A free neutron decays into a proton, an electron and

Options

A. a beta particle
B. an alpha particle
C. an antineutrino
D. a neutrino

Answer

To solve the question regarding the decay of a free neutron, we need to understand the process of beta decay, which is the type of decay that a neutron undergoes. Here’s a step-by-step breakdown of the decay process:

### Step 1: Understand the Components of the Decay
A free neutron (n) decays into three particles:
1. A proton (p)
2. An electron (e⁻)
3. An electron antineutrino (ν̅)

### Step 2: Write the Decay Equation
The decay can be represented by the following equation:
\[ n \rightarrow p + e^- + \bar{\nu}_e \]

### Step 3: Conservation Laws
In this decay process, several conservation laws are satisfied:
- **Conservation of Charge**: The neutron is neutral, the proton has a charge of +1, the electron has a charge of -1, and the antineutrino is neutral. Thus, the total charge before and after the decay remains zero.
- **Conservation of Baryon Number**: The neutron has a baryon number of 1, the proton has a baryon number of 1, and both the electron and antineutrino have a baryon number of 0. Thus, the total baryon number is conserved.
- **Conservation of Lepton Number**: The electron has a lepton number of +1, and the antineutrino has a lepton number of -1. Therefore, the total lepton number is also conserved.

### Step 4: Conclusion
Thus, the correct decay process of a free neutron is:
\[ n \rightarrow p + e^- + \bar{\nu}_e \]