Answer:
(2) −1 e
Explanation:
A quark is the lightest elementary particles which form hadron such as proton and neutron. A quark has fractional charge.
Up, charm and top quarks have [tex]+\frac{2}{3} e[/tex] charge where as down, strange and bottom quarks have [tex] -\frac{1}{3}e[/tex] charge.
The antiparticle of up quark is antiup quark and has charge [tex]-\frac{2}{3}e[/tex] charge.
The antiparticle of down quark is antidown quark and has charge [tex]+\frac{1}{3}e[/tex] charge.
An antibaryon is composed of two anti-up quark and one anti-down quark.
Net charge of the anti-baryon is:
[tex]2\times (-\frac{2}{3} e)+1\times (+\frac{1}{3})e=-1e[/tex]
Thus, antibaryon has -1e charge.