An Actual Top Event
The top quark --> a bottom quark and W;
-
then the W+ --> e+ and a neutrino, and
-
the bottom quark (which emerged as a neutral
anti-B meson) decays into jet 4.
The antitop quark --> an antibottom quark and W-;
-
then the W- --> an anti-up quark (jet 2 or 3) and a down quark
(jet 3 or 2), and
-
the antibottom quark (neutral B meson) decays into jet 1.
(We cannot tell from jets 2 and 3 which is the anti-up quark and
which is the down quark.)
Both the bottom quark and the antibottom quark have
long enough lifetimes and enough energy
to travel a visible distance before they decay.
The bottom went 2.2 mm and the antibottom went 4.5 mm.
Because both quarks emerged as neutral particles, neither
left tracks until they decayed.
Notice that the neutrino left no tracks;
its presence was inferred by the missing momentum
and energy.
Top Quark
Picture of Top Quark Production
To return to the main sequence use your browser's back button.