# E=mc2 Energy converts to matter

1. Mar 25, 2007

### .ultimate

With regard to $$E=mc^2$$

When energy radiation converts to matter, what particle does it generate? (Quark or lepton)

Or is there some mediating virtual matter which afterwards form a hadron?

Thank you

2. Mar 25, 2007

### masudr

It depends on the energy of the colliding photons. There are cross-sections for all the various particle pairs to be created; ultimately we can determine the distribution of particles created, not what colliding photons will become per event.

3. Mar 25, 2007

### pmb_phy

There are certain conservation factors which must be taken into consideration. This will set limits to the products of the resulting products. E.g. the total charge must be zero. Therefore if two photons with enough energy collide they could produce a nutral pion or they could produce a electron-positron pair.

To forum - What other conservation rules apply here? Its been a very long time since I've dabbled with high energy particle physics. I think this will be a lot of help to the OP.

Thanks

Pete

4. Mar 26, 2007

### masudr

Almost everything you can think of is conserved. Photons have no charge, no lepton number, no baryon number etc. so all these things are conserved. Lepton family number, for example, is conserved (so if a tauon is created, we must have either an anti-tauon, or a tau anti-neutrino as well).

5. Mar 26, 2007

### pmb_phy

The reason I asked was that I don't know the complete list of what "everything" consists of.

Pete