The Structure of the Universe :Challenge to the Plasma Theory (Part-III)

     Author : Rumana Reza    

[My previous chapters were basically focused on particle physics. Here I've focused on some biological terms. You may get confused that how  the structure of the universe and some biological terms could be connected with each other. Hold your breathe please .....Time's there. This chapter is dedicated to those readers who had no science background before, to those who had once but now lil forgotten and to those readers who want to understand my findings,analysis and conclusion on this topic clearly,smoothly. ]

What is a cell

Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. They provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions. Cells also contain the body’s hereditary material and can make copies of themselves.

Cells have many parts, each with a different function. Some of these parts, called organelles, are specialized structures that perform certain tasks within the cell. Human cells contain the following major parts, listed in alphabetical order:

Cell of human liver 

Cytoplasm 

Within cells, the cytoplasm is made up of a jelly-like fluid (called the cytosol) and other structures that surround the nucleus.

Microfilaments - Stringy Proteins

You will find microfilaments in most cells. They are the partner of microtubules. They are long,  thin, and stringy proteins (mainly actin) compared to the rounder, tube-shaped microtubules. We'd like to say you can find them here or there, but they are everywhere in a cell. They work with microtubules to form the structure that allows a cell to hold its shape, move itself, and move its organelles.

Microtubules - Thick Protein Tubes

Microtubules are usually discussed with microfilaments. Although they are both proteins that help define cell structure and movement, they are very different molecules. While microfilaments are thin, microtubules are thick, strong spirals of thousands of subunits. Those subunits are made of the protein called tubulin. And yes, they got their name because they look like a tube.

Cytoskeleton

The cytoskeleton is a network of long fibers that make up the cell’s structural framework. The cytoskeleton has several critical functions, including determining cell shape, participating in cell division, and allowing cells to move. It also provides a track-like system that directs the movement of organelles and other substances within cells.

Making the Cytoskeleton

All of the microfilaments and microtubules combine to form the cytoskeleton of the cell. The cytoskeleton is different from cytoplasm (cytosol). The cytoskeleton provides structure. Cytoplasm is just a fluid. The cytoskeleton connects to every organelle and every part of the cell membrane. Think about an amoeba. All of the pieces work together so that the foot might reach out towards the food. Then lysosomes and peroxisomes are sent to begin digestion. The movement of the cell membrane, organelles, and cytoplasm is all related to the tubules and filaments.

You will also find many microfilaments in muscle tissue. They are called myofibrils when you find them in muscles. The two proteins myosin and actin work together to help the muscle cells relax and contract. The two proteins need each other and together they are called actomyosin. Combine those protein threads with some ions in the muscle cell and you get a huge contraction. The groups of actomyosin contracting are called sarcomeres. All of the muscle cells work together to make a muscle contract.

Endoplasmic reticulum (ER) 

This organelle helps process molecules created by the cell. The endoplasmic reticulum also transports these molecules to their specific destinations either inside or outside the cell.

Golgi apparatus 

The Golgi apparatus packages molecules processed by the endoplasmic reticulum to be transported out of the cell.

Foundation of Vesicles

The Golgi apparatus gathers simple molecules and combines them to make molecules that are more complex. It then takes those big molecules, packages them in vesicles, and either stores them for later use or sends them out of the cell. It is also the organelle that builds lysosomes (cell digestion machines). Golgi complexes in the plant may also create complex sugars and send them off in secretory vesicles. The vesicles are created in the same way the ER does it. The vesicles are pinched off the membranes and float through the cell.

The Golgi apparatus is a series of membranes shaped like pancakes. The single membrane is similar to the cell membrane in that it has two layers. The membrane surrounds an area of fluid where the complex molecules (proteins, sugars, enzymes) are stored and changed. Because the Golgi complex absorbs vesicles from the rough ER, you will also find ribosomes in those pancake stacks.

Working with the Rough ER

The Golgi complex works closely with the rough ER. When a protein is made in the ER, something called a transition vesicle is made. This vesicle or sac floats through the cytoplasm to the Golgi apparatus and is absorbed. After the Golgi does its work on the molecules inside the sac, a secretory vesicle is created and released into the cytoplasm. From there, the vesicle moves to the cell membrane and the molecules are released out of the cell.

Lysosomes and peroxisomes 

These organelles are the recycling center of the cell. They digest foreign bacteria that invade the cell, rid the cell of toxic substances, and recycle worn-out cell components.

Lysosome Action

Mitochondria 

Mitochondria are complex organelles that convert energy from food into a form that the cell can use. They have their own genetic material, separate from the DNA in the nucleus, and can make copies of themselves.

Mitochondria Structure

Mitochondria are shaped perfectly to maximize their productivity. They are made of two membranes. The outer membrane covers the organelle and contains it like a skin. The inner membrane folds over many times and creates layered structures called cristae. The fluid contained in the mitochondria is called the matrix.

The folding of the inner membrane increases the surface area inside the organelle. Since many of the chemical reactions happen on the inner membrane, the increased surface area creates more space for reactions to occur. If you have more space to work, you can get more work done. Similar surface area strategies are used by microvilli in your intestines.

What’s in the matrix? It's not like the movies at all. Mitochondria are special because they have their own ribosomes and DNA floating in the matrix. There are also structures called granules which may control concentrations of ions. Cell biologists are still exploring the activity of granules.

Using Oxygen to Release Energy

How does cellular respiration occur in mitochondria? The matrix is filled with water and proteins (enzymes). Those proteins take organic molecules, such as pyruvate and acetyl CoA, and chemically digest them. Proteins embedded in the inner membrane and enzymes involved in the citric acid cycle ultimately release water (H₂O) and carbon dioxide (CO₂) molecules from the breakdown of oxygen (O₂) and glucose (C₆H₁₂O₆). The mitochondria are the only places in the cell where oxygen is reduced and eventually broken down into water.

Mitochondria are also involved in controlling the concentration of calcium (Ca²⁺) ions within the cell. They work very closely with the endoplasmic reticulum to limit the amount of calcium in the cytosol. 

Nucleus 

The nucleus serves as the cell’s command center, sending directions to the cell to grow, mature, divide, or die. It also houses DNA (deoxyribonucleic acid), the cell’s hereditary material. The nucleus is surrounded by a membrane called the nuclear envelope, which protects the DNA and separates the nucleus from the rest of the cell.

Life Before a Nucleus

Not all cells have a nucleus. Biology breaks cell types into eukaryotic (those with a defined nucleus) and prokaryotic (those with no defined nucleus). You may have heard of chromatin and DNA. You don't need a nucleus to have DNA. If you don't have a defined nucleus, your DNA is probably floating around the cell in a region called the nucleoid. A defined nucleus that holds the genetic code is an advanced feature in a cell.

Important Materials in the Envelope

The things that make a eukaryotic cell are a defined nucleus and other organelles. The nuclear envelope surrounds the nucleus and all of its contents. The nuclear envelope is a membrane similar to the cell membrane around the whole cell. There are pores and spaces for RNA and proteins to pass through while the nuclear envelope keeps all of the chromatin and nucleolus inside.

When the cell is in a resting state there is something called chromatin in the nucleus. Chromatin is made of DNA, RNA, and nuclear proteins. DNA and RNA are the nucleic acids inside of the cell. When the cell is going to divide, the chromatin becomes very compact. It condenses. When the chromatin comes together, you can see the chromosomes. You will also find the nucleolus inside of the nucleus. When you look through a microscope, it looks like a nucleus inside of the nucleus. It is made of RNA and protein. It does not have much DNA at all.

Mixing and Matching Amino Acids

When are ribosomes used in the process of protein synthesis? When the cell needs to make a protein, mRNA is created in the nucleus. The mRNA is then sent out of the nucleus and to the ribosomes. When it is time to make the protein, the two subunits come together and combine with the mRNA. The subunits lock onto the mRNA and start the protein synthesis.

The process of making proteins is quite simple. First, you need an amino acid. Another nucleic acid that lives in the cell is transfer RNA. tRNA is bonded to the amino acids floating around the cell. With the mRNA offering instructions, the ribosome connects to a tRNA and pulls off one amino acid. The tRNA is then released back into the cell and attaches to another amino acid. The ribosome builds a long amino acid (polypeptide) chain that will eventually be part of a larger protein.

Special Fluids in the Nucleus

Nucleoplasm has a little different composition. Nucleoplasm can only be found inside of the nucleus. It doesn't have big organelles in suspension. The nucleoplasm is the suspension fluid that holds the cell's chromatin and nucleolus. It is not always present in the nucleus. When the cell divides, the nuclear membrane dissolves and the nucleoplasm is released. After the cell nucleus has reformed, the nucleoplasm fills the space again.

Ribosomes

Ribosomes are organelles that process the cell’s genetic instructions to create proteins. These organelles can float freely in the cytoplasm or be connected to the endoplasmic reticulum .

Plasma membrane 

The plasma membrane is the outer lining of the cell. It separates the cell from its environment and allows materials to enter and leave the cell.

Flexible Containers

The cell membrane is not a solid structure. It is made of millions of smaller molecules that create a flexible and porous container. Proteins and phospholipids make up most of the membrane structure. The phospholipids make the basic bag. The proteins are found around the holes and help move molecules in and out of the cell. There are also proteins attached to the inner and outer surfaces of the membrane.

Scientists use the fluid mosaic model to describe the organization of phospholipids and proteins. The model shows you that phospholipid molecules are shaped with a head and a tail region. The head section of the molecule likes water (hydrophilic) while the tail does not (hydrophobic). Because the tails want to avoid water, they tend to stick to each other and let the heads face the watery (aqueous) areas inside and outside of the cell. The two surfaces of molecules create the lipid bilayer.

Ingrained in the Membrane

What about the membrane proteins? Scientists have shown that many proteins float in the lipid bilayer. Some are permanently attached while others are only attached temporarily. Some are only attached to the inner or outer layer of the membrane while the transmembrane proteins pass through the entire structure. The transmembrane proteins that cross the bilayer are very important in the active transport of ions and small molecules.

Cell_membrane detailed diagram

Different Membranes of the Cell

As you learn more about cell organelles, you will find that they all have a membrane. Organelle membranes do not have the same chemical makeup as the cell membrane. They have different lipids and proteins that make them unique. The membrane that surrounds a lysosome is different from the membrane around the endoplasmic reticulum.

Some organelles have two membranes. A mitochondrion has an outer and inner membrane. The outer membrane contains the mitochondrion parts. The inner membrane holds digestive enzymes that break down food. While we talk about membranes all the time, you should remember they all use a basic phospholipid bilayer structure, but you will find many variations throughout the cell.

Membrane Proteins - Bumpy Surfaces

We have a page on the basic structure of the cell membrane and other membranes within the cell. They are basic bilayers made of lipids that surround the cell and organelles. The lipid bilayer is not smooth because there are a variety of proteins attached to the surface and embedded in the membrane. You will find millions of embedded protein molecules when you look at the cell membrane. Each type of protein has a specific purpose. Examples of membrane proteins include ion channels, receptor proteins, and proteins that allow cells to connect to each other.

A Tale of Two Types

You will learn about two types of membrane proteins: peripheral proteins and integral proteins. Peripheral proteins have weaker and temporary connections to the membrane. Some just sit on the surface, anchored with a few ionic bonds while others might have small sections that dip into the hydrophobic section of the bilayer. When you look at the entire membrane, there are more peripheral proteins when compared to the number of integral proteins.

As you can guess from the name, integral proteins are permanently connected to the cell membrane. They are hard workers and have large sections embedded in the hydrophobic (middle) layer of the membrane.

Transmembrane proteins are integral proteins that cross the membrane and can act as pathways for ions and molecules. Polytopic transmembrane proteins cross the membrane several times. Some are receptor proteins while others form channels. Ion movement that does not require work is called passive transport while active transport systems use work to move molecules. Active transport is regularly used when membrane proteins pump ions against the concentration gradient.

Discovering Structures

This structure of the membrane with embedded proteins and a lipid bilayer , first developed the theory of the "Fluid Mosaic Model." It was described in several different methods, such as the freeze-fracture technique and electron micrographs, to look closely at the cell membrane and its structure. It was identified as the proteins that sat on the surface, were sunk into the membrane, and the others that crossed the membrane.  

Cell Wall 

Cell membranes surround every cell you will study. Cell walls made of cellulose are only found around plant cells and a few other organisms. Cellulose is a specialized sugar that is classified as a structural carbohydrate and not used for energy. If a plant cell is like a water balloon, the cell wall is like a cardboard box that protects the balloon. The balloon is protected from the outside world by a structure that provides protection and support.

While many sugars, such as glucose, can dissolve in water (H₂0), cellulose will not dissolve in water and can form long chains to support plants. When you eat plant material, you can’t even digest and break down cellulose for energy. Cows and other herbivores have special bacteria in their stomachs to digest the cellulose polymers.

While cell walls protect the cells, they also allow plants to grow to great heights. You have a skeleton to hold you up. A 100-foot tall redwood tree does not. It uses the strong cell walls to maintain its shape. For overall support, dense cells in the core of the trunk can let a tree grow very high. Cell walls are slightly elastic for smaller plants, leaves, and thin branches. Winds can push them from side to side and they bounce back. Big redwoods need strength in high winds and sway very little (except at the top).

Another Hole in the Wall

A cell wall is not an impenetrable fortress around the delicate plant cell. There are small holes, called plasmodesmata, in the cell walls between plant cells. The cell membranes of neighboring cells are able to connect through these holes. The connections allow the transfer of nutrients, waste, and ions (symplastic pathways). Molecules can also pass through the spaces within the cell walls, avoiding the cells completely (apoplastic pathways).

It is great that nutrients can move from cell to cell, but there is also a problem with all the holes. Cells can lose water. Plants lose large amounts of water in the middle of the day or on very hot days. When the air heats up and the water vapor pressure decreases, plants lose water through the process of transpiration. The water escapes through pores on the surface of the plant called stomata. Even when the plant cells lose water, the basic shape is maintained by the cell walls. The plant may droop or wilt, but it can recover when water returns to the system. It will look just the same as when it started.  

Cell Connections and Communication

All living things communicate in one way or another. When you start looking at the world on a cellular level, you won't find communication in writing or words. Cellular communication is on a molecular level. This section talks about cells in a larger organism that are near each other. We don't cover the communication between single-celled organisms. They behave in different ways.

Gap Junctions

Gap junctions are one type of cell connection. When two cells are right next to each other, their cell membranes may actually be touching. A gap junction is an opening from one cell to another. It's not a big opening, but it is large enough for cytoplasm to move from one cell to another. The connections are called channels and they act like tunnels for the movement of molecules.

Desmosomes

Desmosomes are a second type of cell connection. They physically connect cells like the gap junction, but no opening is created. Proteins that bond the membrane of one cell to its neighbor create the desmosomes. You will find desmosomes in your skin cells. All of those proteins hold your skin together. The distance between the cells, however small, is about 10 times wider than the gap junction connections.

Tight Junction

The last type of connection we will introduce is the tight junction. Tight junctions happen when two membranes actually bond into one. It makes a very strong barrier between two cells. Cells have some distance with a desmosome. Gap junctions allow molecules to pass. Tight junctions form solid walls. These types of connections are often found where one area needs to be protected from the contents of other areas.

by Twooars

To Be Continued..........

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The Structure of the Universe :Challenge to the Plasma Theory (Part-II)

    Author : Rumana Reza    

On my previous post, some basic or primary ideas like state of matters,atom,Bohr model, atomic orbital,chemical bond,Quantum state were briefly highlighted. Here we are going to understand their types more  closely.

Particle Physics

All elementary particles are—depending on their spin—either bosons or fermions. These are differentiated via the spin–statistics theorem of quantum statistics. Particles of half-integer spin exhibit Fermi–Dirac statisticsand are fermions.Particles of integer spin, in other words full-integer, exhibit Bose–Einstein statistics and are bosons.

Elementary fermions:

·         Matter particles

·         Quarks:

·         up, down

·         charm, strange

·         top, bottom

·         Leptons:

·         electron, electron neutrino (a.k.a., "neutrino")

·         muon, muon neutrino

·         tau, tau neutrino

·         Antimatter particles

·         Antiquarks

·         Antileptons

Elementary bosons:

·         Force particles (gauge bosons):

·         photon

·         gluon (numbering eight)

·         W⁺, W⁻, and Z⁰ bosons

·         graviton (hypothetical)

·         Scalar boson

·         Higgs boson

Graphic representation of the standard model of elementary particles. Spin, charge, approximate mass and participation in different force interactions are shown. by   Zhitelew

Description

Mass:

   more than 80 GeV/c^2

   1-5 GeV/c^2

   90-110 MeV/c^2

   less than 16 MeV/c^2

   Massless

Note the gradual increase of mass from the periphery to the center (with possible exception of neutrinos). Also note the similarities in distribution of masses between the left and the right sides of the diagram.

---

Spin (small blue circles in the middle):
empty circle: 0
full circle: 1
half-circle: 1/2

---

Charge (external circles):

   positive

   negative

full circle: 1 or -1 respectively
2/3 circle: 2/3 or -2/3 respectively
1/3 circle: 1/3 or -1/3 respectively
Note the similarities in distribution of charges between the left and the right sides of the diagram.

---

Participation in interactions:

   Weak force (note: only particles with non-zero mass are here)

   Electromagnetic force

   Strong force

Note the bilateral symmetry.

Matter Wave:

The wave-like behavior of matter is crucial to the modern theory of atomic structure and particle physics.All matter can exhibit wave-like behavior. For example a beam of electrons can be diffracted just like a beam of light or a water wave.Matter waves are a central part of the theory of quantum mechanics, being an example of wave–particle duality. The concept that matter behaves like a wave is also referred to as the de Broglie hypothesis.  Matter waves are often referred to as de Broglie  waves.

The de Broglie wavelength is the wavelength, λ, associated with a massive particle and is related to its momentum, p, through the Planck constant, h:

Propagation of a de broglie wave byMaschen

Electron:

The electron is a subordinate particle, symbol  e− or β−, with a negative elementary electric charge. Electrons belong 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.Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle.Like all matter, electrons have properties of both particles and waves, and so can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons.Many physical phenomena involve electrons in an essential role, such as electricity, magnetism, and thermal conductivity, and they also participate in gravitational, electromagnetic and weak interactions. An electron generates an electric fieldsurrounding it. An electron moving relative to an observer generates a magnetic field. 

Electron Cloud Quantum Nucleus Probability and Energy bytop-img.com

Proton:

The proton is a subatomic particle, symbol p or p+, with a positive electric charge of +1e elementary charge and mass slightly less than that of a neutron.The nucleus consists of Z protons, where Z is called the atomic number, The atomic number defines the chemical properties of the atomOne or more protons are present in the nucleus of an atom. Although the proton was originally considered a fundamental particle, it is composed of three valence quarks: two up quarks and one down quark.

The quark structure of the proton. There are two up quarks in it and one down quark. The strong force is mediated by gluons (wavey). The strong force has three types of charges, the so-called red, green and the blue. Note that the choice of green for the down quark is arbitrary; the "color charge" is thought of as circulating among the three quarks. by Arpad Horvath

Hydrogen ion

Protium, the most common isotope of hydrogen, consists of one proton and one electron (it has no neutrons). The term "hydrogen ion" (H+) implies that that H-atom has lost its one electron, causing only a proton to remain. Thus, in chemistry, the terms "proton" and "hydrogen ion" (for the protium isotope) are used synonymously

The proton is a "bare charge" with only about 1/64,000 of the radius of a hydrogen atom, and so is extremely reactive chemically. The free proton, thus, has an extremely short lifetime in chemical systems such as liquids and it reacts immediately with the electron cloud of any available molecule. 

The ion produced by removing the electron from a deuterium atom is known as a deuteron, not a proton. Likewise, removing an electron from a tritium atom produces a triton.

Human exposure

The Apollo Lunar Surface Experiments Packages (ALSEP) determined that more than 95% of the particles in the solar wind are electrons and protons, in approximately equal numbers.Because the Solar Wind Spectrometer made continuous measurements, it was possible to measure how the Earth's magnetic field affects arriving solar wind particles. For about two-thirds of each orbit, the Moon is outside of the Earth's magnetic field. At these times, a typical proton density was 10 to 20 per cubic centimeter, with most protons having velocities between 400 and 650 kilometers per second. For about five days of each month, the Moon is inside the Earth's geomagnetic tail, and typically no solar wind particles were detectable. For the remainder of each lunar orbit, the Moon is in a transitional region known as the magnetosheath, where the Earth's magnetic field affects the solar wind but does not completely exclude it. In this region, the particle flux is reduced, with typical proton velocities of 250 to 450 kilometers per second. During the lunar night, the spectrometer was shielded from the solar wind by the Moon and no solar wind particles were measured.

Protons also occur in from extra solar origin in space, from galactic cosmic rays, where they make up about 90% of the total particle flux. These protons often have higher energy than solar wind protons, but their intensity is far more uniform and less variable than protons coming from the Sun, the production of which is heavily affected by solar proton events such as coronal mass ejections.

Neutron:

The neutron is a subatomic particle, symbol n or n0, with no net electric charge and a mass slightly larger than that of a proton .The nucleus consists of  N neutrons, where N is the neutron number.

The neutron number determines the isotope or nuclide. The terms isotope and nuclide are often used synonymously, but they refer to chemical and nuclear properties, respectively.The neutron is essential to the production of nuclear power and  was used to effect many different types of nuclear transmutations. With the discovery of nuclear fission in 1938,it was quickly realized that, if a fission event produced neutrons, each of these neutrons might cause further fission events, etc., in a cascade known as a nuclear chain reaction.These events and findings led to the first self-sustaining nuclear reactor (Chicago Pile-1, 1942) and the first nuclear weapon (Trinity, 1945).

The quark structure of the neutron. There are two down quark in it and one up quark. The strong force is mediated by gluons (wavey). The strong force has three types of charges, the so called red, green and the blue. Note that the choice of blue for the up quark is arbitrary; the "color charge" is thought of a circulating between the three quarks.Made by Arpad Horvath.

Neutron compounds:

Dineutrons and tetraneutrons

The existence of stable clusters of 4 neutrons, or tetraneutrons, has been hypothesized by a team led by Francisco-Miguel Marqués at the CNRS Laboratory for Nuclear Physics based on observations of the disintegration of beryllium-14 nuclei. This is particularly interesting because current theory suggests that these clusters should not be stable.

The dineutron is another hypothetical particle. In 2012, Artemis Spyrou from Michigan State University and coworkers reported that they observed, for the first time, the dineutron emission in the decay of ¹⁶Be. The dineutron character is evidenced by a small emission angle between the two neutrons. The authors measured the two-neutron separation energy to be 1.35(10) MeV, in good agreement with shell model calculations, using standard interactions for this mass region.

Neutronium and neutron stars

At extremely high pressures and temperatures, nucleons and electrons are believed to collapse into bulk neutronic matter, called neutronium. This is presumed to happen in neutron stars.
The extreme pressure inside a neutron star may deform the neutrons into a cubic symmetry, allowing tighter packing of neutrons.

Fermions:

A fermion can be an elementary particle, such as the electron, or it can be a composite particle, such as the proton. Fermions are particles with half-integer spin. As a consequence of the Pauli exclusion principle, only one fermion can occupy a particular quantum state at any given time. If multiple fermions have the same spatial probability distribution, then at least one property of each fermion, such as its spin, must be different. Fermions are usually associated with matter.At low temperature fermions show superfluidity for uncharged particles and superconductivity for charged particles. Composite fermions, such as protons and neutrons, are the key building blocks of everyday matter

In quantum statistics, a branch of physics, Fermi–Dirac statistics describes a distribution of particles over energy states in systems consisting of many identical particles that obey the Pauli exclusion principle.

Fermi–Dirac (F–D) statistics applies to identical particles with half-integer spin in a system in thermodynamic equilibrium. Additionally, the particles in this system are assumed to have negligible mutual interaction. This allows the many-particle system to be described in terms of single-particle energy states. The result is the F–D distribution of particles over these states and includes the condition that no two particles can occupy the same state, which has a considerable effect on the properties of the system. Since F–D statistics applies to particles with half-integer spin, these particles have come to be called fermions. It is most commonly applied to electrons, which are fermions with spin 1/2. 

Antisymmetric wavefunction for a (fermionic) 2-particle state in an infinite square well potential TimothyRias - Own work

Elementary fermions

The Standard Model recognizes two types of elementary fermions, quarks and leptons. In all, the model distinguishes 24 different fermions. There are six quarks (up, down, strange, charm, bottom and top quarks), and six leptons (electron, electron neutrino, muon, muon neutrino, tau particle and tau neutrino), along with the corresponding antiparticle of each of these.

Mathematically, fermions come in three types - Weyl fermions (massless), Dirac fermions (massive), and Majorana fermions (each its own antiparticle). Most Standard Model fermions are believed to be Dirac fermions, although it is unknown at this time whether the neutrinos are Dirac or Majorana fermions. Dirac fermions can be treated as a combination of two Weyl fermions. So far there is no known example of Weyl fermion in particle physics. In July 2015, Weyl fermions have been experimentally realized in Weyl semimetals.

Composite fermions

Composite particles (such as hadrons, nuclei, and atoms) can be bosons or fermions depending on their constituents. More precisely, because of the relation between spin and statistics, a particle containing an odd number of fermions is itself a fermion. It will have half-integer spin.
Examples include the following:

• A baryon, such as the proton or neutron, contains three fermionic quarks and thus it is a fermion.
• The nucleus of a carbon-13 atom contains six protons and seven neutrons and is therefore a fermion.
• The atom helium-3 (³He) is made of two protons, one neutron, and two electrons, and therefore it is a fermion.

The number of bosons within a composite particle made up of simple particles bound with a potential has no effect on whether it is a boson or a fermion.

Fermionic or bosonic behavior of a composite particle (or system) is only seen at large (compared to size of the system) distances. At proximity, where spatial structure begins to be important, a composite particle (or system) behaves according to its constituent makeup.

Fermions can exhibit bosonic behavior when they become loosely bound in pairs. This is the origin of superconductivity and the superfluidity of helium-3: in superconducting materials, electrons interact through the exchange of phonons, forming Cooper pairs, while in helium-3, Cooper pairs are formed via spin fluctuations.

The quasiparticles of the fractional quantum Hall effect are also known as composite fermions, which are electrons with an even number of quantized vortices attached to them.

Skyrmions

Standard Model of particle physics
Large Hadron Collider tunnel at CERN

In a quantum field theory, there can be field configurations of bosons which are topologically twisted. These are coherent states (or solitons) which behave like a particle, and they can be fermionic even if all the constituent particles are bosons. The fermions made of bosons are named skyrmions after its discoverer Tony Skyrme

Skyrme's original example involved fields which take values on a three-dimensional sphere, the original nonlinear sigma model which describes the large distance behavior of prions. In Skyrme's model, reproduced in the large N or string approximation to quantum chromodynamics (QCD), the proton and neutron are fermionic topological solitons of the prion field.
Whereas Skyrme's example involved pion physics, there is a much more familiar example in quantum electrodynamics with a magnetic monopole. A bosonic monopole with the smallest possible magnetic charge and a bosonic version of the electron will form a fermionic dyon.
The analogy between the Skyrme field and the Higgs field of the electroweak sector has been used to postulate that all fermions are skyrmions. This could explain why all known fermions have baryon or lepton quantum numbers and provide a physical mechanism for the Pauli exclusion principle.

Boson:

Particles with integer spin are bosons. They are generally force carrier particles.An important characteristic of bosons is that their statistics do not restrict the number of them that occupy the same quantum state. This property is exemplified by helium-4 when it is cooled to become a super-fluid. Unlike bosons, two identical fermions cannot occupy the same quantum space. Whereas the elementary particles that make up matter (i.e. leptons and quarks) are fermions, the elementary bosons are force carriers that function as the 'glue' holding matter together. This property holds for all particles with integer spin (s = 0, 1, 2 etc.) as a consequence of the spin–statistics theorem. When a gas of Bose particles is cooled down to absolute zero then the kinetic energy of the particles decreases to a negligible amount and they condense into a lowest energy level state. This state is called Bose-Einstein condensation. It is believed that this phenomenon is the secret behind super fluidity of liquids.

Symmetric wavefunction for a (bosonic) 2-particle state in an infinite square well potential.

Elementary bosons

All observed elementary particles are either fermions or bosons. The observed elementary bosons are all gauge bosons: photons, W and Z bosons, gluons, and the Higgs boson.

• Photons are the force carriers of the electromagnetic field.
• W and Z bosons are the force carriers which mediate the weak force.
• Gluons are the fundamental force carriers underlying the strong force.
• Higgs Bosons give other particles mass via the Higgs mechanism. Their existence was confirmed by CERN on 14 March 2013.

Finally, many approaches to quantum gravity postulate a force carrier for gravity, the graviton, which is a boson of spin plus or minus two.

Composite bosons

Composite particles (such as hadrons, nuclei, and atoms) can be bosons or fermions depending on their constituents. More precisely, because of the relation between spin and statistics, a particle containing an even number of fermions is a boson, since it has integer spin.

Examples include the following:

• Any meson, since mesons contain one quark and one anti quark.
• The nucleus of a carbon-12 atom, which contains 6 protons and 6 neutrons.
• The helium-4 atom, consisting of 2 protons, 2 neutrons and 2 electrons.

The number of bosons within a composite particle made up of simple particles bound with a potential has no effect on whether it is a boson or a fermion.

An example of simulated data modeled for the CMS particle detector on the Large Hadron Collider (LHC) at CERN. Here, following a collision of two protons, a Higgs boson is produced which decays into two jets of hadrons 

Antiparticle:

Corresponding to most kinds of particles, there is an associated antimatter antiparticle with the same mass and opposite charge (including electric charge). For example, the antiparticle of the electron is the positively charged electron, or positron, which is produced naturally in certain types of radioactive decay.
The laws of nature are very nearly symmetrical with respect to particles and antiparticles. For example, an antiproton and a positron can form an antihydrogen atom, which is believed to have the same properties as a hydrogen atom. This leads to the question of why the formation of matter after the Big Bang resulted in a universe consisting almost entirely of matter, rather than being a half-and-half mixture of matter and antimatter. The discovery of Charge Parity violation helped to shed light on this problem by showing that this symmetry, originally thought to be perfect, was only approximate.

Particle-antiparticle pairs can annihilate each other, producing photons; since the charges of the particle and antiparticle are opposite, total charge is conserved. For example, the positrons produced in natural radioactive decay quickly annihilate themselves with electrons, producing pairs of gamma rays, a process exploited in positron emission tomography.

Antiparticles are produced naturally in beta decay, and in the interaction of cosmic rays in the Earth's atmosphere. Because charge is conserved, it is not possible to create an antiparticle without either destroying a particle of the same charge (as in beta decay) or creating a particle of the opposite charge. The latter is seen in many processes in which both a particle and its antiparticle are created simultaneously, as in particle accelerators. This is the inverse of the particle-antiparticle annihilation process.

Although particles and their antiparticles have opposite charges, electrically neutral particles need not be identical to their antiparticles. The neutron, for example, is made out of quarks, the antineutron from antiquarks, and they are distinguishable from one another because neutrons and antineutrons annihilate each other upon contact. However, other neutral particles are their own antiparticles, such as photons, the hypothetical gravitons, and some WIMPs.

Illustration of electric charge of particles (left) and antiparticles (right). From top to bottom; electron/positron, proton/antiproton, neutron/antineutron.

Hole theory

Solutions of the Dirac equation contained negative energy quantum states. As a result, an electron could always radiate energy and fall into a negative energy state. Even worse, it could keep radiating infinite amounts of energy because there were infinitely many negative energy states available. To prevent this nonphysical situation from happening, Dirac proposed that a "sea" of negative-energy electrons fills the universe, already occupying all of the lower-energy states so that, due to the Pauli exclusion principle, no other electron could fall into them. Sometimes, however, one of these negative-energy particles could be lifted out of this Dirac sea to become a positive-energy particle. But, when lifted out, it would leave behind a hole in the sea that would act exactly like a positive-energy electron with a reversed charge. These he interpreted as "negative-energy electrons" and attempted to identify them with protons in his 1930 paper A Theory of Electrons and Protons.

However, these "negative-energy electrons" turned out to be positrons, and not protons.

Dirac was aware of the problem that his picture implied an infinite negative charge for the universe. Dirac tried to argue that we would perceive this as the normal state of zero charge. Another difficulty was the difference in masses of the electron and the proton. Dirac tried to argue that this was due to the electromagnetic interactions with the sea, until Hermann Weyl proved that hole theory was completely symmetric between negative and positive charges.

Dirac also predicted a reaction e− + p+ → γ + γ, where an electron and a proton annihilate to give two photons. Robert Oppenheimer and Igor Tamm proved that this would cause ordinary matter to disappear too fast. A year later, in 1931, Dirac modified his theory and postulated the positron, a new particle of the same mass as the electron. The discovery of this particle the next year removed the last two objections to his theory.

However, the problem of infinite charge of the universe remains. Also, as we now know, bosons also have antiparticles, but since bosons do not obey the Pauli exclusion principle (only fermions do), hole theory does not work for them. A unified interpretation of antiparticles is now available in quantum field theory, which solves both these problems.

String theory

In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and interact with each other. On distance scales larger than the string scale, a string looks just like an ordinary particle, with its mass, charge, and other properties determined by the vibrational state of the string. In string theory, one of the vibrational states of the string corresponds to the graviton, a quantum mechanical particle that carries gravitational force. Thus string theory is a theory of quantum gravity.

String theory has been applied to a variety of problems in black hole physics, early universe cosmology, nuclear physics, and condensed matter physics. Because string theory potentially provides a unified description of gravity and particle physics, it is a candidate for a theory of everything, a self-contained mathematical model that describes all fundamental forces and forms of matter.

A string can be open (a line) or closed in a loop (a one-dimensional sphere, like a circle). As a string moves through space it sweeps out something called a world sheet. String theory predicts 1- to 10-branes (a 1-brane being a string and a 10-brane being a 10-dimensional object) that prevent tears in the "fabric" of space using the uncertainty principle (E.g., the electron orbiting a hydrogen atom has the probability, albeit small, that it could be anywhere else in the universe at any given moment).

String theory proposes that our universe is merely a 4-brane, inside which exist the 3 space dimensions and the 1 time dimension that we observe. The remaining 6 theoretical dimensions either are very tiny and curled up (and too small to be macroscopically accessible) or simply do not/cannot exist in our universe (because they exist in a grander scheme called the "multiverse" outside our known universe).

Some predictions of the string theory include existence of extremely massive counterparts of ordinary particles due to vibrational excitations of the fundamental string and existence of a massless spin-2 particle behaving like the graviton.

Despite much work on these problems, it is not known to what extent string theory describes the real world or how much freedom the theory allows to choose the details.

Cross section of the quintic Calabi–Yau manifold. Produced using the methods described in Hanson (1994), "A construction for computer visualization of certain complex curves", Notices of the Amer.Math.Soc. 41 (9): 1156-1163

Acceleron Theory

Accelerons are the hypothetical subatomic particles that integrally link the newfound mass of the neutrino and to the dark energy conjectured to be accelerating the expansion of the universe.

In theory, neutrinos are influenced by a new force resulting from their interactions with accelerons. Dark energy results as the universe tries to pull neutrinos apart.

Particle-antiparticle annihilation

An example of a virtual prion pair that influences the propagation of a kaon, causing a neutral kaon to mix with the antikaon. This is an example of re-normalization in quantum field theory— the field theory being necessary because the number of particles changes from one to two and back again.

If a particle and antiparticle are in the appropriate quantum states, then they can annihilate each other and produce other particles. Reactions such as e− + e+ →  γ + γ (the two-photon annihilation of an electron-positron pair) are an example. The single-photon annihilation of an electron-positron pair, e− + e+ → γ, cannot occur in free space because it is impossible to conserve energy and momentum together in this process.

However, in the Coulomb field of a nucleus the transitional in-variance is broken and single-photon annihilation may occur.The reverse reaction (in free space, without an atomic nucleus) is also impossible for this reason. In quantum field theory, this process is allowed only as an intermediate quantum state for times short enough that the violation of energy conservation can be accommodated by the uncertainty principle. This opens the way for virtual pair production or annihilation in which a one particle quantum state may fluctuate into a two particle state and back. These processes are important in the vacuum state and re-normalization of a quantum field theory. It also opens the way for neutral particle mixing through processes such as the one pictured here, which is a complicated example of mass re-normalization.

An overview of the various families of elementary and composite particles, and the theories describing their interactions Headbomb - Own work

 New Sub-Atomic Particle Called a Pentaquar

Quarks are a series of charged sub-atomic particles that come together to form larger particles—such as protons and neutrons, which are each made of three of the things (a class of particle referred to as baryons). First proposed in 1964 by American physicist Murray Gell-Mann, their existence changed the way people thought about particle physicists.

But quarks can come together to form other entities, too. For a long time, people have speculated that another class of quark ensemble, called the pentaquark, could in theory exist. The pentaquark is, perhaps unsurprisingly, supposed to be made up of five smaller entities—four quarks and an anti-quark. Now, for the first time, researchers working on the LHCb experiment at the Collider have found evidence for their existence.

“The pentaquark is not just any new particle,” said Guy Wilkinson from the LHCb in a press release. “It represents a way to aggregate quarks, namely the fundamental constituents of ordinary protons and neutrons, in a pattern that has never been observed before in over fifty years of experimental searches. Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted.”

The team has identified the existence of the peantaquark by watching for the decay of a baryon known as Lambda b. As it split up into three well-known particles—well known to physicists at least: a J-psi, a proton and a charged kaon, if you’re keeping track—the scientists observed a transition state in which two previously unobserved particles could be identified.

“Benefiting from the large data set provided by the LHC, and the excellent precision of our detector, we have examined all possibilities for these signals, and conclude that they can only be explained by pentaquark states”, says LHCb physicist Tomasz Skwarnicki in a press release. “More precisely the states must be formed of two up quarks, one down quark, one charm quark and one anti-charm quark.”

Discovery Of Massless Weyl Fermion Particle 

Weyl fermions were first hypothesized by German mathematician and physicist Hermann Weyl in 1929. They were proposed as being among the building blocks of subatomic particles, and were also said to be unique in that they would have no mass and also behave as both matter and antimatter – which has the same mass but opposite charge and other properties to regular matter – inside a crystal.
Initially, they were wrongly identified as neutrinos, until it was found in 1998 that neutrinos have a very small amount of mass. Now the researchers say they have solved the 85-year-old mystery for good. The research by both teams was published in the journal Science.

They found the fermions independently by firing photons at crystals of a semi-metal called tantalum arsenide, which has properties between an insulator and a conductor. They cannot exist by themselves as standalone particles, but instead exist as quasiparticles – a "disturbance" in a medium that behaves like a particle. “In other words, they are electronic activity that behaves as if they were particles in free space,” IEEE explains.

But they are important, because Weyl fermions are very stable, and they will also only interact with other Weyl fermions, staying on the same course and at the same speed until they do. This means that, for example, they can carry a charge for long distances without getting scattered and creating heat, like electrons, according to Live Science.
“The physics of the Weyl fermion are so strange, there could be many things that arise from this particle that we're just not capable of imagining now,” said co-author Zahid Hasan, a Princeton professor of physics who led the research team, in a statement.

Weyl fermions are essentially "holes" where other electrons would appear. Shutterstock/general-fmv 



Particles are essentially divided into two groups. Fermions are said to be those that make up matter, while bosons are the force particles that hold them together. All other fermions are known to have mass, making the Weyl fermion unique among its “peers.”

And its unique properties could make it incredibly useful for electronics in the future, including the development of quantum computing, Hasan told IFLScience. For one thing, they can move independently of one another, and they can also create massless electrons. The consequence is they could flow more easily and lose less heat, making electrons more efficient. "It's like they have their own GPS and steer themselves without scattering," Hasan added in the statement.

To Be Continued..........

Copyright © 2015 by Rumana Reza (Aurny)