Elementary particles
(THE PHOTO ON THE COVER IS CUSTOM-DESIGNED AND AI -GENERATED FOR ARTICLE PURPOSES )
All the elementary particles fall into two classes.
Leptons: The Greek word ‘lepton’ means light or swift. Leptons are the simplest particles of all. They are truly elementary with no hint of internal structures. Leptons are affected only by the gravitational, weak and electromagnetic interactions. There are six known leptons and their antiparticles. Electrons are leptons. There are two types of electrons. The well-known negatively charged electron is called the negatron and the antiparticle of it is positively charged, which is known as positron. The others are neutrino, muon, mu-neutrino, tao and tau-neutrino.
Hadrons: The Greek word ‘hadron’ means heavy or strong. Hadrons are affected by the strong interaction as well as the others. Hadrons have internal structures. Hadrons are composed of fundamental particles which are known as quarks. Hadrons consist of either two or three quarks. Hadrons that are composed of three quarks are called baryons and that are composed of two quarks are called mesons. Protons and neutrons are baryons. They have three quarks. Protons and neutrons are called the nucleons and they have antiparticles. Proton is the lightest baryon. One of the mesons is pion and consists of three quarks. Kaons and eta are also mesons.
Quarks: Quarks are the most fundamental particles and they are structureless. Hadrons are made of quarks. Baryons have three quarks (that means- protons and neutrons have three quarks each) and mesons have two quarks (that is- pions have two quarks). There are six types of quarks. They are- up, down, strange, charm, top and bottom quarks. Quarks have charges. The ‘up’, ‘charm’ and ‘top’ quarks have the charge of +⅔. The others have the charge of -⅓ . Protons consist of two up quarks and one down quark and so the total charge is +⅔+⅔-⅓=1. Again we know that neutrons have no charge or the charge is zero. Because neutrons consist of one up quark and two down quarks. So the total charge is +⅔-⅓-⅓=0. Quarks have spin ½. The antiparticles of the quarks are known as antiquarks. They have the same properties like same mass, mean lifetime, spin as their respective quarks but they have opposite charges of opposite sign.
Antiparticles: Antiparticles can be defined as the subatomic particles which have opposite charge or opposite magnetic moment of the known ordinary particles. Positrons are antiparticles of electrons (negatrons). The neutrons do not have charges but the antineutrons have the opposite magnetic polarity. The neutrino spins counterclockwise whereas the antineutrino spins clockwise.
Antimatter: If a matter can be composed with antiparticles like- antiprotons, antineutrons and positrons, that will be called an antimatter. Antimatter should behave like ordinary matter as the antiparticles have the same properties as the ordinary ones. In this situation, distinguishing between the two matters is quite impossible. If matter comes to contact with antimatter, annihilation will occur and a massive amount of energy will be created.
Particles can be classified into sections on the basis of their spins.
Bosons: Spin of the bosons are 0,1,..etc. Bosons carry energy. Some examples of bosons are- photon, gluon, w and z bosons. Spin of the photon is 1.
Fermions: Spin of the fermions are ½ , 3/2 ,5/2… etc. Fermions are known as the building blocks of matter. They are either quarks or leptons. So electrons are fermions.
- Hussain Haider Saador
Reference:
Concepts of modern physics, Arthur beiser.
Introduction to nuclear engineering, John R. Lamarsh and Anthony J. Baratta.
Wikipedia.
Comments
Post a Comment