论文标题
在3和4中，爱丽丝的中央衍射和超外侧碰撞
Central diffraction and ultra-peripheral collisions in ALICE in Run 3 and 4
论文作者
论文摘要
LHC的爱丽丝实验正在长时间关闭2（2019-2021）进行重大升级。特别是，时间投影室（TPC）配备了新的基于宝石的读数室，并且几个探测器的读数电子设备正在用更快，更灵活的技术代替。这将使爱丽丝在连续模式下读取大多数检测器，并在运行3（2021-2024）中以约50 kHz的速率记录最小偏差PB-PB事件，并运行4（2027-2030）。爱丽丝合作还考虑使用在线和离线预选罕见事件，以约1 MHz的相互作用速率收集大量质子质子碰撞样本。这些目标需要一个全新的在线计算系统，该系统将用于执行数据流的快速重建和压缩。事件选择策略对于中央衍射事件和超外外PB-PB碰撞的情况尤其具有挑战性，其特征在于向前和向后方向的速度差距迅速，只有很少的轨道在中心速度。在这一贡献中，提出了研究中央衍射和超外外事件的动机，并将给出其在Run 3和4中选择的可行性研究。
The ALICE experiment at the LHC is undergoing a major upgrade during the Long Shutdown 2 (2019-2021). In particular, the Time Projection Chamber (TPC) is being equipped with new GEM-based readout chambers and the readout electronics of several detectors are being replaced with faster and more flexible technology. This will allow ALICE to read out most of the detectors in the continuous mode and record minimum bias Pb-Pb events at rates of about 50 kHz in Run 3 (2021-2024) and Run 4 (2027-2030). The ALICE Collaboration is also considering the possibility to collect a large sample of proton-proton collisions at interaction rates of about 1 MHz using online and offline preselection of rare events. These goals require a completely new online computing system that will be used to perform fast reconstruction and compression of the data stream. The event selection strategy becomes especially challenging for the case of central diffractive events and ultra-peripheral Pb-Pb collisions characterized by rapidity gaps at forward and backward directions with only few tracks at central rapidity. In this contribution, the motivation for studying central diffractive and ultra-peripheral events is presented, and feasibility studies for their selection in Run 3 and 4 will be given.
