# Charged pion decay in to Tau

• Oreith
In summary, the decay of a Pion into a (anti) Tau and (anti) Tau neutrino is prevented by the conservation of energy. The Tau lepton is heavier than the Pion, so it requires more energy to decay into it. This is something that needs to be checked every time there is a decay of the form X \rightarrow A_1 + A_2 + ... + A_n, but it does not apply to decays like X+Y \rightarrow N- \text{particles}.

#### Oreith

This may be a silly question, but what prevents the decay of a Pion into a (anti) Tau and (anti)Tau neutrino. I can see the process for the electron but not for the tau.

Conservation of energy. The tau lepton is heavier than the pion.

In the CM of the pion, it will have $E = m_\pi \approx 135 ~MeV$
Then decaying to something that needs at least (for its mass purposes) energy of $E \sim M_\tau \approx 1777 ~MeV$ is impossible.
That's something one has to check everytime he has a decay of the form : $X \rightarrow A_1 + A_2 + ... +A_n$
That's not though the case of $X+Y \rightarrow N- \text{particles}$

## 1. What is charged pion decay?

Charged pion decay is a process in which a charged pion particle, which is a type of subatomic particle, breaks down or decays into smaller particles.

## 2. What is a tau particle?

A tau particle is a type of subatomic particle that is similar to an electron but much heavier. It is also a type of lepton, which is a fundamental particle that does not experience strong nuclear force.

## 3. How does a charged pion decay into a tau particle?

In the process of charged pion decay, the pion particle emits a W boson, which then decays into a tau particle and its corresponding neutrino. The tau particle and neutrino carry away the energy and momentum from the pion, causing it to decay.

## 4. What are the implications of charged pion decay into tau particles?

This process is important in understanding the behavior of subatomic particles and their interactions. It also plays a role in particle physics experiments and can be used to study the properties of the tau particle.

## 5. How is charged pion decay into tau particles studied?

Scientists study this process through high-energy particle collisions, such as those produced by particle accelerators. They can also observe the decay products, such as the tau particle and neutrino, to gather information about the process.