H. I. Alrebdi, T. M. Aliev, K. Şimşek
The strong coupling constant of doubly heavy baryons with light pseudoscalar mesons $ π$ and $ K $ are computed within the light cone sum rules. We take into account two-particle and three-particle distribution amplitudes of the said pseudoscalar mesons. We compare our result with the one existing in the literature.
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On the basis of the perturbative QCD and the relativistic quark model we investigate the relativistic and bound state effects in the production processes of a pair of $S$-wave doubly heavy mesons with opposite charge conjugation consisting of $b$ and $c$ quarks. All possible relativistic corrections in the production amplitude including the terms connected with the transformation law of the bound state wave function to the reference frame of the moving pseudoscalar ${\cal P}-$ and vector ${\cal V}-$ mesons are taken into account. We obtain a growth of the cross section for the reaction $e^++e^…
The strong coupling constants are basic quantities that carry information of the strong interactions among the baryon and meson multiplets as well as information on the natures and internal structures of the involved hadrons. These parameters enter to the transition matrix elements of various decays as main inputs and they play key roles in analyses of the experimental data including various hadrons. We determine the strong coupling constants among the doubly heavy spin-$ 3/2 $ baryons, $Ξ^*_{QQ'} $ and $Ω^*_{QQ'}$, and light pseudoscalar mesons, $π$, $K$ and $η$, using the light-cone QCD. The…
The strong coupling constants of hadronic multiplets are fundamental parameters which carry information of the strong interactions among participating particles. These parameters can help us construct the hadron-hadron strong potential and gain information about the structure of the involved hadrons. Motivated by the recent observation of the doubly charmed $Ξ_{cc}$ state by LHCb, we determine the strong coupling constants among the doubly heavy spin-1/2 baryons, $ Ξ^{(\prime)}_{QQ^\prime }$, $ Ω^{(\prime)}_{QQ^\prime}$ and light pseudoscalar mesons, $ π$, $ K $, $η$ and $ η^\prime $ within th…
In this paper, we analyze the doubly heavy spin-3/2--spin-1/2 baryons and light meson vertices within the method of light-cone QCD sum rules. These vertices are parametrized in terms of one (three) coupling constant(s) for the pseudoscalar (vector) mesons. The said coupling constants are calculated for all possible transitions. The results presented here can serve to be useful information in experimental as well as theoretical studies of the properties of doubly heavy baryons.
New data on the decays of the charmed particles $D^0$, $D^+$, and $D_s$ to pairs of light pseudoscalar mesons $P$ allow the testing of flavor symmetry and the extraction of key amplitudes. Information on relative strong phases is obtained. One sees evidence for the expected interference between Cabibbo-favored and doubly-Cabibbo-suppressed decays in the differing patterns of $D^0 \to K_{S,L} π^0$ and $D^+ \to K_{S,L} π^+$ decays.
We adopt the heavy baryon chiral perturbation theory (HBChPT) to calculate the scattering lengths of $ϕB_{cc}^{(*)}$ up to $\mathcal{O}(p^3)$, where $ϕ$ is the pseudoscalar mesons. The recoil effect and the mass splitting between the spin-$1\over 2$ and spin-$3\over 2$ doubly charmed baryons are included. In order to give the numerical results, we construct the chiral Lagrangians with heavy diquark-antiquark (HDA) symmetry in a formally covariant approach. Then, we relate the low energy constants (LECs) of the doubly charmed baryons to those of $D^{(*)}$ mesons. The LECs for the $ϕD^{(*)}$ sca…
The mass and coupling of the doubly charmed $J^P=0^{-}$ diquark-antidiquark states $T_{cc;\bar{s} \bar{s}}^{++}$ and $T_{cc;\bar{d} \bar{s}}^{++}$ that bear two units of the electric charge are calculated by means of QCD two-point sum rule method. Computations are carried out by taking into account vacuum condensates up to and including terms of tenth dimension. The dominant $S$-wave decays of these tetraquarks to a pair of conventional $ D_{s}^{+}D_{s0}^{\ast +}(2317)$ and $D^{+}D_{s0}^{\ast +}(2317)$ mesons are explored using QCD three-point sum rule approach, and their widths are found. The…
A recent update of data on the decays of $D^0$, $D^+$, and $D_s^+$ to pairs of light pseudoscalars calls for a renewed analysis of key decay amplitudes and tests of flavor symmetry. The present data change our previous understanding of relative phases between amplitudes that describe Cabibbo-favored decays of the charmed mesons. The new data also seem to favor a smaller octet-singlet mixing angle for the $η$ and $η'$ mesons when singly-Cabibbo-suppressed processes are taken into account. We also discuss the effects of the new data on interference between Cabibbo-favored and doubly-Cabibbo-supp…
We present our recent results on the hadronic light-by-light pseudoscalar-exchange contribution to the anomalous magnetic moment of the muon using rational approximants. Our work provides a generalization of Padé approximants to the bivariate case to describe the most general doubly-virtual transition form factor, which is required in the calculation. This method provides a powerful tool to systematically implement the known experimental data on transition form factors in the space-like region and low energies in a model-independent way. Given the lack of experimental data on the doubly-virtua…
Many meson processes are related to the U_A(1) axial anomaly, present in the Feynman graphs where fermion loops connect axial vertices with vector vertices. However, the coupling of pseudoscalar mesons to quarks does not have to be formulated via axial vertices. The pseudoscalar coupling is also possible, and this approach is especially natural on the level of the quark substructure of hadrons. In this paper we point out the advantages of calculating these processes using (instead of the anomalous graphs) the Feynman graphs where axial vertices are replaced by pseudoscalar vertices. We elabora…
The light-by-light contribution to the anomalous magnetic moment of muon (g-2)_μ from the hadronic exchanges in the neutral pseudoscalar meson channel is calculated in the nonlocal chiral quark model. The full kinematic dependence of the meson-two-photon vertices on the virtualities of the mesons and photons is taken into account. The status of various phenomenological and QCD short-distance constraints is discussed and the comparison with the predictions of other models is performed. It is demonstrated that the effect of the full kinematic dependence in the meson-photon vertices is to reduce …
By studying the $η_c$ exclusive decay to double glueballs, we introduce a model to mimic phenomenologically the gluon-pair-vacuum interaction vertices, namely the $0^{++}$ model. Based on this model, we study glueball production in pseudoscalar quarkonium decays, explicitly $η_c \to f_0(1500)η(1405)$, $η_b\to f_0(1500)η(1405)$ and $η_b\to f_0(1710)η(1405)$ processes. Among them $f_0(1500)$ and $f_0(1710)$ are well-known scalars possessing large glue components and $η(1405)$ is a potential candidate for pseudoscalar glueball. The preliminary calculation results indicate that these processes are…
Using an extended chromomagnetic model, we perform a systematic study of the masses of the doubly heavy tetraquarks. We find that the ground states of the doubly heavy tetraquarks are dominated by color-triplet $\ket{(qq)^{\bar{3}_{c}}(\bar{Q}\bar{Q})^{3_{c}}}$ configuration, which is opposite to that of the fully heavy tetraquarks. The combined results suggest that the color-triplet configuration becomes more important when the mass difference between the quarks and antiquarks increases. We find three stable states which lie below the thresholds of two pseudoscalar mesons. They are the $IJ^{P…
We study the decay of dynamically generated resonances from the interaction of two vectors into a $γ$ and a pseudoscalar meson. The dynamics requires anomalous terms involving vertices with two vectors and a pseudoscalar, which renders it special. We compare our result with data on $K^{*+}(1430)\to K^+γ$ and $K^{*0}(1430)\to K^0γ$ and find a good agreement with the data for the $K^{*+}(1430)$ case and a width considerably smaller than the upper bound measured for the $K^{*0}(1430)$ meson.
The strong coupling constants, $g_{D_{s}DK_0^*}$, $g_{B_{s}BK_0^*}$, $g_{D^{\ast}_{s}D K}$, $g_{B^{\ast}_{s}BK}$, $g_{D^{\ast}_{s}D K_1}$ and $g_{B^{\ast}_{s}BK_1}$, where $K_0^*$, $K$ and $K_1$ are scalar, pseudoscalar and axial vector kaon mesons, respectively are calculated in the framework of three-point QCD sum rules. In particular, the correlation functions of the considered vertices when both $B(D)$ and $K_0^*(K)(K_1)$ mesons are off-shell are evaluated. In the case of $K_1$, which is either $K_1(1270)$ or $K_1(1400)$, the mixing between these two states are also taken into account. A c…
Doubly heavy hadron production in ultraperipheral collisions
本文研究了重离子超外围碰撞中赝标重夸克偶素、双重重子及四夸克态的遍历产生，数值结果表明在未来的HL-LHC和FCC上对部分双重强子进行实验研究是可行的。
Probing a long-lived pseudoscalar in type-I 2HDM with displaced vertices and jets at the LHC
研究在LHC上通过位移顶点和喷注探测类型I二双态模型中长寿命赝标量A的发现前景，分析其在不同参数空间中的排除情况。
The main goal of this paper is to elaborate the model-framework parametrization of effective coupling constants of the extended chiral lagrangian which is suitable for the description of the low-energy matrix elements of vector, axial-vector, scalar and pseudoscalar currents as well as of the matrix elements of the pseudoscalar gluon density. We establish the connection between the structural coupling constants of the phenomenological chiral lagrangian and the coefficients of effective lagrangians obtained in the QCD-bosonization models by means of the derivative expansion. The large-N_c relat…
Pseudoscalar Higgs Production at Muon Colliders: The Role of One-Loop Effective Vertices
本文在Type-II和Type-X 2HDM框架下，利用EFT方法研究μ子对撞机上赝标量希格斯玻色子A的NLO产生，发现包含γγA、γZA和ZZA单圈有效顶点可分别带来约2倍和10倍的截面增强，表明μ子对撞机是探测扩展希格斯扇区的可行途径。
Many meson processes are related to the U_A(1) axial anomaly, present in the Feynman graphs where fermion loops connect axial vertices with vector vertices. However, the coupling of pseudoscalar mesons to quarks does not have to be formulated via axial vertices. The pseudoscalar coupling is also possible, and this approach is especially natural on the level of the quark substructure of hadrons. In this paper we point out the advantages of calculating these processes using (instead of the anomalous graphs) the graphs where axial vertices are replaced by pseudoscalar vertices. We elaborate espec…
In this work we study the possible QCD exotic states in the doubly charmed baryon sector. Within chiral effective theory, it is predicted that several excited baryons result from the $S$-wave scattering of ground-state doubly charmed baryons ($Ξ_{cc}^{++}, Ξ_{cc}^{+}, Ω_{cc}^{+}$) and light pseudoscalar mesons ($π, K, η$). The excited doubly charmed baryons can be classified by the strangeness ($S$) and isospin ($I$) quantum numbers. Two of the excited states are clearly exotic, in the sense that they cannot be explained by the conventional baryons with three quarks, since their quantum number…
We estimate the values of Yukawa couplings of a light pseudoscalar A with a mass of about 17 MeV, which would explain the $^8Be$ anomaly observed in the Atomki pair spectrometer experiment. The resulting couplings of A to up and down type quarks are about 0.3 times the coupling of the standard Higgs boson. Then constraints from K and B decays require that loop contributions to flavour changing vertices cancel at least at the 10% level. Constraints from beam dump experiments require the coupling of A to electrons to be larger than about 4 times the coupling of the standard Higgs boson, leading …
Pseudoscalar meson dominance and nucleon structure
本文基于扩展部分轴矢流守恒和赝标量介子主导性，利用PDG数据确定π核子耦合常数及Goldberger-Treiman偏差，结果与近平坦的π核子顶点一致。
The light-by-light contribution from the lightest neutral pseudoscalar and scalar mesons to the anomalous magnetic moment of muon is calculated in the framework of the nonlocal SU(3)x SU(3) quark model. The model is based on chirally symmetric four-quark interaction of the Nambu-Jona-Lasinio type and Kobayashi-Maskawa-t`Hooft U_A(1) breaking six-quark interaction. Full kinematic dependence of vertices with off-shell mesons and photons in intermediate states in the light-by-light scattering amplitude is taken into account. The small positive contributions from the scalar mesons stabilize the to…
The interaction between pseudoscalar and/or vector mesons can be studied using hidden gauge Lagrangians. In this framework, the interaction between charmed mesons has been studied. Furthermore, doubly charmed states are also predicted. These new states are near the $D^*D^*$ and $D^*D^*_s$ thresholds, and have spin-parity $J^P=1^+$. We evaluate the decay widths of these states, named as $R_{cc}(3970)$ and $S_{cc}(4100)$ (with strangeness), and obtain $44$ MeV for the non-strangeness, and $24$ MeV for the doubly charm-strange state. Essentially, the decay modes are $DD_{(s)}π$ and $DD_{(s)}γ$, b…
The discovery of $Ξ_{cc}^{++}$ by the LHCb Collaboration triggers predictions of more doubly charmed baryons. By taking into account both the $P$-wave excitations between the two charm quarks and the scattering of light pseudoscalar mesons off the ground state doubly charmed baryons, a set of negative-parity spin-1/2 doubly charmed baryons are predicted already from a unitarized version of leading order chiral perturbation theory. Moreover, employing heavy antiquark-diquark symmetry the relevant low-energy constants in the next-to-leading order are connected with those describing light pseudos…
We use a continuum quark+diquark approach to the nucleon bound-state problem in relativistic quantum field theory to deliver parameter-free predictions for the nucleon axial and induced pseudoscalar form factors, $G_A$ and $G_P$, and unify them with the pseudoscalar form factor $G_5$ or, equivalently, the pion-nucleon form factor $G_{πNN}$. We explain how partial conservation of the axial-vector current and the associated Goldberger-Treiman relation are satisfied once all necessary couplings of the external current to the building blocks of the nucleon are constructed consistently; in particul…
The discovery of $Ξ_{cc}^{++}$ has inspired new interest in studying doubly heavy baryons. In this study, the weak decays of a doubly charmed baryon ${\cal B}_{cc}$ to a light baryon ${\cal B}$ and a charm meson $D^{(*)}$ (either a pseudoscalar or a vector one) are calculated. Following our previous work, we calculate the short distance contributions under the factorization hypothesis, whereas the long distance contributions are modeled as the final state interactions which are calculated with the one particle exchange model. We find that the ${\cal B}_{cc}\to {\cal B} D^{*}$ decays' branching…
The strong coupling constants of spin-3/2 to spin-1/2 doubly heavy baryon transitions with light vector mesons are estimated within the light-cone QCD sum rules method. Moreover, using the vector-meson dominance ansätz, the widths of radiative decays $B_{QQ}^* \to B_{QQ} γ$ are calculated. The results for the said decay widths are compared to the predictions of other approaches.
The electroweak properties of light and charmed D and Ds pseudoscalar mesons are investigated within a unified covariant constituent quark model. The quark-antiquark-meson vertices are assumed to have a symmetric form by the exchange of quark momenta, which is successful in describing the light pseudoscalar meson properties. The flavor decomposition of the elastic electromagnetic form factors, electromagnetic charge radii, and weak decay constants are calculated. Based on the results a discussion on the SU(3) and SU(4) symmetry breaking is made and a comparison with the pion and kaon propertie…
We introduce a parametrization scheme for $J/ψ(ψ^\prime)\to VP$ where the effects of SU(3) flavor symmetry breaking and doubly OZI-rule violation (DOZI) can be parametrized by certain parameters with explicit physical interpretations. This scheme can be used to clarify the glueball-$q\bar{q}$ mixing within the pseudoscalar mesons. We also include the contributions from the electromagnetic (EM) decays of $J/ψ$ and $ψ^\prime$ via $J/ψ(ψ^\prime)\to γ^*\to VP$. Via study of the isospin violated channels, such as $J/ψ(ψ^\prime)\to ρη$, $ρη^\prime$, $ωπ^0$ and $ϕπ^0$, reasonable constraints on the E…
Using a bottom up phenomenological approach we constructed a simple doubly charged vector lepton $E^{\pm\pm}$ model for the possible 750 GeV diphoton resonance $Φ$ at the LHC assuming it to be a scalar particle. Since no stable doubly charged leptons are seen, to facilitate their decays we complete the model by adding a charged SM electroweak scalar $S^\pm$. $Φ$ is a SM singlet and can be either an inert scalar or a Higgs field. In the inert case more than one vector lepton are required to account for the photon fusion production of the resonance if the model is to remain perturbative. For a H…
We revisit the $U(1)_A$ anomaly in the holographic model of low-energy QCD by Witten, Sakai, and Sugimoto, presenting a new and direct derivation of the Witten-Veneziano mechanism for generating the mass of the $η'$ through an anomalous mixing of the Ramond-Ramond $C_1$ field with the singlet component of the pseudoscalar mesons. The latter turns out to have a kinetic mixing with the normalizable modes of the $C_1$ field representing pseudoscalar glueballs, yielding additional vertices for their production and their decay that dominate over those of the unmixed case considered previously in th…
Non-singlet ${\cal{O}}(α_s^2)$ corrections from light quarks are calculated analytically for the massive quark-antiquark pair production rates through the vector, axial-vector, scalar and pseudoscalar currents for all energies above the threshold. The results are presented in terms of the moments of the absorptive part of the vacuum polarization function of the light quarks which allows for an immediate determination of ${\cal{O}}(α_s^2)$ corrections coming from other types of light particles. The kinematic regime close to the threshold is examined.
Doubly charmed baryon-light meson scattering in chiral effective theory with lattice constraints
在手征有效理论下研究双粲重子与轻介子的散射，通过拟合格点数据确定低能常数，预言共振态、虚态和束缚态，并计算散射长度等物理量。
Stimulated by the new experimental LHCb findings associated with the $Ω_c$ states, some of which we have described in a previous work as being dynamically generated through meson-baryon interaction, we have extended this approach to make predictions for new $Ξ_{cc}$ molecular states in the $C=2$, $S=0$ and $I=1/2$ sector. These states manifest themselves as poles in the solution of the Bethe-Salpeter equation in coupled channels. The kernels of this equation were obtained using the Lagrangians coming from the hidden local gauge symmetry, where the interactions are dominated by the exchange of …
We study exclusive production of scalar $χ_{c0}\equiv χ_c(0^{++})$ and pseudoscalar $η_c$ charmonia states in proton-proton collisions at the LHC energies. The amplitudes for $gg \to χ_{c0}$ as well as for $gg \to η_c$ mechanisms are derived in the $k_{T}$-factorization approach. The $p p \to p p η_c$ reaction is discussed for the first time. We have calculated rapidity, transverse momentum distributions as well as such correlation observables as the distribution in relative azimuthal angle and $(t_1,t_2)$ distributions. The latter two observables are very different for $χ_{c0}$ and $η_c$ case…
Study of transition form factors of the lightest pseudoscalars
本文基于共振旋轮理论研究轻伪标量介子的过渡形式因子，并评估其对μ子异常磁矩轻由光部分的贡献。
The cross sections for $J/ψ$ absorption by $π$ and $ρ$ mesons are studied in a meson-exchange model that includes not only pseudoscalar-pseudoscalar-vector-meson couplings but also three-vector-meson and four-point couplings. We find that they are much larger than in a previous study where only pseudoscalar-pseudoscalar-vector-meson couplings were considered. Including form factors at interaction vertices, the $J/ψ$ absorption cross sections $σ_{πψ}$ and $σ_{ρψ}$ are found to have values on the order of 7 mb and 3 mb, respectively. Their thermal averages in hadronic matter at temperature T=150…
In a long distance Lagrangian approach to the low lying meson phenomenology we present and discuss the most general spin zero multi-quark interaction vertices of non-derivative type which include a set of effective interactions proportional to the current quark masses, breaking explicitely the chiral SU(3)_L X SU(3)_R and U_A(1) symmetries. These vertices are of the sameorder in Nc counting as the 't Hooft flavor determinant interaction and the 8 quark interactions which extend the original leading in Nc four quark interaction Lagrangian of Nambu and Jona-Lasinio. The Nc assignements match the…
We discuss exclusive central diffractive production of scalar ($f_{0}(980)$, $f_{0}(1370)$, $f_{0}(1500)$), pseudoscalar ($η$, $η'(958)$), and vector ($ρ^{0}$) mesons in proton-proton collisions. The amplitudes are formulated in terms of effective vertices required to respect standard rules of Quantum Field Theory and propagators for the exchanged pomeron and reggeons. Different pomeron-pomeron-meson tensorial (vectorial) coupling structures are possible in general. In most cases two lowest orbital angular momentum - spin couplings are necessary to describe experimental differential distributi…
New data on the decays of the charmed particles $D^0$, $D^+$, and $D_s$ to $PV$ final states consisting of a light pseudoscalar meson $P$ and a light vector meson $V$ are analyzed. Following the same methods as in a previous analysis of $D \to PP$ decays, one can test flavor symmetry, extract key key amplitudes, and obtain information on relative strong phases. Analyses are performed for Cabibbo-favored decays and then extended to predict properties of singly- and doubly-Cabibbo-suppressed processes.
The evaluation, systematic analysis and numerical study of the semileptonic $τ$-lepton decays with two mesons in the final state has been made in the frame of the standard model extended by right handed neutrinos. In the analysis, heavy-neutrino nondecoupling effects, finite quark masses, quark and meson mixings, finite widths of vector mesons, chiral symmetry breakings in vector-meson--pseudoscalar-meson vertices and effective Higgs-boson--pseudoscalar-meson couplings have been included. Numerical estimates reveal that the decays $τ^-\to e^-π^-π^+$, $τ^-\to e^-K^-K^+$ and $τ^-\to e^-K^0\bar{K…
Third QED order hadronic light-by-light (LBL) contributions $a_μ^{LBL}(M)$ to the anomalous magnetic moment of the muon $a_μ^{had}$ from the pole terms of scalar $σ$, $a_0(980)$ and pseudoscalar $π^0$, $η$, $η'$ mesons (M) in the framework of the linearized extended Nambu-Jona-Lasinio model are evaluated. The off-shell structure of the photon-photon-meson vertices is taken into account by means of constituent quark triangle loops. The mass of the quark is taken to be $m_u=m_d=m_q=(280 \pm 20)$ MeV. The unknown strong coupling constants of $π^0, η, η'$ and $a_0$ mesons with quarks are evaluated…
Probing long-lived doubly charged scalar in the Georgi-Machacek model at the LHC and in far detectors
本文研究在LHC和远探测器中探测Georgi-Machacek模型中长寿命双电荷标量的潜力，通过分析位移顶点等信号特征，结合LHC与远探测器搜索，预计可覆盖质量50至180 GeV下大部分参数空间。
We calculate the threshold $T$ matrices of the light pseudoscalar meson and heavy meson scattering to fourth order in heavy meson chiral perturbation theory. We determine the low-energy constants by fitting to the lattice QCD data points through both the perturbative and iterated methods and obtain the physical scattering lengths in both formalisms. The values of the scattering lengths tend to be convergent at fourth order for most of the channels in the perturbative method. The value of the scattering length for the channel $DK (I=0)$, which involves the bound state $D_{s0}^{*}(2317)$, is obt…
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…
We calculate the strong coupling constants among the doubly heavy spin-$ \frac{3}{2} $ baryons $Ξ^*_{QQ}$ and $Ω^*_{QQ}$, with $ Q $ and $ Q' $ being $ c$ or $ b $ quark, with light vector meson by means of the light-cone QCD sum rules. The matrix elements defining these vertices are described by four coupling constants $ g_1$, $ g_2$, $ g_3$, and $ g_4 $. The unwanted pollution coming from the doubly heavy spin-$ \frac{1}{2} $ baryons are removed by a special ordering of Dirac matrices and selection of appropriate Lorentz structures. The strong coupling constants are basic parameters that car…
Strong decay widths of S- and P-wave singly- and doubly-heavy charm and bottom baryons
在非相对论夸克模型结合基本发射模型的框架下，研究单重及双重重粲、底重子的两体强衰变宽度，计算结果与实验数据符合合理，为相关重子衰变研究提供了理论参考。
Looking for heavy axial tensor mesons via their strong decays in light cone QCD
本研究利用光锥QCD求和规则方法计算了未观测重轴张量介子与多种介子的强耦合常数，并据此估算了相应的衰变宽度，为未来实验验证提供理论预测。
The doubly charmed baryon $Ξ_{cc}^{++}$ was recently observed by LHCb via the decay processes of $Ξ_{cc}^{++}\to Λ_c^+ K^-π^+π^+$ and $Ξ_c^+π^+$. These discovery channels were successfully predicted in the framework that the short-distance contributions are calculated under the factorization hypothesis and the long-distance contributions are estimated using the rescattering mechanism for the final-state-interaction effects. In this paper, we illustrate the above framework in details by systematic studies on the two-body baryonic decays $\mathcal{B}_{cc}\to\mathcal{B}_{c}P$ involving the doubly…
Examining possible doubly topped baryon configurations
研究以两个重顶夸克为特征的重子构型质量，在两点QCD求和规则框架内评估，纳入微扰与非微扰效应，给出定量预测，为LHC实验搜索及下一代设施灵敏度研究提供理论参考。
For the spacelike momenta k of the virtual photon gamma^*, the pi^0(p) gamma^*(k) gamma(k') transition form factor is considered in the coupled Schwinger-Dyson and Bethe-Salpeter approach in conjunction with the generalized impulse approximation using the dressed quark-photon-quark vertices of the Ball-Chiu and Curtis-Pennington type. These form factors are compared with the ones predicted by the vector meson dominance, operator product expansion, QCD sum rules, and the perturbative QCD for the large spacelike transferred momenta k. The most important qualitative feature of the asymptotic beha…
Fully and Doubly-heavy four-quarks within QCD Laplace sum rule
本文利用QCD拉普拉斯求和规则结合比值与双重比值方法，系统研究了全重和双重重四夸克态的质量与耦合，解释了LHCb观测到的结构，并给出$T_{cc}$态更精确的质量预言。
Masses of singly and doubly charmed baryons are calculated in quenched lattice QCD using an improved action of the D234 type on an anisotropic lattice. The mass differences between spin 3/2 and spin 1/2 baryon states are calculated and compared to mass differences between vector and pseudoscalar mesons. The suppression of spin splittings in mesons containing heavy quarks, characteristic of quenched QCD simulations, is not observed in the baryon sector. The mass dependence of color hyperfine effects is discussed within the context of the quark model and heavy quark effective theory.
The $N_c$-dependence of the vertices $PPPγ$, where $P$ is a pseudoscalar meson and $N_c$ is the number of colors, is analyzed with regard for the $N_c$-dependence of the quark charges. It is shown that the best processes for the determination of $N_c$ are the reactions $Kγ\to Kπ$ and $π^pmγ\toπ^\pmη$ as well as the decay $η\raπ^+π^-γ$. The measurement of the cross section $σ(π^-γ\raπ^-η)$ at the VES facility at the IHEP agrees with the value $N_c=3$.
Final-state rescattering mechanism of double-charm baryon decays: $\mathcal{B}_{cc}\to\mathcal{B}_{c}P$
本研究利用末态再散射机制计算双粲重子非轻子弱衰变的长程贡献，结合LHCb实验数据确定模型参数，预测了67种衰变过程的分支比、衰变不对称参数及CP破坏，为未来识别双粲重子提供了理论框架。
Doubly-hidden scalar heavy molecules and tetraquarks states from QCD at NLO
本文利用逆拉普拉斯变换求和规则在NLO精度下研究双重隐藏标量重分子和四夸克态，改进LO估计并回应方法批评，成功解释LHCb在(6.2–6.9) GeV观测到的结构。
We discuss exclusive central diffractive production of scalar ($f_{0}(980)$, $f_{0}(1370)$, $f_{0}(1500)$), pseudoscalar ($η$, $η'(958)$), and vector ($ρ^{0}$) mesons in proton-proton collisions. We show that high-energy central production of mesons could provide crucial information on the spin structure of the soft pomeron. The amplitudes are formulated in terms of effective vertices respecting standard rules of Quantum Field Theory and propagators for the exchanged pomeron and reggeons. For the scalar and pseudoscalar meson production, in most cases, two lowest orbital angular momentum - spi…
Pseudoscalar meson dominance, the pion-nucleon coupling constant and the Goldberger-Treiman discrepancy
本文通过结合ChPT、共振、Regge行为和pQCD，推导出π-核耦合常数和Goldberger-Treiman矛盾，支持伪标量主导核结构的概念。
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