Question

(a) Determine the quark content of the antineutrons.

(b) Sketch the Feynman diagram for its $\mathbf{\beta }$ decay.

Short answer

(a) The antineutron must be made of$\overline{u}\overline{d}\overline{d}$.

(b) The Feynman diagram is shown in the figure as:

Step-by-step solution

Given data 

The quark content of neutron is$udd$.

Concept of Feynman diagram

A Feynman diagram describes the interactions in quantum field theory. Solid lines, and curved lines are used to represent different types of particle interactions.

Step 3:Determine the quark content of the antineutrons 

(a)

We know that the quark content of neutron is$udd$.

This implies that the quark content of antineutron must be$\overline{u}\overline{d}\overline{d}$.

The antineutron must be made of $\overline{u}\overline{d}\overline{d}$.

Sketch Feynman vertex

(b)

The Feynman diagram is shown in figure 1.

Figure 1

This looks like the neutron decay diagram, except all the particles are changed to their antiparticle partners.