Now move channel B one tick later while keeping the same detector window.
The toy ledger compares 3 seconds against 6 seconds, gets a 3 second gap,
and rejects it because the fixed window is only 2 seconds; real late-hit
decisions also carry timing jitter and dead-time uncertainty.
A tick outside the fixed window is rejected. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A later channel B tick misses the window
Channel B at 6 seconds is 3 seconds after channel A.
∣6−3∣=3
Past the window is rejected
The difference 3 is greater than the 2 second window.