I Is there a limit to the possible masses of particles in the universe?

[Silviu]

Hello! I read that, according to quantum mechanics, any physical process must happen with a certain probability if it is not forbidden by symmetry/conservation laws. And now I just started an internship at the CMS aiming to find a Higgs like particle with mass higher that 125 GeV. And we have Monte Carlo simulations of the signal of this particle at different masses. My question is, as we are able to simulate the signal, it means we have some theory predicting a certain Higgs mass which means that all these simulated masses are possible to be achieved (as they can be modeled theoretical I assume there is nothing to prevent their existence). So I was wondering, is there anything that would prevent the existence of a particle at any mass? Like taking a random mass (300 GeV for example) does it mean that there is a particle in the universe having that mass?

 

[mfb]

You are mixing two different things of "possible" here.

The first one is "possible according to the laws of nature". If a process is possible, it has a non-zero probability. That is basically the definition of "possible".

The second one is "this could be a law of nature - we don't know, it is possible". The universe follows some laws which we do not know fully today. But it only follows a single set of fundamental laws (by definition).
There could be a particle type with a mass of 300 GeV - we don't know. But either there is, or there is not, and it is just a matter of our knowledge.