论文标题
$ x17 $是由四个裸露的夸克组成吗？
Is the $X17$ composed of four bare quarks?
论文作者
论文摘要
在使用QCD总规则的方法研究tetraquark时，我们发现了一些四夸克电流，例如$ \ bar u_lγ_μd_l〜 \ bard_lγ^μu_l$和$ \ bar u_l u_lγ_μD_L〜 \ bar d_r d_r d_rγ^μu_r$，我们计算的方法和查找器非扰动QCD效应对它们贡献不大。这表明可能存在由裸露的夸克组成的四夸克状态。我们将$ x17 $的$ x17 $分配为这样的状态。我们认为，Atomki实验可能会观察到一种新型的核衰减过程，在该过程中，Sea Quarks消除了核的额外能量。这种四夸克分配的独特特征是，我们预测两个宽度显着不同的几乎变性状态。
When studying tetraquark states using the method of QCD sum rules, we find some tetraquark currents, such as $\bar u_L γ_μd_L~\bar d_L γ^μu_L$ and $\bar u_L γ_μd_L~\bar d_R γ^μu_R$, etc. We calculate their correlation functions using the method of operator product expansion, and find that non-perturbative QCD effects do not contribute much to them. This indicates the possible existence of tetraquark states composed of bare quarks with abnormally small masses. We study the possible assignment of the $X17$ as such a state. We argue that the Atomki experiments might observe a new type of nuclear decay process, where sea quarks take away the extra energy of the nucleus. A unique feature of this tetraquark assignment is that we predict two almost degenerate states with significantly different widths.
