# What are bosons?

1. Sep 11, 2008

### thharrimw

I've heard a lot about LHC and how one of it's goles is to make a higgs boson but i don't know what a boson even is so could someone give me an explanation about what a boson it and why pphysicst are so intersted in them?

2. Sep 11, 2008

### ismaili

The particle states in Hilbert space are represented by the irreducible representations of the Lorentz group. The field operators, which contain the creation/annihilation particle operators are represented by the representations of the Lorentz group too.
It can be see that the half-integer spin fields have to obey the certain anticommutation relations, these are fermions; integer spin fields have to obey certain commutation relations, these are boson. The reason is to satisfy the causality, for example, if the generic field $$\psi(x)$$ satisfies
$$[\psi(x),\psi(y)]_{\pm} = 0$$ for $$x,y$$ spacelike separated, where $$[]_{\pm}$$ denotes commutator or anticommutator, then two measurement performed at two spacelike separated location can be no related at all. This is called microcausality.

In short, the micro-causality demands for certain fields, they must obey certain algebra. One of the class of fields is called fermion, the other class of fields is called boson. The composition of fermions can form a boson.

In SM, bosons are the gauge particles and Higgs, the fundamental matter particles are all fermions.

Cheers

3. Sep 11, 2008

### humanino

If you stack apples (or electrons, or fermions) in a box, the box will be filled with them at some point. However, you can not fill a box with bosons (say photons for instance).

4. Sep 12, 2008

### malawi_glenn

You can also say that a boson have integer spin (0,1,2,3...)

and a fermion have spin 1/2, 3/2 etc..

Particle physicsits are interested in these bosons, a certain type of bosons, called Gauge bosons, since they are the force mediators of a force. For instance the electro magnetic force is mediated by virtual photons between electrically charged particles.

The higgs boson is of interest since it is the "last" missing piece of the theory that governs all of this with force mediating particles etc, roughly speaking. The theory that explain how particles interact, the standard model, is the best tested and verified physical theory that exists, but there is one particle missing, and this is a paradox -> Let's search for the higgs boson at LHC and hope we'll find it :-)

5. Sep 12, 2008

### thharrimw

so do they make up protons, netrons,and electrons?

6. Sep 12, 2008

### atyy

As malawi_glenn said, "normal matter" like protons and electrons are not bosons. However, an electron is a charged particle and creates an electromagnetic field, which will affect nearby electrons. The electromagnetic field consists of particles of light called photons, which are a type of boson. So bosons are responsible for the interactions of "normal matter" such as electrons.

7. Sep 12, 2008

### malawi_glenn

What do make up protons, neutrons and electrons? Neutrons and protons are made up of quarks and gluons, and electrons are electrons.

8. Sep 12, 2008

### atyy

Don't you think it might be more interesting if they don't find it?:tongue2:

9. Sep 12, 2008

### malawi_glenn

well hehe, it would be hard to get new \$ to make a new experiment ;-)

10. Sep 12, 2008

### thharrimw

so bosons are particals that control the interactions of electrons? what are quarks and gluons?

11. Sep 12, 2008

### malawi_glenn

there is no equivalence between bosons and gauge bosons... there are bosons which are not gauge bosons.

Last edited: Sep 12, 2008
12. Sep 12, 2008

### thharrimw

what's the difference between bosons and gage bosons?

13. Sep 12, 2008

### malawi_glenn

http://en.wikipedia.org/wiki/Gauge_boson

Gauge bosons are bosons which arises in order to give gauge invariance to a lagrangian.

Bosons are integer spin particles in general.

It's like asking "what's the difference between animals and lions" :-)

14. Sep 12, 2008

### humanino

I disagree with that. There were other BIG devices which have not found what they were meant to find, at they still are in fancy. See the quark-gluon story for instance :uhh:

15. Sep 12, 2008

### malawi_glenn

hehe I know, I'm just so excited that LHC is running that I can't think clear all the time ;-)

16. Sep 12, 2008

### humanino

To be fait I should add, of course, that not finding the Higgs boson would certainly not be a failure at all ! On the contrary.

17. Sep 12, 2008

### Sakha

I just wonder, if they find the Higgs Boson, what would be the next missing particle. It's just a non ending mystery. If they find about what happened billionth of a second after the Big Bang, they will ask what happened a little bit earlier of that moment.

18. Sep 12, 2008

### malawi_glenn

well now the Higgs boson is not particilar important for cosmology...
But we still don't konw what dark matter and dark energy is, that would be the "next step".