91Ó°ÊÓ

A quark is an elementary particle, the combination of quarks forms hadrons.

The table shows the properties of the original quarks:

a)

For the quarks: uds

$$\begin{gathered} Q=\frac{2}{3}+\left(-\frac{1}{3}\right)+\left(-\frac{1}{3}\right) \\ =0 \\ B=\frac{1}{3}+\frac{1}{3}+\frac{1}{3} \\ =+1 \\ S=0+0-1 \\ =-1 \\ C=0+0+0 \\ =0 \end{gathered}$$

Hence, the electric charge, baryon number, strangeness quantum number and charm quantum number for uds are 0, +1, $-1$and 0 respectively.

b)

For the quarks:$c\stackrel{¯}{u}$

$$\begin{gathered} Q=+\frac{2}{3}+\left(-\frac{2}{3}\right) \\ =0 \\ B=\frac{1}{3}-\frac{1}{3} \\ =0 \\ S=0+0 \\ =0 \\ C=1+0 \\ =+1 \end{gathered}$$

Hence, the electric charge, baryon number, strangeness quantum number and charm quantum number for $c\stackrel{¯}{u}$are 0, 0, 0 and +1 respectively.

c)

For the quarks: ddd

$$\begin{gathered} Q=-\frac{1}{3}-\frac{1}{3}-\frac{1}{3} \\ =-1 \\ B=\frac{1}{3}+\frac{1}{3}+\frac{1}{3} \\ =+1 \\ S=0+0+0 \\ =0 \\ C=0+0+0 \\ =0 \end{gathered}$$

Hence, the electric charge, baryon number, strangeness quantum number and charm quantum number for dddare$-1$, +1, 0 and 0 respectively.

d)

For the quarks:$d\stackrel{¯}{c}$

$$\begin{gathered} Q=-\frac{1}{3}-\frac{2}{3} \\ =-1 \\ B=\frac{1}{3}+\left(-\frac{1}{3}\right) \\ =0 \\ S=0+0 \\ =0 \\ C=0-1 \\ =-1 \end{gathered}$$

Hence, the electric charge, baryon number, strangeness quantum number and charm quantum number for$d\stackrel{¯}{c}$ are$-1$, 0, 0 and$-1$ respectively.