The Hadrons — Question 1

Question 1

Strong interaction evidence distinguishes a neutral meson from a lepton

Three hypothetical particles are characterized as follows: A interacts strongly, has B=0 and spin 0; B interacts strongly, has B=1 and spin 1/2; C has no strong interaction, lepton number 1 and spin 1/2. All are electrically neutral.

1. Classify each particle using the given evidence.

2. For one A, two B and three C particles, find net baryon number, lepton number and charge.

Question 1 - Solution

Strong interaction evidence distinguishes a neutral meson from a lepton

(a) Method and calculation

$$\boxed{A:\text{ meson};\quad B:\text{ baryon};\quad C:\text{ lepton}}.$$$$Q_A=Q_B=Q_C=0\quad\text{does not distinguish the classes}.$$

(b) Interpretation and further calculation

$$\boxed{B_{\mathrm{total}}=0+2(1)+3(0)=2}.$$$$\boxed{L_{\mathrm{total}}=0+0+3(1)=3,\quad Q_{\mathrm{total}}=0}.$$

Physical check

Mesons and baryons are hadrons. Electrical neutrality alone does not determine whether a particle has strong interactions or nonzero additive quantum numbers.