The classification of particles is done by their mass and their interactions. There are four fundamental interactions that govern the particle classification and they are a strong force, electromagnetic force, the weak force, and the gravitational force. Hadrons are the heaviest particles while leptons are lightest particles.

What is Hadron?

Hadron is defined as the subatomic particle made of quarks, gluons and anti-quarks. Hadrons are the heaviest particles. It is composed of two or more quarks that are held strongly by the electromagnetic force. Every individual quark has functional electric charges, these combine such that hadrons carry a net integer electric charge. The simple two ways are three quarks of different colours or a quark of one colour and an antiquark that has a corresponding anticolour. Hadrons under the first arrangement are known as baryons and those under the second arrangement are called mesons.

What are the Different Types of Hadrons?

Hadrons are divided into two categories depending on the quarks and they are:

  • Baryons: It is made up of three coloured quarks
  • Mesons: It is made up of 1 quark and 1 anti-quark

What is the difference between a hadron and a lepton?

Following is a table explaining the difference between a hadron and a lepton:

Hadron Lepton
These are the heaviest particles according to the classification of particles These are the lightest particles according to the classification of particles
These particles are subject to strong nuclear forces These particles are subjected to weak nuclear forces
Hadrons are classified into two types: baryons and mesons Leptons are classified into three types: electron, muon, and tau
Examples of hadron are kaon, proton, neutron, antiproton, and antineutron Examples of lepton are an electron, neutron, and  muon

Properties of Hadrons

The properties of hadron sare determined by their valence quarks. Following are the properties exhibited by the hadrons:

  • They carry no net colour charge even though the quarks carry a colour charge. Only a very small part of the mass of a hadron is due to the quarks in it, which is the weird thing about hadrons.
  • Protons are stable, and neutrons bound within the atomic nuclei are stable of the hadrons, while other hadrons are unstable under ordinary conditions.
  • Hadron physics is studied by colliding protons of heavy elements like that of lead and identifying the debris in the produced particle.

What is Baryon?

The baryons are constructed of three valence quarks. Thus, they are fermions i.e. they have odd half-integer spin because they consist of an odd number of quarks. As quarks possess baryon number B = 1/3, the baryon number B = 1. Proton and neutron are the best-known baryons.

Table of Baryon

Particle Symbol Rest mass MeV.c-2 Spin Lifetime
Proton p 938.3 1/2 Stable
Neutron n 939.6 1/2 920
Lambda Λ0 1115.6 1/2 2.6×10-10
Omega Ω 1672 3/2 0.82×10-10
Delta Δ0 1232 3/2 0.6×10-23

What are Mesons?

Mesons are hadrons that consist of a quark-antiquark pair. They are bosons that should possess some integral spin, i.e., o, 1, or -1 since the number of quarks would be even. Their baryon number B = 0. Instances of mesons that are the by-products of particle physics experiments involve kaons and pions. Pions play a major aspect in possessing atomic nuclei using the residual strong force.