AI 中文总结
在协变夸克-双夸克模型中研究奇异重子\(\Sigma_c\)和\(\Lambda_c\)的电磁形状因子，获磁矩等可观测量，计算与晶格QCD结果相符，揭示电形状因子及磁结构差异，还预测总截面，研究结果可被检验。
AI 中文摘要
我们在协变夸克-双夸克模型中对基态奇异重子\(\Sigma_c\)（\(\Sigma_c^{++},\Sigma_c^+,\Sigma_c^0\)）和\(\Lambda_c^+\)的类空电磁形状因子进行了系统研究。基于此框架，得到了它们的磁矩、电荷和磁矩半径。理论计算与\(\Sigma_c^{++}\)和\(\Sigma_c^0\)重子的现有晶格QCD结果定性一致。讨论了数值结果对魅夸克和轻双夸克的依赖机制。发现奇异重子的电形状因子随动量转移\(Q^2\)下降比质子慢，磁结构有显著差异，还预测了\(e^+e^-\to\Sigma_c\bar{\Sigma}_c\)的总截面，结果可在现有和拟建设施中检验。
英文摘要
We present a systematic study of the spacelike electromagnetic form factors of the ground-state singly charmed baryons, $Σ_c$ ($Σ_c^{++},Σ_c^+,Σ_c^0$) and $Λ_c^+$, within a covariant quark-diquark model. Based on this framework, we obtain their magnetic moments as well as electric charge and magnetic moment radii. Such observables are important to understand the internal structure and the inner dynamics of these heavy baryon states. Our theoretical calculations are in qualitative agreement with available lattice QCD results of $Σ_c^{++}$ and $Σ_c^0$ baryons. We also discuss the mechanism behind the dependence of the numerical results on the charm quark and light diquark. A key finding is that the electric form factors of the singly charmed baryons fall off much more slowly with momentum transfer $Q^2$ than that of the proton, indicating a more compact electric charge distribution, which is attributed to the heavy charm quark acting as a localized core. More importantly, we observe a striking difference in the magnetic structure: while the magnetic form factors of $Σ_c$ are dominated by the light axial-vector diquark, those of $Λ_c^+$ are unexpectedly governed by the charm quark due to the vanishing contribution of the scalar diquark. This highlights the decisive role of the light-diquark spin configuration in determining the magnetic properties. Finally, using an empirical asymptotic relation connecting the spacelike and timelike regions, we predict the total cross section for $e^+e^-\toΣ_c\barΣ_c$. Our findings can be tested at existing facilities including the BESIII, Belle II and LHCb, as well as the proposed Super Tau-Charm Facility.
