To determine which subatomic particle has a longer lifespan, we compare the average lifetimes of the tau lepton and the neutral pion. The average lifetime of the tau lepton is 2.906 x 10^-12 seconds, and the average lifetime of the neutral pion is 8.4 x 10^-17 seconds.
Comparing these values, we can see that the average lifetime of the tau lepton (2.906 x 10^-12 seconds) is significantly longer than the average lifetime of the neutral pion (8.4 x 10^-17 seconds).
To calculate how many times longer the lifespan of the tau lepton is compared to the neutral pion, we divide the average lifetime of the tau lepton by the average lifetime of the neutral pion:
(2.906 x 10^-12 seconds) / (8.4 x 10^-17 seconds) = 3.453 x 10^4
Therefore, the tau lepton has a lifespan that is approximately 3.453 x 10^4 (34,530) times longer than the neutral pion.