Physik World

What is Particle Physics ? You see everywhere there is patterns in the universe but if you travel inside it; you will see small particles rather than big things i.e. universe itself. So, the branch of physics that deals with the small fundamental particles is called particle physics. Particle physics studies the sub-atomic particles inside an atom. Fundamental particles means not regarded as made up of other particles like electron. But what about proton and neutron ?  Proton and neutron are elementary particles. Elementary particles means which can be sub-divided into other particles. All matter around us is made of elementary particles, the building block of matter. These particles occur in two basic types called quarks and leptons.

What are Quarks ? As we know that proton and neutron are elementary particles which means they can be sub divided into another particles and that another particles are named as quarks. It means after breaking out proton or neutron we get quarks. If we look at the standard model of particle physics we come to know that there are I,II,III generation  of quarks. The lightest and more stable particles make up the first generation, whereas the havier and less stable particles belongs to the II and III generations. All the stable matter in the universe are made up of I-generation. And the most important thing is any heavier particles quickly decay into next most stable level means III to II and II to I generation. The six quarks are paired in three generations; the "up quarks" and the "down quarks" from the I generation; followed by the "charm quark", then the "top quarks" and "bottom quarks". Quarks also comes in thre...

What is spin in quantum physics ? Spin is an intrinsic form of angular momentum carried by particles. There are two types of spin. They are "Spin Up" and "Spin Down". Spin up ↑  means +1/2 whereas spin down  ↓  means -1/2. While spinning they exhibits magnetic properties too. So, what about the spin of Proton and Neutron? This concept of spin up or down leads to the phenomenon called Quantum Entanglement.

Hardons Hardons are the composite particle; means particles that are made of more than one quark. Hardons are sub-divided into two types of particles called Baryons and Mesons.  Baryons: Proton and Neutron are known as baryons; means that they are made of exactly three quarks . Baryons are in the family of Hardons, which means that they are made of quark. NOTE: Composite Fermions(especially 3 quarks) in which case they are called baryons. Baryons are called composite fermions because it follows Pauli exclusion principle (half-integer spin). Mesons: The only other subcategory of Hardons is Mesons, which are made of one quark and one antiquark. NOTE: Composite bosons(especially 2 quarks) in which case they are called meson. Mesons are called composite bosons because it doesn't follow Pauli exclusion principle.(Thus have integer spin and called composite bosons).

Spin Statistics Theorem According to the spin-statistics theorem  in any reasonable relativistic quantum field theory, particles with integer spin are bosons, while particles with half-integer spin are fermions. Fermions follows Fermi-Dirac statistics whereas Bosons  has integer spin and follows Bose-Einstein condensate.

Fermions: Fermions are those particles which includes  quarks and leptons. Quarks and leptons are spin -1/2  particles, implying that they are fermions according to the spin-statistics theorem . Fermions follows Fermi-Dirac statistics. These particles obey the Pauli exclusion principle. The Pauli exclusion principle is the quantum mechanical principle which states that two or more identical fermions (particle with half integer spin) cannot occupy the same quantum state within a quantum system simultaneously. In the case of electrons in atoms, it can be stated as follows: n, the principle quantum number, l, the angular momentum, m l , themagnetic quantum number and m s, the spin quantum number. For example, if two electron reside in the same orbital, and if their n, l and  m l value are same, then their  m s  must be different and thus the electrons must have opposite half-integer spin projection of 1/2 and -1/2. (Spin Up and Down) ...

Leptons The elementary particle which has half-integer spin (spin 1/2) and does not undergo strong interactions are called leptons. Two main classes of leptons are electron-like leptons (a.k.a. the  electron like leptons), and neutral leptons (a.k.a. neutrinos). Charged leptons combines to form various composite particles such as atom and postronium, while neutrinos rarely interact with anything, and are consequently rarely observed. The best known of all leptons is electron.

Heisenberg Uncertainty Principle The more you know about position the less you know about momentum and vice-versa. For example, if you throw a ball in the air and clicked picture of it, you can perfectly know the position of that ball (where it is exactly) but you can't know it's momentum because to know momentum distance should be covered, you can't travel from point A to point A (meaning position). And if you want to measure momentum, it should cover distance from point A to point B means you will be uncertain about position .

Electron Electrons belongs to the first generation of the lepton  particle family, and are generally thought to be elementary particles because they have no known components or substructure. Like all elementary particles, electrons exhibits properties of both particles and waves. Electrons are spin  -1/2 particles, implying that they are fermions  according to the spin-statistics theorem . All fermions are characterized by half-integer spin, where spin corresponds to the intrinsic angular momentum of the particle.

Muon A muon is a elementary particle which is unstable because it is in second generation in lepton family and decays quickly with a mean lifetime of 2.2 micro seconds. It do not reacts with strong interaction. Muon decay is slow because the decay is mediated by the weak interaction. Like all the elementary particles, the muon has a corresponding antiparticle of opposite charge (+1e) but equal mass and spin: the antimuon a.k.a. positive muon  ( μ + ) .

Tau Tau is the elementary particle of lepton family which mass is heavier than that of electron and muon because it is in third generation of lepton family. Being so massive, the tau is unstable. Like the electron and muon, the tau is electrically charged member, the tau is negatively charged, while its antiparticle is positively charged. It decays via weak force into other particles.

Boson: Boson is a particle that follows Bose-Einstein statistics . Boson make up one of two classes of particles, the other being fermions. Bosons are two types Vector bosons and Scalar bosons. Vector Bosons:  In particle physics a vector bosons also known as Gauge bosons which is a force carrier with the spin equals to 1. The force carriers of fundamental interaction are: The photon of electromagnetism, the W and Z bosons of the weak interaction, and the gluons of the strong interaction. Scalar Bosons: Scalar bosons also know as Higgs bosons which has 0 spin which is recently discovered, and the hypothetical graviton of quantum gravity. Gauge bosons are different from the other kind of bosons: first, fundamental scalar bosons (the Higgs boson); second, mesons, which are composite bosons, made of quarks, third, larger composite, non-force carrying bosons, such as certain atoms.

Gauge Bosons Or Vector Bosons (Force Carrier): In particle physics, a vector boson is a boson with the spin equals to 1.  Gauge Bosons includes: The photon of electromagnetism. The W and Z bosons of the weak interaction. The gluon of the strong interaction. All known gauge bosons includes spin 1. Therefore, all known gauge bosons are vector bosons.  Gauge bosons are different from other kinds of bosons : Fundamental scalar bosons (the higgs bosons), mesons, larger composite non-force-carrying bosons, such as certain atoms.

Gluon: The binding sub-atomic particle for quarks are called gluon. They are so-called messenger particle of the strong nuclear force. Quarks interact by emitting and absorbing gluons. In Quantum Chromodynamics (QCD), the interactions of quarks described in terms of eight types of massless gluon, which like photon, all carry one unit of intrinsic angular momentum or spin. Like quarks, the gluons carry "strong charge" known as color; this means that gluons can interact between themselves through the strong force. In technical terms, gluons are vector gauge bosons that madiate strong interactions of quarks in quantum chromodynamics(QCD).

W and Z Bosons The W and Z Bosons are more generally known as intermediate vector bosons. It is responsible for weak interaction. Symbol  W⁺ , W⁻ , and Z. The W bosons have either a positive or negative electric charge of 1 elementary charge and are each others antiparticles. The Z bosons is electrically neutral and is its own antiparticle. All three of three particles are very short-lived with half life.

Higgs Bosons Higgs Bosons are scalar bosons which has spin zero "0". Higgs mechanism is responsible for giving mass to the W and Z when they interact with an invisible field, now called the "Higgs Field" which pervades the universe. The more a particle interacts with this field, the heavier it is. Particles like photon that do not interact with it are left with no mass at all. Like all fundamental fields, the Higgs field has an associated particle- the Higgs Boson is the visible manifestation of the Higgs field, rather like a wave at the surface of the see. The Higgs boson is an elementary particle in the Standard model of particle physics,  produced by the quantum excitation of the Higgs field.