Acciarri R, Adams C, Asaadi J, Baller B, Bolton T, Bromberg C, Cavanna F, Edmunds D, Fitzpatrick R S, Fleming B, Harnik R, James C, Lepetic I, Littlejohn B R, Liu Z, Luo X, Palamara O, Scanavini G, Soderberg M, Spitz J, Szelc A M, Wu W, Yang T
Fermi National Accelerator Lab, Batavia, Illinois 60510, USA.
Argonne National Lab, Lemont, Illinois 60439, USA.
Phys Rev Lett. 2020 Apr 3;124(13):131801. doi: 10.1103/PhysRevLett.124.131801.
A search for millicharged particles, a simple extension of the standard model, has been performed with the ArgoNeuT detector exposed to the Neutrinos at the Main Injector beam at Fermilab. The ArgoNeuT liquid argon time projection chamber detector enables a search for millicharged particles through the detection of visible electron recoils. We search for an event signature with two soft hits (MeV-scale energy depositions) aligned with the upstream target. For an exposure of the detector of 1.0×10^{20} protons on target, one candidate event has been observed, compatible with the expected background. This search is sensitive to millicharged particles with charges between 10^{-3}e and 10^{-1}e and with masses in the range from 0.1 to 3 GeV. This measurement provides leading constraints on millicharged particles in this large unexplored parameter space region.
利用费米实验室主注入器束流中暴露于中微子的阿贡中微子探测器（ArgoNeuT），对作为标准模型简单扩展的千分之一电荷粒子进行了搜索。阿贡中微子液态氩时间投影室探测器能够通过探测可见电子反冲来搜索千分之一电荷粒子。我们搜索与上游靶标对齐的两个软击（兆电子伏特级能量沉积）的事件特征。对于探测器在靶上1.0×10²⁰ 质子的曝光量，观测到了一个候选事件，与预期背景相符。该搜索对电荷在10⁻³e至10⁻¹e之间且质量在0.1至3 GeV范围内的千分之一电荷粒子敏感。此测量为这个未被充分探索的大参数空间区域中的千分之一电荷粒子提供了主要限制。
