The fundamental four forces and their carrier
Quarks and lepton are the building blocks of matter. But, what hold these particles together? All the forces in the universe and particles interactions are the result of four fundamental forces:
5.1. Gravitational Force:
Gravitational force is the most pervasive force in the universe, it acts on everything that has a mass over extremely large distances. For example, a skier uses it to race downhill, the solar system is held together due to it and the sun is formed from a vast cloud of gas that is gravitationally contracted. Gravitational force can be calculated using Newton’s law of gravitation:
F_G= (G M_1 M_2)/r^2 r : is the distance between the centers of mass.
M : the mass of an object.…show more content… They combine together to make particles with total relative charge of 0 or ±1. For example, proton consists of three quarks (two up and one down). Thus, total charge for proton = +2/3+2/3-1/3=+1. While, neutron consists of two down quarks and one up quarks. Consequently, the total charge of neutron = +2/3-1/3-1/3=0 . Baryon Number
Some particle interactions never happen even though charge and mass/energy can be conserved. For example, protons don’t decay into positrons: p → e^++π^0
To explain this, scientist came up with another property that must be conserved, called Baryon number. All quarks carry baryon number of +1/3 while for anti-quarks it is -1/3 . So, in the above interaction, the total Bryon number is +1 on the left and 0 on the right. As a result, the reaction will never happen because baryon number should be conserved.
Strangeness
It is a particle property that is used for particles’ decay description in strong and electromagnetic reaction. Particles that contain strange quarks are called strange particles and they are unusually long-lived. A particle can have a strangeness number from +3 to -3 depending on the number of strange or anti-strange quarks it
