We have applied isovector and isoscalar tensor current to evaluate the tensor form factors of the $ N(1535) \rightarrow N $ transition with the help of the light-cone QCD sum rule method. In numerical computations, have used the most general forms of the interpolating current for the nucleon and the tensor current together with two different sets of the input parameters in the DAs of the $N(1535)$ state. We have obtained that the values of $N(1535) \rightarrow N$ transition tensor form factors very sensitive to the input parameters of the distribution amplitudes of the $N(1535)$ state. We have acquired that the $Q^2$ dependence of $N(1535) \rightarrow$ transition tensor form factors is well defined by a p-pole fit function.
The recent precise measurements of the $e^+e^-\to K_SK_L$ and $e^+e^-\to K^+K^-$ cross sections and the hadronic spectral function of the $τ^-\to K^-K_Sν_τ$ decay are used to extract the isoscalar and isovector electromagnetic kaon form factors and their relative phase in a model independent way. The experimental results are compared with a fit based on the vector-meson-dominance model.
This study revisits the issue of the extraction of estimates for the masses and for the partial decay widths to two pions of the scalar-isoscalar $I^G\,(J^{PC}) = 0^+\,(0^{++})$ and vector-isovector $I^G\,(J^{PC}) = 1^+\,(1^{--})$ mesons below $2$ GeV, from the data contained in the recent compilation by the Particle Data Group.
Based on the accurately calibrated interaction FSUGold, we show that including isovector scalar $δ$ meson and its coupling to isoscalar scalar $σ$ meson in the relativistic mean field (RMF) model can soften the symmetry energy $E_{\rm{sym}}(n)$ at intermediate densities while stiffen the $E_{\rm{sym}}(n)$ at high densities. We find this new RMF model can be simultaneously compatible with (1) the constraints on the equation of state of symmetric nuclear matter at suprasaturation densities from flow data in heavy-ion collisions, (2) the neutron skin thickness of $^{208}$Pb from the PREX-II exper…
In this letter we study the reaction e^{+}e^{-} \to ϕπ^0 ηwith the π^{0}ηsystem in an isoscalar s-wave configuration. We use a formalism recently developed for the study of e^{+}e^{-} \to ϕππand e^{+}e^{-} \to ϕK^{+}K^{-}. The obtained cross section is within the reach of present e^{+}e^{-} machines. Measuring this channel would test the absence of an isovector companion of the X(2175) as predicted by the three body approach to this resonance.
We discusses the charge asymmetry in $ B\rightarrow D\bar DK$ decays with an invariant mass of the $D\bar D$ pair near the $Ψ(3770)$ resonance. Unlike $ Ψ(3770) $ decays in $ e^+e^- $ annihilation, in $B^+$ decays the probability of $D^0\bar D^0$ production is almost three times higher than $D^+ D^-$. In $B^0$ decays, the ratio of these probabilities will be opposite. The effect is explained by the fact that, in $B$ -meson decays, the $D\bar D$ pair is produced in a superposition of isoscalar and isovector states, and only in combination with $K$ -mesons the total state has $ 1/2 $ isospin. We…
We present an analysis of two isovector scalar resonant contributions to the $B$ decays into charmonia plus $K\bar K$ or $πη$ pair in the perturbative QCD approach. The Flatté model for the $a_0(980)$ resonance and the Breit Wigner formula for the $a_0(1450)$ resonance are adopted to parametrize the timelike form factors in the dimeson distribution amplitudes, which capture the important final state interactions in these processes. The predicted distribution in the $K^+K^-$ invariant mass as well as its integrated branching ratio for the $a_0(980)$ resonance in the $B^0\rightarrow J/ψK^+K^-$ m…
Complementarity Between Neutrino Neutral and Charged Current Events in the Search for New Physics
Colorado State University（科罗拉多州立大学）；National Centre for Nuclear Research（国家核研究中心）；Fermi National Accelerator Laboratory（费米国家加速器实验室）；Shanghai Jiao Tong University（上海交通大学）
We present a dispersive representation of the $η'$ transition form factor that allows one to account, in a consistent way, for the effects of $ρ$-$ω$ mixing in both the isoscalar and the isovector contributions. Using this formalism, we analyze recent data on $η'\to π^+π^-γ$ to constrain the isovector part of the form factor, individually and in combination with data for the pion vector form factor. As a first application, we use our results, in combination with the most recent input for the isoscalar part of the form factor, to predict the corresponding spectrum of $η'\to\ell^+\ell^-γ$, in pa…
Sensitivity of tensor analyzing power in the process $d+p\to d+X$ to the longitudinal isoscalar form factor of the Roper resonance electroexcitation
在核子共振电激发的代数集体模型中，在$ω$交换的框架下，研究了动量间隔为3.7 ~ 9 GeV/c的氘核前向散射过程$d + p \to d + X$的张量分析能力.我们指出了一个特殊的敏感性的张量分析功率的等幅纵向形状因子的罗珀共振激发。主要论点是$S_{11}(1535)$、$D_{13}(1520)$和$S_{11}(1650)$共振只有等矢量纵向形状因子。它是Roper激发的纵向形状因子，其在张量分析功率的$t-$依赖性中起重要作用。我们讨论了强子随激发能增加而膨胀的可能证据。
We present a theoretical parametrization of the nucleon electromagnetic form factors (FFs) based on a combination of chiral effective field theory and dispersion analysis. The isovector spectral functions on the two-pion cut are computed using elastic unitarity, chiral pion-nucleon amplitudes, and timelike pion FF data. Higher-mass isovector and isoscalar t-channel states are described by effective poles, whose strength is fixed by sum rules (charges, radii). Excellent agreement with the spacelike proton and neutron FF data is achieved up to Q^2 \sim 1 GeV^2. Our parametrization provides prope…
