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Standard Model of Atom? (1 Viewer)

Xayma

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The standard model of the atom is the model that contains the Quarks, Leptons and Force Carriers.

Leptons include the neutrinos, and electrons (and the corresponding II and III generation particles).

Leptons are thought to be fundamental particles.

Hadrons, (those that experience the strong nuclear force) consist of quarks.

Baryon's are those with 3 quark combinations. They include the Proton (Up, Up, Down quarks) and Neutron (Up, Down, Down) with the quarks having a charge of +2/3 of an electron and -1/3 of an electron.

Quarks are the reason for the strong nuclear force due to them possesing a colour charge (dont really need to know of colour though). Quarks are thought to be fundamental particles.

Both Baryons and Leptons have 1/2 integer spins and obey Pauli's Exclusion principle.

Bosons (Force Carriers) have integer spins and do not obey Pauli's Exclusion Principle. They include photons, for the electroweak force, and gluons for the strong nuclear force.

Tommy_Lamp said:
i think its the rutherford model
namely a dense nucleus orbited by electrons

though im probably wrong
Don't edit you cheat :p
 
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Tommy_Lamp

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I drew up a flowchart that shows the basic idea behind the Standard Model.
Ive put it in the resources section but it wont be up for a while, so ill post it here aswell
 

Xayma

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Fermions are particles with half integer spins.

Mesons aren't fermions.
 

Xayma

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Tommy_Lamp said:
really?!

according to my text book they are,
Quite simply.... Your textbook is wrong :p
 

thaoroxy2001

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Hold on!! a Meson is a Hadron but a Hadron is a Fermion...doesn't that make Mesons a Fermion?

Even my teacher says that a meson is a fermion!! Someone plz sort this out for me coz I'm really lost now!!!
 

Xayma

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Ok thats were the is an error with Tommy's chart.

Lets go through some simple definitions (no use drawing a chart because lines would go everywhere).

Hadron - A particle that experiences the strong nuclear force, they are composed of quarks and antiquarks. They can be further devided into mesons and Baryons

Quark - Thought to be a fundamental unit, they pair up in multiples (3 for protons, neutrons a quark and anti quark for mesons, [4 quarks 1 antiquark for pentaquarks etc outside syllabus]). They have charges of +2/3 and -1/3 that of an electron.

Lepton - Thought to be a fundamental unit, comprise electron's neutrinos and there IInd and IIIrd generation particles.

Fermion - Particles with an odd half-integer spin (eg 1/2, -1/2, 3/2) fermions include Baryons (3 quark combinations) and Leptons. All fermions obey Pauli's Exclusion Principle.

Boson - Particles with a 0 or integer spin. Bosons follow Bose-Einstein Statistics and DO NOT obey Pauli's Exclusion principle. They can be force carriers and include gluons, photons, mesons and some atoms (eg He-4)
 

Constip8edSkunk

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think about it this way, mesons contain 2 quarks, and each quark has a half spin, therefore mesons cannot have a half spin (only zero or integer spin ispossible), therefor they are bosons
 

Xayma

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I wouldn't say 2 quarks, its a quark, anti-quark pairing. Although it makes it easier to think of, it disrupts the netural colour needed [again outside the syllabus]
 

:: ck ::

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hahaha xayma u pwned tommy pretty bad ;D

thx guys u helped me in a way too ;P
 

junior04

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Xayma said:
Lepton - Thought to be a fundamental unit, comprise electron's neutrinos and there IInd and IIIrd generation particles.
)
Whats the IInd and IIIrd generation about?
 

:: ck ::

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second and third gen contain more complex quarks not experienced in the "everyday" world .. if u kno wot i mean - eg : particle accelerators

these are unstable and decay into first generation quarks (up and down)

each generation is more massive than the previous generation
 

Jase

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e.g -
Gen I -> Electron-Neutrino ; Up down
GenII -> Muon-Neutrino ; Charm Strange
GenIII -> Tau-Neutrino ; Bottom Top

as well as each repespective antipairing.

Mesons are really interactive bosons, so its also a hadron with integer spin right? so the chart is half right. which means, mesons can be both fermion and boson.. which isnt really surprising considering the nature of quanta in the first place.. i guess?

Wait. cant we say, mesons are *composed* of fermions but are bosons by nature of spin. like a composite particle.

its hard to flowchart the standard model since they all kinda overlap.
Hadrons are composed of fermions and gluons(which are bosons).
damnit now im confused
 

Xayma

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I suppose they are composed of fermions, but I wouldn't say that since quarks can't exist by themselves. But basically yes, they are composed the of fermions the same way that He-4 atom is.

It is alot easier to not refer to them as fermions and just as quarks, since leptons are also fermions.

Basically:

Bosons (Integer spins):
Mesons, Force carriers (photons/gluons), any atom where the sum of the spins is 0 such as He-4.

Hadron (quark composed particle):
Mesons, Baryons etc.

Lepton (Fundamental Particles):
Electrons, neutrinos.

Baryon (n/2 integer spins, were n is odd, Hadrons):
Protons, Neutrons

Fermions (n/2 integer spins, where n is odd, obey Pauli's Exclusion principle):
Baryons, Leptons.
 
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thaoroxy2001

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Do we need to know about the 2nd and 3rd generations or the limitations of the model coz my teacher hasn't even mentioned that! Well...I'm stuffed aren't I?
 

Jase

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not particularly. If you know all about the 'normal' generation particles, that should keep everyone happy. I guess you could just briefly mention the existence of such generations.. but its not entirely neccesary.
Likewise, i dont think its too important to discuss limitations. The only thing i can think of is the absence of the gravity particle.. and mabye Uncertainty?.. and all of life's greatest mysteries.
 

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