Elementary Particles
By: Brianna Malavenda

In particle physics, there are 2 concepts of particles, elementary particles and fundamental particles, both of which do not have substructures (being made of smaller atoms). If an elementary particle has no substructure, then it is one of the basic building blocks of the universe from which all other particles are made. The Standard Model is made up of 3 elementary particles known as quarks, leptons and gauge. Before, hadrons known as protons and neutrons or "mesons and baryons" or whole atoms were looked upon as being elementary particles. In the 20th century "quanta" was a central feature of elementary particles. This changed the knowledge of electromagnetic radiation and found quantum mechanics. In math terms, elementary particles are looked as point particles, however some theories (string theory) offer a physical dimension.

Fermions VS. Bosons
All elementary particles are either or fermions (depending on their spin). The spin statistics theorem identifies the resulting quantam statistics that differentiates fermions from bosons. According to this methodology: particles normally associated with matter are fermions. They have half integer spin and are divided into twelve flavours. Particles associated with fundemental forces are bosons and they have integer spin.

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What makes up the different types of Fermions and Bosons?

Fermions have two categories, Quarks ,which consist of up, down, charm, strange, top, and bottom. The other category being Leptons, which consist of electron

neutrino, electron, muon neutrino, muon, tau neutrino, and tau.
Bosons have two categories as well, Guage bosons, which consist of gluon, W and Z bosons, and photon. The other category being the Other bosons, which consists of the Higgs boson and graviton.
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LEPTONS
QUARKS

Matter- particles:
Electron

Charge: -1

Responsible for electricity and chemical reactions.
Electron-neutrino

Charge: none.

Also possibly no mass.

Move by billions per second through our body.
Quark-Up

Charge: +2/3.

Protons contain two, neutrons one.
Quark-Down

Charge: -1/3.

Protons contain one, neutrons two.











These were made after the Big Bang.

Now they are found by nature only in cosmic radiation.
Muon

A more heavy variant of the electron.

Exists only one two millionth part of a second.
Muon-neutrino

Comes into existence together with muons when particles fall apart.
Quark-Charm

More heavy relation of the up-quark.
Quark-Strange

More heavy relation of the down-quark.

Tau

More heavy than Muon.

Very unstable.
Tau-neutrino

Not yet discovered. The existence is assumed.
Quark-Top

More heavy than Charm.
Quark-Bottom

More heavy than Strange.









Force- particles:

Bearers of the four fundamental interactions of nature.
Gluons
Bearers of the strong nuclear force of quarks.external image gluon.gif
Photons
Light particles.

Bearers of the electromagnetic force.external image foton.gif
Intermediate vector bosons

W and Z particles.

Bearers of the weak nuclear forces.external image vboson.gif
Gravitons
Bearers of the gravitational forces.

Hypothetical, Gravitons are not yet discovered.external image gravi.gif
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The release of nuclear energy during nulear reactions is a result of the strong nuclear force.
Electricity, magnetism and chemistry are results of the electro-magnetic force.
Some forms of radioactivity are a result of the weak nuclear force.
Our experience of 'weight' is a result of the gravitational force.





The Standard Model and Gravity?.........

In our world there is quantum mechanics and the standard model, which describes the world of the very small. On the other hand there is general relativity, which describes gravity and the world of the very large. With one exception, all particles can be explained by the standard model with the exception of graviton, the force particle behind gravity.
Superstring theorists believe they are on their way to developing a framework that incorporates both general relativity and quantum mechanics. If they succeed, they will have discovered a theory that solves the greatest problem in physics—that of unifying the laws of nature.


Experimental Evidenceexternal image Higgs-Boson-March-2011.png


-----“As of May 2011 the Higgs boson has yet to be confirmed experimentally despite large efforts invested in accelerator experiments at CERN and Fermilab. In April 2011, there were suggestions in the media that evidence for the Higgs boson might have been discovered at the Large Hadron Collider (LHC) in Geneva, Switzerland. however these had been debunked by mid May. In regard to these rumors Jon Butterworth, a member of the High Energy Physics group on the Atlas experiment, stated they were not a hoax, but were based on unofficial, unreviewed results and that the scientific process requires prudence before making any conclusion.
The Higgs boson is often referred to as "the God particle" by the media, after the title of Leon Lederman's book, The God Particle: If the Universe Is the Answer, What Is the Question?. While use of this term may have contributed to increased media interest in particle physics and the Large Hadron Collider, many scientists dislike it, since it overstates the particle's importance, not least since its discovery would still leave unanswered questions about the unification of QCD, the Electroweak interaction and gravity, and the ultimate origin of the universe. In a renaming competition, a jury of physicists chose the name "the champagne bottle boson" as the best popular name.”---------

Relativity and quantum mechanics, changed almost all of the physical conceptions that existed prior to them. They were extremely important fields that gave rise to other new fields in physics that haven't been explored before. They weren't explored before because of two main reasons:
  1. Theoretical laws and conceptions were a lot confused with each other and not understood thoroughly.
  2. The technology present at that time was so basic that it couldn't withstand the experiments which was needed in order to confirm theoretical predictions.
The field of elementary particle physics was motivated because these two reasons were, in a large part, demolished. Theoretical physics had a firm ground, thanks to relativity and quantum mechanics. Technology was vastly improving by engineers throughout the world. One of the keys to these advances was the beginning of designing particle accelerators.
Accelerators!!!
  • Van De Graff Accelerator
  • Cyclotron
  • Linear Accelerator (LINAC)
  • Betatron
  • Synchrotron
  • Storage Ring Collider Accelerators

Sources:
http://www.daviddarling.info/images/Standard_Model.gif
http://www.iguanaworks.net
**http://library.thinkquest.org/18188/english/universe/theory/element.htm**
**http://video.ezinemark.com/learn-about-particle-physics-430c77bb3d8.html**
Fritzsch, Harald. Elementary Particles:building blocks of matter . Singapore:
World scientific publication co., 1943.