In search of almost undetectable subatomic particles .
以寻找几乎无法探测的次原子微粒。
Almost undetectable with even the most delicate instruments .
即使最精密的仪器都几乎无法察觉的。
Exactly what could cause memory problems among people with af is not fully understood , but people with af may have a series of tiny , undetectable strokes that could result in the mental impairment .