If mass translates to energy and energy being lossy, shouldn't the mass of nucleus decrease over time? :-)

Anyway, the article seems to indicate that the energy produced from the interaction between quarks and gluons account for the extra mass. What is to say that the energy produced from the interaction is always the same? If not always the same, it implies that the mass of neutron may vary over period of time!

Btw, the article doesn't care to summarize how the super-computers were used in the proof (except for that last quote in the article).