论文标题
Belle II在Superkekb上的梁背景期望
Beam background expectations for Belle II at SuperKEKB
论文作者
论文摘要
SuperkekB电子峰值撞机的Belle II实验旨在收集$ \ rm 50〜 {\ rm ab}^{ - 1} $的前所未有的数据集，以研究$ b $ -Meson系统中的$ cp $ - 抗化，以超越标准模型（BSM）。 Superkekb已经是世界上最高的露光对撞机。为了在大约一十年内收集计划的数据集，目标是达到$ \ rm 6.3 \ times 10^{35} 〜cm^{ - 2} s^{ - 1} $的峰值光度，通过进一步增加束电流并通过在相互作用上降低相互作用点，并通过挤压betatron funcance $^^$ { y} = \ rm 0.3〜mm $。在这种情况下，梁背景是一个关键挑战。我们估计未来十年中预期的背景演变，并讨论潜在的挑战和背景缓解策略。我们发现背景将保持较高但可以接受，直到至少$ \ rm 2.8 \ times 10^{35} 〜cm^{ - 2} s^{ - 1} $以$β^{*} _ {\ rm y} = \ rm 0.6〜mm $。除了这种亮度之外，由于计划的相互作用区域的重新设计，预测是高度不确定的。对最终，最大发光操作的不确定性减少的背景估计的改进将需要完成此重新设计。
The Belle II experiment at the SuperKEKB electron-positron collider aims to collect an unprecedented data set of $\rm 50~{\rm ab}^{-1}$ to study $CP$-violation in the $B$-meson system and to search for Physics beyond the Standard Model (BSM). SuperKEKB is already the world's highest-luminosity collider. In order to collect the planned data set within approximately one decade, the target is to reach a peak luminosity of $\rm 6.3 \times 10^{35}~cm^{-2}s^{-1}$ by further increasing the beam currents and reducing the beam-size at the interaction point by squeezing the betatron function down to $β^{*}_{\rm y}=\rm 0.3~mm$. Beam backgrounds are a key challenge in this context. We estimate the expected background evolution in the next ten years and discuss potential challenges and background mitigation strategies. We find that backgrounds will remain high but acceptable until a luminosity of at least $\rm 2.8\times 10^{35}~cm^{-2}s^{-1}$ is reached at $β^{*}_{\rm y}=\rm 0.6~mm$. Beyond this luminosity, predictions are highly uncertain, owing to a planned redesign of the interaction region. Improved background estimates with reduced uncertainties for the final, maximum-luminosity operation will require completion of this redesign.
