Elementary Particles: Bosons & Fermions

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Discussion Overview

The discussion centers around the classification and interaction of elementary particles, specifically focusing on bosons and fermions. Participants explore the number of discovered elementary particles, definitions of bosons and fermions, and the nature of their interactions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the total number of discovered elementary particles and the definitions of bosons and fermions.
  • Another participant provides a count of 28 or 36 particles depending on whether gluons are included, referencing Wikipedia for information.
  • A different participant challenges the counting method, suggesting that anti-particles and variations of the same particle should be counted differently, proposing a total of 16 known particles.
  • Definitions of bosons and fermions are presented, with bosons having symmetric wave functions and fermions having anti-symmetric wave functions.
  • Interactions between specific fermions and bosons are noted to depend on the particles involved, with examples given such as neutrinos and photons not interacting, while electrons and photons do.
  • Another participant discusses the nuances in counting particles, mentioning the difference between types of quarks and the symmetry between particles and their antiparticles as an open question.

Areas of Agreement / Disagreement

Participants express differing views on the total number of elementary particles and the criteria for counting them. There is no consensus on the exact number or the symmetry between particles and antiparticles, indicating ongoing debate.

Contextual Notes

Participants reference varying definitions and counting methods, which may depend on specific contexts or interpretations. The discussion highlights the complexity and evolving nature of particle classification.

aman.yash
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how many...

till now how many elementary particles are disovered?

what are bosons?

what happens when fermions interact with bosons?
 
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malawi_glenn said:
1) google: http://en.wikipedia.org/wiki/List_of_particles (I got 28 when I counted, but there is 36 if you include gluons)
no offense but you counted wrong. Typically anti-particles and different types of the same particle (different color, different charge etc) are all counted as 1. There are 4 known bosons, 6 leptops, and 6 quarks = 16. There is also a few predicted particles that havnt been discovered yet (higgs, neutralino, etc.).

A boson is defined as a type of particle where multi-particle systems have a symmetric wave function. That is, if two bosons are exchanged the wave function stays exactly the same.

A fermion is defined as a type of particle where multi-particle systems have a anti-symmetric wave function. That is, if two fermions are exchanged the wave function gains a phase change of -1.

like glenn says, the interaction between a boson and a fermion depends on the specific particles interacting. For example:
neutrino (fermion) and a photon (boson) do not interact
but
electron (fermion) and a photon (boson) do.
 


Well it is a difference between "a red upquark and a green upquark" and "an electron and a positron".

Same holds for the W+ / W- boson, it just depends on how you count.

Is the symmetry between antiparticles and particle exact? Well that is an open question at the moment... the symmetry between colours are belived to be exact.

No offence made, but even lectures at CERN gave us different numbers on the total number of different elementary particles beeing discovered.
 


thank you for helping!
 

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