Quantum Chromodynamics 101


The Weak Force

The weak force is so named because although it is stronger than gravity, it is only effective at very short distances (10-18 m).  Technically, it is one of the strongest forces, but because the particles involved are so big, their travel is limited to the short distance listed above.  The W and Z bosons that make the weak force weigh in at 80 GeV and 91 GeV respectively.  This is in comparison to the proton, which weighs .9 GeV. 



Beta decay is just one example of the weak force.  During beta decay a neutron disappears and is replaced by a proton, an electron and a neutrino (anti-electron).  It is also proven that a down quark disappears and an up quark is produced.  The up quark eventually turns into the electron and neutrino.  This can all be illustrated using the diagram below.



If the weak force were not to exist, many types of matter would become much more stable.  Elements like plutonium and uranium could be handled without protection. Without the weak force, the sun would cease to exist.  The weak force allows the fusion of protons and neutrons to form deuterium.  The excess energy from this fusion is the source of heat from the sun.



Click on the links below to move to another force.

Gravity Weak Force Electromagnetic Force Strong force