Quarks*

quark type baryon number charge strangeness** charm** bottom** top** mass (MeV)

down (d) 1/3 –(1/3)e 0 0 0 0 5–15

up (u) 1/3 +(2/3)e 0 0 0 0 2–8

strange (s) 1/3 –(1/3)e –1 0 0 0 100–300

charm (c) 1/3 +(2/3)e 0 1 0 0 1,000–1,600

bottom (b) 1/3 –(1/3)e 0 0 –1 0 4,100–4,500

top (t) 1/3 +(2/3)e 0 0 0 1 180,000

*Note that antiquarks exist for all flavours of quark and have opposite values for all the quantum numbers listed here.

**These are quantum numbers that must be assigned to the quarks to differentiate the various flavours.