Peoples Physics Book Version-3

http://www.ck12.org Chapter 22. Standard Model of Particle Physics

mesons. In reality, most of the mass of a proton, neutron, etc. is made up of binding energy and virtual

particles.

• Particles differ in their mass, their electric charge, their family (in the case of leptons), and their “spin.” Spin
  is a quantum mechanical concept that is best explained as a magnetic moment intrinsic to the particle and
  manifested as angular momentum.

MEDIA

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Interactions

• There are four fundamental forces in nature. From weakest to strongest, these are the gravitational force, the
  weak nuclear force, the electromagnetic force, and the strong nuclear force.


• Each fundamental force is transmitted by its own boson(s): for gravity, they are called gravitons; for the weak
  nuclear force, they are called W−,W+,and Z◦bosons; for the electromagnetic force, they are called photons;
  and for the strong nuclear force, they are called gluons.


• In summary, the building blocks of matter and the interactions between matter consist of the following
  fundamental particles :

TABLE22.1:

Fermions Fermions

Leptons Quarks

electron up

electron neutrino down

muon strange

muon neutrino charm

tau top

tau neutrino bottom

TABLE22.2:

Bosons Bosons

Force Transmitted Associated Boson

gravity graviton

electromagnetic photon

weak W−,W+,and Z◦

strong gluons