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?