There are many resources you can use in the net. The first that comes to mind is the "Particle adventure" site.
I don't know how much time you want to invest on this, or how long should your presentation be, but here are some ideas:
1. If the zetchok is a stable particle, its mass needs to be smaller than that of the neutron, since it is "always" there. On the other hand, if it is an unstable particle, it can have pretty much any mass you want.
2. I'd go for an unstable particle. Then, you can also say what its lifetime is.
3. Another thing you can choose is if your particle is:
a) A combination of quarks that was not seen before (you may know that these days there is a lot of excitement in many laboratories because some of them have found evidence for "pentaquarks"; all particles known to date are combinations of either two or three quarks, and finding one made out of five quarks would be quite a discovery), or
b) Something else (a new quark? a new lepton? something completely new?)
4. Many particles are "mediators" for a force. You can say that your particle is the exchange particle for a new interaction. So far, we know of four fundamental interactions, each one carried by its own particle: gravity (graviton), electromagnetism (photons), weak nuclear force (W and Z bosons) and strong nuclear force (gluons); there is no evidence of any other force, but you can invent one along with your particle.