and above 1 GeV (as well as those of their pseudoscalar chiral partners) and has provided a coherent global picture for the physical properties and quark substructure of these states. It is found that the linear sigma m…
Recent evidence for a CP violating asymmetry in the semileptonic decays of B_s mesons cannot be accommodated within the Standard Model. Such an asymmetry can be explained by new physics contributions to Delta B=2 components of either the mass matrix or the decay matrix. We show that mixing with a hidden pseudoscalar meson with a mass around 5 GeV can result in a new CP violating contribution to the mixing and can resolve several anomalies in this system including the width difference, the average width and the charge asymmetry. We also discuss the effects of the hidden meson on other b physics…
We have recently extended the scalar-pseudoscalar sector of a generalized NJL Lagrangian that includes all NLO non derivative interactions in Nc counting (including explicit symmetry breaking ones) in order to incorporate the spin 1 mesons in the low-lying ground state of QCD [1]. Upon bosonization, the well known mixing of the scalar-vector and of the pseudoscalar- axial-vector fields occurs in the quadratic part of the Lagrangian. We show that a linearized diagonalization of these terms can be effected in a completely general way without compromising the underlying symmetries of the Lagrangi…
We investigate the importance of dynamical spin effects in the holographic light-front wavefunctions of the pseudoscalar mesons. We find that these effects are crucial to describe the pion data while they are not necessary to describe the available kaon data. For $η-η^\prime$ system, we find that dynamical spin effects are required to describe their transition form factors data.
We study two nonets of excited vector mesons, predominantly corresponding to radially excited vector mesons with quantum numbers $n\hspace{0.08cm} ^{2S+1}L_{J}$ $=2^3S_1$ and to orbitally excited vector mesons with quantum numbers $n\hspace{0.08cm} ^{2S+1}L_{J}=1^3D_1$. We evaluate two types of decays of these mesons: into two pseudoscalar mesons and into a pseudoscalar and a ground-state vector meson. We compare the results with experimental data taken from PDG. We also make predictions for the strange-antistrange state in the $1^3D_1$ nonet denoted as $ϕ(1930)$, which has not yet been discov…
We study the decays of the pseudotensor mesons $[ π_{2}(1670) , K_{2}(1770) , η_{2}(1645) , η_{2}(1870) ]$ interpreted as the ground-state nonet of $1^1 D_{2}$ $\bar{q}q$ states using interaction Lagrangians which couple them to pseudoscalar, vector, and tensor mesons. While the decays of $π_2 (1670)$ and $K_2 (1770)$ can be well described, the decays of the isoscalar states $η_2 (1645)$ and $η_2 (1870)$ can be brought in agreement with experimental data only if the mixing angle between nonstrange and strange states is surprisingly large (about $-42^\circ$, similar to the mixing in the pseudos…
Scalar glueball is implemented in single nonet linear sigma model (SNLSM) which basically includes lowest lying scalar and pseudoscalar mesons. Our new version of SNLSM involves mixing among scalar matter fields and glueball field which is enforced by scale symmetry considerations and the associated anomaly. Performing iterative Monte Carlo simulations, it is found that among the three candidates of scalar glueball, i.e., $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$, only $f_0(1500)$ is predominately a glueball state with the mass prediction of $1.566 \pm 0.046$ GeV and the other two are predomina…
While the ground-state tensor ($J^{PC}=2^{++}$) mesons $a_{2}(1320)$, $K_{2}^{\ast}(1430)$, $f_{2}(1270)$, and $f_{2}^{\prime}(1525)$ are well known experimentally and form an almost ideal nonet of quark-antiquark states, their chiral partners, the ground-states axial-tensor ($J^{PC}=2^{--}$) mesons are poorly settled: only the kaonic member $K_2(1820)$ of the nonet has been experimentally found, whereas the isovector state $ρ_2$ and two isoscalar states $ω_2$ and $ϕ_2$ are still missing. Here, we study masses, strong, and radiative decays of tensor and axial-tensor mesons within a chiral mode…
The Scalar q bar q nonet and Confirmation of the broad sigma meson
用六个参数和一个非常一般的模型，把a0（980），f0（980），f0（1300）和K*0（1430）介子的数据拟合成一个畸变的0++九重态。这包括所有轻的双伪标量阈值、阿德勒零点的约束、味对称耦合、么正性和物理上可接受的解析性。发现在大的总耦合作用下，仅从一个q巴q态就可以出现两个物理共振极点。因此，f0（980）和f0（1300）共振极点是同一个s条s状态的两种表现。另一方面，u bar u态在被强子质量位移幺正化并强烈扭曲时，会变成一个极宽的类布赖特-维格纳背景，其极点位于s =（0.158-i0.235）GeV ^[2]。这是手征对称性自发破缺模型所需要的σ介子。
The pseudoscalar and vector excited mesons in the U(3)*U(3) chiral model
构造了一个手征U（3）*U（3）拉格朗日量，它除了包含通常的介子场外，还包含它们的第一径向激发。拉格朗日量是由玻色化的Nambu-Jona-Lasinio夸克模型与可分离的非局域相互作用，与形状因子对应的3维基态和激发态波函数。手征对称性的自发破缺由NJL能隙方程控制。用五种不同的形状因子描述了π介子、K介子和矢量介子九重态的第一径向激发。每个形状因子仅包含一个任意参数。计算了这些介子态的质量和弱衰变常数$F_{π'}, F_K and F_{K'}$。
The observation of the light hybrid candidate $η_1(1855)$ by the BESIII Collaboration brings great opportunities for advancing our knowledges about exotic hadrons in the light flavor sector. We show that this observation provides a crucial clue for establishing the $J^{P(C)}=1^{-(+)}$ hybrid nonet. Based on the flux tube model picture, the production and decay mechanisms for the $J^{P(C)}=1^{-(+)}$ hybrid nonet in the $J/ψ$ radiative decays into two pseudoscalar mesons are investigated. In the $I=0$ sector, we find that the SU(3) flavor octet and singlet mixing is non-negligible and apparently…
The electromagnetic structure of the pseudoscalar meson nonet is completely described by the sophisticated Unitary&Analytic model, respecting all known theoretical properties of the corresponding form factors.
The effective quark interactions that break explicitly the chiral SU(3)_L X SU(3)_R and U_A(1) symmetries by current-quark mass source terms are considered in NLO in $N_c$ counting. They are of the same order as the 't Hooft flavor determinant and the eight quark interactions that extend the LO Nambu-Jona-Lasinio Lagrangian, and complete the set of non-derivative and spin 0 interactions relevant for the $N_c$ scheme. The bosonized Lagrangian at meson tree level describes accurately the empirical ordering and magnitude of the splitting of states in the low lying pseudoscalar and scalar meson no…
The firm understanding of standard quark-antiquark states (including excited states) is necessary to search for non-conventional mesons with the same quantum numbers. In this work, we study the phenomenology of two nonets of excited vector mesons, which predominantly correspond to radially excited vector mesons with quantum numbers $n$ $^{2S+1}L_{J}=2$ $^{3}S_{1}$ and to orbitally excited vector mesons with quantum numbers $n$~ $^{2S+1}L_{J}=1$ $^{3}D_{1}$. We evaluate the decays of these mesons into two pseudoscalar mesons and into a pseudoscalar and a ground-state vector meson by making use …
We discuss for some particular non supersymmetric theories a generalized symmetry that includes both the scale and axial transformations and leads to a single current that may contain also a pseudoscalar term. The method, inspired by the superconformal anomalies has important application for low energy effective models where it allows the introduction of a single complex glueball field with a scalar and a pseudoscalar component on the same footing with the complex meson nonets fields made of quarks. Both axial and trace and axial anomalies are satisfied in accordance to the meson structure and…
We derive the formal Ward identities relating pseudoscalar susceptibilities and quark condensates in three-flavor QCD, including consistently the $η$-$η'$ sector and the $U_A(1)$ anomaly. These identities are verified in the low-energy realization provided by ChPT, both in the standard $SU(3)$ framework for the octet case and combining the use of the $U(3)$ framework and the large-$N_c$ expansion of QCD to account properly for the nonet sector and anomalous contributions. The analysis is performed including finite temperature corrections as well as the calculation of $U(3)$ quark condensates a…
The pseudoscalar mesons with the masses higher than 1 GeV are assumed to belong to the meson decuplet including the glueball as the basis state supplementing the standard $SU(3)_F$ nonet of light $q\bar{q}$ states $(u,d,s)$. The decuplet is investigated by means of an algebraic approach based on hypothesis of vanishing the exotic $SU(3)_F$ commutators of "charges" and their time derivatives. These commutators result in a system of equations determining contents of the isoscalar octet state in the physical isoscalar mesons as well as the mass formula including all masses of the decuplet: $π(130…
