Chapter 32, Problem 42P

To determine

To draw:

The Feynman diagram for the given reaction.

Answer to Problem 42P

Solution:

The Feynman diagram for the given reaction is shown in figure I.

Explanation of Solution

Given info:

The given reaction is ${\text{π}}^{\text{-}}+\text{p}\to {\text{π}}^{\text{0}}+\text{n}$.

The pi meson has one negative charge so, it contains one down quark and one up anti quark. Because the up anti-quark has $-\frac{2}{3}$ charge, while the down quark has $-\frac{1}{3}$ charge. So, the total charge becomes on the $\text{π}$ meson is $-\frac{2}{3}+\left(-\frac{1}{3}\right)=-1$.

Al nucleons that are proton and neutron have Baryon number $+1$. The proton consist three quarks that are up, up and down while the neutron consists of and the neutron have also three quarks up, down and down.

In the reaction the negative pi-meson react with a proton produces a neutral pi-meson by converting proton into neutron. The neutral pi-meson is made up of quark and one antiquark of same type.

The Feynman diagram that represents the given reaction is shown below:

Figure I