Winkler Martin Wolfgang, Linden Tim
Stockholm University and The Oskar Klein Centre for Cosmoparticle Physics, Alba Nova, 10691 Stockholm, Sweden.
Phys Rev Lett. 2021 Mar 12;126(10):101101. doi: 10.1103/PhysRevLett.126.101101.
Recent observations by the Alpha Magnetic Spectrometer (AMS-02) have tentatively detected a handful of cosmic-ray antihelium events. Such events have long been considered as smoking-gun evidence for new physics, because astrophysical antihelium production is expected to be negligible. However, the dark-matter-induced antihelium flux is also expected to fall below current sensitivities, particularly in light of existing antiproton constraints. Here, we demonstrate that a previously neglected standard model process-the production of antihelium through the displaced-vertex decay of Λ[over ¯]_{b}-baryons-can significantly boost the dark matter induced antihelium flux. This process can entirely dominate the production of high-energy antihelium nuclei, increasing the rate of detectable AMS-02 events by 2 orders of magnitude.
阿尔法磁谱仪（AMS - 02）最近的观测初步探测到了少量宇宙射线反氦事件。长期以来，此类事件一直被视为新物理的确凿证据，因为天体物理中反氦的产生预计可忽略不计。然而，暗物质引发的反氦通量预计也会低于当前的灵敏度，尤其是考虑到现有的反质子限制。在此，我们证明了一个先前被忽视的标准模型过程——通过Λ[上划线]₍b₎重子的位移顶点衰变产生反氦——能够显著提高暗物质引发的反氦通量。这个过程可以完全主导高能反氦核的产生，将可探测到的AMS - 02事件发生率提高2个数量级。
