In hadronic high energy particle collisions the shape of the event, i.e. the relative distribution of particles in momentum space, is often used to try to select events with certain topologies. It is claimed that an event shape observable like transverse sphericity is able to discriminate between jet-like events and events that are dominated by soft production from the underlying event.

In this paper we investigate the relationship between the shape of the event and the number of jets found in the respective event for both $e^{+}{e}^{-}$ and pp collisions using the PYTHIA model. In $e^{+}{e}^{-}$ collisions, we find that the transverse sphericity of the event can be used effectively to either enhance or suppress the fraction of jets found in the selected sample, and can even discriminate between single, two, and multi-jet topologies. However, contrary to current literature, we find that in pp collisions this does not hold. It is shown that the transverse sphericity as well as the particle multiplicity is sensitive to the number of multi-parton interactions.

在强子高能粒子碰撞中，事件的形状（即粒子在动量空间中的相对分布）通常用于尝试选择具有特定拓扑的事件。据称，像横向球形一样可观察到的事件形状能够区分喷射状事件和由潜在事件的软生产主导的事件。

在本文中，我们研究了事件的形状与各自事件中发现的喷气机数量之间的关系 ${Ë}^{+}{Ë}^{-}$使用PYTHIA模型进行pp和pp碰撞。在${Ë}^{+}{Ë}^{-}$碰撞时，我们发现该事件的横向球形可以有效地用于增强或抑制在选定样本中发现的射流比例，甚至可以区分单，二和多射流拓扑。但是，与当前文献相反，我们发现在pp碰撞中这并不成立。结果表明，横向球形度和粒子多重性对多部分相互作用的数量很敏感。