标题： 寻找探测LHC超周边重离子碰撞中低质量类轴子粒子的新策略 显示英文标题

标题： Looking for new strategies to probe low mass axion-like particles in ultraperipheral heavy-ion collisions at the LHC

摘要： 在大型强子对撞机（LHC）的超周边$PbPb$碰撞中，研究了寻找衰变为光子的长寿命类轴子粒子（ALPs）的可能性。 我们提出了利用LHCb和ALICE实验来搜索低质量ALPs的策略。 通过要求衰变顶点被重构在预期初级顶点的区域之外来进行ALP识别，这大大抑制了与轻介子衰变相关的贡献。 我们还利用了一部分光子转化为电子-正电子对的事实，从而允许重构粒子的衰变位置。 我们给出了ALPs和光子的伪快速度和横动量分布的预测。 此外，考虑了ALICE和LHCb探测器的特点，针对不同ALP质量和ALP-光子耦合值，给出了相应的标定截面预测。 显示英文摘要

摘要： The possibility of searching for long-lived axion-like particles (ALPs) decaying into photons is investigated in ultraperipheral $PbPb$ collisions at the Large Hadron Collider (LHC). We propose a search strategy for low mass ALPs using the LHCb and ALICE experiments. The ALP identification is performed by requiring the decay vertex be reconstructed outside the region where a primary vertex is expected, which strongly suppress the contribution associated with the decay of light mesons. We also use the fact that a fraction of the photons convert into electron-positron pairs, allowing the reconstruction of the particle decay position. We present the predictions for the pseudo - rapidity and transverse momentum distributions of the ALPs and photons. Moreover, predictions for the fiducial cross-sections, derived considering the characteristics of the ALICE and LHCb detectors, are presented for different values of the ALP mass and the ALP - photon coupling.