标题： Exploring the Di-$J/ψ$ Resonances around 6.9 $\mathrm{GeV}$ Based on {\it{从头开始}} Perturbative QCD 显示英文标题

标题： Exploring the Di-$J/ψ$ Resonances around 6.9 $\mathrm{GeV}$ Based on {\it{ab initio}} Perturbative QCD

摘要： 我们提出了一种{\it{从头开始}}方法来研究新发现的粒子$X$(6900) 的性质。 我们发现，在约 6.9$\mathrm{GeV}$附近的共振区附近应该存在另一个状态，并且$X$(6900) 与未发现状态的产生截面之比对$X$(6900) 的性质非常敏感，而几乎不依赖于横向动量和快速度。 这种行为不太可能被高阶修正所改变。 因此，$X$(6900) 的性质在未来可以通过实验事实得以揭示。 如果在附近存在另一个接近$X$(6900) 的态，且其截面大于$X$(6900) 的一半，则$X$(6900) 应该是一个四夸克态。否则，它应该是一个类似于分子的态。 显示英文摘要

摘要： We propose an {\it{ab initio}} method to explore the nature of the newly discovered particle $X$(6900). We find that there should exist another state near the resonance at around 6.9 $\mathrm{GeV}$, and the ratio of production cross sections of $X$(6900) to the undiscovered state is very sensitive to the nature of $X$(6900), whereas is almost independent of the transverse momentum and rapidity. This behavior is unlikely changed by higher order corrections. Therefore, the nature of $X$(6900) can be uncovered by experimental facts in the near future. If there is another state near $X$(6900) with cross section larger than half of that of $X$(6900), $X$(6900) should be a tetraquark state. Otherwise, it should be a molecule-like state.