# Is baryonium fermion or meson?

1. Aug 27, 2006

### BuckeyePhysicist

Is a baryonium baryon or meson?

For example, deutorium, a n-p bound-state, has total spin 0 pr 1, so it is boson, then, it is meson? But it has baryon number (3+3)/3=2.

For another example, bound-state of $$\Lambda_c - \bar{\Lambda_c}$$, has total spin 0 or 1, so again it is boson, it is meson? But it has baryon number (3-3)/3=0.

Last edited: Aug 27, 2006
2. Aug 28, 2006

### Norman

Fermions are particles with half integer spins. Bosons are particles with integer spins.

Mesons are particles that are composed of a quark-antiquark bound state.
Baryons are composed of 3 quarks (anti-baryons are composed of 3 anti-quarks).

So... just because a particle is a boson does not automatically make it a baryon.

This is similar to an argument about geometric shapes. All squares are rectangles but not all rectangles are squares, there is an additional constraint on a square- all its sides must be the same length.

I hope this helps.

3. Aug 28, 2006

### BuckeyePhysicist

It is relevant. But it does not answer the question.
Thank you any way.

4. Aug 28, 2006

### mathman

Deuterons are neither baryons nor mesons. They are made up of two baryons, each of which is made up of three quarks. As Norman mentioned mesons are made up of quark-antiquark pairs.

5. Aug 28, 2006

### Meir Achuz

d is not a meson.
Mesons have baron number zero.
L-Lbar is a boson and a meson.