How we differentiate between bosons and fermions?

In summary, there are two types of particles - fermions and bosons, distinguished by their spin values. There are various experiments that can differentiate between them, such as the Stern-Gerlach experiment and studying their decay probabilities. The Higgs boson is a boson and can decay into two photons, while electrons and protons must be fermions to explain chemistry and the nuclide chart. There is also a concept of para-statistics, proposed by H.S Green, which can explain the substructure of particles but has been replaced by QCD in modern times.
  • #1
MAKK
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if we have two particle then how we differentiate between boson and fermion ,any experiment that differentiate them?
 
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  • #2
Fermions have half-integer spins (they follow the Pauli exclusion principle), whereas bosons always have integer spins.
 
  • #3
PWiz said:
Fermions have half-integer spins (they follow the Pauli exclusion principle), whereas bosons always have integer spins.
i knw but wht exp that differentiate them??
 
  • #4
There's more than one possibility, but the most famous example would be the Stern–Gerlach experiment. Here's a more detailed description.

Another way (as you would do in particle physics collisions) would to look at the decay of the particle. The spin and parity will affect the various decay probabilities.
 
  • #5
Decay probabilities are rarely used, they depend on too many other things. Just the possibility of a decay channel is sufficient to classify the particle. Finding its actual spin value is then done by angular analysis of the decay products.

In case we suddenly forget all spin values:
Electrons have to be fermions, otherwise all electrons in atoms would occupy the lowest energy state and there would be no chemistry.
Protons and neutrons have to be fermions, otherwise the nuclide chart would look completely different (e. g. more stable large elements).
The decay of a fermion always leads to an odd number of fermions, the decay of a boson always leads to an even number.
In beta decays, neutrons decay to proton+electron+neutrino, therefore the neutrino has to be a fermion. It also follows that the W has to be a boson.
Electron+positron, both fermions, can annihilate to two and three photons, therefore the photon has to be a boson.
Quarks can radiate gluons, which looks like "quark -> quark+gluon", therefore the gluon has to be a boson. The same is true for Z, W, photons and Higgs.
Three valence quarks make up a proton or neutron, therefore quarks have to be fermions.
The Higgs can decay to two photons, therefore it has to be a boson.
 
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  • #6
I read in I think it was Rudolf Haag's Local Quantum Physics, that there was a paper by someone that suggested a different sorting of particles, instead of bosons and fermions.

Yeah, it's on page 35, instead of Bose-Fermi statistics there has been suggested a para-statistics which have been suggested by H.S Green in his paper from 1953 called "A generalized method of field quantization ".(http://journals.aps.org/pr/pdf/10.1103/PhysRev.90.270 ).

The boson/fermion distinction is deduced from this generalized method, I am not sure if this paper is legitimate, since we'd be learning it in university graduate or undergraduate courses if it were.
 
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  • #7
MathematicalPhysicist said:
I am not sure if this paper is legitimate
Parastatistics is a perfectly respectable concept. It can also account for the substructure of mesons and baryons but was later displaced by QCD which gave a more powerful machinery to work with.
 

Related to How we differentiate between bosons and fermions?

1. What is the difference between bosons and fermions?

Bosons and fermions are two types of particles that make up the fundamental building blocks of matter. Bosons have integer spin, meaning they have a whole number value for their intrinsic angular momentum, while fermions have half-integer spin. This difference in spin leads to distinct behaviors and properties for these particles.

2. How do we determine if a particle is a boson or fermion?

One way to differentiate between bosons and fermions is by looking at their spin. As mentioned before, bosons have integer spin, while fermions have half-integer spin. This can be measured using various experimental techniques, such as scattering experiments or magnetic resonance imaging.

3. Can a particle be both a boson and fermion?

No, a particle can only have one type of spin. However, there is a class of particles called anyons that have fractional spin, meaning they exhibit both bosonic and fermionic properties. These particles are still being studied and their existence is not yet fully confirmed.

4. How do bosons and fermions behave differently?

Bosons and fermions have different behaviors due to their distinct spin values. Bosons, with their integer spin, have the ability to occupy the same quantum state, meaning multiple bosons can exist in the same place at the same time. This leads to phenomena such as Bose-Einstein condensates. On the other hand, fermions, with their half-integer spin, follow the Pauli exclusion principle and cannot occupy the same quantum state, leading to the stability of matter and the formation of chemical bonds.

5. What are some examples of bosons and fermions?

Some examples of bosons include photons (particles of light), gluons (particles that mediate the strong nuclear force), and the Higgs boson (a recently discovered particle responsible for giving other particles mass). Examples of fermions include electrons, protons, and neutrons (the building blocks of atoms), as well as quarks (particles that make up protons and neutrons).

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