Can particle physicists in a lab observe a particle in a vacuum without putting a photon on it (without inserting any electromagnetic energy so we don't disturb the position of the electrons)?? 
If they can do that, how does it happen and what will the state of the particle/electron will be ?

If they can't do that, how can we know what's the original state of the electrons? 

Or do they observe the particle, and the electrons as well, with photons... thus observing a false position of how the electron was, before the photon hits, and then calculating the original position of the electron using known equations.