"Theory says it [ie; mass] is created by the force that binds quarks together, called the strong nuclear force. In quantum terms, the strong force is
carried by a field of virtual particles called gluons, randomly popping into existence and disappearing again. The energy of these vacuum fluctuations has to be included in the total mass of the proton and neutron.
Until recently, lattice QCD calculations concentrated on the
virtual gluons, and ignored another important component of the vacuum: pairs of virtual quarks and antiquarks.
Virtual quarks make the calculations much more complicated, involving a matrix of more than 10,000 trillion numbers, says team member
Stephan Dürr of the John von Neumann Institute for Computing in Jülich, Germany.
That will allow physicists to test QCD, and look for effects beyond known physics. For now, Dürr's calculation shows that QCD describes quark-based particles accurately,
and tells us that most of our mass comes from virtual quarks and gluons fizzing away in the quantum vacuum.
The Higgs field is also thought to make a small contribution, giving mass to individual quarks as well as to electrons and some other particles.
The Higgs field creates mass out of the quantum vacuum too, in the form of virtual Higgs bosons. So if the LHC confirms that the Higgs exists,
it will mean all reality is virtual.