"proton mass" is a correct and usable phrase in written English.
For example, you can use it in a sentence like this: "The proton mass is roughly 1,836 times greater than that of an electron."
One GeV is a bit more than one proton mass.
Approximately, one proton mass corresponds to one GeV, so this could happen soon.
From the absence of any signal in the current LHC data one can deduce lower limits on the masses of the strongly interacting superparticles of more than one tera electron volt (short "TeV", about 1000 times the proton mass).
The likelihood that a mutant protein can slip through unnoticed is small: the spectrometer can tell apart proteins that differ by less than a tenth of a proton mass in weight.
The ratio of heavy ions to proton mass densities is also an important factor.
An astrophysics experiment indicates a time variation of the ratio of the proton mass and the electron mass.
There is a bump at about 2 TeV (2000 or so proton masses).
A proton's mass at rest is about 1.6726 yoctograms and a neutron's mass just a tad more at 1.6749 yoctograms.
An electron or proton's mass can't change no matter how much momentum it has — change the mass (and thus its energy) and you change the kind of particle it is.
This difference is tiny: the proton's mass is 99.86% that of the neutron, yet if they were exactly the same mass, we would not be here, as there would not have been enough hydrogen in the universe to make long-lived stars.
But for the brief moment they exist, they could add to the proton's mass, magnetic moment, and the charge inside the proton.
