# Question Video: Identifying the Pair Production of a Tauon and an Antitauon from a High-Energy Gamma Ray Physics • 9th Grade

Which of the equations shows the pair production of a tauon and an antitauon from a high-energy gamma ray?

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### 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).