Resonance states of axion-like particles were searched for via four-wave mixing by focusing two-color pulsed lasers into a quasi-vacuum. A quasi-parallel collision system that allows probing of the sub-eV mass range was realized by focusing the combined laser fields with an off-axis parabolic mirror. A 0.10 mJ/34 fs Ti:Sapphire laser pulse and a 0.14 mJ/9 ns Nd:YAG laser pulse were spatiotemporally synchronized by sharing a common optical axis and focused into the vacuum system. No significant four-wave mixing signal was observed at the vacuum pressure of $3.7 \times 10^{-5}$ Pa , thereby providing upper bounds on the coupling-mass relation by assuming exchanges of scalar and pseudoscalar fields at a 95 % confidence level in the mass range below 0.21 eV. For this search, the experimental setup was substantially upgraded so that optical components are compatible with the requirements of the high-quality vacuum system, hence enabling the pulse power to be increased. With the increased pulse power, a new kind of pressure-dependent background photons emerged in addition to the known atomic four-wave mixing process. This paper shows the pressure dependence of these background photons and how to handle them in the search.
Bridging the divide: axion searches and axino phenomenology at colliders
University of Chicago（芝加哥大学）；Enrico Fermi Institute, University of Chicago（恩里科·费米研究所，芝加哥大学）；Kavli Institute for Cosmological Physics, University of Chicago（卡弗里宇宙物理学研究所，芝加哥大学）；Leinweber Institute for Theoretical Physics, University of Chicago（莱因韦伯理论物理研究所，芝加哥大学）；Kavli Institute for Physics and Mathematics of the Universe (WPI)（宇宙物理与数学卡弗里研究所（WPI））；The University of Tokyo Institutes for Advanced Study（东京大学高等研究院）；The University of Tokyo（东京大学）
Hunan University of Science and Technology（湖南科技大学）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；Universität Bonn（波恩大学）；Forschungszentrum Jülich（于利希研究中心）；Tbilisi State University（第比利斯国立大学）；University of Chinese Academy of Sciences（中国科学院大学）
Non-Resonant Searches for Axion-Like Particles at the LHC
我们提出了一个新的碰撞探测器的轴子样粒子（ALP），更一般的伪戈德斯通玻色子：非共振搜索，利用其与标准模型粒子的相互作用的衍生性质。ALP可以作为离壳介体参与LHC等对撞机上$2 \to 2$散射过程的$s$通道。我们通过使用Run 2 CMS公共数据推导ALP耦合到规范玻色子的新限制来增强这种新型搜索的能力，通过过程$p p \to Z Z$，$p p \to γγ$和$p p \to j j$，探测ALP参数空间中以前未探索的区域。此外，我们提出了未来的非共振搜索涉及ALP耦合到其他电弱玻色子和/或希格斯粒子。
Production of axionlike particles in $PbPb$ collisions at the LHC, HE -- LHC and FCC: A phenomenological analysis
考虑到大型强子对撞机（LHC）下一轮运行的能量以及未来高能LHC（HE-LHC）和未来圆形对撞机（FCC）的能量，研究了超周边$PbPb$碰撞（UPHIC）中类轴子粒子（ALP）的产生.假设四种不同的组合ALP质量和耦合和典型的排他性削减中央和前向检测器，我们估计的横截面和不变的质量，快度，横向动量和{共面}分布与双光子的最终状态中产生的$γγ\rightarrow a \rightarrow γγ$子过程。对背景进行了详细的分析。我们表明，背景可以大大减少排他性削减和前向检测器，作为LHCb，是理想的探测小质量的ALP。最后，我们的结果表明，未来的实验分析的双光子末态在UPHIC可以探测类轴子粒子的存在和性质。
Single-Point Search for eV-scale Axion-like particles with Variable-Angle Three-Beam Stimulated Resonant Photon Collider
Graduate School of Advanced Science and Engineering, Hiroshima University（广岛大学先进理工学研究科）；International Center for Quantum-field Measurement Systems for Studies of the Universe and Particles (QUP), KEK（高能加速器研究机构宇宙与粒子研究量子场测量系统国际中心）；Institute for Chemical Research, Kyoto University（京都大学化学研究所）；Research Institute of Science and Technology, Tokai University（东海大学科学技术研究院）
