### Video Transcript

Which of the following equations
shows the pair production of a tauon and an antitauon from a high-energy gamma
ray? (A) 𝜏 negative plus 𝜏 positive
arrow to 𝛾. (B) 𝛾 arrow to 𝜏 negative plus 𝜏 positive. (C) 𝛾 arrow to 𝑡 plus anti
𝑡. (D) 𝑡 plus anti 𝑡 arrow to 𝛾.
(E) 𝛾 arrow to 𝜇 negative plus 𝜇 positive.

Our problem talks about tauon,
antitauon, and gamma ray. Therefore, we can eliminate any
answer choice that does not include these three particles. We need to recall that a tauon is
represented by the symbol 𝜏 with a negative in the upper right-hand corner. And the antitauon is represented by
𝜏 with a positive symbol in the upper right-hand corner. Each of the answer choices has a
gamma ray represented by the symbol 𝛾. We could eliminate answer choices
(C), (D), and (E) as none of the three of these have a tauon or antitauon in
them.

The problem tells us our equation
is a pair production that takes a high-energy gamma ray and turns it into a tauon
and an antitauon. Looking at our remaining two
equations, only answer choice (B) has a gamma ray being turned into a tauon and an
antitauon. In fact, answer choice (A) is what
we would call a pair annihilation, where a tauon and an antitauon meet and release a
gamma-ray photon. Of the listed equations, the only
one that shows a pair production of a tauon and an antitauon from a high-energy
gamma ray is answer choice (B).