Thursday, March 7, 2013

Elementary Particles and Quarks

Atoms were believed through history to be the elementary particle that matter is formed of till protons, electrons, and neutrons were discovered in 1932. later on scientists noticed that protons in a nucleus don't repel although they have the same charge; that's why strong nuclear force was developed and proven to be existing when its field particles were observed which is known as gluons.. This proved for scientists that other natural fundamental forces were hidden and not revealed yet to our scientific knowledge. In 1949 particle collisions were done in lboratories which leaded to 300 unknown new particles !! this meant that protons, neutrons were not elementary particles. Each time scientists conducted experiments they found newer elementary particles for example neutrinos, muon neutrinos, pions, muons, delta, sigma, etc... each particle of these had its own antiparticle.. that's why this was called the particle zoo because many particles were found without understanding how they formed matter and how they acted as fundamental elementary particles.. This lead to the first classification efforts; classifying them into leptons, and hadrons. Leptons are particles that don't interact through field particles which was believed to have no structure or mass thus believed to be the real elementary particles.. Hadrons is divided into mesons and baryons.. an example of leptons is electrons, muon, tau, electron-neutrino, and some other particles. as for mesons pions, Kaon, and Eta are examples for it. Baryons are protons, neutrons, sigma, lambda and other particles.. This classification was a good start for classifying but it didn't provide an explaining for how baryons and other particles form.. in 1963 Gell-manni and George zwig created the quarks model.. Quarks had 6 states either up, down, strange, charmed, Bottom, and top. these quarks had their own anti-quarks. anti-quarks are opposite in charge and spin. Mesons were composed of two quarks, while baryons were composed of 3 quarks.. this model wasn't so successful therefore a new model called quantum chromodynamics evolved. In this new model quarks had colors but this color had nothing to do with real colors but it resembles the quark's charge. quarks had three colors; Red, Green, Blue, and anti quarks which had anti-colors. for baryons to be formed; three quarks with different colors can attract due to different charge so their colors would neutralize to white ( again this has nothing to do with real color) . as for mesons to form they must have color and anticolor to neutralize to white (zero net charge) . Quarks offered a good classification but it didn't find the real elementary particle that the universe is built from. Quarks suggested that leptons are elementary particles (such as electrons). Scientists who created the quarks model believed that leptons have no mass or structure (such as electrons) but nowadays we found that electrons have mass which means they do have some kind of structure and made up of other elementary particles which is believed to be the strings or membranes in M-Theory when these strings are streched in the 11th dimension... This was one of the reasons to develop M-Theory to find the most minute fundamental elementary unit that will unify even the 4 fundamental fources and their field particles...

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