LHCb探测器及升级计划  

The LHCb experiment and its upgrades

作　　者：李一鸣 刘凯 徐子骏[1] Yiming Li;Kai Liu;Zijun Xu(Institute of High Energy Physics,Chinese Academy of Sciences,Bejing 100049,China;School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China;Frontiers Science Center for Rare Isotopes,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]中国科学院高能物理研究所,北京100049 [2]兰州大学核科学与技术学院,兰州730000 [3]兰州大学稀有同位素前沿科学中心,兰州730000

出　　处：《科学通报》2024年第31期4529-4539,共11页Chinese Science Bulletin

基　　金：国家自然科学基金(11961141015,12175245,12188102);国家重点研发计划(2022YFA1601900,2022YFA1601901);中国科学院“百人计划”资助。

摘　　要：LHCb探测器是大型强子对撞机上的大型粒子物理实验装置,最初为研究重味强子的衰变而设计,目前研究范围得到显著拓展,涵盖了重味强子的CP破坏和稀有衰变、重味强子谱和产生机制、W/Z玻色子性质和重离子碰撞物理等领域.LHCb探测器包含高性能径迹探测系统和粒子鉴别系统,截至2018年一直稳定运行,取得了大量优质科学数据.在刚刚结束的探测器一期升级中,径迹探测器采用新技术重新建造,切伦科夫探测器光学系统全部更新,量能器和缪子探测系统读出电子学也完全更新,使得LHCb实验能够以5倍于升级前的亮度运行.一期升级完全移除硬件触发,实现基于全软件触发的事例实时重建和选择.为充分发挥高亮度大型强子对撞机在味物理研究方面的潜力,LHCb合作组提出二期升级计划并开展新探测技术预研,以期将运行亮度再提高一个量级.本文介绍了LHCb探测器设计原理、主要性能,以及一期升级情况和二期升级计划.LHCb is a detector experiment at the Large Hadron Collider dedicated to heavy flavour physics.It was initially proposed for studies of rare decays and CP violation of B mesons,while now its physics program covers CP violation and rare decays of heavy flavour hadrons,spectroscopy and heavy flavour production,WIZ bosons,and heavy-ion physics.The LHCb detector has a tracking system consisting of the vertex locator,a magnet generating magnetic field in the vertical direction,and tracking stations both located upstream and downstream of the magnet.The particle identification at LHCb is provided by two ring imaging Cherenkov counters,calorimeters and muon detectors.The LHCb detector smoothly operated for over 10 years by 2018 in two LHC Runs and accumulated 9 inverse-femtobarn proton-proton collision data on which a plethora of physics results have been published.The high-quality scientific data empowered by excellent tracking and particleidentification performance have profoundly changed the landscape of flavour physics and studies of heavy hadrons.In the operation up to 2018,the LHC beams are adjusted using so-called luminosity leveling"technique to maintain a stable and relatively low luminosity at the LHCb collision point.During the past Long-Shutdown 2 of the LHC,the LHCb detector has gone through Upgrade I,to enable operation at a luminosity five times of the initial designed value.All subdetectors of the tracking system have been rebuilt using novel technologies,and all other subsystems have gone through major upgrade such as replacement of the whole front-end electronics.The upgraded LHCb detector solved the yield saturation problem of hadronic final states,by completely removing the hardware trigger,allowing for a more flexible and intelligent trigger flow including real-time full event reconstruction.The installation has been completed in 2023,and the experiment is expected to collect data of 50 inverse-femtobarn by end of Run 4 around 2032.The LHC will be upgraded to the High-Luminosity Large Hadron Collider

关 键 词：重味物理实验 粒子探测器 大科学装置 大型强子对撞机 LHCB LHCb升级 

分 类 号：O572.212[理学—粒子物理与原子核物理]